West Nile Virus Transmission in Winter: The 2013 Great Salt Lake Bald Eagle and Eared Grebes Mortality Event

• DOI: 10.1371/currents.outbreaks.b0f031fc8db2a827d9da0f30f0766871
• Publication Date: 2014-04-19T00:27:04Z
• Authors: Hon S. Ip; Arnaud J. Van Wet...; Leslie McFarlane; Valerie Shearn-Bo...; Sammie Lee Dickson; JoDee Baker; Gary Hatch; Kimberly Cavender; Renee Long; Barbara Bodenstein
• Keywords: Bald eagle

West Nile Virus (WNV) infection has been reported in over 300 species of birds and mammals. Raptors such as eagles, hawks falcons are remarkably susceptible, but reports WNV Bald Eagles (Haliaeetus leucocephalus) rare grebes (Podicipediformes) even rarer. We report an unusually large wild bird mortality event involving between 15,000-20,000 Eared Grebes (Podiceps nigricollis) 40 around the Great Salt Lake, Utah, November-December 2013. Mortality was first early November during a period when area unseasonably warm were beginning to gather stage prior migration. Ten out ten collected this RT-PCR and/or isolation positive. This is associated matched scale only by combined outbreaks American White Pelican (Pelecanus erythrorhynchos) colonies north central states 2002-2003. cannot be sure that all infected mosquito transmission; some may have become through contact with shed orally or cloacally from other grebes. Beginning December, Lake observed display neurological signs body tremors, limb paralysis lethargy. At least 43 had died end month. Nine nine examined WNV. To best our knowledge, largest single raptor since became endemic USA. Because majority eagles affected found after onset below-freezing temperatures, we suggest at via consumption horizontal transmission roost sites.