J Wildl Dis.: Experimental infection of Hawaiian amakihi (Hemignathus virens) with West Nile virus and competence of a co-occurring vector, Culex quinquefasciatus: potential impacts on endemic Hawaiian avifauna.
Article Type: Brief article
Subject: West Nile virus (Research)
Forest birds (Health aspects)
Forest birds (Protection and preservation)
Animals (Diseases)
Animals (Research)
Authors: LaPointe, D.A.
Hofmeister, E.K.
Atkinson, C.T.
Pub Date: 06/01/2009
Publication: Name: Journal of Avian Medicine and Surgery Publisher: Association of Avian Veterinarians Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Association of Avian Veterinarians ISSN: 1082-6742
Issue: Date: June, 2009 Source Volume: 23 Source Issue: 2
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: United States Geographic Name: Hawaii Geographic Code: 1USA United States; 1U9HI Hawaii
Accession Number: 252006963
Full Text: Introduced mosquito-borne avian disease is a major limiting factor in the recovery and restoration of native Hawaiian forest birds. Annual epizootics of avian pox (Avipoxvirus) and avian malaria (Plasmodium relictum) likely led to the extinction of some species and continue to impact populations of susceptible Hawaiian honeycreepers (Drepanidinae). The introduction of a novel pathogen, such as West Nile virus (WNV), could result in further population declines and extinctions. During September and October 2004, we infected Hawaiian amakihi (Hemignathus virens) with a North American isolate of WNV by needle inoculation and mosquito bite to observe susceptibility, mortality, and illness in this endemic passerine, and to determine the vector competence of the co-occurring, introduced mosquito Culex quinquefasciatus. All experimentally infected Hawaiian amakihi became viremic, with a mean titer >105 plaque-forming units per ml, and they experienced clinical signs ranging from anorexia and lethargy to ataxia. The fatality rate among needle-inoculated Hawaiian amakihi (n = 16) was 31.3%, but mortality in free-ranging birds is likely to increase because of predation, starvation, thermal stress, and concomitant infections of avian malaria and pox. Surviving Hawaiian amakihi seem to clear WNV from the peripheral blood by 7-10 days after infection, and neutralizing antibodies were detected from 9 to 46 days after infection. In transmission trials, Hawaiian Culex. quinquefasciatus proved to be a competent vector and that Hawaiian amakihi was an adequate amplification host of WNV, which suggests that epizootic WNV could readily become an additional limiting factor of some native Hawaiian bird populations.

et al. 2009;45:257-271.
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