Influenza D Virus Infection in Feral Swine Populations, United States

Lucas Ferguson,Katie Hanson-Dorr,Alicia K Olivier,Richard Webby,Xiu-Feng Wan,Kaijian Luo,Hailiang Sun,Sherry Blackmon,Fred L Cunningham,William Epperson,Mark W Lutman,Bianca Quade,Thomas J Deliberto,John Baroch

doi:10.3201/eid2406.172102

Abstract

Influenza D virus (IDV) has been identified in domestic cattle, swine, camelid, and small ruminant populations across North America, Europe, Asia, South America, and Africa. Our study investigated seroprevalence and transmissibility of IDV in feral swine. During 2012–2013, we evaluated feral swine populations in 4 US states; of 256 swine tested, 57 (19.1%) were IDV seropositive. Among 96 archived influenza A virus–seropositive feral swine samples collected from 16 US states during 2010–2013, 41 (42.7%) were IDV seropositive. Infection studies demonstrated that IDV-inoculated feral swine shed virus 3–5 days postinoculation and seroconverted at 21 days postinoculation; 50% of in-contact naive feral swine shed virus, seroconverted, or both. Immunohistochemical staining showed viral antigen within epithelial cells of the respiratory tract, including trachea, soft palate, and lungs. Our findings suggest that feral swine might serve an important role in the ecology of IDV.

Highlights

Influenza D virus (IDV) has been identified in domestic cattle, swine, camelid, and small ruminant populations across North America, Europe, Asia, South America, and Africa
To identify whether IDV is circulating among feral swine populations in the United States, we performed HA inhibition (HAI) against D/bovine/C00046N/Mississippi/2014 virus (D/46N) and D/bovine/C00013N/Mississippi/2014 virus (D/13N) on 256 serum samples from feral swine collected during October 1, 2012–September 30, 2013 [11]
Of the 39 samples seropositive for D/13N, 8 were seropositive for D/46N, but the other 31 samples were seronegative for D/46N; of the 18 samples seropositive for D/46N, 10 samples were seropositive for D/13N, whereas the other 8 samples were seronegative for D/13N

Summary

Introduction

Influenza D virus (IDV) has been identified in domestic cattle, swine, camelid, and small ruminant populations across North America, Europe, Asia, South America, and Africa. Evidence suggests that IDV circulates in domestic animals, including swine, cattle, camelids, and small ruminants, throughout North America, Asia, Africa, and South America [1,3,4,5,6,7,8,9,10,11,12,13,14,15]. We conducted infection experiments to determine the pathogenesis and transmission of IDV in feral swine

Methods

Results

Conclusion