| Six hundred ring-billed gulls (Larus delawarensis ) were sampled, at two southern Ontario sites, and tested for viruses during the summer of 2004. Antibodies to avian paramyxovirus-1 were found in 54% of adults and 89% of juveniles. The mean hemagglutination inhibition (HI) titre (GMT) was highest in Toronto 3-week-olds (81.8), and a lentogenic strain was isolated from 2% of this group. This indicates that the virus is actively circulating in Ontario gulls.; Antibodies to avian influenza virus were found in 80% of adults, indicating they have been exposed previously. GMT was lower in 3-week-olds than adults, possibly due to maternal antibody. GMT and prevalence were higher in Hamilton 5-week-olds than 3 week-olds, suggesting they were actively infected. Despite this, no virus was isolated.; No West Nile virus was detected in samples from live gulls, mosquitoes or gull carcasses, suggesting that gull colonies did not play a major role in its early amplification. |
