Memorias Do Instituto Oswaldo Cruz[JOURNAL]
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200 papers
Detection of immunogenic protein components in excretion/secretion products of Acanthamoeba T5 using polyclonal antibodies.
Retana-Moreira L, Abrahams-Sandí E, Ruiz-Campos M … +5 more , Alvarado-Ocampo J, Castro J, Lorenzo-Morales J, Sáenz-Arce G, Osuna A
Mem Inst Oswaldo Cruz · 2025 · PMID 40498906 · Full text
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 demons...
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.
Parasitological cure and clinical benefits of benznidazole treatment in patients from the Jequitinhonha Valley, MG, Brazil, with recent chronic infection by Trypanosoma cruzi II.
de Lana M, Suave LT, Assis JCSO … +7 more , de Assis GFM, Milagre MM, Alessio GD, Salgado RA, Martins-Filho OA, Albajar-Viñas P, Torres RM
Mem Inst Oswaldo Cruz · 2025 · PMID 40465897 · Full text
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...
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.
Use of Brazilian flora as the main source of new antimalarials: a systematic review.
Porto ARA, Duval IB, do Amaral LVB … +11 more , Oliveira IDS, de Siqueira JGA, de Albuquerque BA, Rocha MAG, Lemos GGM, Cardozo ME, Rihs JBDR, Fujiwara RT, de Oliveira ALG, Brito RMM, Bueno LL
Mem Inst Oswaldo Cruz · 2025 · PMID 40465896 · Full text
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...
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.
Miltefosine analogues with comparable antileishmanial activity and significantly reduced macrophage cytotoxicity.
Alonso L, Lemes LFN, Magoulas GE … +7 more , Costa BL, Gomes RS, Dorta ML, Bolognesi ML, Romeiro LAS, Calogeropoulou T, Alonso A
Mem Inst Oswaldo Cruz · 2025 · PMID 40435100 · Full text
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 altern...
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.
Anti-PGL-I seropositivity and development of leprosy in contacts: a comprehensive analysis of sociodemographic determinants, genetic susceptibility, and exposure characteristics to Mycobacterium leprae.
Niitsuma ENA, Bueno IC, Fernandes GDR … +2 more , Abreu MNS, Lana FCF
Mem Inst Oswaldo Cruz · 2025 · PMID 40435099 · Full text
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...
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.
Single nucleotide polymorphisms in IFN-gamma, TNF-alpha, IL-6, IL-10, and TGF-beta in pulmonary and extrapulmonary tuberculosis in the State of Ceará, northeastern Brazil.
Luiz RDSS, Campelo TA, Silva CS … +5 more , Nogueira LL, Sancho SO, da Silva AKA, Frota CC, Carvalho-Costa FA
Mem Inst Oswaldo Cruz · 2025 · PMID 40396869 · Full text
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...
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.
Lessons from the "Urbanorum spp." controversy: a supposed parasite and the need for scientific rigor and quality research in Latin America.
Echeverry DF, Sarria MA, Palma GI
Mem Inst Oswaldo Cruz · 2025 · PMID 40332188 · Full text
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-parasi...
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.
Concomitant occurrence of chronic Schistosoma mansoni infection and chronic colitis restore immune imbalance and dysbiosis leading to protection against intestinal colitis and schistosome egg-induced intestinal fibrosis.
Lin YR, Lam LY, Chang CM … +1 more , Lam HYP
Mem Inst Oswaldo Cruz · 2025 · PMID 40332187 · Full text
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,...
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.
Impact of dengue virus infection on the cytoadherence of Plasmodium vivax-infected erythrocytes.
da Cruz MGS, Dos Santos RO, Sousa MGT … +4 more , Costa FT, de Lacerda MVG, Lopes SCP, Lalwani P
Mem Inst Oswaldo Cruz · 2025 · PMID 40298772 · Full text
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,...
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.
Acute Chagas disease in Amazonia, western Pará: perspectives from medical assistance to genetic elucidation.
Esper HR, de Freitas VLT, Assy JGPL … +6 more , Berreta OCP, Brandão ADS, Nakanishi EYS, Fonseca CA, França FOS, Lopes MH
Mem Inst Oswaldo Cruz · 2025 · PMID 40298771 · Full text
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 epide...
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.
Pandemic ST131 Escherichia coli presenting the UPEC/EAEC and ExPEC/EAEC hybrid pathotypes recovered from extraintestinal infections in a clinical setting of the Brazilian Amazon region.
Bighi NM, Fonseca ÉL, Freitas FS … +2 more , Morgado SM, Vicente ACP
Mem Inst Oswaldo Cruz · 2025 · PMID 40243867 · Full text
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...
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.
Agglomerative hierarchical cluster analysis and temporal trend of leprosy indicators in Brazilian states, 2012-2022.
de Freitas LRS, Nóbrega FF
Mem Inst Oswaldo Cruz · 2025 · PMID 40243866 · Full text
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 fo...
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.
Leukocyte telomere length and telomerase activity in Long COVID patients from Rio de Janeiro, Brazil.
Dos Reis GG, Silvestre RT, Alves G … +9 more , Delmonico L, Chantre-Justino M, Moreira ADS, Müller BLA, do Nascimento CR, da Silva DLP, Dos Santos LS, Mattos-Guaraldi AL, Ornellas MH
Mem Inst Oswaldo Cruz · 2025 · PMID 40243865 · Full text
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 symptom...
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.
Prognostic value of soluble TNF receptors in Chagas cardiomyopathy: observational study.
Ávila MR, de Souza DM, de Oliveira LFF … +12 more , Figueiredo PHS, Silva LMC, Silva WT, Mediano MFF, Teixeira LADC, de Oliveira LFL, de Alcantara MA, Faria SCC, Arrieiro AN, Mendonça VA, Lacerda ACR, Costa HS
Mem Inst Oswaldo Cruz · 2025 · PMID 40197936 · Full text
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 fu...
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.
Aedes aegypti reproductive aspects: constant light significantly affects the embryonic development.
Farnesi LC, Alves GDSO, Araripe LO … +1 more , Bruno RV
Mem Inst Oswaldo Cruz · 2025 · PMID 40172429 · Full text
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 ma...
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.
First record of natural infection by Angiostrongylus cantonensis (Nematoda: Metastrongyloidea) in Tanychlamys indica (Godwin-Austen, 1883) in the city of São Paulo, Brazil.
da Mota DJG, Rocco SC, Luca LRD … +6 more , Dos Santos JA, Werneck EFP, Baccin AO, Gava R, Pereira-Chioccola VL, de Melo LCV
Mem Inst Oswaldo Cruz · 2025 · PMID 40172428 · Full text
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...
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.
Silent dissemination of HTLV-1: evidence of intrafamilial transmission in a Brazilian reference centre.
Alves DL, Silva RML, Santos JPMF … +8 more , Amorim RL, Santana CS, Andrade FO, Ribeiro SO, Costa GCS, Santos LA, Costa DT, Barreto FK
Mem Inst Oswaldo Cruz · 2025 · PMID 40172427 · Full text
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...
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.
Heterochromatin protein 1 (HP1) of Schistosoma mansoni: non-canonical chromatin landscape and oviposition effects.
da Trindade NS, Valentini MB, Rognon A … +5 more , Mendes TMF, Gomes MS, Allegretti SM, Grunau C, Cabral FJ
Mem Inst Oswaldo Cruz · 2025 · PMID 40172426 · Full text
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...
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.
Mapping special areas of the Brazilian National Malaria Control Program in the Amazon region: a territorial-based approach to surveillance.
Albuquerque HG, Santos GBG, Siqueira ASP … +7 more , Coelho RR, Dos Santos JPC, Praça HLF, Peiter PC, Pereira LHV, Oliveira-Ferreira J, Mutis MCS
Mem Inst Oswaldo Cruz · 2025 · PMID 40172425 · Full text
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. OBJECTI...
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.
Understanding the genetic complexity of Leishmania infantum in the Americas: a focus on 3'NT/NU gene deletion.
Florêncio M, Cupolillo E, Boité MC
Mem Inst Oswaldo Cruz · 2025 · PMID 40136219 · Full text
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 Leishman...
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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