The risk of mosquitoes transmitting West Nile virus has been diminishing recently, and this weekend’s cold, damp weather should accelerate that trend, Baker County’s chief mosquito killer said.
“The season’s winding down,” said Matt Hutchinson, who manages the Baker Valley Vector Control District. “Especially with this upcoming cold snap — I think that’s really going to put them to bed for the year.”
Not that Hutchinson will be tucking in the covers or adjusting soft pillows for the bloodsucking insects.
He’s responsible for controlling mosquitoes in a 200,000-acre district that includes most of Baker, Bowen and Keating valleys. That’s approximately 10% of the county’s land mass, and includes some of the prime breeding grounds for mosquito species that breed in permanent water sources as well as those that prefer ground inundated seasonally for flood irrigation.
Hutchinson said mosquito numbers, including the culex varieties that are the most common carriers of West Nile virus, have been declining for the past few weeks.
“We haven’t had any complaint calls for the past couple weeks,” he said.
Hutchinson said mosquito populations typically dip substantially around early September, in response to lower temperatures and, in the case of floodwater species, the end of flood irrigation in most places.
Health officials announced Tuesday that two Baker County residents had been infected with West Nile virus from mosquito bites.
Officials declined to release any information about the two victims, including whether or not they lived within the Vector Control District, and how severe their symptoms were.
They are the first human cases of the virus in Baker County since 2014, when two women who live at New Bridge, about 3 miles north of Richland, were infected. That is outside the Vector Control District. Both women recovered.
Earlier this summer four pools of mosquitoes trapped inside the Vector Control District tested positive for the virus. All of those mosquitoes were trapped in the Keating Valley, about 15 miles east of Baker City.
The Vector Control District gets revenue from a pair of property tax levies, one permanent, which raises about $282,000 annually, and a local option levy that goes before voters every four years and brings in about $87,500 per year.
Both levies are affected by “compression” — the effect of a 1990 voter-approved statewide ballot measure that limits property tax increases. The permanent levy loses about $6,200 annually to compression, meaning the money isn’t assessed on property owners or received by the district. Compression has a much larger effect on the local option levy. Its nominal amount is $140,000 yearly, but the district actually collects about $87,500.