#Hantavirus #stability and #inactivation

 

Abstract

Hantaviruses are zoonotic viruses that can cause highly pathogenic disease, including hantavirus cardiopulmonary syndrome (HCPS) and haemorrhagic fever with renal syndrome (HFRS), in humans with case-fatality rates of up to 50%. However, our understanding of the basic viral life cycle and the underlying causes of viral pathogenesis remains sparse, in large part due to a lack of molecular biology tools for hantaviruses and the need to work in high-containment laboratory facilities with these viruses. The stability and inactivation of hantavirus particles has been examined in some limited previous studies, however, a comprehensive, detailed and robust investigation of the stability of multiple hantaviruses has not been performed yet. Here, we investigated the kinetics of infectious Tula virus (TULV) particle production in Vero E6 cells and subsequent stability in cell culture media. In addition, we evaluated the stability of infectious virus particles in response to different physical and environmental stresses, including heat, freezing, dehydration and UV exposure, answering key questions about the environmental transmission potential of hantaviruses. Interestingly, we observed a remarkable stability of TULV when stored at room temperature or colder, as well as after dehydration, which suggests that hantaviruses could remain infectious for a sustained period of time after being secreted by their host species. Subsequently, we determined the ability of commonly used virus inactivation methods, including RNA and protein extraction buffers, to inactivate TULV both in a cell-free and cell-associated context and found that TULV was efficiently inactivated by all these methods similar to other enveloped RNA viruses. Finally, we successfully validated the complete inactivation using these inactivation methods using the highly pathogenic HCPS-causing New World Andes virus (ANDV) and the HFRS-causing Old World Hantaan virus (HTNV). These results provide valuable information about safe and effective inactivation methods of viral samples and about the environmental risk potential of hantaviruses.

Source: 

Link: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0013781

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A versatile #H5N1-VSV #platform for safe #influenza virus #research applications

 

ABSTRACT

The H5N1 strain of influenza A virus (IAV) continues to cause severe infections in a range of avian and mammalian species, including sporadic but concerning cases in humans. There is growing concern that circulating H5N1 strains could lead to widespread human outbreaks. Research with highly pathogenic H5N1 viruses is restricted to Biosafety Level 3 (BSL-3) laboratories. Vesicular stomatitis virus (VSV)-based vaccine vectors expressing heterologous viral proteins from Ebola, SARS-CoV-2, Lassa virus, etc., have previously been shown to be safe and effective in animal models and human clinical trials. Here, we report the development of a recombinant VSV expressing the hemagglutinin (HA) and neuraminidase (NA) genes of H5N1 IAV (H5N1-VSV), which serves as a versatile platform to study various aspects of H5N1 IAV biology. H5N1-VSV replicated robustly to titers comparable to those of the full H5N1 virus in multiple cell lines. In mice, H5N1-VSV vaccination was safe, elicited strong immunity, and conferred protection against a circulating H5N1 strain. Notably, we found that polymorphisms in antigenic site Sa of circulating strains emerged under immune selection pressure in cattle, resembling the evolution of pandemic IAV in humans. These findings suggest that H5N1-VSV can serve as a safe, adaptable platform for influenza research.

Source: Journal of Virology, https://journals.asm.org/doi/full/10.1128/jvi.00975-25?af=R

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#Biosecurity uptake and perceived #risk of avian #influenza among people in contact with #birds

Abstract

Introduction: 

Recent intercontinental spread of highly pathogenic avian influenza (HPAI) A(H5N1) among kept and wild birds, and transmission to mammalian hosts, including cattle and humans, has heightened the need to review public health risk assessments. Biosecurity is essential for limiting disease spread, but how widely practices are implemented is not fully known. 

Methods: 

Here, we report on uptake of biosecurity measures and risk perception of avian influenza virus (AIV) in the context of preventing zoonotic transmission to persons potentially at high risk of exposure. Questionnaire data from 225 people in contact with birds in the UK (Avian Contact Study, May to July 2024) was analysed. 

Results: 

We found hand washing after contact with birds was the most common biosecurity measure implemented (89%, 196/218), followed by using disinfecting footwear dips (78%, 170/218). Individuals in contact with a higher number of birds were more likely to use at least one PPE measure for the face or body (χ^2 (1, n=217) = 32.452, p<0.001) or at least one footwear-related PPE measure (Df=1, n=217, p<0.001). The perceived risk of AIV to the health of birds was high for individuals in contact with large flocks (≥1001 birds) and associated with uptake of at least one footwear-related PPE measure (χ^2 (1, n=185)= 9.171, p=0.002). Perceived risk of AIV to respondents' own health was low, regardless of the number of birds a respondent had daily contact with. 

Conclusions: 

Routinely used biosecurity measures are implemented to limit AIV spread among birds, but not with the purpose of limiting zoonotic transmission from birds to humans. Identifying cohort characteristics which could lead to low BM uptake, alongside barriers and facilitators to BM uptake is important for informing zoonotic AIV public health campaigns.

Competing Interest Statement

LES, SG, SM, JT and RP are employees of the UK Health Security Agency. LES receives consultancy fees from the Sanofi group of companies and other life sciences companies. PM is an employee of the Animal Plant and Health Agency. The views expressed are those of the authors and not necessarily those of the UKHSA or the Department of Health and Social Care.

Funding Statement

Funding for the Avian Contact Study was awarded by PolicyBristol from the Research England QR Policy Support Fund (QR PSF) 2022-24 for investigating Zoonotic spillover of avian influenza. AT is funded by the Wellcome Trust, Early Career Award [227041/Z/23/Z]. EBP acknowledges support from the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Evaluation and Behavioural Science at the University of Bristol (NIHR207385).

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2025.04.23.25326059v2

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#Thermal #tolerance and #inactivation of #Ebola virus

{Summary}

HIGHLIGHTS

• The investigation demonstrated a high level of tolerance of EBOV to thermal disinfection.

• A water-bath is recommended and the tubes should be fully submerged during the process.

• The established inactivation guidelines should be followed very strictly.

Dear Editor,

Viruses of the genus Orthoebolavirus cause sporadic outbreaks of severe haemorrhagic fever, with case fatality rates ranging from 25% to 90% (Mahanty and Bray, 2004). Six species of the virus (Orthoebolavirus zairense, sudanense, bundibugyoense, taiense, restonense, and bombaliense) have so far been identified (Biedenkopf et al., 2023). Among these, Orthoebolavirus zairense, commonly known as Ebola virus (EBOV), stands out as the most virulent. Given its high contagiousness and lethality, EBOV must be manipulated under biosafety level 4 (BSL-4) conditions, as stipulated by the National Health Commission of the People's Republic of China's list of human pathogenic microorganisms. Prior to being removed from a BSL-4 laboratory, it is imperative that infectious EBOV undergoes complete inactivation. Here we systematically evaluate viral thermostability under BSL-4 containment conditions, demonstrating EBOV’s marked thermotolerance.

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Source: Virologica Sinica, https://www.sciencedirect.com/science/article/pii/S1995820X25000975

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