Migrating Birds as Dispersal Vehicles for West Nile Virus

Abstract

Whereas migrating birds have been implicated in the spread of West Nile virus (WNV), there is no direct evidence of birds actively migrating while infectious. The role of birds in WNV dispersal is difficult to assess in the field. However, this role can be evaluated experimentally because birds in migratory disposition display increased locomotor activity or restlessness under captive conditions. We tested the following hypotheses: (1) migrating passerine birds continue to exhibit migratory activity while infectious with WNV and(2) the migratory state of the individual affects the magnitude of viremia. We examined the migratory activity of two neoarctic-neotropical passerine migrants, SwainsonÕs thrush (Catharus ustulatus) and gray catbird (Dumetella carolinensis), during acute WNV infection. All gray catbirds and six of nine SwainsonÕs thrushes exhibited migratory activity while infectious. Moreover, migratory status did not appear to influence viremia titers, as might be expected if individuals were immunosuppressed during migration. Therefore, we demonstrate that migrating passerine birds are potential dispersal vehicles for WNV.

Ecology of West Nile Virus Transmission and Its Impact on Birds in the Western Hemisphere

“…Eff orts to determine the role of migrating birds in the spread of WNV have included laboratory infection studies with birds in migratory condition (Owen et al 2006), eff orts to isolate virus from birds during migratory periods (R. McLean et al unpubl. data), sampling of birds killed by communication towers and skyscrapers (P. Marra and A. DuPuis unpubl.…”

“…Laboratory infection studies to estimate host competence have been published for 44 species of nondomesticated birds in 23 families and 11 orders Reisen et al 2005aReisen et al , b, 2006Reisen et al , 2007aClark et al 2006;Nemeth et al 2006;Owen et al 2006;Reisen and Hahn 2007;Platt et al 2008), 3 species of wild mammals (Tiawsirisup et al 2005b, Root et al 2006, Platt et al 2007, and 5 species of reptiles and one amphibian Komar 2003, Klenk et al 2004). In these experiments, animals are infected by either allowing infectious mosquitoes to feed on them or by an intramuscular or subcutaneous injection of virus.…”

Vector Control of Zoonotic Arbovirus Disease in Indonesia

“…Dengan kata lain, burung yang bermigrasi berperan sebagai kendaraan bagi penyebaran virus WN (Owen et al 2006;Botha et al 2008). Virus dapat bertahan selama musim dingin dan siklus infeksi virus pada burung dapat bertahan bertahun-tahun.…”

West Nile Virus: Basic Principles, Replication Mechanism, Immune Response and Important Genetic Determinants of Virulence

“…crows, blue jays, goshawks, magpies [111,112,94,6]. Various avian species were found to be viremic for 6 days post inoculation and viremic titers high enough to transmit the virus to mosquitoes via their bites [113]. In wild birds, infectious WNV was detected for as long as 6 weeks in tissues [114,115].…”