Surveillance
To check for the presence of West Nile virus in our communities, local county and city agencies, along with Fort Lewis Army Base, conduct surveillance activities. Efforts involve testing of birds, mosquitoes and tracking cases of West Nile virus reported from veterinarians and health care providers.
Bird Surveillance
Dead bird surveillance is important because birds, particularly crows, ravens and stellar jays, are natural hosts of West Nile virus. Dead specimens of these types of birds are indicators of the presence of the virus in an area. For example, two dead birds tested positive in 2002 as well as one in 2005. All in Yakima County. With this in mind, surveillance activities performed by the Health Department and other local agencies include:
- Testing of dead birds (crows, ravens, jays and raptors) reported to the Health Department by local agencies and the public.
- Tracking the location of reported dead birds in Pierce County.
Mosquito Surveillance
Mosquitoes are collected to see what species live here in Pierce County. Only certain species of mosquitoes are able to pass on West Nile virus. As of 2005, forty eight species of mosquitoes have been identified in Washington State. Of these, only nine are potential carriers of West Nile virus. Eight of the nine species have been found in Pierce County. In 2005 surveillance of 81 mosquito pools found no positive cases of West Nile virus in mosquitoes in Pierce County. These mosquito pools also revealed no new potential vector mosquito species. With this is mind, surveillance activities this year include:
- Collection of mosquito larvae and adults
- Identification of mosquito species that can carry the virus
- Testing of mosquitoes for West Nile virus
To report a dead bird or mosquito infestation please call 253 798-6578.
Last Updated: Aug 20, 2009 3:23 PM