Survivability of H5N8 mixed wild bird droppings in different conditions
Authors: Jiahao Zhang, Taifang Zhou, Tao Zhang, Ming Liao, Wenbao Qi
Journal: The Lancet Microbe (2022)

We read with interest a recent Correspondence,1Dai M Yan N Huang Y Zhao L Liao M Survivability of highly pathogenic avian influenza virus on raw chicken meat in different environmental conditions.Lancet Microbe. 2021; (published online Dec 22.)https://doi.org/10.1016/S2666-5247(21)00333-5Google Scholar published in The Lancet Microbe, that described the transmission chain of H5N8 avian influenza virus on raw chicken meat as having the potential to infect humans. During the 2020–21 winter season, Eurasia experienced a sudden recurrence of clade 2.3.4.4b H5N8 viruses in wild bird populations;2Zhang J Li X Wang X et al.Genomic evolution, transmission dynamics, and pathogenicity of avian influenza A (H5N8) viruses emerging in China, 2020.Virus Evol. 2021; 7veab046Crossref Scopus (9) Google Scholar, 3Shi W Gao GF Emerging H5N8 avian influenza viruses.Science. 2021; 372: 784-786Crossref PubMed Scopus (24) Google Scholar these H5N8 viruses were found to have caused human infections in Russia in December, 2020.4Pyankova OG Susloparov IM Moiseeva AA et al.Isolation of clade 2.3.4.4b A (H5N8), a highly pathogenic avian influenza virus, from a worker during an outbreak on a poultry farm, Russia, December 2020.Euro Surveill. 2021; 262100439Crossref PubMed Scopus (29) Google Scholar Strikingly, a sharp increase in the number of human infections with 2.3.4.4b H5N6 viruses occurred in China during 2021.5WHOAssessment of risk associated with influenza A (H5N6) virus.https://www.who.int/publications/m/item/assessment-of-risk-associated-with-influenza-a(h5n6)-virusDate: Nov 19, 2021Date accessed: December 1, 2021Google Scholar Given frequent reports of the presence of viruses in pond water and mud during the influenza outbreaks in wild bird populations,6Hood G Roche X Brioudes A et al.A literature review of the use of environmental sampling in the surveillance of avian influenza viruses.Transbound Emerg Dis. 2021; 68: 110-126Crossref PubMed Scopus (7) Google Scholar the potential for H5N6 and H5N8 viruses in the environment to infect humans in wetlands and small-scale family-based farms should not be ignored. Here, we report the survivability of representative H5N8 viruses (appendix p 5) in wild bird droppings, dry mud, and mud water with different environmental variables to monitor the potential transmission chain (full methods are described in the appendix pp 2–4). First, we measured the viral titres by conducting a median tissue culture infectious dose (TCID50) assay of H5N8 in fresh wild bird droppings mixed with dry mud and with mud water (ie, lake water and dry mud) at different temperatures for 10 days. The untreated H5N8 remained viable at 4°C for 10 days and at 20°C for 6 days (appendix pp 6, 9). The longest-surviving H5N8 in mud water mixed with virus-contaminated wild bird droppings tested at 20°C was 3 days; however, the H5N8 could be detected on day 10 at 4°C (appendix pp 6–7). No virus was detected in dry mud containing the virus-contaminated wild bird droppings after 2 days (appendix pp 6, 8). Next, we naturally dried the virus-contaminated wild bird droppings to test the survival of the viruses on different days. The H5N8 only remained viable for 2 days at 20°C (appendix pp 6, 10). We also investigated the virucidal effects of different disinfectants on virus-contaminated droppings that were attached to cloths. The H5N8 could not be detected when inoculated with 84-disinfectant, acetic acid, and ethanol; however the viruses were not susceptible to 2 min of inoculation with laundry detergent (appendix p 11). In sum, the long-term survival of the H5N8 viruses occurred in virus-contaminated wild bird droppings and mud water with a low temperature, which could be the potential sources of transmission to humans and free-range domestic birds. Therefore, prevention and control measures should be restored to levels seen before the COVID-19 pandemic or stricter in wetlands, live poultry markets, and poultry farms during the winter, including measures designed to keep domestic birds away from wild birds and for thoroughly disinfecting environments during highly pathogenic avian influenza outbreaks. This work was supported by the National Natural Science Foundation of China (31672586 and 31830097), the Earmarked Found for China Agriculture Research System (CARS-41-G16), the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2018, WQ), and the Young Scholars of Yangtze River Scholar Professor Program (2019, WQ). The authors declare no competing interests. JZ, ML, and WQ designed the study, supervised the experiments, collected and analysed data, and drafted the Correspondence. JZ, TZho, and TZha performed experiments. All authors have read and approved the final Correspondence. Download .pdf (2.4 MB) Help with pdf files Supplementary appendix Survivability of highly pathogenic avian influenza virus on raw chicken meat in different environmental conditionsHighly pathogenic avian influenza (HPAI) viruses, such as H7N9 and H5N8, can cause huge economic losses in the poultry industry, and they can pose a serious risk to public health.1,2 In Japan, HPAI viruses have been repeatedly detected on raw poultry, reportedly transported by international flight passengers from China and Vietnam.1 Here, we report the survivability of HPAI viruses on raw chicken meat in different environmental conditions. Full-Text PDF Open Access