Neutralizing antibodies (nAbs) are a critical part of coronavirus disease 2019 (COVID-19) research as they are used to gain insight into the immune response to severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infections. Among the technologies available for generating nAbs, DNA-based immunization methods are an alternative to conventional protocols. In this pilot study, we investigated whether DNA-based immunization by needle injection in rabbits was a viable approach to produce a functional antibody response.
View Article and Find Full Text PDFParasit Vectors
May 2022
Several studies have described the effects of human tumor necrosis factor alpha (hTNF-α) on Schistosoma mansoni. hTNF-α affects the worm's development, metabolism, egg-laying, gene expression and protein phosphorylation. The available data on the influence of hTNF-α on egg-laying in S.
View Article and Find Full Text PDFDengue is the most prevalent arboviral disease in humans in tropical and subtropical regions, especially in urban areas, and can cause major epidemics. Although a self-limiting illness, it may sometimes have serious hemorrhagic manifestations, and the outcome of dengue hemorrhagic fever has similar clinical manifestations as in other infections, which could result in death. Therefore, autopsy procedures are required under certain circumstances such as in hemorrhagic fevers, sometimes to confirm or to clarify the diagnosis that may have epidemiological consequences.
View Article and Find Full Text PDFBackground: Brain abnormalities are a concern in COVID-19, so we used minimally invasive autopsy (MIA) to investigate it, consisting of brain 7T MR and CT images and tissue sampling via transethmoidal route with at least three fragments: the first one for reverse transcription polymerase chain reaction (RT-PCR) analysis and the remaining fixed and stained with hematoxylin and eosin. Two mouse monoclonal anti-coronavirus (SARS-CoV-2) antibodies were employed in immunohistochemical (IHC) reactions.
Results: Seven deceased COVID-19 patients underwent MIA with brain MR and CT images, six of them with tissue sampling.
Clin Infect Dis
December 2021
Background: Minimally invasive autopsies, also known as minimally invasive tissue sampling (MITS), have proven to be an alternative to complete diagnostic autopsies (CDAs) in places or situations where this procedure cannot be performed. During the coronavirus disease 2019 (COVID-19) pandemic, CDAs were suspended by March 2020 in Brazil to reduce biohazard. To contribute to the understanding of COVID-19 pathology, we have conducted ultrasound (US)-guided MITS as a strategy.
View Article and Find Full Text PDFBackground: Multi-organ damage is a common feature of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, going beyond the initially observed severe pneumonia. Evidence that the testis is also compromised is growing.
Objective: To describe the pathological findings in testes from fatal cases of COVID-19, including the detection of viral particles and antigens, and inflammatory cell subsets.
From 2016 to 2018, an epidemic wave of yellow fever (YF) occurred in Brazil, affecting a large number of Platyrrhini monkeys. Titi monkeys ( spp.) were severely affected yet pathological characterizations are lacking.
View Article and Find Full Text PDFBackground: COVID-19 in children is usually mild or asymptomatic, but severe and fatal paediatric cases have been described. The pathology of COVID-19 in children is not known; the proposed pathogenesis for severe cases includes immune-mediated mechanisms or the direct effect of SARS-CoV-2 on tissues. We describe the autopsy findings in five cases of paediatric COVID-19 and provide mechanistic insight into the mechanisms involved in the pathogenesis of the disease.
View Article and Find Full Text PDFInt J Parasitol
June 2021
The study aim was to analyze whether microvesicles and exosomes, named extracellular vesicles (EVs), purified from Toxoplasma gondii are able to stimulate the protective immunity of experimental mice when administered, as challenge, a highly virulent strain. EVs excreted from T. gondii tachyzoites (RH strain) were purified by chromatography and used for immunization assays in inbred mouse groups (EV-IM).
View Article and Find Full Text PDFA major outbreak of yellow fever (YF) occurred in Brazil during 2016-2018. Epizootics in New World nonhuman primates are sentinel events for YF virus circulation. However, genus-specific susceptibilities and suitability for YF surveillance remain poorly understood.
View Article and Find Full Text PDF(CeMV; ) is the most significant pathogen of cetaceans worldwide. The novel "multi-host" Guiana dolphin (; GD)-CeMV strain is reported in South American waters and infects Guiana dolphins and southern right whales (). This study aimed to describe the pathologic findings, GD-CeMV viral antigen distribution and detection by RT-PCR (reverse transcriptase polymerase chain reaction), and infectious comorbidities in 29 Guiana dolphins that succumbed during an unusual mass-mortality event in Rio de Janeiro state, Brazil, between November 2017 and March 2018.
View Article and Find Full Text PDFJ Med Primatol
April 2020
Background: Non-human primates (NHPs) are susceptible to dogs' attacks, events that may cause muscle damage along with stress, and could be in some extent compatible with capture myopathy, a syndrome that results in myoglobinuria and renal damage.
Methods: We aimed to evaluate by histopathology pre-existing lesions and subsequent sequelae related to dogs' attacks, acute tubular necrosis (ATN) and myoglobinuria, as well as the usefulness of Pearls Stain and IHC to diagnose it. Histopathology was performed in available organs, and sections of kidney submitted to Prussian blue stain and myoglobin immunohistochemistry.
Aims: The clinical spectrum of yellow fever (YF) ranges from asymptomatic to fulminant hepatitis. During the sylvatic YF epidemic in the metropolitan area of São Paulo, Brazil in 2018, seven orthotopic liver transplantations (OLTs) were performed in our institution to treat fulminant YF hepatitis. Three patients recovered, while four patients died following OLT.
View Article and Find Full Text PDF(CeMV; ) causes epizootic and interepizootic fatalities in odontocetes and mysticetes worldwide. Studies suggest there is different species-specific susceptibility to CeMV infection, with striped dolphins (), bottlenose dolphins (), and Guiana dolphins () ranking among the most susceptible cetacean hosts. The pathogenesis of CeMV infection is not fully resolved.
View Article and Find Full Text PDFCetacean morbillivirus (CeMV) is a major natural cause of morbidity and mortality in cetaceans worldwide and results in epidemic and endemic fatalities. The pathogenesis of CeMV has not been fully elucidated, and questions remain regarding tissue tropism and the mechanisms of immunosuppression. We compared the histopathologic and viral immunohistochemical features in molecularly confirmed CeMV-infected Guiana dolphins (Sotalia guianensis) from the Southwestern Atlantic (Brazil) and striped dolphins (Stenella coeruleoalba) and bottlenose dolphins (Tursiops truncatus) from the Northeast-Central Atlantic (Canary Islands, Spain) and the Western Mediterranean Sea (Italy).
View Article and Find Full Text PDFAmerican cutaneous leishmaniasis (ACL) causes a local inflammatory process, inducing expression of several cytokine genes. Particularly, IFN-γ can predict to disease susceptibility. Based in these data, this study was aimed to investigate the gene expression profile of IFN-γ, IL-10, IL-27, TNF-γ, TGF-β and IL-6 produced in biopsies from ACL patients; and whether the gene expression profile of IFN-γ could determine the disease evolution.
View Article and Find Full Text PDFEctopic thyroid results from a migration defect of the developing gland during embryogenesis causing congenital hypothyroidism. But it has also been detected in asymptomatic individuals. This study aimed to investigate the histopathological, functional, and genetic features of human ectopic thyroids.
View Article and Find Full Text PDFWe report the pathological, immunohistochemical, and molecular features of fatal acute systemic toxoplasmosis in an adult, female, free-living southern muriqui (Brachyteles arachnoides) from São Paulo state, Brazil. PCR-RFLP genotyping analysis identified the #21 genotype of Toxoplasma gondii. This represents the first report of acute toxoplasmosis involving this genotype in humans and animals.
View Article and Find Full Text PDFGene
October 2016
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View Article and Find Full Text PDFBackground: Zika virus is an arthropod-borne virus that is a member of the family Flaviviridae transmitted mainly by mosquitoes of the genus Aedes. Although usually asymptomatic, infection can result in a mild and self-limiting illness characterised by fever, rash, arthralgia, and conjunctivitis. An increase in the number of children born with microcephaly was noted in 2015 in regions of Brazil with high transmission of Zika virus.
View Article and Find Full Text PDFParasitol Res
September 2016
Sand flies are recognized as the major vector of canine visceral leishmaniasis. However, in some areas of Brazil where sand flies do not occur, this disease is found in humans and dogs. There has been speculation that ticks might play a role in transmission of canine visceral leishmaniasis and the DNA of Leishmania spp.
View Article and Find Full Text PDFExp Parasitol
June 2016
This study investigated the genetic features of Toxoplasma gondii isolated directly in autopsies of HIV-infected patients who died with severe disseminated toxoplasmosis. This retrospective analysis was conducted in a cohort of 15 HIV-infected patients with clinical and laboratory data. They had previous cerebral toxoplasmosis at least 6 months before the disseminated toxoplasmosis episode.
View Article and Find Full Text PDFRocky Mountain spotted fever (RMSF), a tick-borne zoonosis caused by Rickettsia rickettsii, is among the deadliest of all infectious diseases. To identify the distribution of various genotypes of R. rickettsii associated with fatal RMSF, we applied molecular typing methods to samples of DNA extracted from formalin-fixed, paraffin-embedded tissue specimens obtained at autopsy from 103 case-patients from seven countries who died of RMSF.
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