> 6,000 carcasses; >3400 to lab ~ 550 WNV+ > 13,000 sightings Jul 28 Jul 8 May 19 Jun 14 Sept 13

Time elapsed - pick-up of carcass to report of test result

Humans Quebec - 1 prob; 7 conf Ontario - 72 prob - 5 deaths; 48 conf - 1 death Alberta - 1 conf (US) Horses Quebec - 2 Ontario - > 80 Manitoba - ~ 150 Saskatchewan - 10

Direct transmission bird-to-bird: crows, ?others - epidemiological implications - ? risk of human handling WNV found in many organs/tissues high titre in oronasal cavity & feces/urine in many bird spp. New in 2002

>100 spp of wild & pet birds susceptible - sig. mortality in some - Mammals: squirrels, dog, wolf, reindeer, mountain goat etc. Implications for wildlife populations, zoos, endangered species, handlers & rehabilitators, veterinarians, laboratorians, animal/pet owners Implications of WNV in wild & domestic animals New in 2002

Recrudescent Endemic vs. Introduced Epidemic pattern Does WNV overwinter in mosquitoes, ?birds/mammals, to emerge again in the spring, or does it need to be reintroduced annually, presumably by migratory birds? Implications: predictability of recurrence; climate, overwintering vectors overwintering - earlier initiation of cycle, longer time for amplification - ?greater human risk bird surveillance necessary/useful or not mosquito surveillance necessary/useful or not larvicide or not public health message & public attitudes

New in 2002 Recrudescent WNV? Peel – May, 2002

Dead birds Testing, if done, may be provincial or local responsibility Issues: Utility of repeated testing in known WN virus-positive localities & dead bird sighting data VecTest: 20 minute test; ~$15; 85% sensitivity, 92% specificity on oropharyngeal swab – crows; ? Useful for local testing; ?reporting & communications; ?confirmation WNV Surveillance 2003