Development of a New Multispecies Protein A-Based ELISA for Serodiagnosis of Hepatitis E Infection with Validation in Domestic Swine.

Hepatitis E virus (HEV) infects roughly 20 million people worldwide, causing self-limiting acute hepatic disease that can evolve into a chronic course. HEV-3, HEV-4, and HEV-7 genotypes are zoonotic and transmitted to humans by consuming raw or undercooked meat. Here, we developed an indirect ELISA based on the recombinant HEV-3 capsid and performed a seroprevalence study on domestic swine in northeastern Brazil. Our in-house ELISA was initially validated using a subset of 79 sera characterized by concordant results for two distinct commercial ELISA kits. Our ELISA exhibited excellent sensitivity (94%) and specificity (100%), with an area under the curve of 0.99 Further testing, including 212 swine sera, revealed a seroprevalence of 57.5% (95% confidence interval, 50.6-64.3%). Our findings indicate that the novel ELISA test could accurately detect specific anti-HEV antibodies in domestic pigs and should be further validated in humans and other mammals.

Emergence of Oropouche fever in Latin America: a narrative review.

Since its discovery in 1955, the incidence and geographical spread of reported Oropouche virus (OROV) infections have increased. Oropouche fever has been suggested to be one of the most important vector-borne diseases in Latin America. However, both literature on OROV and genomic sequence availability are scarce, with few contributing laboratories worldwide. Three reassortant OROV glycoprotein gene variants termed Iquitos, Madre de Dios, and Perdões virus have been described from humans and non-human primates. OROV predominantly causes acute febrile illness, but severe neurological disease such as meningoencephalitis can occur. Due to unspecific symptoms, laboratory diagnostics are crucial. Several laboratory tests have been developed but robust commercial tests are hardly available. Although OROV is mainly transmitted by biting midges, it has also been detected in several mosquito species and a wide range of vertebrate hosts, which likely facilitates its widespread emergence. However, potential non-human vertebrate reservoirs have not been systematically studied. Robust animal models to investigate pathogenesis and immune responses are not available. Epidemiology, pathogenesis, transmission cycle, cross-protection from infections with OROV reassortants, and the natural history of infection remain unclear. This Review identifies Oropouche fever as a neglected disease and offers recommendations to address existing knowledge gaps, enable risk assessments, and ensure effective public health responses.

Epidemiological, virological and clinical characterization of a Dengue/Zika outbreak in the Caribbean region of Costa Rica 2017-2018.

The increase in incidence and geographical expansion of viruses transmitted by the Aedes mosquitoes, such as dengue (DENV) and zika (ZIKV) in the Americas, represents a burden for healthcare systems in tropical and subtropical regions. These and other under-detected arboviruses co-circulate in Costa Rica, adding additional complexity to their management due to their shared epidemiological behavior and similarity of symptoms in early stages. Since diagnostics of febrile illness is mostly based on clinical symptoms alone, we gathered acute-phase serum and urine from 399 samples of acute dengue-like cases from two healthcare facilities of Costa Rica, during an outbreak of arboviruses from July 2017 to May 2018, and tested them using molecular and serological methods. The analyses showed that of the clinically presumptive arbovirus cases that were reported, only 39.4% (n=153) of the samples were confirmed positive by RT-PCR to be DENV (DENV (10.3%), CHIKV (0.2%), ZIKV (27.3%), or mixed infections (1.5%). RT-PCR for other alphaviruses and flaviviruses, and PCR for Leptospira sp were negative. Furthermore, to assess flavivirus positivity in post-acute patients, the negative sera were tested against Dengue-IgM. 20% of sera were found positive, confounding even more the definitive number of cases, and emphasizing the need of several distinct diagnostic tools for accurate diagnostics. Molecular characterization of the prM and E genes from isolated viruses revealed that the American/Asian genotype of DENV-2 and the Asian lineage of ZIKV were circulating during this outbreak. Two different clades of DENV-2 American/Asian genotype were identified to co-circulate in the same region and a difference in the platelet and leukocyte count was noted between people infected with each clade, suggesting a putative distinct virulence. Our study sheds light on the necessity for healthcare strategies in managing arbovirus outbreaks, emphasizing the importance of comprehensive molecular and serological diagnostic approaches, as well as molecular characterization. This approach aids in enhancing our understanding of the clinical and epidemiological aspects of arboviral diseases during outbreaks. Our research highlights the need to strengthen training programs for health professionals and the need to increase research-based on laboratory evidence for diagnostic accuracy, guidance, development and implementation of public health interventions and epidemiological surveillance.

Assessing vulnerability for future Zika virus outbreaks using seroprevalence data and environmental suitability maps.

The 2015-17 Zika virus (ZIKV) epidemic in the Americas subsided faster than expected and evolving population immunity was postulated to be the main reason. Herd immunization is suggested to occur around 60-70% seroprevalence, depending on demographic density and climate suitability. However, herd immunity was only documented for a few cities in South America, meaning a substantial portion of the population might still be vulnerable to a future Zika virus outbreak. The aim of our study was to determine the vulnerability of populations to ZIKV by comparing the environmental suitability of ZIKV transmission to the observed seroprevalence, based on published studies. Using a systematic search, we collected seroprevalence and geospatial data for 119 unique locations from 37 studies. Extracting the environmental suitability at each location and converting to a hypothetical expected seroprevalence, we were able to determine the discrepancy between observed and expected. This discrepancy is an indicator of vulnerability and divided into three categories: high risk, low risk, and very low risk. The vulnerability was used to evaluate the level of risk that each location still has for a ZIKV outbreak to occur. Of the 119 unique locations, 69 locations (58%) fell within the high risk category, 47 locations (39%) fell within the low risk category, and 3 locations (3%) fell within the very low risk category. The considerable heterogeneity between environmental suitability and seroprevalence potentially leaves a large population vulnerable to future infection. Vulnerability seems to be especially pronounced at the fringes of the environmental suitability for ZIKV (e.g. Sao Paulo, Brazil). The discrepancies between observed and expected seroprevalence raise the question: "why did the ZIKV epidemic stop with large populations unaffected?". This lack of understanding also highlights that future ZIKV outbreaks currently cannot be predicted with confidence.

Self-prescribed Ivermectin use is associated with a lower rate of seroconversion in health care workers diagnosed with COVID, in a dose-dependent response

ABSTRACT Background: Over-the-counter use of ivermectin amongst other drugs as SARS-CoV-2 treatment has been increasingly common, despite the lack of evidence on its clinical efficacy. Objective: To evaluate the effect of ivermectin use on production of antibodies against SARS-CoV-2 in health care workers (HCW) diagnosed with COVID-19 and of Th1/Th2 cytokines by stimulated peripheral blood mononuclear cells of the same cohort (PBMCs). Methods: This cross-sectional study evaluated seroconversion and neutralizing antibodies production in HCW at Complexo Hospitalar Universitário Professor Edgard Santos (Salvador, Brazil), diagnosed with COVID-19 from May to July, 2020, as well as in vitro production of antibody against SARS-CoV-2 and Th1/Th2 cytokines. Analyses were performed between December 2020 and February 2021. Participants were stratified according to the use of ivermectin (≤ 1 dose vs. multiple doses) for treatment of COVID-19. Results: 45 HCW were included (62% women). Mean age was 39 years, and disease severity was similar across groups. Neutralizing antibodies were detected less frequently in multiple doses (70%) vs. ≤ 1 dose (97%) groups, p = 0.02). PBMCs of patients in multiple doses group also were less likely to produce antibodies against SARS-CoV-2 following in vitro stimulation with purified spike protein in comparison with patients in ≤ 1 dose group (p < 0.001). PBMC's production of Th1/Th2 cytokines levels was similar across groups. Abdominal pain (15% vs 46%, p = 0.04), diarrhea (21% vs. 55%, p = 0.05) and taste perversion (0% vs. 18%, p = 0.05) were more frequently reported by participants that used multiple doses of ivermectin. Conclusions: Although there was no evidence for differential disease severity upon ivermectin use for treatment of COVID-19 it was associated with more gastro-intestinal side-effects and impairment of anti-SARS-CoV2 antibodies production, in a dose dependent manner. This potentially impacts the effectiveness of immune response and the risk of reinfection and warrants additional studies for clarifying the mechanisms and consequences of such immunomodulatory effects.

Expansão da circulação do vírus Zika da África à América, 1947-2018: revisão da literatura / Expansión de la circulación del virus Zika de África a América, 1947-2018: una revisión de literatura / Expansion of Zika virus circulation from Africa to the Americas, 1947-2018: a literature review

Objetivo: descrever as expansões temporal e geográfica da circulação do vírus Zika (ZIKV) em países e territórios, desde seu isolamento até 2018. Métodos: revisão não sistemática da literatura do período entre 1947 e 2018, utilizando a base MEDLINE e estimativas da Organização Mundial da Saúde. Resultados: desde seu isolamento em 1947, a circulação do ZIKV expandiu-se pela África, Ásia e Pacífico, até chegar à América em 2013, causando manifestações clínicas graves; as maiores soroprevalências foram registradas na ilha de Yap (74%) e no Brasil (63%); mutações genéticas, a ausência de imunidade e a alta susceptibilidade dos vetores podem ter influenciado sua transmissibilidade e ajudam a explicar a magnitude de sua expansão. Conclusão: a expansão da circulação do ZIKV nas Américas foi a mais ampla já registrada, possivelmente resultado de características populacionais e geográficas dos locais por onde o vírus circulou.

Objetivo: Describir las expansiones temporal y geográfica de la circulación del virus Zika en países y territorios, desde su aislamiento hasta 2018. Métodos: Revisión no sistemática de la literatura del período comprendido entre 1947 y 2018 utilizando la base MEDLINE y estimaciones de la Organización Mundial de la Salud. Resultados: Desde su aislamiento en 1947 la circulación del virus Zika se expandió por África, Asia y el Pacífico hasta llegar a América en 2013, causando manifestaciones clínicas graves. Las mayores seroprevalencias se registraron en la isla Yap (74%) y en Brasil (63%). Mutaciones genéticas, ausencia de inmunidad y alta susceptibilidad de los vectores pueden haber influenciado su transmisibilidad y ayudan a explicar la magnitud de su expansión. Conclusión: La expansión de la circulación del virus Zika en las Américas fue la más amplia ya registrada, posiblemente como resultado de características poblacionales y geográficas de los lugares por donde el virus circuló.

Objective: to describe the temporal and geographical expansion of Zika virus (ZIKV) circulation in countries and territories, from the time it was first isolated until 2018. Methods: This was a non-systematic literature review covering the period from 1947 to 2018 using the MEDLINE database and World Health Organization estimates. Results: Since its isolation in 1947, ZIKV circulation spread through Africa, Asia and the Pacific before reaching the Americas in 2013, causing serious clinical manifestations; the highest seroprevalence rates were recorded in Yap (74%) and in Brazil (63%); genetic mutations, absence of immunity and high vector susceptibility may have influenced ZIKV transmissibility and help to explain the magnitude of its expansion. Conclusion: The spread of ZIKV circulation in the Americas was the most extensive recorded thus far, possibly as a result of population and geographical characteristics of the sites where the virus circulated.

Low seroprevalence of Zika virus in Cameroonian blood donors

Abstract A Zika virus seroepidemiology study was performed in 1084 blood donors collected from August to October 2015 in six sites of Cameroon representing a large panel of eco-environments. Samples were tested using an anti-NS1 IgG ELISA detection kit and positives were further confirmed by seroneutralization. The observed global seroprevalence was low (around 5%, peaking at 10% and 7.7% in Douala and Bertoua, respectively) with risk factors associated with seropositivity pointing to the existence of a local (peri-)sylvatic cycle of transmission. These results call attention to the potential introduction and subsequent spread in African urban areas of Asian genotype Zika virus currently circulating in the Americas and adapted to transmission by peri-domestic mosquitoes. They should leverage reinforced surveillance efforts in Africa.

Theories about evolutionary origins of human hepatitis B virus in primates and humans

Introduction: The human hepatitis B virus causes acute and chronic hepatitis and is considered one of the most serious human health issues by the World Health Organization, causing thousands of deaths per year. There are similar viruses belonging to the Hepadnaviridae family that infect non-human primates and other mammals as well as some birds. The majority of non-human primate virus isolates were phylogenetically close to the human hepatitis B virus, but like the human genotypes, the origins of these viruses remain controversial. However, there is a possibility that human hepatitis B virus originated in primates. Knowing whether these viruses might be common to humans and primates is crucial in order to reduce the risk to humans. Objective: To review the existing knowledge about the evolutionary origins of viruses of the Hepadnaviridae family in primates. Methods: This review was done by reading several articles that provide information about the Hepadnaviridae virus family in non-human primates and humans and the possible origins and evolution of these viruses. Results: The evolutionary origin of viruses of the Hepadnaviridae family in primates has been dated back to several thousand years; however, recent analyses of genomic fossils of avihepadnaviruses integrated into the genomes of several avian species have suggested a much older origin of this genus. Conclusion: Some hypotheses about the evolutionary origins of human hepatitis B virus have been debated since the '90s. One theory suggested a New World origin because of the phylogenetic co-segregation between some New World human hepatitis B virus genotypes F and H and woolly B virus in basal sister-relationship to the Old monkey human hepatitis World non-human primates and human hepatitis B virus variants. Another theory suggests an Old World origin of human hepatitis B virus, and that it would have been spread following prehistoric human migrations over 100,000 years ...

In vitro detection of hepatitis C virus in platelets from uninfected individuals exposed to the virus

Introduction Despite hepatocytes being the target cells of hepatitis C virus (HCV), viral ribonucleic acid RNA has been detected in other cells, including platelets, which have been described as carriers of the virus in the circulation of infected patients. Platelets do not express cluster differentiation 81 CD81, the main receptor for the virus in hepatocytes, although this receptor protein has been found in megakaryocytes. Still, it is not clear if HCV interacts with platelets directly or if this interaction is a consequence of its association with megakaryocytes. The aim of this study was to evaluate the interaction of HCV with platelets from non-infected individuals, after in vitro exposure to the virus. Methods Platelets obtained from 50 blood donors not infected by HCV were incubated in vitro at 37°C for 48h with serum containing 100,000IU∕mL of genotype 1 HCV. After incubation, RNA extracted from the platelets was assayed for the presence of HCV by reverse transcription – polymerase chain reaction RT-PCR. Results After incubation in the presence of virus, all samples of platelets showed HCV RNA. Conclusions The results demonstrate that, in vitro, the virus interacts with platelets despite the absence of the receptor CD81, suggesting that other molecules could be involved in this association. .