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Mosquito and W est N ile virus surveillance in northeast M ontana, U.S.A., 2005 and 2006
Author(s) -
FRIESEN K. M.,
JOHNSON G. D.
Publication year - 2014
Publication title -
medical and veterinary entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 82
eISSN - 1365-2915
pISSN - 0269-283X
DOI - 10.1111/mve.12011
Subject(s) - biology , aedes vexans , west nile virus , culex , vector (molecular biology) , outbreak , population , arbovirus , aedes , ecology , zoology , veterinary medicine , virology , virus , larva , demography , medicine , biochemistry , sociology , gene , recombinant dna
Mosquito and W est N ile virus (WNV) surveillance was conducted on a national wildlife refuge in northeast M ontana in 2005 and 2006, during which outbreaks of WNV in a colony of A merican white pelicans ( Pelecanus erythrorhynchos G melin) (Pelecaniformes: Pelecanidae) resulted in juvenile mortality rates of ∼ 31%. Both years, floodwater species Ochlerotatus dorsalis ( M eigen) (Diptera: Culicidae), Aedes vexans ( M eigen) (Diptera: Culicidae) and Ochlerotatus flavescens ( M uller) (Diptera: Culicidae) comprised 78% of the total collection and heightened host‐seeking activity was observed from mid‐ J une to mid‐ J uly. Culex tarsalis C oquillett (Diptera: Culicidae) was most active from mid‐ J uly to mid‐ A ugust and comprised 18% of the collection in 2005 and 20% in 2006. However, fewer than 10% of the Cx. tarsalis females collected in 2006 were obtained adjacent to the pelicans' nesting grounds. Minimum infection rates per 1000 Cx. tarsalis tested for WNV were 1.36 in 2005 and 1.41 in 2006. All pools in which WNV was detected in 2006 were composed of females collected 10 km from the nesting grounds. Substantial juvenile pelican mortality in 2006 despite reductions in the population of the primary vector and in mosquito infection rates near the colony suggests that the methods used to detect the introduction of WNV were too coarse and that amplification of the virus within the colony may reflect causes other than mosquito infection.