WNV detected in mosquito sampling near Moses Lake
MOSES LAKE – The Grant County Health District is advising that mosquitoes testing positive for West Nile virus were collected last month in the Crab Creek area north of Moses Lake.
Grant County is the third county in Washington to report detection of WNV this year. Benton and Yakima counties have previously reported positive mosquito samples. So far in 2025, there are no reports of people or animals infected with WNV in this state.
Most people infected with the virus don’t get sick. But about one in five persons will experience symptoms that can include joint pain and body aches, rash, headache, vomiting and diarrhea. About 1 in 150 people who are infected develop severe illness affecting the central nervous system which may result in encephalitis or meningitis. There is no specific medication for WNV disease, but hospital care may be necessary for severe cases.
Persons may be at higher risk of infection if they are age 60 and older or have underlying medical conditions such as cancer, hypertension, diabetes, or kidney disease.
“Although most people will not get seriously ill from West Nile virus, we do not want anyone to get sick because of a mosquito bite,” said Amber McCoy, GCHD Investigation & Response manager, in a Sept. 4 press release. “If you’re enjoying activities outside, be sure to take the necessary steps to fight the bite.”
WNV is the leading cause of mosquito-borne disease in the United States. Birds and equine animals -- horses, donkeys, and mules – are also vulnerable to the virus and infected animals can get very sick and often die. Equine owners are advised to ask their veterinarian about WNV vaccine.
The last reported human case in Grant County occurred in 2015. But last month, the Idaho Department of Health and Welfare confirmed a WNV-related death of a Twin Falls-area man in his late 60s.
Preventative measures against mosquito bites include staying indoors at dawn and dusk when mosquitoes are most active, wearing protective clothing including a hat and long-sleeved shirts and pants, applying EPA-registered repellents, and eliminating potential breeding areas of standing water.
Moses Lake-based Grant County Mosquito Control District 1 collected its positive samples during routine testing on Aug. 24 and the presence of WNV was confirmed on Sept. 3 by a diagnostic laboratory in Oregon.
Grant County has three mosquito control districts – in the Moses Lake, Coulee City, and Electric City/Grand Coulee areas – which trap mosquitos for testing and conduct control efforts within their respective boundaries.
“We will continue to target both larval and adult mosquitoes in an effort to reduce the spread of the virus to other areas of the district” added Ann Belchik-Moser, district manager of GCMCD1, in the press release.
