Avian influenza viruses and paramyxoviruses in wintering and resident ducks in Texas.

Cloacal swabs were collected from teal (Anas crecca, Anas cyanoptera, Anas discors), mottled duck (Anas fulvigula) and northern pintail (Anas acuta) in Brazoria County, Texas, USA, during February 2001, mottled ducks during August 2001, and blue-winged teal (A. discors) during February 2002. Prevalence of avian influenza virus (AIV) infections during each sampling period were 11, 0, and 15%, respectively. The hemagglutinin (H) subtypes H2 and H7 were detected in both years, while the H8 subtype was detected in 2001 and the H1 subtype was detected in 2002. Avian paramyxovirus type 1 (APMV-1) was isolated from 13% of mottled ducks sampled in August 2001 and 30.7% of teal in February 2002. The season of isolation of both viruses and the majority of the AIV subtypes detected in this study are not typical based on previous reports of these viruses from North American ducks.