Mink is a highly susceptible host species to circulating human and avian influenza viruses

Honglei Sun,Ting Qi ,Xin Zhang,Yipeng Sun,Yongqiang Wang,Jinshui Yang ,Juan Pu,Jianyong Du,Yuhong Duan,Xiangjun Du,Qingzhi Liu,Yuhai Bi,Litao Liu,Fangtao Li,Chong Li,Jiyu Liu,Yuelong Shu,Haoran Sun,Kin-Chow Chang

doi:10.1080/22221751.2021.1899058

Abstract

ABSTRACT Pandemic influenza, typically caused by the reassortment of human and avian influenza viruses, can result in severe or fatal infections in humans. Timely identification of potential pandemic viruses must be a priority in influenza virus surveillance. However, the range of host species responsible for the generation of novel pandemic influenza viruses remains unclear. In this study, we conducted serological surveys for avian and human influenza virus infections in farmed mink and determined the susceptibility of mink to prevailing avian and human virus subtypes. The results showed that farmed mink were commonly infected with human (H3N2 and H1N1/pdm) and avian (H7N9, H5N6, and H9N2) influenza A viruses. Correlational analysis indicated that transmission of human influenza viruses occurred from humans to mink, and that feed source was a probable route of avian influenza virus transmission to farmed mink. Animal experiments showed that mink were susceptible and permissive to circulating avian and human influenza viruses, and that human influenza viruses (H3N2 and H1N1/pdm), but not avian viruses, were capable of aerosol transmission among mink. These results indicate that farmed mink could be highly permissive “mixing vessels” for the reassortment of circulating human and avian influenza viruses. Therefore, to reduce the risk of emergence of novel pandemic viruses, feeding mink with raw poultry by-products should not be permitted, and epidemiological surveillance of influenza viruses in mink farms should be urgently implemented.

Highlights

Influenza A virus epidemics occur regularly worldwide and are estimated to cause 3–5 million cases of severe illness, with 290,000–650,000 deaths each year [1]
Further analysis of co-infection prevalence in the 1885 Haemagglutination inhibition (HI)+/Virus neutralization (VN)+ samples showed that 34.7% (655/ 1885) of the samples were seropositive for multiple influenza virus subtypes, of which 32.3% (608/1885) contained both avian and human influenza antibodies (Figure 1(B) and Supplementary Figure 1)
Analysis of monthly seroprevalence data for all viruses found that the seroprevalence of human influenza virus in mink correlated with circulating virus levels in humans; it was high from February to March and relatively low from August to October (Supplementary Table 2)

Summary

Introduction

Influenza A virus epidemics occur regularly worldwide and are estimated to cause 3–5 million cases of severe illness, with 290,000–650,000 deaths each year [1]. Historical pandemic influenza viruses, such as the 1957 H2N2, 1968 H3N2, and 2009 H1N1/pdm virus, were all derived from novel reassortant viruses [2,3]. Host species that are susceptible to both human and animal influenza viruses could, serve as “mixing vessels,” as has been described for pigs [4], through co-infections to generate novel reassortant viruses with the potential to cause pandemics. The ferret has been widely accepted as an excellent animal model for understanding the virulence and transmission of influenza viruses as it shares similar lung physiology and sialic acid (SA) receptor distribution to humans [5,6]. Due to a lack of systematic surveillance of influenza viruses circulating in mink, their contribution to influenza virus evolution and susceptibility to prevailing avian and human influenza viruses are unknown

Methods

Results

Conclusion