Intestinal excretion of a wild bird-origin H3N8 low pathogenic avian influenza virus in mallards (Anas Platyrhynchos).
Mallards (Anas platyrhynchos) and other dabbling ducks in the genus Anas are an important component of the wild bird reservoir for avian influenza (AI) virus; these viruses are maintained in migratory duck populations through a fecal-oral transmission route. We provide a detailed characterization of intestinal viral shedding in Mallards infected with a wild bird-origin low pathogenic (LP) AI virus. Five of eight, 1-mo-old Mallards inoculated with a high dose of an H3N8 LP AI virus became infected as determined by reisolation and seroconversion. Infected birds excreted high concentrations of virus for up to 14 days postinoculation (DPI) without exhibiting overt clinical signs of disease. The pattern of viral shedding was relatively consistent between individual birds, with peak shedding on 2-3 DPI and a progressive decline over the remainder of infection. Detection of viral shedding varied depending on sample type (excrement sample or cloacal swab) and diagnostic test (virus isolation or real-time quantitative reverse transcription polymerase chain reaction). Our data provide detailed insights into the intestinal excretion of an H3N8 LP AI virus in Mallards and the performance of diagnostic assays commonly used in wild bird surveillance. Such information is valuable for estimating potential risks for spillover of LP AI viruses from Mallards to domestic animals, developing accurate transmission models for Mallard populations and facilitating the interpretation and comparison of surveillance results from different studies.
Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602, USA. jubrown1@uga.edu
Justin D
JD
Brown
Roy D
RD
Berghaus
Taiana P
TP
Costa
Rebecca
R
Poulson
Deborah L
DL
Carter
Camille
C
Lebarbenchon
David E
DE
Stallknecht
D000818:Animals; D000835:Animals, Wild / Q000821:virology; D002988:Cloaca / Q000821:virology; D004372:Ducks / Q000821:virology*; D005243:Feces / Q000821:virology; D005260:Female; D053123:Influenza A Virus, H3N8 Subtype / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology; D005585:Influenza in Birds / Q000635:transmission / Q000821:virology*; D008297:Male; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D017201:Virus Shedding