What is the West Nile virus? 

West Nile virus was originally isolated in Eastern Africa but introduced to the United States in 1999 in New York City. People become infected with West Nile when a Culex mosquito feeds on an infected bird then bites a human. People and Horses are considered a dead-end host. This means if another Culex mosquito bites an infected human or horse the virus cannot be transmitted, the mosquito would have to bite an infected bird. 

Signs of a bird with West Nile

• Loss of coordinations
• Head tilt
• Tremors
• Weakness
• Staying low to the ground 
• Inability to fly or stand

Call the Vector Control if you suspect a bird having West Nile. Please do not handle to bird. The Vector Control will come out and collect the bird and take it back to the districts lab and test it for West Nile. 

Testing mosquitoes for West Nile

 During the warmer months of the year the Vector Control sets live mosquito traps throughout the county in the evening. This is due to the Culex mosquito (the vector of West Nile) being more active during dusk and dawn. The mosquitoes are loured to the trap by the smell of CO2 mimicking the smell of a human. The following morning the field technician will retrieve the trap and bring it back to the lab. After the mosquitoes are frozen for 90 minutes the lab technician will pull a net that has identifying  information on where the trap was set and the time frame it was out. Then the lab tech will spectate and pull only the Culex mosquito for further testing. The rest of the mosquitoes are still speciated and counted for lab data. After counting the Culex mosquitoes they continue through lab testing procedures. When the Culex mosquitoes are tested each "pool" (50 or less) gets an ID number. This ID is used for record keeping. The lab tech will run a RAMP test which is a highly sensitive test used to identify West Nile in mosquitoes. Even after some pools get testing in the Vector Controls lab they can be sent to Oregon State Unitverity for conformation. This allows the lab technician at the district to know if the equipment is running efficiently.