Resumo em Inglês:

Diphtheria, a severe respiratory infection, was a major killer of children until the early years of the 20th century. Although diphtheria is now largely controlled globally thanks to vaccination, it is still endemic in some world regions and large epidemics can occur where vaccination coverage is insufficient. The pathological effects caused by its main virulence factor, diphtheria toxin, can be diminished by passive transfer of antibodies. Equine diphtheria antitoxin (eDAT), the cornerstone of treatment against toxinic complications of diphtheria, was invented more than 130 years ago, in 1890, and is still in use today. A method to concentrate anti-diphtheria antibodies from hyperimmune equine serum was described in the first issue of Memórias do Instituto Oswaldo Cruz in 1909. On this historic occasion, we present recent knowledge on taxonomic, epidemiological and clinical aspects of diphtheria agents that produce diphtheria toxin, and provide a historical perspective on eDAT treatment, adverse effects, threats on its scarce international supply, and current avenues for alternative therapeutic strategies.

Resumo em Inglês:

Haemosporida research started in the 19th century with the description of Plasmodium and other related parasites infecting mammals and birds. Here, we highlight the pioneering contributions of Henrique Aragão and Arthur Neiva in describing the first two Plasmodium species in lizards from the New World, Plasmodium diploglossi and Plasmodium tropiduri, published in the first printed issue of Memórias do Instituto Oswaldo Cruz in April 1909. We use these discoveries as a background to explore some historical and taxonomic aspects of Plasmodium species infecting reptiles, with a particular emphasis on the advancements made over the past 115 years in the Neotropics. Our review underscores the complexities and persistent challenges in the taxonomic classification of reptile haemosporidians and discusses some scientific advances in the field that improved our understanding of the biology and evolution of these parasites.

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BACKGROUND The works of Lutz & Neiva, published 115 years ago in the Memórias do Instituto Oswaldo Cruz, are pioneering for the study of Neotropical Tabanidae. These studies emphasised the importance of biological collections and the description of species from the exploration of South American areas. Dasybasis Macquart, 1847 has traditionally been considered a large genus of tabanids restricted to the Australasian, Neotropical, and Andean regions. Dasybasis species exhibit a high degree of morphological similarity, making specific differentiation challenging. Moreover, some of these features are also present in other taxa, suggesting that they may not be homologous characters and should not be used to define the genus. OBJECTIVES This study aimed to assess the monophyly of Dasybasis and establish its major monophyletic groups. METHODS We conducted an implied weighting analysis using morphological characters, and wing landmarks from 91 terminal species. FINDINGS For the total evidence analyses, aligning with either Tabanus Linnaeus or Dasybasis appendiculata Macquart yielded slightly different trees. Classical morphology and total evidence topology aligned with D. appendiculata are the same, while differing from the total evidence topology aligned with Tabanus in two nodes. MAIN CONCLUSIONS Our results indicate that Dasybasis was not a monophyletic group, and that this name should be restricted to species with a distribution in Australasia; while Neotropical Dasybasis species are recovered in different clades. The genera Archiplatius, Pseudoselasoma, and Stypommia are revalidated. This study provides a revised phylogenetic framework for “Dasybasis” and related taxa, highlighting the need for a more nuanced understanding of morphological character evolution within the tribe Diachlorini.

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Free-living amoebas (FLA) are ubiquitous protists found in the environment. They have shown exceptional resistance to environmental challenges and play significant roles in controlling microbial populations through their predatory behaviour and microbicidal activity in both soil and aquatic ecosystems environments. However, although rare, a limited group of FLA can cause serious infections in the central nervous system and other diseases, particularly in immunocompromised individuals with high mortality rates. They can also cause keratitis in otherwise healthy individuals. This review offers a comprehensive overview of freshwater naked amoebae but does not cover all aspects in detail. Its goal is to provide a historical context for our current understanding while addressing the most critical elements of FLA biology, their pathogenic potential, and their interactions with important human pathogens.

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The 2015-16 Zika virus (ZIKV) epidemic has posed unprecedented concern for maternal-infant health, mainly due to the substantial risk of microcephaly and other neurological birth abnormalities associated with congenital ZIKV syndrome (CZS). As licenced vaccines and effective antivirals are still unavailable, attention has been focused on post-delivery in vitro or translational in vivo studies to understand the impact of maternal ZIKV infection on placentation and neurodevelopmental consequences for the foetus. Here, we review clinical and translational studies highlighting ZIKV-induced maternal-foetal interface dysfunction, adding to our previous observations of experimental ZIKV vertical transmission to pregnant rhesus monkeys and newly published post-epidemic findings about the theme. This comparative review focuses on the mechanisms by which the virus has a cytopathic effect on trophoblasts and macrophages during placentation in humans, nonhuman primates, and rodent transgenic models, crosses the placental barrier, replicates, and establishes a persistent uteroplacental infection. When considering the mechanism of ZIKV-induced birth defects in humans and other susceptible hosts, it becomes apparent how the various stages of the ZIKV cycle in the host (both the parent and offspring) unfold. This understanding presents specific opportunities for pharmacological intervention and the development of preventative vaccines.

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Visceral Leishmaniasis in the Americas is primarily associated with Leishmania (Leishmania) infantum. This parasite is non-native and was imported during the colonisation era. The constitutive instability of the Leishmania genome allows this parasite to express flexibility in adapting to environmental fluctuations and different selective pressures, such as those the parasite faced when arrived in the New World. Therefore, genetic diversity is expected among the populations of L. infantum in the Americas, despite the bottle neck of importation route. Indeed, subpopulation of strains of L. infantum carrying a homozygous deletion in the genome was detected exclusively in the continent. These strains are more spread across Brazilian territory to the detriment of the non-deleted; the locus includes four genes, two of which encode the enzyme ecto-3’-nucleotidase/nuclease (3’NT/NU), a virulence factor in L. infantum. In this review, we highlight the sub estimated genetic complexity of L. infantum populations in Brazil, addressing the biological importance of the 3’NT/NU enzyme and the possible phenotypic impacts of its deletion, pointing out how it may configure an adaptive strategy for L. infantum. Finally, we raise the discussion of how the genome of L. infantum might be shaped in a unique way under the ecological conditions of Brazil.

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Plants represent an important source of compounds for treating malaria, highlighting the rich biodiversity of Brazilian flora as a vital resource for developing new, effective antimalarial drugs. The present study sought to shed light on the search for new compounds with antimalarial activity obtained from the Brazilian flora. In this sense, a systematic review was conducted using screening techniques based on “The Preferred Reporting Items for Systematic Reviews and Meta-Analysis” (PRISMA) protocol. Most of the plants collected in the studies were from the Amazon Rainforest, north of Brazil. Most of the isolated compounds were from the Apocynaceae family and the alkaloids were the main compounds isolated with significant antiplasmodial activity, followed by flavonoids and phenolic compounds. The Brazilian flora can source many compounds with potential antimalarial activity that can challenge Plasmodium drug resistance. However, new studies are still needed to elucidate the natural compounds activity for future application in Malaria treatment.

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The history of the plague, caused by Yersinia pestis, is marked by some of the most devastating pandemics. Its arrival in Brazil on the turn of the 19-20th century led to significant public health challenges and responses. Here, we discuss a comprehensive perspective on the history of the plague in Brazil, emphasising epidemiological trends, public health responses and scientific advances. Understanding the history of the plague in Brazil provides valuable insights into infectious disease control. The study highlights the importance of early detection, robust public health infrastructure, and ongoing research, emphasising the lasting influence of epidemic diseases on society.

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In 1909, Arthur Neiva published an article titled “Contribuição para os estudos dos dipteros. Observação sobre a biolojia e sistematica das anofelinas brasileiras e suas relações com o impaludismo”, highlighting the biology, ecology, and distribution of Anophelinae mosquitoes and the need for more taxonomic studies in Brazil. This came 11 years after Ronald Ross and Grassi demonstrated mosquito roles in transmitting Plasmodium to birds and humans. Despite considerable advances in the understanding of Anophelinae species, knowledge remains insufficient given the complexity of Brazil’s ecosystems, the intensified anthropogenic environmental changes since the mid-20th century, and the persistent public health challenges posed by malaria. This perspective article presents the distribution of Plasmodium vectors and potential vector species in Brazil using climate variables and a maximum entropy model. Geographical distribution maps of Anophelinae species, including putative species, are provided. The article also discusses the current knowledge of vector species distribution in relation to Brazil’s malaria elimination plan, along with the ecological and anthropogenic factors influencing vector distribution.

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Malaria, caused by Plasmodium spp., remains a major public health problem. Cerebral malaria is its deadliest form, with a 15-25% mortality rate, despite artemisinin-based treatments. In addition, the World Health Organization (WHO) strictly defines cerebral malaria as the presence of coma, 1 h after a seizure or the correction of hypoglycemia, in patients with P. falciparum parasitemia. Consequently, 25% of survivors experience neurocognitive and behavioral sequelae, particularly in children. However, more recently, neurocognitive and behavioral impairments were also reported in severe non-cerebral malaria, non-severe malaria, and even during asymptomatic Plasmodium infection. Such impairments have been observed in school-aged children, the elderly, and in animal models without classic cerebral malaria pathology. Additionally, mild vasogenic edema has been detected in neuroimaging of patients with severe non-cerebral and non-severe P. falciparum malaria. Therefore, given that approximately 98% of malaria cases in the world are non-severe, neurocognitive and behavioral sequelae may account for a significant proportion of global malaria morbidity. Taken together, these observations suggest that systemic inflammation from malaria, even without traditional cerebral malaria signs, can disrupt brain function and lead to long-term sequelae. We propose that the current definition of cerebral malaria may not fully capture the observed evidence and a new conceptualization is necessary to encompass these findings.

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Tuberculosis (TB) is a preventable and curable disease caused by the bacillus Mycobacterium tuberculosis. In 2022, according to the World Health Organisation (WHO), TB was the second leading cause of death worldwide caused by a single infectious agent, after coronavirus disease (COVID-19). Brazil is ranked among the 30 countries with the highest TB burden. Currently, the neonatal Bacillus Calmette-Guérin (BCG) is the only vaccine against TB and offers significant efficacy against disseminated and meningeal disease in children. However, BCG has a limited efficacy in preventing adult-type cavitary TB, reinforcing the need for a new effective vaccine against pulmonary TB. There are currently over 22 TB vaccines under evaluation in clinical trials worldwide. Despite significant advancements, several challenges persist in developing and producing an effective TB vaccine. These include understanding the immune mechanisms that confer protection against M. tuberculosis, identifying immune correlates of protection, defining immune responses in BCG-vaccinated individuals, establishing efficacy endpoints for TB vaccine trials, and ensuring vaccine safety and effectiveness in individuals with human immunodeficiency virus (HIV), among other obstacles. Therefore, this study aims to explore the key obstacles in developing new TB vaccines and potential strategies to overcome them.

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BACKGROUND Non-O1 and non-O139 Vibrio cholerae (NOVC) that cause bacteraemia have attracted the attention of the public health community around the world, mainly due to the prospect of outbreaks and the way to treat such infections. OBJECTIVES To identify V. cholerae lineages and their antibiotic resistance and virulence factors associated with bacteraemia. METHODS Vibrio cholerae genomes associated with strains isolated from blood were retrieved and subjected to core genome-based phylogenomic analysis with Roary. The virulome and resistome were searched with abricate using the VFDB and CARD databases. FINDINGS Analysis showed that, in addition to V. cholerae, Vibrio paracholerae also causes bacteraemia. The NOVC group was highly diverse, although genomes from different countries were related. Most bacteraemic Vibrios came from countries not affected by epidemic/endemic cholera. The NOVCs virulome presented factors, such as type III and VI secretion systems, HapA, HlyA, RTX, and TLH. Importantly, no resistance to third-generation cephalosporin has been identified in the resistome of NOVCs. MAIN CONCLUSIONS The presence of multiple NOVC lineages that cause bacteraemia in different parts of the world shows that there is no geographic and socioeconomic restriction for these cases. Therefore, healthcare systems need to be aware of this uncommon but deadly Vibrio infection.

Resumo em Inglês:

BACKGROUND The nematode Angiostrongylus cantonensis, which is endemic to Southeast Asia and adjacent Pacific Islands, has already been recorded in more than 30 countries, including Brazil and other South American nations. It is one of the principal etiological agents of the zoonosis Eosinophilic Meningitis (EoM), which has a number of different species of terrestrial gastropods that act as its intermediate hosts. OBJECTIVE The present study investigated the occurrence of the larvae of this nematode in specimens of terrestrial molluscs collected in half of the municipalities of the Brazilian State of Rio de Janeiro. METHODS The study is based on the surveillance of this nematode in the Brazilian State of Rio de Janeiro, where terrestrial snails and slugs were collected in more than half of the state’s municipalities (46 in all), and examined for parasitological infections. The nematode larvae retrieved from these specimens were identified based on their morphology and cytochrome oxidase I (COI) mitochondrial DNA sequences. FINDINGS Angiostrongylid larvae were found in 230 (8.8%) of the 2,600 terrestrial molluscs examined, collected from 26 municipalities. Overall, 14 terrestrial gastropod species were identified, including both native and exotic taxa, and six were found to be infected naturally by A. cantonensis. The natural infection rates by Angiostrongylus in the different terrestrial molluscs species were 12.5% in Angustipes erinaceus, 9.7% in Achatina fulica, 6.8% in Bradybaena similaris, 6.3% in Sarasinula linguaeformis, 3.9% in Leptinaria unilamellata, and 4.6% in Subulina octona. A. fulica was the most frequent and extensively distributed species, with infected snails being found in 22 municipalities. MAIN CONCLUSIONS The data from this first comprehensive survey of A. cantonensis in Rio de Janeiro highlights the potential epidemiological risk of human infection in this state. Mapping the spread of infected molluscs will also provide essential information for the evaluation of the risk of human infection, and should help local health authorities to provide a faster and more accurate diagnosis whenever neuroangiostrongyliasis is suspected.

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BACKGROUND The neglected illness Chagas disease is treated with limited efficacy and adverse effects by old drugs. Due to the low interest of pharmaceutical industry in targeting economically depressed-patients, repurposing is a tool that should be applied because it can introduce new anti-Chagas entities into the clinic at reduced costs. OBJECTIVES To investigate the repurposing/combination of medicines strategies as anti-Chagas treatment. METHODS Epimastigotes, trypomastigotes and amastigotes of Trypanosoma cruzi were in vitro exposed to 28 Uruguayan-approved medicines not previously tested, 28 FDA-approved medicines previously evaluated, and three reference agents. Parasite inhibition was assessed and for the best drugs, in pairs-isobolographic studies, looking for synergism/additivity/antagonism, were done. Macrophages were used to study selectivity. For some relevant agents, we analysed whether medicines mammals´ action mechanisms are operative in epimastigotes-T. cruzi. FINDINGS From the anti-epimastigotes monotherapy-screening, we found that 18% of them showed better/comparable activities than references. Additionally, for the binary-combinations 8% were additive, 4% were synergic and the rest showed antagonism. Favourably, in macrophages-cytotoxicity four of the binary-combinations were antagonists. Naftazone and pinaverium bromide, not previously tested against T. cruzi, maintained their activity against trypomastigotes and amastigotes. The identified action mechanisms open the door to new strategies designing anti-T. cruzi drugs. MAIN CONCLUSIONS Using approved-medicines is a good strategy for new anti-Chagas treatments.

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BACKGROUND Chagas disease (CD) is a neglected tropical disease caused by Trypanosoma cruzi. The current drugs used to treat these diseases have limited efficacy and produce severe side effects. 4-aminoquinoline derivatives were shown to be a promising class of inhibitors of cysteine proteases cruzain and TbrCATL. OBJECTIVES To evaluate the trypanocidal activity of a new series of aminoquinolines as potential inhibitors of cruzain and TbrCATL. METHODS Three aminoquinolines were synthesised and their in vitro activity was evaluated against cruzain and TbrCATL as well as against amastigotes and trypomastigotes forms of T. cruzi. In silico studies were also carried out to try to understand the experimental results. FINDINGS Compound 5 showed promising activity against cruzain and TbrCATL, with better performance than E60, the reference drug. Compound 5 inhibited cruzain and TbrCATL at IC50 of 23 µM ±3 and 29 µM ±1, respectively, but this inhibition showed characteristics of promiscuous inhibition by colloidal aggregation. On the other hand, the compound 4 showed to be more promising activity against T. cruzi with IC50 2.57 µM ± 0.03 lower than the reference drug benznidazole 3.8 µM. MAIN CONCLUSIONS The results of this study can guide new drug development for the treatment of trypanosomiasis.

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BACKGROUND Benznidazole (BNZ) is the primary treatment for Chagas disease. While pharmacokinetic studies of BNZ began in the 1970s, its metabolism and excretion are not fully understood. Alternatives like Benznidazol Lafepe® and Abarax® have replaced the original Radanil®. OBJECTIVES To compare the pharmacokinetic profiles of both currently available formulations of BNZ in adults with chronic Trypanosoma cruzi infection. METHODS The study involved 13 subjects each one receiving 100 mg of both presentations one week apart. Blood samples were collected over 48 hours post-administration to analyse BNZ concentration and calculate pharmacokinetic parameters. FINDINGS The analysis showed that both presentations had similar maximum plasma concentration and time to reach maximum plasma concentration values. Area under curve (AUC) values were slightly lower in Abarax® than Benznidazol Lafepe®. High intra-individual variability was observed, attributed to erratic absorption patterns with multiple peaks in concentration-time curves. The half-life values for both formulations were 9.1 and 8.0 h, respectively, with a significant intra-individual variability over 30%. MAIN CONCLUSIONS The mean difference in the AUC was lower than 10%, but exceeded the 90% confidence interval for the higher bioequivalence limit. Despite the high variability that confirms erratic absorption, the pharmacokinetic parameters of both formulations were within expected ranges.

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BACKGROUND Bacillus Calmette-Guérin (BCG) is one of the most successful vaccines in the world and evidence suggests it can be used as a bacterial vector to deliver heterologous antigens. OBJECTIVES We evaluated whether BCG could be biotinylated and used as a carrier of Schistosoma mansoni antigen tetraspanin-2 (TSP-2) fused with rhizavidin, an avidin analog. METHODS BCG was grown and biotinylated. The recombinant protein Rzv:TSP-2 was produced and purified from Escherichia coli. The biotinylation and antigen coupling was analysed by flow cytometry, enzyme-linked immunosorbent assay (ELISA) and Western blot. Vaccine immunogenicity was tested in immunised mice by the assessment of lung and splenic T cells. FINDINGS BCG can be biotinylated, which in turn, can be coupled with Rzv:TSP-2. After a series of optimisations which involved molarity of the biotin, ratio of BCG:reagent and the concentration of Rzv:TSP-2 used, almost 50% of the bacteria were biotinylated and 35% coupled with antigen. Although a clear adjuvant effect of BCG was observed, evaluation of immune response in immunised mice demonstrated an overall low immunogenicity of the BCG-Rzv:TSP-2. MAIN CONCLUSION These results demonstrated the use of BCG as a carrier of avidin-tagged antigens. Further optimisations are needed in order to strengthen the stability of tagged proteins in order to produce antigen-specific immune responses.

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BACKGROUND The Atlantic Forest harbours a rich mosquito assemblage, including vectors for diverse arbovirus. Mosquito species adapt to urban-forest landscape changes, acting as bridge vectors for pathogens. OBJECTIVES This study evaluated different collection methods for immature and adult mosquitoes combined with improving field personnel qualifications in a transition area between urbanised and sylvatic environments. METHODS Immature and adult mosquitoes were collected from 33 collection points established in urban and peri-urban, sylvatic and transitional areas using different capture methods. During the course, 107 professionals were qualified. FINDINGS Vectors (Anophelinae and Culicinae) were dominant in the urban/peri-urban environment (51.49%), followed by the transitional (26.69%) and sylvatic (21.82%) environments. Aedes (Stegomyia) albopictus (Skuse), Ae. (Ochlerotatus) scapularis (Rondani), Ae. (Stg.) aegypti (Linnaeus), Haemagogus (Conopostegus) leucocelaenus (Dyar & Shannon), undetermined Culex, Cx. (Melanoconion) pilosus (Dyar and Knab), Cx. (Carrollia) urichii (Coquillett), and Sabethes (Sabethes) albiprivus Theobald were most abundant, with Ae. albopictus collected from all ecotopes. Ovitrap provided a robust sample of the immature stages (92.8%), whereas other methods contributed 3.59% of total immatures, but greatest species richness (14 species). For adult mosquitoes, Shannon light trap resulted in greatest abundance (86.16%). MAIN CONCLUSIONS The use of varied sampling techniques led to collection of a high mosquito species richness, which, combined with programs for training local professionals, should be an integral part of health surveillance for monitoring the risk of vector-borne diseases.

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BACKGROUND Toxocariasis is a neglected global zoonosis. The immunological diagnosis has setbacks that hinder further knowledge about its pathology, epidemiology, and public control measures, and lack of financial support and attention prevents innovative research. Although studies on synthetic peptides are common for several infectious pathologies, none evaluated chemically synthetic peptides for toxocariasis diagnosis. OBJECTIVE This study aimed to identify potential synthetic peptides from C-type lectin 1 (Tc-CTL-1) from Toxocara canis. METHODS In silico analyses were made by five B-cell peptide prediction programs, 3-D modelling, BLASTp homology analysis, and signal-peptide identification. SPOT-synthesis was used for epitope mapping and assessed by dot-blot. Sera from non-infected and T. canis, Strongyloides venezuelensis, Ascaris suum, or Schistosoma mansoni-infected animals were used to assess the peptide’s immunogenicity and cross-reactivity. The selection of potential immunogenic epitopes included the most immunogenic peptides with the least cross-reactivity. FINDINGS Fifty-five peptides were selected by in silico analysis. Dot-blot showed intense recognition by anti-Toxocara IgG and cross-reactivity with A. suum-infected mice. Selection criteria identified four epitopes with diagnostic potential. MAIN CONCLUSIONS The findings demonstrate that synthetic peptides should be explored for innovation of toxocariasis diagnosis, and suggest the adaptation of dot-blot using the SPOT-synthesis technique as a potential immunodiagnostic platform.

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BACKGROUND Efflux pumps represents one of the most important mechanisms of antibiotic resistance. They allow bacteria to expel antibiotics from their cells before they reach the target site. OBJECTIVES The main objective of this work was to examine how cultivation temperature and its variations affect the activity of efflux pumps in Acinetobacter junii, Bacillus cereus, and Enterobacter cloacae isolated from a skin swab. METHODS The isolation and purification of bacterial colonies were done through the streak plate method. For the identification of bacterial species, MALDI-TOF was utilised. To detect the activity of efflux pumps, agar-ethidium bromide cartwheel method was implemented. FINDINGS The accumulation of ethidium bromide (EtBr) in bacterial cells was higher at 43ºC than at 30ºC, so the activity of efflux pumps was reduced at 43ºC in all isolates. A temperature of 7ºC also caused increased cumulation of EtBr in the cells, hence decreasing the activity of efflux pumps in isolated bacteria. Moreover, B. cereus was more sensitive to meropenem at 43ºC than at 36ºC. MAIN CONCLUSIONS The activity of efflux pumps and antibiotic resistance can be strongly affected by changes in incubation temperature in vitro in tested human opportunistic bacterial pathogens.

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BACKGROUND Rickettsia is a genus of Gram-negative bacteria that causes various diseases, including epidemic typhus, Rocky Mountain spotted fever, and Mediterranean spotted fever. Ticks transmit these diseases and commonly found in developing regions with poor sanitation. As a result, it is difficult to estimate the number of these diseases cases, making it challenging to create prevention and diagnostic mechanisms. OBJECTIVES Thus, this study aimed to develop an in silico multi-epitope vaccine against Rickettsia. METHODS Eight proteins were previously identified as potential vaccine candidates through reverse vaccinology and were screened for epitopes that bind to MHC class I and II molecules. The epitopes were then analysed for antigenicity, allergenicity, and toxicity. The selected epitopes were linked with AAY and GPGPG sequences peptide and a known adjuvant, the B-chain of Escherichia coli heat-labile enterotoxin, to form a chimeric multi-epitope protein. The protein’s three-dimensional structure was predicted, and molecular docking analysis was performed against the toll-like receptor 4 (TLR4). Finally, the immune response to the protein was simulated using C-ImmSim tool. FINDINGS A total of 26 immunogenic epitopes, formed the multi-epitope vaccine RGME-VAC/ATS-1. The vaccine showed excellent immunogenic parameters and was predicted to do not be toxic or allergenic to the host. It also showed good potential stimulation of immune cells, with a propensity to generate memory cells and elicit IFN-γ secretion. MAIN CONCLUSIONS The in silico validations suggest that our study successfully designed an innovative multi-epitope vaccine against Rickettsia, addressing the challenges posed by the elusive nature of diseases caused by this genus. We provide a promising potential for further experimental exploration and the development of targeted prevention and diagnostic strategies for these diseases.

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BACKGROUND Heterochromatin protein 1 (HP1) is widespread in several organisms playing a role in control of gene expression by heterochromatin formation and maintenance of silent chromatin. Schistosoma mansoni is a human parasite that is responsible for Schistosomiasis, a tropical neglected disease in the tropical and subtropical areas in the world, where the intermediate host Biomphalaria glabrata is present. OBJECTIVES In this study we attempted to investigate if the SmHP1 is enriched in S. mansoni chromatin in cercariae larvae stage, compared with another larvae stage sporocysts and its importance for S. mansoni life cycle progression and parasite oviposition. METHODS We used ChIPmentation with commercial antibody ab109028 that passed in-house quality control. We also used RNA interference, mice infection and histology. FINDINGS Our data show that S. mansoni HP1 enrichment is non-canonical with a peak at the transcription end sites of protein coding genes. We did not find strong differences in SmHP1 chromatin landscapes between sporocysts and cercariae. Knock- down of SmHP1 in schistosomula and in vivo experiments in mice unexpectedly increased parasite oviposition. MAIN CONCLUSIONS Our results suggest that SmHP1 may influence chromatin structure in a non-canonical way in S. mansoni stages and may play a role in regulation of parasite oviposition.

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BACKGROUND The importance of the mosquito Aedes aegypti as a vector of arboviruses like dengue, Zika, and chikungunya justifies the interest in investigating this species’ physiology and reproductive biology. For the maintenance and expansion of Ae. aegypti populations, copulation, oogenesis, female oviposition capacity, embryo development and larval hatching are crucial processes regulated by biological clocks. Many of these parameters have currently been investigated under environmental and laboratory conditions. However, there are specific gaps regarding the effect of light on these critical reproductive aspects. In this study, the influence of light on some aspects of Ae. aegypti biology was evaluated. OBJECTIVES We investigated, in laboratory conditions, the effects of constant light on Ae. aegypti reproductive features: spermathecal content, embryo morphology, females’ fecundity, and egg viability. METHODS Morphological and physiological assays were performed using Ae. aegypti females and eggs obtained from forced egg laying. The reproductive aspects were analysed under constant light (LL = light/light) and light/dark cycles (LD12:12 = 12 h of light and 12 h of dark). FINDINGS and MAIN CONCLUSIONS Our results proved the negative effect of constant light on egg production (decreasing the fecundity) and embryonic development (causing a drop in egg viability and perceptive damage in the embryos). The results presented here bring new information on the impacts that a source of constant light may have on the reproductive biology of Ae. aegypti.

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BACKGROUND The HTLV-1 affects 5 to 10 million people worldwide. It is estimated that 5 to 10% of the infected individuals develop severe diseases, such as HTLV-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) or Adult T-Cell Leukaemia/Lymphoma (ATLL). HTLV-1 transmission can occur mainly through unprotected sexual contact and from mother to child during breastfeeding. No vaccines can contain this infection, and strategies to prevent transmission become a priority. Therefore, it is important to know the main dissemination routes of each region to design the best public health strategies for controlling the spread of this virus. OBJECTIVES This study aimed to evaluate the prevalence of family aggregation in HTLV-1 infection among patients treated at a reference centre in Brazil. METHODS A cross-sectional study was conducted with patients between July 2021 and August 2022. A total of 67 individuals were attended, of which 17 were classified as index cases due to a history of family aggregation, with 120 family contacts. FINDINGS We found a prevalence of 36% of individuals positive for HTLV-1 and the same for HTLV-1 negative, while 28% of the family members had unknown serology. The possible transmission routes were identified, and the familial transmission histories within each family were hypothesised. MAIN CONCLUSIONS These data can support specific decisions regarding the local reality, such as a better health strategy, especially in preventing new HTLV-1 cases.

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BACKGROUND Tanychlamys indica (Godwin-Austen, 1883) was reported as a serious pest in India. The snails are voracious and feed on a wide range of commercial crops. It has also been identified as an intermediate nematode host of Angiostrongylus cantonensis in Bombay, India. T. indica was recently introduced in Brazil by international trade of citrus fruit seedlings. First in the State of Santa Catarina and then in Paraná. Recently, it has been detected in the city of São Paulo threatening to spread to other Brazilian states. OBJECTIVES We report the first record, in Brazil, of the natural infection by L3 larvae of A. cantonensis isolated from T. indica collected in the Vila Leopoldina neighbourhood, located in the west zone of São Paulo city. METHODS In January 2023, a team from LABFAUNA and UVIS Lapa collected 36 molluscs identified as T. indica in Vila Leopoldina, São Paulo city. Of these, 20 molluscs were subjected to individual parasitological analysis at the Instituto Adolfo Lutz, using the modified Rugai methodology. FINDINGS A total of 145 larvae were identified morphologically and classified according to Ash’s criteria. These larvae were identified as third - stage larvae (L3) of A. cantonensis by real time polymerase chain reaction (PCR). MAIN CONCLUSIONS It is evident that further research is imperative to map the distribution of T. indica in Brazil and to assess its potential as an intermediate host for the nematode A. cantonensis, as well as the economic risks to agriculture. Over the past two decades, human cases of neuroangiostrongyliasis have been documented in the Southeast, North, Northeast, and South regions of Brazil. Additionally, there are records of natural infection with A. cantonensis in molluscs and rodents.

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BACKGROUND The malaria control strategy of the Brazilian Ministry of Health involves the classification of transmission contexts into special areas based on the distinct determinants of malaria in each location. OBJECTIVE To search, find, organise, and map data about special areas using Brazilian databases and show their distribution among the states of the Brazilian Amazon. METHODS A search related to the socioenvironmental determinants of malaria was conducted in Brazilian databases using the special areas of the Ministry of Health as a reference. Data were compiled by states in the Brazilian Amazon. FINDINGS Indigenous areas occupy a significant portion of the Amazon territory and exhibit high incidence rates of malaria. Rural settlements also cover large areas of the Amazon, and in some states, more than 10% of malaria cases are associated with this typology. Legal and illegal mining areas, despite occupying small portions of the Amazon territory, contribute to the malaria caseload. In contrast, urban areas cover smaller regions, with low incidence rates. MAIN CONCLUSIONS Despite the progress represented by the typological structure of special areas by the Ministry of Health’s, our findings reveal limitations related to them because of their complexities and emphasise the need to further substratify these areas to devise control strategies more adapted to them.

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BACKGROUND Chronic Chagas cardiomyopathy (CCC) is the most severe clinical form of the Chagas disease. There is a strong correlation between soluble tumor necrosis factor receptors (sTNFR1 and sTNFR2) and cardiac and functional parameters in CCC, but their prognostic value remains unknown. OBJECTIVE To verify the prognostic value of sTNFR1 and sTNFR2 in CCC. METHODS A longitudinal study was conducted. Sixty-nine patients with CCC (53.70 ± 9.66 years, NYHA I-II) were submitted to blood collection and echocardiography, and followed for 43.81 ± 1.21 months. The outcome was determined by the combination of cardiac death, heart transplantation, or stroke. FINDINGS After the follow-up, 15 patients (22%) presented adverse cardiovascular events. Only left ventricular ejection fraction (LVEF) [heart rate at rest (HR): 0.935, 95% CI 0.878 to 0.994; p = 0.033] and sTNFR2 (HR: 1.002, 95% CI 1.001 to 1.003; p = 0.006) remained as independent predictors of adverse cardiovascular events. The optimal cutoff point to identify these patients was the value of 1784.00 pg/mL. There was a significant difference between the groups with lower and higher sTNFR2 levels (long-rank < 0.001). MAIN CONCLUSIONS High serum levels of sTNFR2, together with lower LVEF, are strong independent predictors of adverse cardiovascular events in CCC, making them valuable for risk stratification.

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BACKGROUND Leprosy, a neglected tropical disease caused by Mycobacterium leprae, presents significant public health challenges in Brazil due to its slow progression, dermato-neurological manifestations, and potential for disability. Understanding leprosy’s spatial distribution and temporal trends is important for effective control and elimination strategies. OBJECTIVES This study aimed to identify clusters of leprosy in Brazilian states using agglomerative hierarchical clustering and to analyse their temporal trends from 2012 to 2022. METHODS An ecological study was conducted using data from the National System of Notifiable Diseases (SINAN). The agglomerative hierarchical clustering method was used to group states using the new case detection rate (NCDR) of leprosy per 100,000 inhabitants, the proportion of new cases of leprosy with grade 2 physical disability at the time of diagnosis (G2R), and the Gini index, a measure of socioeconomic inequality. Temporal trends within the clusters were assessed using Prais-Winsten regression analysis. FINDINGS In the period 2012-2022, 293,030 new cases of leprosy were reported in Brazil. Five distinct clusters were identified. Cluster 4, comprising Mato Grosso and Tocantins, had the highest NCDR and stable temporal trends (APC: 3.2%, 95% CI: -0.1%, 6.7%). Clusters 1 and 3 had the highest proportions of grade 2 disability, indicating late diagnosis. Clusters 4 and 5 had the lowest percentages of individuals with incomplete/complete higher education (7.6% and 7.4%, respectively). Cluster 4 had the highest percentage of individuals with the Diforma clinical form (69.8%) and with cases classified as multibacillary (84.5%). MAIN CONCLUSIONS The use of agglomerative hierarchical clustering, a novel application of a non-supervised algorithm in this context, highlighting the integration of multiple epidemiological and socioeconomic variables for a better understanding the dynamics of leprosy transmission in Brazil. Significant variations in the spatial distribution and temporal trends of leprosy were observed across Brazilian states. To improve leprosy surveillance and control in Brazil, targeted interventions are needed, particularly in high-endemicity regions with late diagnosis.

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BACKGROUND Coronavirus disease 2019 (COVID-19) is caused by the new coronavirus 2 (severe acute respiratory syndrome coronavirus 2 - SARS-CoV-2). Long COVID is a new condition associated with persistent COVID-19 symptoms and/or new emerging symptoms. Telomeres are specialised structures for genome protection at the end of chromosomes and telomerase is the enzyme that synthesises telomere DNA. OBJECTIVES Patients with Long COVID symptoms were recruited at the Pedro Ernesto University Hospital (HUPE) in Rio de Janeiro, Brazil, with the main purpose of investigating the association between telomere length and Long COVID. METHODS Leukocyte telomere length (LTL) was determined by quantitative real-time polymerase chain reaction (qPCR) in 34 Long COVID patients compared to a control group (n = 122). Telomerase activity was determined by qPCR assays using the commercial kit from ScienCell. A questionnaire on symptoms, vaccine doses and blood count was completed. FINDINGS The Long COVID patients were found to have an increase in LTL. Telomerase activity was also examined in a smaller number of patients and found to be reactivated in the blood. MAIN CONCLUSIONS It will be necessary to conduct further studies and monitor Long COVID patients to determine if future health issues could be linked to telomerase activity and elongated telomeres.

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BACKGROUND Escherichia coli is a commensal organism but may become pathogenic by the acquisition of virulence factors involved with intestinal (IPEC) or extraintestinal (ExPEC) infections. Some strains, known as hybrids, may harbour virulence determinants of both IPEC and ExPEC pathotypes, increasing their virulence potential. Reports of hybrid E. coli in Brazil are rare, and the associated lineages were poorly explored. OBJECTIVES This study characterised ExPEC E. coli strains focusing on the occurrence of hybrid pathotypes. METHODS Fifteen clinical ExPEC strains were submitted to multilocus sequence typing (MLST), susceptibility test, and polymerase chain reaction (PCR) targeting IEC/ExPEC virulence markers. FINDINGS All strains were multidrug-resistant, and 11 STs were determined among the 15 ExPEC strains, including local/new and pandemic lineages, such as ST69 and ST131. Twelve/15 isolates were classified as hybrids, due to the presence of virulence markers of both Enteroaggregative E. coli (EAEC) and ExPEC or UPEC pathotypes. These UPEC/EAEC (n = 10) and ExPEC/EAEC (n = 2) hybrid strains were found among distinct phylogroups and lineages, including new STs. Interestingly, most hybrids belonged to the pandemic ST131 lineage, and this genotype had never been previously reported in the ST131 circulating in Brazil. MAIN CONCLUSIONS Therefore, this study provides new information on the epidemiological scenario of hybrid E. coli, contributing to a better understanding of the occurrence and pathogenic potential of these organisms.

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BACKGROUND The experience of the USP Tropical Medicine Centre (NUMETROP) team in providing medical care during acute Chagas disease (ACD) outbreaks in Santarém, Pará, motivated this study. OBJECTIVES To study the epidemiological, clinical-laboratory, and socio-cultural aspects of confirmed cases of ACD in outbreaks in Santarém from March 2016 to March 2018. METHODS Observational case series study of ACD outbreaks in two communities: Marimarituba in 2016 and Cachoeira do Aruã in 2017. Diagnostic characterisation included classification into discrete typing units (DTUs). FINDINGS Eight cases were diagnosed as ACD TcIV in Marimarituba and seven cases were identified as ACD TcI in Cachoeira do Aruã. Women of childbearing age were numerous in both groups, and one miscarriage and two possible vertical transmissions were observed. Fever and rash were the most common findings in Marimarituba, with a fatality rate of 12.5%. In both outbreaks, serological surveillance was performed three to 21 months after treatment, with no confirmation of a “serological cure”. MAIN CONCLUSIONS We observed possible vertical transmission, diverse DTUs in the same municipality, and a lack of knowledge about patient outcomes. We highlight that, despite the importance of ACD in the Amazon region, there is no institutional follow-up of patients from diagnosis to cure.

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BACKGROUND Coinfections of Plasmodium parasites and the dengue virus have been linked to severe disease in some patients. The interactions between these two pathogens, particularly their effects on disease progression, highlight the clinical importance of understanding the mechanisms underlying the potential synergistic effects. OBJECTIVES The primary objective of this study was to investigate the adhesion dynamics of Plasmodium vivax-infected erythrocytes (Pv-iRBCs) in the presence of dengue virus (DENV) infection. By examining the interaction between these pathogens, the study aimed to provide insights into how coinfections might influence disease severity and progression. METHODS HepG2 cells were infected with DENV to observe changes in adhesion receptors and Pv-iRBCs adhesion capacity. Experiments using trypsin-treated Pv-iRBCs and UV-inactivated DENV dissected the adhesion process. Small molecule inhibitors were used to assess innate activation. ICAM-1 expression and its functional significance was quantified using a monoclonal anti-ICAM-1 antibody. FINDINGS We noted a significant increase in cytoadherence of Pv-iRBCs following DENV infection compared to mock conditions. Both trypsin treatment of Pv-iRBCs and UV inactivation of DENV led to a reduction in cytoadherence, underscoring their impact on the adhesion process. Notably, DENV infection induces an innate immune activation upregulating ICAM-1 on the cell surface and blocking with a monoclonal anti-ICAM-1 antibody significantly reduced the cytoadherence of Pv-iRBCs. MAIN CONCLUSIONS Elevated ICAM-1 levels on DENV-permissive cells may not only trap parasites within several niches but also contribute to endothelial and haematological disturbances in individuals with coinfections. Further research is required to fully elucidate the roles of cytoadherence and immune activation in the pathogenesis of dengue and malaria coinfections.

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BACKGROUND Schistosomiasis is one of the most devastating tropical diseases in developing countries and is usually misdiagnosed with colitis because the prevalence of co-occurrence of both diseases is high. Previously, infection of Schistosoma japonicum cercariae has been shown to provide immediate protection against dextran sodium sulphate (DSS)-induced acute colitis in mice models. Studies using synthesised peptides or soluble proteins from parasites also revealed similar protection against colitis. However, most of these studies were done within a short timeframe, which cannot completely represent the actual situation where natural infection of Schistosoma or colitis is usually chronic. OBJECTIVES This study aims to investigate how chronic schistosomiasis affects chronic intestinal inflammation. METHODS Mice were infected with Schistosoma mansoni and induced simultaneously with chronic colitis. The symptoms and severity of intestinal inflammation and fibrosis were investigated by disease activity index, histology, enzyme-linked immunosorbent assay (ELISA), and quantitative polymerase chain reaction (qPCR). Furthermore, immune analysis by ELISA and qPCR and microbiome analysis by 16S rDNA sequencing were done to investigate the underlying mechanism. FINDINGS Concomitant occurrence of chronic schistosomiasis and chronic colitis significantly alleviated colitis symptoms, lessened intestinal inflammation, and reduced egg-induced fibrosis. Further analysis revealed an alternation of the intestinal immunity and gut microbiome community in mice with both diseases, which could be the potential reason for this outcome. MAIN CONCLUSIONS Our results represent a mechanism of how schistosomiasis and chronic intestinal inflammation affect each other.

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BACKGROUND Despite insufficient parasitological and clinical evidence, infections attributed to a putative protozoan named “Urbanorum spp.” have been associated with gastrointestinal disease and treated with anti-parasitic drugs. OBJECTIVES This study aimed to clarify the nature of “Urbanorum spp.” and provide guidance for health and biomedical professionals encountering this structure in human stool, emphasising the importance of rigor and quality in biomedical research. METHODS Coprological analyses were employed to detect intestinal parasites, lipids, and “Urbanorum spp.” in 249 samples. Samples positive for “Urbanorum spp.” underwent staining with trichrome, acid-fast, and Sudan IV and contrasted with positive controls. Examination with polarised light microscopy and a fragility test using ethanol were conducted. FINDINGS Of the tested samples, 19.4%, 2.5% and 1.3% were positive for intestinal parasites, lipids, and “Urbanorum spp.” respectively. Following trichrome and acid-fast staining, few “Urbanorum spp.” structures remained intact and exhibited no discernible eukaryotic characteristics; Sudan IV stain, polarized light microscopy and fragility test approaches indicated a cholesterol-based content. MAIN CONCLUSIONS “Urbanorum spp.” is not a protozoan parasite; therefore, antiparasitic drugs are unwarranted. This structure should be identified as lipid-based material and investigated for possible malabsorption syndrome. Rigorous scientific standards were missed in related publications and peer review, contributing to the spread of this pseudoparasitism case.

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BACKGROUND Single nucleotide polymorphisms (SNP) in genes encoding cytokines influence tuberculosis (TB) outcomes. OBJECTIVES To characterise genotypes of the SNPs IFN-gamma +874 T > A, TNF-alpha -308 G > A, IL-6 -174 G > C, IL-10 -1082A > G, TGF-beta codon 10 T > C, and TGF-beta codon 25 G > C in patients with pulmonary (PTB) and extrapulmonary TB (EPTB). METHODS 82 PTB and 45 EPTB cases were compared, concerning genotype distribution of the mentioned SNPs, characterised via sequence-specific primer polymerase chain reaction (PCR). FINDINGS Regarding IFN-gamma +874 T > A, AA genotype was the most frequent in both groups, TA was more frequent in PTB and TT in EPTB, with no statistical significance. For SNP TNF-alpha -308 G > A, GG was more frequent in both groups of patients. Regarding the IL-6 -174 G > C polymorphism, GG predominated in both groups, while CG and GG were significantly more frequent in patients with PTB and EPTB, respectively. Concerning IL-10 -1082 A > G, AA predominated in both PTB and EPTB. Concerning TGF-beta codon 10 T > C, CC predominated in PTB while TC predominated in EPTB, but the differences were not statistically significant. Genotype GG of TGF-beta codon 25 G > C predominated among PTB and EPTB patients. MAIN CONCLUSIONS Except for IL-6, the genotype profile could not differentiate PTB and EPTB. Hence, the studied SNPs are not significantly associated with the extrapulmonary involvement of TB.

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BACKGROUND The treatment of the early chronic phase of Chagas disease (CD) may result in high rates of parasitological cure, which may be associated with clinical benefits. OBJECTIVES To evaluate children with CD from the Jequitinhonha Valley, MG, Brazil, treated with benznidazole (BZ), employing classic and alternative methodologies. METHODS Before and after treatment, nine individuals were examined by haemoculture, polymerase chain reaction (PCR), conventional enzyme-linked immunosorbent assay (ELISA), electrocardiogram, echocardiogram, and thoracic and gastrointestinal X-ray. Eight individuals were in the indeterminate clinical form of CD, and one was in the mild cardiac form. After treatment, all individuals were re-evaluated periodically for 4-26 years using the same methodologies cited and anti-live trypomastigotes antibodies by flow-cytometry-FC-ALTA and quantitative PCR (qPCR). FINDINGS The cure rate by the classic cure criteria was 33.33%. By the alternative cure criteria using FC-ALTA and qPCR, the rates of cure were 50% and 78%, respectively. Post-treatment clinical evaluations revealed stability in 5/9 and discrete clinical evolution in 4/9 individuals. MAIN CONCLUSIONS It was demonstrated the effectiveness of BZ treatment in recent chronic infections of CD with low or higher rates of parasitological cure according to the cure criterion used after long-term follow-up. The clinical status of the individuals remained stable or evolved slowly, suggesting clinical benefits from BZ treatment.

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BACKGROUND Miltefosine (MIL) is the only oral drug approved for leishmaniasis treatment, but its use is limited by gastrointestinal toxicity. Novel alkylphospholipid analogues may provide safer and more effective alternatives. OBJECTIVES This study aimed to assess the antileishmanial activity, cytotoxicity, and membrane interactions of three MIL analogues TC387, TC388, and TC437 against Leishmania amazonensis. METHODS Antileishmanial and cytotoxic activities were evaluated in L. amazonensis, J774.A1 macrophages, and erythrocytes. Membrane interactions were characterized using spin-label electron paramagnetic resonance (EPR) spectroscopy. FINDINGS TC387, TC388, and TC437 demonstrated EC50 values of 10-16 µM for intracellular amastigotes, compared to 17 µM for MIL, with selectivity indices (SI) ranging from 43-163, significantly higher than MIL’s SI of 5. EPR data revealed that the analogues increased membrane protein dynamics and caused greater disruption at the lipid-protein interface of parasite membranes relative to MIL. This disruption likely enhances pore formation, ion leakage, and reactive oxygen species (ROS) production, leading to parasite death. MAIN CONCLUSIONS The MIL analogues TC387, TC388, and TC437 exhibited superior SI and comparable or slightly enhanced antileishmanial activity relative to MIL, along with very low hemolytic potential. These findings support further investigation of these analogues as promising oral therapeutic candidates for leishmaniasis.

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BACKGROUND Leprosy is an infectious disease that remains hyperendemic in several Brazilian regions. Patient contacts face a higher risk for infection and illness, which can subsequently contribute to the persistence of the disease. OBJECTIVE This study investigates the risk factors associated with anti-phenolic glycolipid-I (anti-PGL-I) seropositivity and leprosy development among contacts of leprosy patients in a highly endemic region. METHODS A cohort of 629 contacts from the Almenara microregion, Minas Gerais, Brazil, was followed from 1998 to 2018. Our research group assessed risk factors, including sociodemographic determinants, bacillus exposure, and genetic susceptibility. FINDINGS Analysis revealed that living with a multibacillary (MB) leprosy patient [odds ratio (OR): 3.01, 95% confidence interval (CI): 1.02-8.86] and with a patient with grade II disabilities (OR: 4.43, 95% CI: 1.08-18.1) significantly increased the likelihood of anti-PGL-I seropositivity among asymptomatic contacts. Risk factors for leprosy included living with a patient in a shared residence (OR: 2.84, 95% CI: 1.21-6.67) and blood relation to the patient (OR: 2.56, 95% CI: 1.18-5.54). Notably, 98% of contacts who developed leprosy had lived with more than one patient. MAIN CONCLUSIONS Clinical characteristics of index patients play a critical role in infection risk among contacts. Leprosy progression appears to depend on genetic susceptibility, type of contact, and extent of bacillus exposure.

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BACKGROUND Acanthamoeba is a free-living amoeba widely distributed, responsible for keratitis and granulomatous amoebic encephalitis. The presence of virulence factors in its excretion/secretion products has been demonstrated. Characterisation of these products, including the determination of immunogenic protein components using polyclonal antibodies, could be the basis for the development of new diagnostic tools and help to understand aspects related to its pathogenesis. OBJECTIVES To identify immunogenic protein components in Acanthamoeba conditioned medium (ACM) and extracellular vesicles (EVs) using polyclonal anti-Acanthamoeba antibodies produced in the laboratory and to evaluate the effect of these antibodies in adhesion and cytopathic effect. METHODS Excretion/secretion products were obtained after the axenic culture of a potentially pathogenic environmental Acanthamoeba T5 isolate. The presence of immunogenic components in lysates of trophozoites, ACM and EVs was determined using polyclonal anti-Acanthamoeba antibodies produced in Wistar rats. Proteomic analyses to identify the immunogenic protein components in ACM and EVs were included. Experiments to evaluate the effect of polyclonal anti-Acanthamoeba antibodies in adhesion and cytopathic effect in vitro were also performed in Vero cells. FINDINGS Protein recognition by anti-Acanthamoeba antibodies in lysates, ACM and EVs was demonstrated, and these components were identified using proteomics. Decreases in adhesion and cytopathic effect after the preincubation of trophozoites with antibodies, prior to the contact with cells, were observed. MAIN CONCLUSION The development of polyclonal antibodies, capable of recognising proteins related to pathogenesis in ACM and EVs, and with significant effects in adhesion, provides an important tool for the search for new therapeutic and diagnostic targets in infections caused by Acanthamoeba.

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BACKGROUND Malaria transmission is prevalent in tropical regions and is heavily influenced by environmental factors such as deforestation, which is particularly significant in the Brazilian Amazon, especially in Pará State. OBJECTIVE This study aimed to assess the relationship between deforestation indicators and malaria incidence across all 144 municipalities in Pará. METHODS Using municipal-level data from 2008 to 2019, the study applied geographically weighted regression (GWR) to analyse spatial relationships between malaria incidence and deforestation metrics. These metrics included forest cover loss from the previous year, pastureland, forest cover, fragmentation, urbanisation, and water levels, analysed over three distinct 4-year periods. The study also incorporated poverty levels to examine their influence on municipalities with high malaria risk. FINDINGS During the study period, the total deforested area in Pará was 30,000 km2, with 679,846 malaria cases reported. Malaria incidence rates varied across municipalities, with stable rates in high-risk areas, and were linked to pastureland, forest loss, fragmentation, and forest cover. The GWR models effectively captured spatial heterogeneity in these interactions. MAIN CONCLUSIONS Malaria incidence was associated with areas of Pará State experiencing significant forest loss and fragmentation, indicating that changes in forest composition and configuration influence malaria risk.

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BACKGROUND Human enterovirus C99 (HEV-C99) is a member of the species Enterovirus C. Currently, three complete genomes of HEV-C99 were reported in Brazil, all obtained from children with gastroenteritis symptoms. Notwithstanding, no HEV-C99 complete genome associated with AFP cases in Brazil have been analysed so far. OBJECTIVES In light of this, molecular characterisation of an HEV-C99 isolated from a case of acute flaccid paralysis (AFP) in Brazil was carried out. METHODS In 2005, an HEV-C99 strain was isolated from a 2-year-old female child in Santa Catarina State, Brazil, showing classic symptoms of AFP. Stool sample was inoculated into specific cell cultures. Viral RNA was extracted, and polymerase chain reaction (PCR) were performed to amplify the VP1 gene; the sequence was analysed for molecular identification. Subsequently, the complete genome was sequenced and analysed, including a phylogenetic analysis of the VP1 gene. FINDINGS The isolate, denominated HEV-C99/33322/BRA/2005 presented 85.85% identity to other HEV-C99 strains also described in Brazil, subsequently. Besides, the isolate grouped together with HEV-C99 cluster C strains. To our knowledge, this was the first described HEV-C99 isolated from an AFP case in Brazil. MAIN CONCLUSIONS The data generated in this study bolster the role of HEV-C99 as an etiologic agent of AFP. Furthermore, this research enhances our knowledge regarding the HEV-C99 genetic diversity.

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BACKGROUND In malaria-endemic regions, rapid diagnostic tests (RDTs) play a crucial role in promptly identifying infections, especially in remote areas with limited microscopy services. OBJECTIVES Conduct a cross-sectional, multi-site study to determine whether the local prevalence of mutations in the Plasmodium falciparum hrp2/3 genes in false-negative RDTs has reached a threshold that might require a local or national change in diagnostic strategy in accordance with the WHO guidelines (2018). METHODS Individuals were screened for P. falciparum with microscopy and HRP2-based RDT at health facilities. Discordant results between these two tests triggered diagnostic confirmation by polymerase chain reaction (PCR) and detection of the pfhrp2/pfhrp3 genes. FINDINGS Among the 347 patients included, false negatives constituted 4.61% (16/347). Molecular analysis revealed all 16 false negatives were P. falciparum positive with hrp2 gene present, displaying high polymorphism. However, hrp3 gene deletion was observed in 93.8% (15/16) of these cases. MAIN CONCLUSIONS The prevalence of false-negative RDTs is low, and these results were not linked to deletions in the hrp2 gene. This suggests that there is no immediate need to modify the RDTs used along the Colombian Pacific Coast. However, molecular surveillance for hrp2 deletions remains crucial to detect any potential increase in prevalence.

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BACKGROUND Chagas disease (CD), a neglected tropical disease caused by Trypanosoma cruzi, remains a significant often underdiagnosed public health challenge in endemic regions, affecting millions globally. Accurate and timely diagnosis is critical, but the performance of existing diagnostic methods varies widely in sensitivity and specificity. OBJECTIVES This multicentre study assessed the diagnostic performance of 17 serological assays for detecting anti-T. cruzi antibodies. METHODS Commercial enzyme immunoassays (EIA), indirect haemagglutination assays (IHA), indirect immunofluorescence assays (IIF), rapid diagnostic tests (RDT), and a chemiluminescent microparticle immunoassay (CMIA) were included in this study. FINDINGS Some EIA-based tests achieved 100% sensitivity, while IHAs and IIFs demonstrated reduced specificity. CMIA exhibited 100% sensitivity, highlighting its potential as a robust screening tool. Combining EIAs with IHAs or IIFs improved overall sensitivity, often surpassing 99%, although specificity remained variable. Cross-reactivity with other parasitic diseases posed challenges to specificity, particularly in assays employing crude antigens. MAIN CONCLUSIONS These findings emphasise the importance of tailoring diagnostic tool selection to regional epidemiological contexts and advancing antigen refinement to enhance diagnostic accuracy and accessibility, particularly in resource-limited settings.

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BACKGROUND Chikungunya virus (CHIKV) causes an infection that leads to the activation of the innate immune response, triggering receptor pathways such as toll-like receptors (TLRs). OBJECTIVE The present study aimed to investigate the association of single nucleotide polymorphisms (SNPs) in genes encoding toll-like receptors 3, 7, and 8 and IRF5 in susceptibility to CHIKV infection and persistent joint pain. METHODS A case-control study was carried out. The study included 121 symptomatic cases, 29 asymptomatic cases, and 182 healthy controls matched for age and sex. Polymorphisms were identified by TaqMan® SNP Genotyping assays. FINDINGS The G allele of the TLR7 variant (rs3853839 G/C) and the G allele of TLR8 (rs3764879 G/C) were associated with protection against CHIKV infection [adjusted odd ratio (OR) = 0.64; p = 0.02 and adjusted OR = 0.54; p = 0.001, respectively]. Moreover, individuals who presented the G allele in the rs3764879 variant have a greater chance of developing the asymptomatic form (adjusted OR =2.88; p =0.004). The development of persistent joint pain was not associated with any investigated SNPs in positive anti-CHIKV IgG individuals. MAIN CONCLUSIONS This study identified TLR7 and TLR8 gene polymorphisms as protective factors for Chikungunya infection.

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BACKGROUND Elite controllers (ECs) are a rare subset of individuals who naturally suppress human immunodeficiency virus type 1 (HIV-1) replication in the absence of antiretroviral therapy. Specific polymorphisms in the accessory proteins Vif and Vpr have been associated with diminished viral fitness in vitro and are more frequently detected in ECs compared to other individuals infected with HIV-1. OBJECTIVE To assess the frequency of gross genetic defects or polymorphisms that may attenuate the function of the HIV-1 accessory proteins Vif and Vpr within the proviral quasispecies of ECs. METHODS We performed single-genome amplification (SGA) and sequence analysis of the proviral quasispecies of the accessory genes vif and vpr in samples obtained from eight ECs with over 10 years of suppressive viral control and no evidence of disease progression. FINDINGS In subjects EC11, EC38 and EC52, most proviral clones encode full-length, intact vif and vpr open reading frames without known attenuating polymorphisms. Subject EC35 displayed stop codons in a substantial fraction of vif (33%) and vpr (67%) proviral clones. Subject EC36 exhibited the attenuating polymorphisms Vpr-Q3R + R77Q combined in all proviral clones. Subject EC17 showed stop codons in 20-30% of vif-vpr proviral clones, hypermutated sequences in 20% of vif proviral clones, and the attenuating polymorphism Vpr-R77Q in all proviral clones. Subject EC19 presented stop codons in 8-17% of vif-vpr proviral sequences, hypermutated sequences in 25% of vif-vpr proviral clones, and the polymorphisms Vif-R132S+Ins61(EDK) and Vpr-R77Q in all clones analysed. Finally, subject EC42 displayed stop codons in 25-38% of vif-vpr proviral sequences, hypermutated sequences in 25% of vif proviral clones, and the polymorphisms Vif-T20A+R132S and Vpr-R77Q in most (> 80%) proviral clones. MAIN CONCLUSIONS Mutations associated with attenuation of HIV-1 Vif and/or Vpr functions may contribute to the long-term control of viral replication and disease progression in certain ECs.

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BACKGROUND Titan cells in Cryptococcus species play a critical role in fungal virulence by resisting oxidative stress, phagocytosis, and antifungal treatments. Developing reliable methods to induce titan cells is crucial for understanding the mechanisms of Cryptococcus pathogenesis. OBJECTIVES In this study we report an unexpected discovery of a simple in vitro induction of titan cells in Cryptococcus neoformans and Cryptococcus gattii using Neurobasal™ (NB) medium. METHODS AND FINDINGS By employing established in vitro culture methods, we demonstrate a significantly higher capacity for titan cell formation in Cryptococcus spp. Cells grown in complete NB medium exhibited larger cell bodies, increased capsule sizes, and a higher percentage of titan cells compared to those grown in minimal medium (MM). NB medium without the B27 supplement significantly impacted titan cell formation. MAIN CONCLUSIONS Our findings indicate that NB medium, originally developed for neuronal cell cultures, is a useful tool for studying titan cell biology. This is particularly relevant given the association between titan cells and the central nervous system, highlighting their potential role in Cryptococcus pathogenesis.

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BACKGROUND Dermatomycoses are caused by various fungi, including dermatophytes and Candida species, which are the most prevalent in isolated or associated forms. A great number of virulence factors expressed by these fungi are important for infection, and biofilm formation leads to the persistence of these infections. OBJECTIVES This work aimed to evaluate the dynamics of Candida albicans filamentation genes in biofilms formed by Candida albicans and Trichophyton rubrum. METHODS The effect of the supernatants on the biofilms was assessed by XTT reduction assay, confocal microscopy, and gene expression profile analysis by real-time polymerase chain reaction (RT-PCR). FINDINGS The supernatants did not reduce the metabolic activities or damage the topography of the monospecies biofilms but caused a reduction in their thickness. The filamentation of C. albicans was inhibited when both fungi were cultivated directly. The filamentation genes studied (CPH1, HWP1, and EFG1) were negatively modulated in C. albicans. MAIN CONCLUSIONS Our findings suggest that the antagonistic relationship shown by T. rubrum against C. albicans may be attributed to alterations of C. albicans filamentous genes.

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BACKGROUND The Haemagogus genus includes nine mosquito species reported in Brazil, each with distinct distribution patterns. Haemagogus leucocelaenus, a major yellow fever vector, is widely distributed throughout the country, while Haemagogus leucophoebus, a morphologically similar species, has only been identified in Acre State. OBJECTIVES This study evaluated the presence of Haemagogus species in southern Brazil by comparing their morphological and molecular characteristics. METHODS Mosquitoes were collected from five municipalities in southern Santa Catarina State, Brazil. Each specimen was identified morphologically and photographed. Genomic DNA was extracted, and a Cytochrome C Oxidase Subunit I (COI) gene fragment was amplified using polymerase chain reaction (PCR). The positive amplicons were sequenced for molecular identification. FINDINGS New records of Hg. leucocelaenus were found in Santa Rosa de Lima, Rio Fortuna, Braço do Norte, São Martinho, and Pedras Grandes, located at the southern edge of the Atlantic Forest. This study expands the known distribution of Hg. leucocelaenus, the only Haemagogus species identified in the area, with 91 specimens collected. Although some specimens exhibited morphological variations that might lead to misidentification as Hg. leucophoebus, molecular identification confirmed that all were Hg. leucocelaenus. MAIN CONCLUSIONS This study is the first to report Hg. leucocelaenus in Santa Catarina, Brazil, and provides DNA barcoding sequences from southern Brazil. This method offers a reliable alternative for species identification, especially when combined with morphological analysis. Further molecular studies are needed to determine whether the morphological variations observed indicate intraspecific differences.