Is the Occurrence of Avian Influenza Virus in Charadriiformes Species and Location Dependent?

Abstract

ABSTRACT:Birds in the order Charadriiformes were sampled at multiple sites in the eastern half of the continental USA, as well as at Argentina, Chile, and Bermuda, during 1999-2005, and tested for avian influenza virus (AIV). Of more than 9,400 birds sampled, AIV virus was isolated from 290 birds. Although Ruddy Turnstones (Arenaria interpres) comprised just 25% of birds sampled, they accounted for 87% of isolates. Only eight AIV isolations were made from birds at four locations outside of the Delaware Bay, USA, region; six of these were from gulls (Laridae). At Delaware Bay, AIV isolations were predominated by hemagglutinin (HA) subtype H10, but subtype diversity varied each year. These results suggest that AIV infection among shorebirds (Scolopacidae) may be localized, species specific, and highly variable in relation to AIV subtype diversity.

Avian Influenza Virus Infection Dynamics in Shorebird Hosts

“…The consistent temporal pattern of infection and seroconversion (between and within years) at this site suggests an annual and localized epidemic; reported AIV isolations from Ruddy Turnstones at Delaware Bay each May since 1985 (Krauss et al, 2004;Hanson et al, 2008;Krauss et al, 2010) clearly demonstrate this predictable event.…”

“…Shorebirds and gulls were captured with cannon nets as part of long-term population studies. Following banding and measurement, swab samples for virus isolation were collected, stored, processed, and tested in embryonated chicken eggs as previously described (Hanson et al, 2008). Cloacal swabs were collected from all birds; in addition, oropharyngeal swabs were collected from Laughing Gulls in 2008 and analyzed separately (none were positive).…”

“…Fresh Laughing Gull feces were swabbed in limited cases and only from within the borders of monospecific breeding colonies. Presence of AIV was confirmed by hemagglutination (Swayne et al, 1998) and reverse transcriptase polymerase chain reaction (RT-PCR) for matrix gene Hanson et al (2008). For each species, data from all 9 yr (4 yr for Laughing Gulls; were used to estimate the average trend, if any.…”

“…Prevalence increased with day (#30 May), and with mass (#80 g), and was positively correlated with prevalence in Ruddy Turnstones. Sanderlings appear relatively resistant to AIV infection (perhaps due to decreased susceptibility or limited contact), given low prevalence and antibody prevalence at Delaware Bay, and zero prevalence at other times and locations (Hlinak et al, 2006;Munster et al, 2007;Winker et al, 2007;Escudero et al, 2008;Hanson et al, 2008;Iverson et al, 2008;Ghersi et al, 2009). Because infections in Sanderlings are sporadic and likely depend on the infected proportion of syntopic birds, they are probably due to spillover events from Ruddy Turnstones acting as amplifying hosts (Fenton and Pedersen, 2005).…”

“…Estimated mean springtime prevalence among shorebirds and gulls was 6.3% across 21 yr (Krauss et al, 2010). Both studies recognized one shorebird species, the Ruddy Turnstone (Arenaria interpres morinella), as disproportionately infected, and Hanson et al (2008) reported that mean springtime prevalence was significantly higher among Ruddy Turnstones (11%) than among 10 other species (0.5%). Despite this consistent seasonal pattern of infection among shorebirds at Delaware Bay, AIV have not been detected more than occasionally in shorebirds at other times and locations, particularly in the western hemisphere (e.g., Escudero et al, 2008;Iverson et al, 2008;Winker et al, 2008;Ghersi et al, 2009).…”