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Volume 11, Number 3—March 2005

West Nile Virus Risk Assessment and the Bridge Vector Paradigm

A. Marm Kilpatrick*Comments to Author , Laura D. Kramer†, Scott R. Campbell‡, E. Oscar Alleyne§, Andrew P. Dobson¶, and Peter Daszak*
Author affiliations: *Consortium for Conservation Medicine, Wildlife Trust, Palisades, New York, USA; †New York State Department of Health, Albany, New York, USA; ‡Suffolk County Department of Health Services, Yaphank, New York, USA; §Rockland County Health Department, Pomona, New York, USA; ¶Princeton University, Princeton, New Jersey, USA

Main Article


Risk of mosquito species transmitting West Nile virus (WNV) to humans

Species Relative abundance WNV MIR* Vector competence† (reference) Fraction mammal‡ Risk % Risk
Aedes vexans 20.7 0.05 0.17 (16) 0.86 (126) 0.14 4.5
Coquillettidia perturbans 11.3 0.01 0.11 (17) 0.83 (191) 0.01 0.5
Culex pipiens + Cx. restuans 37.2 0.95 0.38 (1618) 0.19 (373) 2.52 80.2
Cx. salinarius 0.6 0.85 0.36 (17) 0.67 (91) 0.12 3.9
Culiseta melanura 5.2 0.17 0.28 (19 0.11 (141) 0.03 0.8
Ochlerotatus canadensis 14.9 0.00 0.55 (16,18 1.00 (107) 0.00 0.0
Oc. japonicus 0.5 0.33 0.93 (16) 0.95 (57) 0.16 5.0
Oc. sollicitans 2.0 0.07 0.16 (16) 1.00 (28) 0.02 0.7
Oc. trivittatus 7.6 0.05 0.55 (16,18 0.64 (115) 0.14 4.4

*MIR, minimum infection rate.
†The fraction of WNV-infected mosquitoes that will transmit virus in a subsequent bite.
‡Number of mosquito blood meals identified in parentheses (9,10, Kramer et al., unpub. data).
§Vector competence value taken from study on Cs. inornata. Risk increases to 0.09 and 3.0%, assuming a maximum vector competence of 1.0.
¶Genus average used. Risk with a vector competence of 1.0 would be 0 and 0% for Oc. canadensis and 0.25 and 8.0% for Oc. trivittatus.

Main Article

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