West Nile virus back in Washington state, earlier than ever

WEST RICHLAND, Wash. -- The West Nile virus, which brings fever, headache, body aches, skin rash, and swollen lymph nodes, is back again in Washington state.

The Benton County Mosquito Control District found the infected mosquito that tested positive for West Nile virus in a sample taken from a trap on May 18 near the Tri-Cities.

Severe symptoms of the mosquito-carried virus include stiff neck, sleepiness, disorientation, coma, tremors, convulsions, and paralysis.

Not only is West Nile back, the populations of the mosquitoes that carry the virus are going off the chart. At the trap site that captured the West Nile mosquito, they usually find about 197 mosquitoes. The data on some of these traps go back about 10 years. The same trap last year saw only about 100 mosquitoes in mid-May,  likely due to the epic dry winter and spring in 2015.

This year, however, the mid-May sample found so many mosquitoes, there were just too many to count. So the scientists weighed the sample and estimated it contained about 2,500 mosquitoes. That's an increase of more than 1,000%.

Angela Beehler, with the Benton County Mosquito Control District, tells Q13 News that sometimes if a trap is nearby where the mosquitoes hatch, the numbers can be skewed somewhat. But, this year mosquitoes have been a big problem east of the Cascades..

"It's been pretty nonstop since about March," Beehler says.

There are more than a dozen mosquito control districts across Washington that try and eradicate the pests.

Beehler says, "The West Nile virus is pretty well-established in Eastern Washington, so it's not a question of whether the virus returns each year-- but just a matter of when."

Beehler says weather plays a huge role in the mosquito population. They use standing water anywhere they can find it to lay their eggs. The swampier the water, the better it is for their larvae. This year's wet and relatively mild winter on both sides of the Cascades means many of the blood-sucking pests could have survived over the winter to lay even more eggs.

Beehler says in a typical year, they don't usually detect West Nile virus in mosquito samples until the summer. The Washington State Department of Health says year after year, south-central Washington has been a “hot spot” for the virus with the most in-state human and animal cases exposed in this area. A man died last year from West Nile virus and 10 other were infected.

It took a long time for West Nile virus to even make it into Washington. The virus first appeared in August 2002 in the Evergreen State. After intense control efforts, it disappeared only briefly. In 2004, Washington state and Maine were the only two states without West Nile. It made a big comeback in 2005 with 38 cases, 14 of those in Benton County. The Washington State Department of Health says West Nile virus is primarily a bird disease, and often dead birds are an early sign that the disease is active in an area. People may report dead birds online to public health officials.

The kind of mosquitoes (Culex Tarsalis and Culex Pipiens) that transmit West Nile virus don't live west of the Cascades, but since all it takes is one mosquito bite to get the infection, the health department wants people to know who travel to around Washington state to be aware of the dangers that mosquitoes carry.