Assessing #Ebola virus circulation in the Tshuapa province (#DRC): A #OneHealth #investigation of wildlife and #human interactions

Abstract

The wildlife reservoir and spillover mechanisms of Ebola virus remain elusive despite extensive research efforts in endemic areas. This study employed a One Health approach to examine the virus’ circulation in wildlife and the associated human exposure risks in the Tshuapa province of the Democratic Republic of the Congo. We screened 1049 samples from 919 animals, predominantly small mammals, collected in 2021, and 380 samples from inhabitants of Inkanamongo village, the site of an Ebola virus disease outbreak in 2014. These samples were screened for evidence of current (RNA) or past (IgG antibodies) Ebola virus infections. We also conducted interviews with 167 individuals in the surrounding districts to assess their interactions with wildlife. While no Ebola virus RNA was detected in the wildlife samples, anti-orthoebolavirus IgG antibodies were found in 13 bats and 38 rodents. Among the human participants, 120 individuals had IgG antibodies against at least 1 orthoebolavirus antigen, with 12 showing seropositivity for 2 antigens of the same orthoebolavirus, despite not having a prior Ebola disease diagnosis. Furthermore, the majority of respondents reported frequent visits to the forest to hunt a variety of wild animals, particularly ungulates and rodents, which could account for occasional viral spillovers. The absence of active Ebola virus circulation in wildlife may reflect seasonal patterns in reservoir ecology, as those observed in bats. Similarly, seasonal human activities, such as hunting and foraging, may result in periodic exposure risks. These findings highlight the importance of continuous, multidisciplinary surveillance to monitor changes in seasonal spillover risks.

Author summary

Since its discovery in 1976 in the Democratic Republic of Congo (DRC), Ebola virus (EBOV) has caused more than 20 outbreaks in humans, with fatality rates as high as 90%. While the virus is believed to have an animal origin, naturalist reservoir and the mechanisms of transmission to humans remain poorly understood. Gaining insight into which species may harbour the virus and how transmission occurs is essential to predict and prevent future outbreaks. In this study, we investigate EBOV exposure in wildlife and humans in a region of the DRC with a documented history of outbreaks. Although we did not detect active infection in animals, we found serological evidence of prior exposure in several bat and rodent species, as well as among local residents. Interviews with community members revealed frequent contact with wildlife through hunting and handling, practices that could elevate the risk of animal-to-human transmission. These findings offer new clues about possible EBOV reservoirs and highlight the role of human behaviours in facilitating facilitate spillover events. Our results underscore the need for continued, integrated surveillance to improve understanding of Ebola virus ecology and to help reduce the risk of future Ebola outbreaks in endemic regions.

Source:

Link: https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1013628

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#Neuroinvasive #Oropouche virus in a patient with #HIV from extra-Amazonian #Brazil

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No evidence of immune #exhaustion after repeated #SARS-CoV-2 #vaccination in vulnerable and healthy populations

Abstract Frequent SARS-CoV-2 vaccination in vulnerable populations has raised concerns that this may contribute to T cell exhaustion , which could negatively affect the quality of immune protection. Herein, we examined the impact of repeated SARS-CoV-2 vaccination on T cell phenotypic and functional exhaustion in frail older adults in long-term care (n = 23), individuals on immunosuppressive drugs (n = 10), and healthy adults (n = 43), in Canada . Spike-specific CD4+ and CD8+ T cell levels did not decline in any cohort following repeated SARS-CoV-2 vaccination, nor did the expression of exhaustion markers on spike-specific or total T cells increase. T cell production of multiple cytokines (i.e. polyfunctionality) in response to the spike protein of SARS-CoV-2 did not decline in any cohort following repeated vaccination. None of the cohorts displayed elevated levels of terminally differentiated T cells following multiple SARS-CoV-2 vaccinations. Thus, repeated SARS-CoV-2 vaccination was...

Chimeric #hemagglutinin and #M2 #mRNA #vaccine for broad #influenza subtype protection

Abstract Since multiple and unpredicted influenza viruses cause seasonal epidemics and even high-risk pandemics , developing a universal influenza vaccine is essential to provide broad protection against various influenza subtypes. Combined with the mRNA lipid nanoparticle-encapsulated (mRNA-LNP) vaccine platform and chimeric immunogen strategy , we developed a novel cocktail mRNA vaccine encoding chimeric HAs (cH5/1-BV, cH7/3) and intact M2 (termed Fluaxe), which confers broad protection against major circulating IAVs and IBVs , as well as highly pathogenic avian influenza . Two-dose intramuscular immunization of Fluaxe in mice elicited cross-reactive neutralizing antibodies , T cell responses, and long-lived immunity, resulting in robust protection against multiple lethal influenza virus infections and severe acute lung injuries . In particular, intramuscular administration stimulated systemic immunity together with a prominent lung tropism of memory cells . Moreover, Fluaxe immuniza...

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