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The coinfection between malaria (ML) and arboviral diseases represents a major global public health problem, particularly in tropical and subtropical countries. Despite its relevance, this topic is still insufficiently discussed in the current literature. Here, we aimed to investigate the worldwide distribution, symptoms, and diagnosis during coinfection between ML and arboviral diseases. We conducted a systematic review following the Preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement and assessed the selection and eligibility criteria, created and diagrammed maps, and analysed major symptoms with 95% confidence intervals (CI) using prevalence ratio and effect size, also performing latent class analysis. A total of 85,485 studies were retrieved, of which 56 were included: 57.14% in Asia, 25% in Africa, 14.30% in South America, and 3.56% in Europe. A total of 746 individuals were reported to be coinfected with Plasmodium and arbovirus. Concurrent ML, Dengue (DEN), Chikungunya (CHIK), and Zika (ZIK) patients are more likely to present headache and skin rash. Regarding diagnosis, 58,253 were made, of which 38,176 were positive (ML and at least one arboviral disease). The magnitude of these pathogens’ coexistence points out the pressing need for improvements in public health policies towards diagnosis and prevention of both diseases, especially in endemic areas.

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The incorporation of different molecules by eukaryotic cells occurs through endocytosis, which is critical to the cell’s survival and ability to reproduce. Although this process has been studied in greater detail in mammalian and yeast cells, several groups working with pathogenic protists have made relevant contributions. This review analysed the most relevant data on the endocytic process in anaerobic protists (Entamoeba histolytica, Giardia intestinalis, Trichomonas vaginalis, and Tritrichomonas foetus). Many protozoa can exert endocytic activity across their entire surface and do so with great intensity, as with E. histolytica. The available data on the endocytic pathway and the participation of PI-3 kinase, Rab, and Rho molecular complexes is reviewed from a historical perspective.

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Sand flies play a crucial role as vectors of bacteria, viruses, and protists, with Leishmania being the most notable among them, transmitted to vertebrate hosts during blood feeding. Understanding the feeding behaviours of sand flies is imperative for gaining insights into their eco-epidemiological roles in the transmission of these infectious agents. This systematic review aimed to answer the question ‘What are the blood-feeding sources identified in Brazilian sand flies?’ to provide an analysis of their blood-feeding habits. The diverse range of at least 16 vertebrate orders identified as blood sources for 54 sand fly species across different geographic regions was summarised, and the factors potentially associated with the risk of bias in the included studies were analysed. The findings broaden the discussion concerning methods used to identify blood meal sources and shed light on the implications of sand fly feeding behaviours for the transmission dynamics of Leishmania.

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Extracellular vesicles (EVs) are lipid-bilayered membrane-delimited particles secreted by almost any cell type, involved in different functions according to the cell of origin and its state. From these, cell to cell communication, pathogen-host interactions and modulation of the immune response have been widely studied. Moreover, these vesicles could be employed for diagnostic and therapeutic purposes, including infections produced by pathogens of diverse types; regarding parasites, the secretion, characterisation, and roles of EVs have been studied in particular cases. Moreover, the heterogeneity of EVs presents challenges at every stage of studies, which motivates research in this area. In this review, we summarise some aspects related to the secretion and roles of EVs from several groups of pathogens, with special focus on the most recent research regarding EVs secreted by extracellular protozoan parasites.

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BACKGROUND Acanthamoebae are causative agents of severe and complicated human infections without a standard effective therapy to date. Therefore, the research is focused on the development of new amoebicidal drugs based on the natural products. Plants of the family Lamiaceae are typical with several phenolic secondary metabolites that make them interesting in medical point of view. OBJECTIVE In this review, we concentrate on anti-Acanthamoeba activities of plant extracts, essential oils, and phytochemicals of Lamiaceae in the published literature. FINDINGS A total of 13 articles in the research field were found. Totally, 16 plant species belonging to family Lamiaceae were studied against trophozoites and cysts of Acanthamoeba in in vitro conditions. Low toxicity of the Lamiaceae plant extracts to tissue cultures enhances their possible potential for clinical use. The research demonstrated promising trophocidal and cysticidal effects against acanthamoebae. Further research is needed with inclusion of more clinical isolates and in vivo studies. MAIN CONCLUSION Reviewing the related literature highlights the promising amoebicidal activities of plant extracts, essential oils and bioactive compounds of family Lamiaceae. Identifying the active components could lead to production new effective and well-tolerated drugs for the Acanthamoeba infections treatment.

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Twenty-five years have passed since the initial observation of endemic zoonotic sporotrichosis in Rio de Janeiro, Brazil. Since then, this disease has spread throughout South America. Accompanying the emergence of this mycosis, some progress has been made, including the expansion of a research network in this field and higher visibility of sporotrichosis within government authorities and funding agencies. However, there are still some challenges to curbing the expansion of this disease in the coming years. These include the development of rapid and accurate diagnostic tests, new antifungal drugs, particularly for the treatment of extracutaneous manifestations of sporotrichosis, and more comprehensive care for cats with sporotrichosis. Including these actions in the sporotrichosis research agenda is required so as to change the development of this disease in the years to come.

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Chagas disease is a tropical neglected disease that affects millions of people worldwide, still demanding a more effective and safer therapy, especially in its chronic phase which lacks a treatment that promotes substantial parasitological cure. The technical note of Romanha and collaborators published in 2010 aimed establish a guideline with the set of minimum criteria and decision gates for the development of new agents against Trypanosoma cruzi with the focus on developing new antichagasic drugs. In this sense, the present review aims to update this technical note, bringing the state of the art and new advances on this topic in recent years.

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Tuberculosis (TB) continues to be the world’s leading killer of infectious diseases. Despite global efforts to gradually reduce the number of annual deaths and the incidence of this disease, the coronavirus disease 19 (COVID-19) pandemic caused decreased in TB detection and affected the prompt treatment TB which led to a setback to the 2019 rates. However, the development and testing of new TB vaccines has not stopped and now presents the possibility of implanting in the next five years a new vaccine that is affordable and might be used in the various key vulnerable populations affected by TB. Then, this assay aimed to discuss the main vaccines developed against TB that shortly could be selected and used worldwide, and additionally, evidence the Brazilian potential candidates’ vaccines in developing in Brazil that could be considered among those in level advanced to TB end.

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This perspective presents and supports arguments for a new formulation of epoxy-α-lapachone loaded microemulsion (ELAP-ME), a nanosystem, as a prototype drug for the treatment of leishmaniasis. The benefits of ELAP as a multitarget compound, with properties that affect key physiological pathways of Leishmania spp. are discussed. ELAP-ME demonstrated efficacy in murine infection models, particularly with the binomial BALB/c-Leishmania (Leishmania) amazonensis. Furthermore, it is proposed that the technological maturity of ELAP-ME be classified as Technology Readiness Level 4 (TLR 4) within the context of innovative drugs for American Cutaneous Leishmaniasis (ACL).

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Chagas disease (CD), caused by Trypanosoma cruzi, is a life-threatening neglected anthropozoonosis primarily transmitted by triatomine bugs. Affecting an estimated 5.7 million people globally, CD has significant morbidity and mortality, particularly in Latin America. The Oxente Chagas Bahia Project aims to screen approximately 30,000 individuals, validate a rapid diagnostic test in a real-world setting, and provide crucial data on its diagnostic performance and cost-effectiveness. Additionally, a biobank will be established to support further research on disease biomarkers and treatment cure rates. By enhancing access to timely diagnosis and treatment, the project will evaluate a strategy to reduce the CD burden.

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BACKGROUND Eosinophils are granulocytes that rapidly increase frequency in the bloodstream during helminthic infections and allergic responses. They are found in tissue infected by Leishmania during early disease, but their role during infection is not entirely understood. OBJECTIVES We aim to compare the disease due to Leishmania amazonensis in BALB/c and Δdbl-GATA1 mice, which lack eosinophils. METHODS BALB/c and Δdbl-GATA1 mice infected with L. amazonensis were observed for several weeks. The parasite load and dissemination pattern were assessed. FINDINGS The Δdbl-GATA1 mice developed an anticipated dissemination of L. amazonensis and a worsening disease. No differences were found in the lesion development or the parasite load in the footpad among Δdbl-GATA1 mice and BALB/c eight weeks after infection. However, nine weeks after infection, massive growth of metastatic lesions appeared in several parts of the skin in Δdbl-GATA1 mice, weeks earlier than BALB/c. We observed increased parasites in the bloodstream, probably an essential dissemination route. Thirteen weeks after infection, metastatic lesions were found in all Δdbl-GATA1 mice. MAIN CONCLUSION These results suggest a protective role of eosinophils in delaying the disease caused by L. amazonensis, although several limitations of this mice strain must be considered.

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BACKGROUND The incidence of visceral leishmaniasis (VL) has increased in the Southern region of Brazil in recent years, especially in the State of Paraná. New species have been suggested with potential to act as vector in VL endemic areas. OBJECTIVES Identify the Leishmania species in sand fly specimens collected from 2016 to 2018 in the municipality of Itaperuçu, Vale do Ribeira, Paraná, Brazil. METHODS Light traps were used for collections and for the analysis of sand fly were used the multiplex polymerase chain reaction (PCR) methodology and subsequent sequencing. FINDINGS Among the collected specimens, 88.62% were attributed to the species Nyssomyia neivai, which were grouped into 176 pools. Three positive pools were detected: two with Leishmania (Viannia) braziliensis and one with L. (Leishmania) infantum. The positivity rate for the parasite was 0.25% based on the presence of at least one infected insect in the pool. MAIN CONCLUSIONS The detection of L. infantum in Ny. neivai draws attention due to its abundance and anthropophily in the State of Paraná. Moreover, this finding is considered as an alert and suggests that the vector competence of Ny. neivai and the criteria for its incrimination should be carried out, given its wide distribution in southern of Brazil.

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BACKGROUND In Brazil, transmission of visceral and cutaneous leishmaniasis has expanded geographically over the last decades, with both clinical forms occurring simultaneously in the same area. OBJECTIVES This study characterised the clinical, spatial, and temporal distribution, and performed entomological surveillance and natural infection analysis of a leishmaniasis-endemic area. METHODS In order to characterise the risk of leishmaniasis transmission in Altos, Piauí, we described the clinical and socio-demographic variables and the spatial and temporal distribution of cases of American visceral leishmaniasis (AVL) and American cutaneous leishmaniasis (ACL) cases and identified potential phlebotomine vectors. FINDINGS The urban area concentrated almost 54% of ACL and 86.8% of AVL cases. The temporal and spatial distribution of AVL and ACL cases in Altos show a reduction in the number of risk areas, but the presence of permanent disease transmission foci is observed especially in the urban area. 3,808 phlebotomine specimens were captured, with Lutzomyia longipalpis as the most frequent species (98.45%). Of the 35 females assessed for natural infection, one specimen of Lu. longipalpis tested positive for the presence of Leishmania infantum and Leishmania braziliensis DNA. MAIN CONCLUSION Our results indicate the presence of risk areas for ACL and AVL in the municipality of Altos and highlight the importance of entomological surveillance to further understand a possible role of Lu. longipalpis in ACL transmission.

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BACKGROUND American tegumentary leishmaniasis (ATL) is an endemic neglected tropical disease (NTD), its conventional treatment is toxic, slow, and invasive. Rapid diagnosis is crucial for the clinical management of suspected patients, so the development and use of low-cost, miniaturised and portable devices could be the key. OBJECTIVES This work aimed to develop a simple paper-based electrochemical platform for the serological detection of ATL. METHODS Platform was fabricated in Whatman N°1 paper, contains a hydrophobic zone generated by wax printing, two pencil graphite electrodes, and uses specific crude extracts (CA) antigens for ATL immuno-determination. The platform performance was analysed by measuring the relative impedance change for different antigen-antibody combinations. Then, 10 serum human samples previously diagnosed by the gold standard (five positive ATL cases and five non-ATL cases) were evaluated. FINDINGS The platform presented a linear response for the charge transfer resistance (ΔRct) and the interface reactance (ΔXc). Also, optimal working conditions were established (1/60 serum dilution and 180 µg/mL CA concentration). Then, the platform permits to distinguish between ATL and non-ATL (p < 0.05) human serum samples. MAIN CONCLUSIONS Our platform could allow the diagnosis, management, and monitoring of leishmaniasis while being an extremely simple and environmentally friendly technology.

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BACKGROUND Leprosy is a highly neglected disease that is considered a serious public health problem in many countries. This illness is characterised by a variety of clinical and histopathological manifestations that are related to the patient immune response. OBJECTIVES This work aimed evaluate the profile of circulating immune mediators in the plasma from patients classified clinically as paucibacillary (PB), multibacillary (MB), households contacts (HHC), type1 leprosy reaction (T1R), type2 leprosy reaction (T2R) and control individuals without medical history of leprosy (CTL). METHODS To assessment of the plasma immune mediators was used multiplex microbeads immunoassay “Luminex”. FINDINGS The results showed that patients (PB) had a regulatory-biased profile, while MB revealed a pro-inflammatory trend of highly expressed biomarkers. HHC display conspicuously increased levels in the plasma of the chemokines (CCL2, CCL3, CCL4, CCL5 and CXCL8), pro-inflammatory cytokines (IFN-γ,TNF and IL-1β), modulating cytokines (IL-9 and IL-1Ra) and growth factors (PDGF, G-CSF and IL-2). Interestingly, HHC displayed superior production of IFN-γ as compared to other leprosy groups, indicating a putative protective role for this cytokine during chronic Mycobacterium leprae exposure. MAIN CONCLUSION Further investigations are currently underway to elucidate the potential of these mediators as biomarkers applicable to the diagnosis/prognosis of leprosy and also T1R and T2R leprosy reactions.

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BACKGROUND Leishmaniases encompass a spectrum of neglected diseases caused by parasites of the genus Leishmania, grouped in two forms: tegumentary and visceral leishmaniasis. OBJECTIVES In this study, we propose Friend Virus B NIH Jackson (FVB/NJ) mouse strain as a new experimental model of infection with Leishmania (Leishmania) amazonensis, the second most prevalent agent of tegumentary leishmaniasis in Brazil. METHODS AND FINDINGS We performed in vitro infections of FVB/NJ macrophages and compared them with BALB/c macrophages, showing that BALB/c cells have higher infection percentages and a higher number of amastigotes/cell. Phagocytosis assays indicated that BALB/c and FVB/NJ macrophages have similar capacity to uptake parasites after 5 min incubations. We also investigated promastigotes’ resistance to sera from FVB/NJ and BALB/c and observed no difference between the two sera, even though FVB/NJ has a deficiency in complement components. Finally, we subcutaneously infected FVB/NJ and BALB/c mice with 2 × 106 parasites expressing luciferase. Analysis of lesion development for 12 weeks showed that FVB/NJ and BALB/c mice have similar lesion profiles and parasite burdens. MAIN CONCLUSIONS This work characterises for the first time the FVB/NJ mouse as a new model for tegumentary leishmaniasis caused by Leishmania (L.) amazonensis.

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BACKGROUND Malaria is an infectious disease caused by protozoan parasites belonging to the genus Plasmodium. Human-to-human transmission depends on a mosquito vector; thus, the interruption of parasite transmission from humans to mosquitoes is an important approach in the fight against malaria. The parasite stages infectious to mosquitoes are the gametocytes, sexual stages that are ingested by the vector during a blood meal and transform into male and female gametes in the midgut. Immunity against sexual stage antigens expressed by gametocytes, gametes, and the zygote formed after fertilisation can interrupt the parasite sexual cycle in the mosquito. This transmission blocking immunity is mediated by specific antibodies ingested during the mosquito blood feed, inhibiting the parasite development in the midgut. Merozoite thrombospondin related anonymous protein (MTRAP) is a merozoite and gametocyte surface protein essential for gamete egress from erythrocytes and for parasite transmission to mosquitoes. OBJECTIVES Here, we evaluated the potential of the P. berghei MTRAP to elicit antibodies with the ability to inhibit gamete fertilisation in vitro. METHODS We expressed a soluble recombinant PbMTRAP and used it to immunise BALB/c mice. The transmission blocking activity of the anti-rPbMTRAP antibodies was tested through in vivo challenge experiments followed by in vitro conversion assays. FINDINGS Immunisations with the rPbMTRAP induced a strong antibody response and the antibodies recognised the native protein by Western Blot and IFA. Anti-rPbMTRAP present in the blood stream of immunised mice partially inhibited gamete conversion into ookinetes. CONCLUSION Our results indicate that antibodies to PbMTRAP may reduce but are not sufficient to completely block transmission.

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BACKGROUND The availability of genes and protein sequences for parasites has provided valuable information for drug target identification and vaccine development. One such parasite is Bartonella quintana, a Gram-negative, intracellular pathogen that causes bartonellosis in mammalian hosts. OBJECTIVE Despite progress in understanding its pathogenesis, limited knowledge exists about the virulence factors and regulatory mechanisms specific to B. quintana. METHODS AND FINDINGS To explore these aspects, we have adopted a subtractive proteomics approach to analyse the proteome of B. quintana. By subtractive proteins between the host and parasite proteome, a set of proteins that are likely unique to the parasite but absent in the host were identified. This analysis revealed that out of the 1197 protein sequences of the parasite, 660 proteins are non-homologous to the human host. Further analysis using the Database of Essential Genes predicted 159 essential proteins, with 28 of these being unique to the pathogen and predicted as potential putative targets. Subcellular localisation of the predicted targets revealed 13 cytoplasmic, eight membranes, one periplasmic, and multiple location proteins. The three-dimensional structure and B cell epitopes of the six membrane antigenic protein were predicted. Four B cell epitopes in KdtA and mraY proteins, three in lpxB and BQ09550, whereas the ftsl and yidC proteins were located with eleven and six B cell epitopes, respectively. MAINS CONCLUSIONS This insight prioritises such proteins as novel putative targets for further investigations on their potential as drug and vaccine candidates.

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BACKGROUND Conventional microscopic counting is a widely utilised method for evaluating the trypanocidal effects of drugs on intracellular amastigotes. This is a low-cost approach, but it is time-consuming and reliant on the expertise of the microscopist. So, there is a pressing need for developing technologies to enhance the efficiency of low-cost anti-Trypanosoma cruzi drug screening. OBJECTIVES In our laboratory, we aimed to expedite the screening of anti-T. cruzi drugs by implementing a fluorescent method that correlates emitted fluorescence from green fluorescent protein (GFP)-expressing T. cruzi (Tc-GFP) with cellular viability. METHODS Epimastigotes (Y strain) were transfected with the pROCKGFPNeo plasmid, resulting in robust and sustained GFP expression across epimastigotes, trypomastigotes, and intracellular amastigotes. Tc-GFP epimastigotes and intracellular amastigotes were exposed to a serial dilution of benznidazole (Bz). Cell viability was assessed through a combination of microscopic counting, MTT, and fluorimetry. FINDINGS The fluorescence data indicated an underestimation of the activity of Bz against epimastigotes (IC50 75 µM x 14 µM). Conversely, for intracellular GFP-amastigotes, both fluorimetry and microscopy yielded identical IC50 values. Factors influencing the fluorimetry approach are discussed. MAIN CONCLUSIONS Our proposed fluorometric assessment is effective and can serve as a viable substitute for the time-consuming microscopic counting of intracellular amastigotes.

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OBJECTIVES We report the first case of Oropouche fever detected in the border region of Colombia. METHODS Using a multiplex real-time polymerase chain reaction (PCR), genetic sequencing and clinical characteristics during the dengue epidemic in 2019, a total of 175 samples were analysed, from cases notified to the system epidemiological surveillance such as dengue. FINDINGS The Oropouche virus (OROV) isolate from Leticia belongs to lineage 2 according to both M and S genome segments maximum likelihood (ML) analysis, shares a common ancestor with samples obtained in Esmeraldas, Ecuador and Turbaco, Colombia. The patient: a woman resident in the border neighbourhood of the municipality of Leticia had the following symptoms: fever, headache, retro-orbital pain and myalgias. MAIN CONCLUSION This cross-border surveillance can be useful to give an alert about the entry or exit of arboviruses circulation in the region, which are often underreported in public health surveillance systems.

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BACKGROUND Leishmania tarentolae is a non-pathogenic species found in lizards representing an important model for Leishmania biology. However, several aspects of this Sauroleishmania remain unknown to explain its low level of virulence. OBJECTIVES We reported several aspects of L. tarentolae biology including glycoconjugates, proteolytic activities and metabolome composition in comparison to pathogenic species (Leishmania amazonensis, Leishmania braziliensis, Leishmania infantum and Leishmania major). METHODS Parasites were cultured for extraction and purification of lipophosphoglycan (LPG), immunofluorescence probing with anti-gp63 and resistance against complement. Parasite extracts were also tested for proteases activity and metabolome composition. FINDINGS Leishmania tarentolae does not express LPG on its surface. It expresses gp63 at lower levels compared to pathogenic species and, is highly sensitive to complement-mediated lysis. This species also lacks intracellular/extracellular activities of proteolytic enzymes. It has metabolic differences with pathogenic species, exhibiting a lower abundance of metabolites including ABC transporters, biosynthesis of unsaturated fatty acids and steroids, TCA cycle, glycine/serine/threonine metabolism, glyoxylate/dicarboxylate metabolism and pentose-phosphate pathways. MAIN CONCLUSIONS The non-pathogenic phenotype of L. tarentolae is associated with alterations in several biochemical and molecular features. This reinforces the need of comparative studies between pathogenic and non-pathogenic species to elucidate the molecular mechanisms of virulence during host-parasite interactions.

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BACKGROUND Monitoring and analysing the infection rates of the vector of Trypanosoma cruzi, that causes Chagas disease, helps assess the risk of transmission. OBJECTIVES A study was carried out on triatomine in the State of Paraná, Brazil, between 2012 and 2021 and a comparison was made with a previous study. This was done to assess the risk of disease transmission. METHODS Ecological niche models based on climate and landscape variables were developed to predict habitat suitability for the vectors as a proxy for risk of occurrence. FINDINGS A total of 1,750 specimens of triatomines were recorded, of which six species were identified. The overall infection rate was 22.7%. The areas with the highest risk transmission of T. cruzi are consistent with previous predictions in municipalities. New data shows that climate models are more accurate than landscape models. This is likely because climate suitability was higher in the previous period. MAIN CONCLUSION Regardless of uneven sampling and potential biases, risk remains high due to the wide presence of infected vectors and high environmental suitability for vector species throughout the state and, therefore, improvements in public policies aimed at wide dissemination of knowledge about the disease are recommended to ensure the State remains free of Chagas disease.

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BACKGROUND The impact of Schistosoma mansoni infection over the immune response and the mechanisms involved in pathogenesis are not yet completely understood. OBJECTIVES This study aimed to evaluate the expression of innate immune receptors in three distinct mouse lineages (BALB/c, C57BL/6 and Swiss) during experimental S. mansoni infection with LE strain. METHODS The parasite burden, intestinal tissue oogram and presence of hepatic granulomas were evaluated at 7- and 12-weeks post infection (wpi). The mRNA expression for innate Toll-like receptors, Nod-like receptors, their adaptor molecules, and cytokines were determined at 2, 7 and 12 wpi in the hepatic tissue by real-time quantitative polymerase chain reaction (qPCR). FINDINGS Swiss mice showed 100% of survival, had lower parasite burden and intestinal eggs, while infected BALB/c and C57BL/6 presented 80% and 90% of survival, respectively, higher parasite burden and intestinal eggs. The three mouse lineages displayed distinct patterns in the expression of innate immune receptors, their adaptor molecules and cytokines, at 2 and 7 wpi. MAIN CONCLUSIONS Our results suggest that the pathogenesis of S. mansoni infection is related to a dynamic early activation of innate immunity receptors and cytokines important for the control of developing worms.

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BACKGROUND In Brazil, Leishmania (Leishmania) infantum is a widely distributed protozoan parasite. The human leishmaniasis caused by this species is often associated with visceral form. Tegumentary leishmaniasis (TL) cases due to L. (L.) infantum in the country are considered rare but may be underestimated. Although probably uncommon, these cases represent a new challenge to the prevention and control of leishmaniasis. OBJECTIVES Here, we describe two distinct cases of TL with atypical clinical presentations caused by L. (L.) infantum. METHODS AND FINDINGS Parasites were isolated from cutaneous lesions of the two patients and typed as L. (L.) infantum after sequencing of the ribosomal DNA internal transcribed spacer. The dermotropic L. (L.) infantum isolates were compared in terms of growth culture patterns, metacyclogenesis and in vitro infectivity in macrophages. MAIN CONCLUSIONS This study addresses the emergence of L. (L.) infantum as a causative agent of cutaneous disease in a visceral leishmaniasis hotspot located in northeast Brazil. The data presented provides novel information about the presence of dermotropic L. (L.) infantum in the country and demonstrates the infectivity potential of theses isolates.

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BACKGROUND Leishmania (Viannia) braziliensis Thor strain exhibits a heterogeneous composition comprised of subpopulations with varying levels of infectivity. Clonal subpopulations were previously obtained from the strain Thor by sorting single-parasites and proceeding cultivation. The subpopulations used in this study are named Thor03, Thor 10 and Thor22. OBJECTIVES Phenotypic characteristics of the parasite, specially focusing on virulence factors and resistance to the antimicrobial mechanisms of macrophages, were investigate in these subpopulations. METHODS Cellular and molecular biology, as well as biochemistry approaches were applied to obtain the data analysed in this study. FINDINGS Relative quantification of gene expression was measured for calpain, cysteine protease B (CPB), and subtilisin proteases but no significant differences in these genes’ expression among subpopulations was observed. However, subtilisin and CPB proteins were assessed as more abundant in Thor03 by fluorescence-labelled flow cytometry technique. Western Blotting assays, as semi-quantitative analysis in gel, showed higher concentrations of subtilisin (110 to 50 kDa) and CPB (40 to 18 kDa) in extract of intracellular amastigotes from subpopulations Thor03 and Thor10 and calpain (60 to 25 kDa) showed no significant differences among subpopulations. Complementary, higher trypanothione reductase activity was observed in Thor10 intracellular amastigotes and assays of susceptibility to hydrogen peroxide-inducing agents and nitric oxide donors conducted with promastigotes revealed greater resistance to in vitro oxidative stress induction for Thor10, followed by Thor03. MAIN CONCLUSIONS The data obtained for the virulence factors explored here suggest how multiple coexisting phenotypic-distinct subpopulations may contribute in adaptability of a single L. (V.) braziliensis strain during infection in the host cells.

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BACKGROUND Giant viruses have brought new insights into different aspects of virus-cell interactions. The resulting cytopathic effects from these interactions are one of the main aspects of infection assessment in a laboratory routine, mainly reflecting on the morphological features of an infected cell. OBJECTIVES In this work, we follow the entire kinetics of the cytopathic effect in cells infected by viruses of the Mimiviridae family, spatiotemporally quantifying typical features such as cell roundness, loss of motility, decrease in cell area and cell lysis. METHODS Infections by Acanthamoeba polyphaga mimivirus (APMV), Tupanvirus (TPV) and M4 were carried out at multiplicity of infection (MOI) 1 and MOI 10 in Acanthamoeba castellanii. Monitoring of infections was carried out using time lapse microscopy for up to 72 hours. The images were analyzed using ImageJ software. FINDINGS The data obtained indicate that APMV is the slowest virus in inducing the cytopathic effects of rounding, decrease in cell area, mobility and cell lysis. However, it is the only virus whose MOI increase accelerates the lysis process of infected cells. In turn, TPV and M4 rapidly induce morphological and behavioral changes. MAIN CONCLUSIONS Our results indicate that mimiviruses induce different temporal responses within the host cell and that it is possible to use these kinetic data to facilitate the understanding of infection by these viruses.

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BACKGROUND Chagas disease is a systemic illness with widespread microvascular involvement. Experimental and clinical studies suggest that functional and structural microcirculatory abnormalities might be relevant to the disease progression. OBJECTIVES To show the presence of sublingual microcirculatory alterations in patients with chronic Chagas disease. METHODS This was a cross-sectional study including adult patients with serologic diagnosis of Chagas disease (n = 41) and control volunteers with negative serology (n = 38), from an endemic rural population. Study participants underwent clinical, electrocardiographic, echocardiographic, and sublingual videomicroscopic assessment. Videos were acquired by a sidestream-dark-field (SDF) imaging device and evaluated by a software-assisted analysis (AVA 3.2 software). FINDINGS Most of Chagas disease patients were in the indeterminate phase (n = 34) and had lower heart rate and more echocardiographic abnormalities than control group (50 vs. 26%, p = 0.03). They also exhibited higher small microvessels total and perfused vascular density (20.12 ± 2.33 vs. 19.05 ± 2.25 and 20.03 ± 2.28 vs. 19.01 ± 2.25 mm/mm2, p < 0.05 for both). Other microvascular variables did not differ between groups. MAIN CONCLUSIONS Patients with chronic Chagas disease exhibited increases in sublingual total and perfused microvascular density. Angiogenesis might be the underlying mechanism. The videomicroscopic assessment of mucosal sublingual microcirculation might be an additional tool in the monitoring of Chagas disease.

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BACKGROUND The impact of nutrient availability on the survival of Mycobacterium leprae and the development of leprosy remains largely unknown. Iron is essential for the survival and replication of pathogens, while vitamin D has been involved with pathogen elimination and immunoregulation. OBJECTIVES We evaluated the influence of dietary iron and vitamin D supplementation and restriction on the inflammatory response of mouse immune cells in vitro. METHODS After 30 days of standard or modified diets, peritoneal cells and splenocytes were stimulated with the alive microorganisms and sonicated antigens of M. leprae, respectively. The production of inflammatory cytokines, reactive oxygen species, and cell proliferation were evaluated. FINDINGS In peritoneal cells, vitamin D supplementation and iron restriction reduced the production of IL-6 and TNF in response to M. leprae, while splenocytes presented a reduction in TNF production under the same conditions. Lower levels of IFN-γ and TNF were observed in both iron-supplemented and iron-deficient splenocytes. Besides, iron supplementation also reduced the production of IL-6 and IL-10. No changes in the production of reactive oxygen species or in cell proliferation were observed related to different diets. MAIN CONCLUSIONS Taken together, these data point to an interference of the status of these nutrients on the interaction between the host and M. leprae, with the potential to interfere with the progression of leprosy. Our results highlight the impact of nutritional aspects on this neglected disease, which is significantly associated with unfavourable social conditions.

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BACKGROUND The immunological response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and immunisation is variable. OBJECTIVES To describe the humoral immune response by correlating IgA and IgG antibodies with NAbs titration following CoronaVac® immunisation and an mRNA (Comirnaty®) booster among healthcare workers (HCWs) and to compare the cytokine and interleukin profiles between HCWs vaccinated with CoronaVac and coronavirus disease 2019 (COVID-19) infected patients. METHODS Samples from 133 HCWs collected at 20 (T1) and 90 (T2) days after CoronaVac immunisation and 15 (T3) days after a booster dose with the Comirnaty vaccine were analysed for IgA and IgG EIA and neutralisation assay. Cytokine levels from vaccinated individuals at T1 day and COVID-19 patients were compared. FINDINGS Neutralising antibodies (NAbs) were observed in 81.7% of participants at T1, but only 49.2% maintained detectable NAbs after 90 days. The booster dose increased NAbs response in all participants. The cytokines with the highest levels post-vaccination were IL-6 and MCP-1. The MCP-1, IL-18, and IFN- γ levels were higher in COVID-19 patients than in vaccinated HCWs, while IL-22 levels increased in the vaccinated HCWs group. MAIN CONCLUSIONS The neutralisation titres in the T2 samples decreased, and antibody levels detected at T2 showed a more significant reduction than the neutralisation. The higher IL-22 expression in immunised individuals compared to those with COVID-19 suggests that IL-22 may be beneficial in protecting against severe disease.

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BACKGROUND The city of El Pedregal grew out of a desert, following an agricultural irrigation project in southern Peru. OBJECTIVES To describe infestation patterns by triatomines and bed bugs and their relationship to migration and urbanization. METHODS We conducted door-to-door entomological surveys for triatomines and bed bugs. We assessed spatial clustering of infestations and compared the year of construction of infested to un-infested households. To gain a better understanding of the context surrounding triatomine infestations, we conducted in-depth interviews with residents to explore their migration histories, including previous experiences with infestation. FINDINGS We inspected 5,164 households for Triatoma infestans (known locally as the Chirimacha); 21 (0.41%) were infested. These were extremely spatially clustered (Ripley’s K p-value < 0.001 at various spatial scales). Infested houses were older than controls (Wilcoxon rank-sum: W = 33; p = 0.02). We conducted bed bug specific inspections in 34 households; 23 of these were infested. These were spatially dispersed across El Pedregal, and no difference was observed in construction age between bed bug infested houses and control houses (W = 6.5, p = 0.07). MAIN CONCLUSIONS The establishment of agribusiness companies in a desert area demanded a permanent work force, leading to the emergence of a new city. Migrant farmers, seeking work opportunities or escaping from adverse climatic events, arrived with few resources, and constructed their houses with precarious materials. T. infestans, a Chagas disease vector, was introduced to the city and colonized houses, but its dispersal was constrained by presence of vacant houses. We discuss how changes in the socioeconomic and agricultural landscape can increase vulnerability to vector-borne illnesses.

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BACKGROUND Leishmaniasis is a neglected zoonosis caused by parasites of Leishmania spp. The main drug used to treat cutaneous leishmaniasis (CL) is the antimoniate of meglumine. This drug, which has strong adverse and toxic effects, is usually administered intravenously, further complicating the difficult treatment. Factors such as Leishmania gene expression and genomic mutations appear to play a role in the development of drug resistance. OBJECTIVES This systematic review summarises the results of the literature evaluating parasite genetic markers possibly associated with resistance to pentavalent antimony in CL. METHODS This study followed PRISMA guidelines and included articles from PubMed, SciELO, and LILACS databases. Inclusion criteria were studies that (i) investigated mutations in the genome and/or changes in gene expression of Leishmania associated with treatment resistance; (ii) used antimony drugs in the therapy of CL; (iii) used naturally resistant strains isolated from patients. The Joanna Briggs Institute Critical Appraisal Checklist was used to assess article quality and risk of bias. FINDINGS A total of 23 articles were selected, of which 18 investigated gene expression and nine genomic mutations. Of these 23 articles, four examined gene expression and genomic mutations in the same samples. Regarding gene expression, genes from the ABC transporter protein family, AQP1, MRPA, TDR1 and TRYR were most frequently associated with drug resistance. In one of the articles in which mutations were investigated, a mutation was found in HSP70 (T579A) and in three articles mutations were found in AQP1 (A516C, G562A and G700A). A limitation of this review is that in most of the included studies, parasites were isolated from cultured lesion samples and drug resistance was assessed using in vitro drug susceptibility testing. These approaches may not be ideal for accurate genetic evaluation and detection of treatment failure. MAIN CONCLUSIONS The development of further studies to evaluate the genetic resistance factors of Leishmania spp. is necessary to elucidate the mechanisms of the parasite and improve patient treatment and infection control.

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BACKGROUND In response to the coronavirus disease 2019 (Covid-19) pandemic, Brazil authorised the Astra Zeneca/Fiocruz vaccine in January 2021. As the Delta variant emerged in May 2021, interval between vaccine doses was adjusted. By September 2021, the Brazilian National Immunisation Program recommended a booster dose for individuals over 70, and later expanded the recommendation to all adults. OBJECTIVES Assess the equivalence of IgG antibody response against the Covid-19 S protein before and approximately 28 days after the third dose of a Covid-19 recombinant vaccine. Two groups received initial two doses with intervals of eight and 12 weeks. METHODS This is a phase IV clinical study, uncontrolled, non-randomised. The study proposes calculating the ratio of geometric means titres (GMT) 28 days after the third dose, with a target ratio of confidence interval (CI) between 0.77 and 1.3. FINDINGS In the primary endpoint, there was no equivalence between the eight- and 12-week intervals with a slight variation favouring the eight-week group. Post-third dose, both groups showed increases titres at 28 days, three months, six months and 12 months. Both groups responded similarly to Delta and Omicron BA.1, with a more significant increase for Delta. MAIN CONCLUSIONS The study showed strong and consistent immune response in all age groups receiving the Covid-19 recombinant vaccine. Third dose elicited an increase in GMT by at least three times aligned with Ministry of Health strategies emphasising Bio-Manguinhos crucial role in pandemic control in the country.

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BACKGROUND Human immunodeficiency virus (HIV)-1 infection can activate the expression of human endogenous retroviruses (HERVs), particularly HERV-K (HML-2). HIV controllers (HICs) are rare people living with HIV (PLWHs) who naturally control HIV-1 replication and overexpress some cellular restriction factors that negatively regulate the LTR-driven transcription of HIV-1 proviruses. OBJECTIVES To understand the ability of HICs to control the expression of endogenous retroviruses. METHODS We measured endogenous retrovirus type K6 (ERVK-6) RNA expression in peripheral blood mononuclear cells (PBMCs) of HICs (n = 23), antiretroviral (ART)-suppressed subjects (n = 8), and HIV-1-negative (NEG) individuals (n = 10) and correlated the transcript expression of ERVK-6 with multiple HIV-1 cellular restriction factors. FINDINGS Our study revealed that ERVK-6 RNA expression in PBMCs from HICs was significantly downregulated compared with that in both the ART and NEG control groups. Moreover, we detected that ERVK-6 RNA levels in PBMCs across all groups were negatively correlated with the expression levels of p21 and MCPIP1, two cellular restriction factors that limit the activation of macrophages and T cells by downregulating the activity of NF-kB. MAIN CONCLUSIONS These findings support the hypothesis that HICs activate innate antiviral mechanisms that may simultaneously downregulate the transcription of both exogenous (HIV-1) and endogenous (ERVK-6) retroviruses. Future studies with larger cohorts should be performed to confirm this hypothesis and to explore the role of p21 and MCPIP1 in regulating HERV-K expression in physiological and pathological conditions.

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BACKGROUND PPE 59, which is absent from bacillus Calmette Guérin (BCG) strains, seems to induce a humoral immune response in patients with tuberculosis (TB). Additional studies are needed to better evaluate this protein in immune response to tuberculosis. OBJECTIVES To evaluate the response of antibodies to PPE59 in TB individuals, its combination with IgG response to other, previously tested mycobacterial antigens (Ag) and with sputum smear microbiology (SM) results. METHODS We have cloned and expressed the rv3429 gene that encodes PPE59, then IgG, IgM, and IgA against PPE59 antigens measured by enzyme-linked immunosorbent assay (ELISA) in 212 sera samples obtained from the following subject cohorts: TB residents from Italy (79) and in Brazil (52); and an all-Brazilian cohort of 55 patients with other respiratory disorders; 10 patients infected with non-tuberculous mycobacteria, and 16 asymptomatic subjects. Drawing on results from a previous study(17) of serum samples from Brazilian subjects tested for IgG by ELISA against mycobacterial antigens ESAT-6, 16kDa, MT10.3, MPT-64 and 38kDa, the results were analysed in combination with those of the PPE59 and SM tests. FINDINGS Keeping the specificity rate at 97%, the overall PPE59 IgA sensitivity was 42.7%, while IgG and IgM showed lower performance (p < 0.0001). Combining PPE59 IgA/16kDa IgG results increased sensitivity to 71%, and even higher rates when the results were combined with SM results (86.5%, p = 0.001), at 88.9% specificity. Positive IgA was associated with pulmonary image alterations of high TB probability (p < 0.05). MAIN CONCLUSIONS Tests with TB patients found a moderate frequency of positivity for PPE59 IgA. However, the higher level of sensitivity attained in combination with PPE59 IgA/16kDa IgG/SM results unheard of before, although imperfect, suggests that this may be a potential additional tool for rapid detection of TB in low-resource areas.

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BACKGROUND During the coronavirus disease 19 (COVID-19) pandemic, diagnostic testing of the general population proved challenging due to limitations of the gold-standard diagnostic procedure using reverse transcription real-time polymerase chain reaction (RT-qPCR) for large-scale testing on the centralised model, especially in low-resource areas. OBJECTIVES To address this, a point-of-care (PoC) diagnostic protocol for COVID-19 was developed, providing fast, reliable, and affordable testing, particularly for low-mid develop areas. METHODS The PoC diagnostic process combines a simple paper-based RNA extraction method housed within a 3D-printed plastic device with a colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay. Nasopharyngeal/oropharyngeal swabs (NOS) and saliva samples were tested between 2020 and 2021, with the assistance of Santa Catarina’s State Health Secretary, Brazil. FINDINGS The developed diagnostic protocol showed a limit of detection of 9,900 copies and an overall diagnostic specificity of 98% for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from 1,348 clinical analysed samples. The diagnostic sensitivity was 95% for NOS samples, 85% for early morning saliva, and 69% for indiscriminate saliva. MAIN CONCLUSIONS In conclusion, the developed device successfully extracted SARS-CoV-2 viral RNA from swabs and saliva clinical samples. When combined with colorimetric RT-LAMP, it provides results within 45 min using minimal resources, thus delivering a diagnostic kit protocol that is applicable in large-scale sampling.

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BACKGROUND Kissing bugs are the vectors of Trypanosoma cruzi, the etiological agent of Chagas disease (CD). Despite their epidemiological relevance, kissing bug species are under sampled in terms of their diversity and it is unclear what biases exist in available kissing bug data. Under climate change, range maps for kissing bugs may become less accurate as species shift their ranges to track climatic tolerance. OBJECTIVES Quantify inventory completeness in available kissing bug data. Assess how well range maps are at conveying information about current distributions and potential future distributions subject to shift under climate change. Intersect forecasted changes in kissing bug distributions with contemporary sampling gaps to identify regions for future sampling of the group. Identify whether a phylogenetic signal is present in expert range knowledge as more closely related species may be similarly well or lesser understood. METHODS We used species distribution models (SDM), specifically constructed from Bayesian additive regression trees, with Bioclim variables, to forecast kissing bug distributions into 2100 and intersect these with current sampling gaps to identify priority regions for sampling. Expert range maps were assessed by the agreement between the expert map and SDM generated occurrence probability. We used classical hypothesis testing methods as well as tests of phylogenetic signal to meet our objectives. FINDINGS Expert range maps vary in their quality of depicting current kissing bug distributions. Most expert range maps decline in their ability to convey information about kissing bug occurrence over time, especially in under sampled areas. We found limited evidence for a phylogenetic signal in expert range map performance. MAIN CONCLUSIONS Expert range maps are not a perfect account of species distributions and may degrade in their ability to accurately convey distribution knowledge under future climates. We identify regions where future sampling of kissing bugs will be crucial for completing biodiversity inventories.

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BACKGROUND The human immunodeficiency virus 1 (HIV-1) infections in Brazil are predominantly caused by two subtypes, B and C. OBJECTIVES Here we present the characterisation of a novel HIV-1 recombinant form, indicating a new Brazilian CRF_BC, named CRF146_BC. METHODS RDP, JphMM and Simplot recombination tools were used to evaluate the mosaic pattern. FINDINGS In this work, we identified three HIV-1 nucleotide sequences previously classified as unique recombinant forms (URFs), plus one new partial genome sharing the same BC recombination pattern. The mosaic genome is almost entirely represented by the subtype C sequence, with a small subtype B recombination region in the pol gene, at the Integrase level. The phylogenetic analyses strongly indicate a common origin between the strains, which were isolated in Rio Grande do Sul, Rio de Janeiro and Bahia states. MAIN CONCLUSIONS Thus, the new HIV-1 CRF146_BC is circulating in three different Brazilian regions: South, Southeast and Northeast.

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BACKGROUND Anopheles darlingi is the most efficient vector of malaria parasites in the Neotropics. Nevertheless, the specificities of its larval habitats are still poorly known. OBJECTIVES Characterize permanent larval habitats, and population dynamics of An. darlingi and other potential vectors in relation to climate, physicochemical variables, insect fauna and malaria cases. METHODS A 14-month longitudinal study was conducted in Porto Velho, Rondônia, western Brazilian Amazon. Monthly, 21 permanent water bodies were sampled. Immature anophelines and associated fauna were collected, physicochemical characteristics, and climate variables were recorded and analyzed. FINDINGS Five types of habitats were identified: lagoon, stream, stream combined with lagoon, stream combined with dam, and fishpond. A total of 60,927 anophelines were collected. The most abundant species in all habitats were Anopheles braziliensis and An. darlingi. The highest density was found in the lagoon, while streams had the highest species richness. Abundance was higher during the transition period wet-dry season. There was a lag of respectively four and five months between the peak of rainfall and the Madeira River level and the highest abundance of An. darlingi larvae, which were positively correlated with habitats partially shaded, pH close to neutrality, increase dissolved oxygen and sulphates. MAIN CONCLUSIONS The present study provides data on key factors defining permanent larval habitats for the surveillance of An. darlingi and other potential vectors as well as a log-linear Negative Binomial model based on immature mosquito abundance and climate variables to predict the increase in the number of malaria cases.

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BACKGROUND Echinococcosis and schistosomiasis, caused by parasitic worms, pose significant threats to millions of people in the world. Rapid and effective pathogen detection and epidemic control by public health authorities are urgently needed. OBJECTIVES In this study, we aimed to develop rapid on-site detection method to detect echinococcosis and schistosomiasis. METHODS Recombinase polymerase amplification (RPA) was utilised to examine its efficacy of detection of echinococcosis and schistosomiasis. FINDINGS The detection probes for RPA were created through comparing parasitic genomes from international genomic data and the sequences generated by our group. We established an optimised RPA on-site testing platform, which significantly reduces the detection time (less than 30 min) and simplifies the operation (free of expensive equipment) as compared to traditional polymerase chain reaction (PCR) method. MAIN CONCLUSIONS This RPA detection platform in our study for identifying echinococcosis or schistosomiasis pathogens would be greatly applicable for epidemic investigation, border screening, and early clinical diagnosis.

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BACKGROUND The presence of Aedes albopictus in Bolivia has been a subject of controversy, with a lack of concrete documentation. OBJECTIVES This study aimed to provide evidence of Ae. albopictus presence in Bolivia. METHODS Larval habitats were sampled in Rosario del Yata and San Agustín, Guayaramerín Municipality, Beni Department, northern Bolivia. Collected mosquito larvae were reared to the L4 and adult stages for morphological identification, with some specimens sequenced for confirmation. FINDINGS Aedes albopictus was identified in multiple larval habitats within peridomestic areas, such as buckets, canisters, and cut plastic bottles used as flower vases in both localities, confirming its establishment in the area. This represents the first concrete documentation of the species in Bolivia. The collections (larvae and adults) have been deposited in the Medical Entomology Laboratory of the Universidad Mayor de San Simón in Cochabamba, Bolivia, and the Laboratory of Entomology of the Instituto Nacional de Laboratorios de Salud of the Ministry of Health in La Paz, Bolivia. MAIN CONCLUSION Given its role as a vector for arboviruses such as dengue and Chikungunya, Ae. albopictus should be incorporated into the Bolivian National Programme of Vector Control for monitoring.

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BACKGROUND The Golden Syrian hamster (Mesocricetus auratus), Ferrets (Mustela putorius furo), and macaques have been described as useful laboratory animals naturally susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. OBJECTIVES To study the mechanism of lung injury, we describe the histopathological features of SARS-CoV-2 infection in Golden Syrian hamsters inoculated intranasally with the A.2 Brazilian strain. METHODS Hamsters were intranasally inoculated with the A.2 variant and euthanised at 3-, 5-, 10- and 15-days post-inoculation. The physical examination and body weight were recorded daily. Neutralising antibodies and viral RNA load of the respiratory tract were assessed during necropsies. FINDINGS The coronavirus disease 2019 (COVID-19) model presented body weight loss, high levels of respiratory viral RNA load, severe segmentary pneumonitis, and bronchial fistula besides lymphatic trapping and infiltration, like the human SARS-COV-2 pathogenesis. The presence of subepithelial lymphoeosinophilic infiltrate was highlighted in our results; it contributed to the detachment of SARS-CoV-2 nucleocapsid-positive epithelial cells resulting in the infectious cell plugs. MAIN CONCLUSIONS The SARS-CoV-2 caused segmentary pneumonia and vascular damage. In our comprehension, the infectious cell plugs, as being aspirated from the upper respiratory tract into the terminal bronchial lumen, work as a “Trojan horse”, thus contributing to the dissemination of the SARS-CoV-2 infection into specific regions of the deep lung parenchyma.

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BACKGROUND Corynebacterium auriscanis is a bacterial species frequently isolated from dogs with external otitis or dermatitis and a zoonotic pathogen transmitted by dog bite. It is considered an opportunistic pathogen, but its pathogenicity mechanisms are poorly studied. Comparative genomics can identify virulence and niche factors that could contribute to understanding its lifestyle. OBJECTIVES The objectives of this project was to compare genomes of C. auriscanis to identify genes related to its virulence and lifestyle. METHODS The genome of strain 32 was sequenced using Illumina HiSeq 2500 (Illumina, CA, USA) and assembled using Unicycler. The two other non-redundant genomes from the same species available in GenBank were included in the analysis. All genomes were annotated and checked for taxonomy, assembly quality, mobile elements, CRISPR-Cas systems, and virulence and antimicrobial resistance genes. The virulence genes in the three genomes were compared to the ones from other pathogens commonly isolated with C. auriscanis. FINDINGS The species has 42 virulence factors that can be classified as niche factors, due to the absence of true virulence factors found in primary pathogens. The gene rbpA could confer basal levels of resistance to rifampin. MAIN CONCLUSIONS The absence of true virulence factors in the three genomes suggests C. auriscanis has an opportunistic pathogen lifestyle.

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BACKGROUND Herpesviruses are common co-pathogens in individuals infected with human immunodeficiency virus (HIV). Herpes simplex virus type 1 (HSV1) enhances HIV-1 replication and has evolved mechanisms to evade or disrupt host innate immune responses, including interference with interferon (IFN) signalling pathways. OBJECTIVES The aimed of this work was evaluated whether it HSV1 affects HIV-1 replication through the modulation of the IFN pathway in human macrophages. METHODS Co-infections with HSV1 and HIV-1 were performed in monocyte-derived human macrophages (hMDMs). The production of infectious HIV-1 and HSV-1 was monitored 48 h post-coinfection. Additionally, mRNA and protein expression levels of interferon-stimulated genes (ISGs) were evaluated in both HIV-1-HSV1 coinfections and HSV1 mono-infections. FINDINGS The HSV1 coinfection increasing the HIV-1 productive replication, following of downregulation of interferon-alpha (IFN-α) and interferon-induced transmembrane protein 3 (IFITM3) expression in hMDMs. Acyclovir treatment, in a dose-dependent manner, mitigated HSV1’s ability to decrease IFITM3 levels. Knockdown of HSV1 Us11 and virion host shutoff (VHS) genes reactivated the IFN pathway, evidenced by restored IFITM3 expression and activation of eIF2-α and PKR. This knockdown also returned HIV-1 replication to baseline levels. MAIN CONCLUSIONS Our data suggested that HSV1 increases HIV-1 replication in human macrophages is associated with the downregulating interferon pathways and ISGs expression.

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BACKGROUND Undifferentiated acute febrile illness (UAFI) cause by several pathogens poses a diagnostic challenge due to the similarity on the clinical manifestations across these diseases. Precise pathogen detection is vital for appropriate medical intervention, early treatment, and timely outbreak alerts regarding emerging pathogens. In tropical regions, UAFI is predominantly linked to a wide range of viral, bacterial, and parasitic infections. Hence, confirmatory laboratory tests are essential for specific pathogen identification. OBJECTIVES Our primary goal was to develop two real-time multiplex polymerase chain reaction (PCR) assays for simultaneous detection of six neglected pathogens (Leptospira spp., Rickettsia spp., Borrelia spp., Anaplasma spp., Brucella spp., and Bartonella spp.), known for causing UAFI in tropical regions. METHODS We rigorously assessed assays parameters including: linearity, efficiency, sensitivity, and reproducibility in both singleplex and multiplex formats. FINDINGS Our results demonstrated that these multiplex assays are reliable and sensitive methods. They showed good performance with low intra- and inter-variability (< 10%) and consistently high efficiencies (> 90%). MAIN CONCLUSIONS These assays offer the alternative of streamlining work, reducing processing costs, and minimizing sample volume use. In conclusion, we present two dependable, user-friendly, rapid, and cost-effective methods for simultaneously detecting six neglected bacteria, as a significant laboratory tool in resource-limited tropical settings.

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BACKGROUND Rhodnius neivai, a kissing bug found in the dry regions of Colombia and Venezuela, has limited documented occurrences. While it is not deemed a significant vector for Chagas disease, distributional and ecological studies are essential in monitoring species domiciliation and shedding light on the evolutionary aspects of the Rhodniini tribe. OBJECTIVES The study aims to provide a detailed revision of R. neivai distribution and evaluate general spatial data quality for ecological niche modelling (ENM). It will also provide the first published ENM for the species, which may aid species sampling and future analytical improvement. METHODS Registers and other spatial information were gathered by literature review; data georeferencing, preliminary geographical investigations, and model editing were conducted in GIS platforms; ENMs were built using R and explored the uncertainty of parameters and algorithms. FINDINGS Twenty four unique sites were identified, unearthing 17 previously uncovered records. Data lacks robust spatial and temporal precision; however, ENMs had acceptable validations. The models present some variation in suitability but with objective areas for sampling effort. MAIN CONCLUSIONS Rhodnius neivai distribution is better explained by conditions that characterise dry ecotypes, but further sampling is essential to improve modelling and advance with ecological and evolutive matters.

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BACKGROUND Trypanosoma rangeli is a haemoflagellate parasite that infects triatomine bugs and mammals in South and Central America. Trypanosoma cruzi, the etiological agent of Chagas disease, has a partially overlapping geographical distribution with T. rangeli, that leads to mixed human infections and cross-reactivity in immunodiagnosis. Although T. rangeli can be detected long after mammal infection, its multiplicative forms have not yet been described. OBJECTIVES To enhance our understanding of T. rangeli development in mammals, this study assessed various infection parameters in mice over time. METHODS The parasitaemia, body temperature, and weight of Swiss Webster mice were monitored over 120 days after exposing them to the bites of Rhodnius prolixus nymphs containing metacyclic trypomastigotes in their salivary glands. On day 132 post-infection, spleens and mesenteric lymph nodes were analysed for T. rangeli DNA using polymerase chain reaction (PCR) and quantitative PCR (qPCR). FINDINGS Parasites were detectable in mice blood since day 2 post-infection, detection peaking on day 5 and becoming undetectable by day 120. PCR and qPCR detected T. rangeli DNA in the spleens and mesenteric lymph nodes of infected mice. Infected mice showed higher body temperatures and a slower weight gain over time compared to controls. MAIN CONCLUSIONS The study confirmed that T. rangeli establishes a persistent infection in mice, detectable in lymphoid organs long after parasites had disappeared from blood. In addition, infected mice exhibited physiological changes, suggesting potential subclinical effects. These findings highlight the need for further studies on the immune response and potential impacts of T. rangeli infection in mammalian hosts.

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BACKGROUND Although blood transfusion is an essential therapeutic procedure, it can present risks, including transmitting infectious diseases, such as malaria. In Acre, the thick blood smear microscopic examination (TBS) is used to screen infected malaria blood donors. However, TBS has low sensitivity for detecting Plasmodium in situations of low parasitaemia, such as those presented by asymptomatic clinically healthy individuals. OBJECTIVES To investigate the pertinence of using polymerase chain reaction (PCR) to detect malarial infection for screening blood donors in Cruzeiro do Sul, Acre, an endemic high-risk malaria area in the Legal Amazon. METHODS A cross-sectional study was conducted among individuals eligible and ineligible to be blood donors, according to clinical and epidemiological criteria. Besides the mandatory screening of HCV, HBV, and HIV tests, malaria PCR and TBS were also carried out on all blood donor candidates who attended the Cruzeiro do Sul Blood Centre from July to September 2022. FINDINGS Of the 230 participants, 209 (91%) were eligible for blood donation by clinical-epidemiological screening. Surprisingly, no blood donor candidate reported a history of malaria. All TBS microscopic tests were negative at the time of recruitment. However, samples from four blood donor candidates (two eligible by clinical and epidemiological malaria criteria and two ineligible by hypertension and recent tattoo) were positive by Plasmodium and P. vivax molecular tests. MAIN CONCLUSIONS Malaria molecular techniques for screening blood donors should be introduced in the Brazilian Blood Centres to maximise recipient safety. Furthermore, selecting zero-risk donors could pave the way to build a transmissible malaria-free environment in the blood bank context in the near future.

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BACKGROUND Strigomonas culicis is a monoxenic trypanosomatid parasite of insects that naturally contains an endosymbiotic bacterium. The aposymbiotic strain can be obtained, making this strain a model for evolutive research about organelle origins. In addition, S. culicis contains homologues of virulence factors of pathogenic trypanosomatids, which functions are waiting for further analysis. In this sense, the publication of S. culicis proteome makes feasible additional investigations regarding the differential expression of peptidases from the wild-type (WT) and the aposymbiotic (APO) strains. OBJECTIVES Here, we analysed two proteomic data from S. culicis WT and APO strains screening for peptidases differentially expressed and assessed the differential expression of cysteine and metallopeptidases. METHODS A comparative proteomic screening between WT and APO identified 43 modulated peptidases. FINDINGS Cysteine and metallopeptidases, such as calpains and GP63, were the major classes, highlighting their significance. GP63 exhibited an increased proteolysis in a specific metallopeptidase substrate, an up-modulation gene expression in RT-PCR, and a higher protein identification by flow cytometry in the aposymbiotic strain. Notwithstanding, the wild-type strain showed enhanced cysteine peptidase activity. MAIN CONCLUSION Our study highlighted the endosymbiont influence in S. culicis peptidase expression, with GP63 expression and activity raised in the aposymbiotic strain, whereas cysteine peptidase levels were reduced.

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BACKGROUND Bat-borne hantaviruses have been identified worldwide but little is known about neotropical bats in the megadiverse biomes of the American continent. Although serological evidence has hinted at hantavirus circulation in Brazil, the scarce number of genomic detection represents a gap to understand viral diversity, prevalence, and ecology of bat-borne hantaviruses. OBJECTIVE We aim to investigate and evaluate the presence and prevalence of bat-borne hantavirus in the Brazilian Atlantic Forest. METHODS Here in, 97 lung and kidney tissue samples from bats captured in the Brazilian Atlantic Rainforest were submitted to hantavirus-specific nested reverse transcription-polymerase chain reaction (RT-PCR) targeted the hantaviral L segment and metagenomic analysis. FINDINGS Hantavirus RNA was detected in five tissue fragments of 20 Seba’s short-tailed bats (Carollia perspicillata). Phylogenetic analysis, based on partial L-segment sequence using maximum likelihood method, demonstrated that the identified virus formed a monophyletic clade and a highly divergent bat-borne lineage comprising other recent strains found in the genus Carollia from South America. MAIN CONCLUSIONS Our findings suggest the presence of a novel bat-borne hantavirus in Brazil, tentatively named Mamanguape virus (MGPV). Additional genomic data will help to extend our knowledge about the classification of MGPV within the Hantaviridae family and the evolution origins of new world bat-borne hantaviruses.