PORTLAND, Ore. (KOIN) — Health officials in Clark and Multnomah County are urging prevention and protection as a record year for mosquitoes is in full swing.

According to Multnomah County, high water has settled into standing pools across the county, creating a breeding ground for the largest mosquito outbreak since at least 2010. However, officials say the worst is yet to come.

They suggest for people to check screens at home and dump standing water, along with wearing long sleeves and using skeeter spray.

“With the rain and the heat, we’re headed into right now, we’re about halfway up that bell curve,” said ecologist Bek Sudia, who leads a team that conducts mosquito surveillance and control for Multnomah County. “July is really our peak time.”

Sudia’s team travels the county to examine breeding habitats and detect the presence of mosquito-borne disease. From May through September, the team sets up traps in 150 locations.

According to the county, the team has trapped well over 20,000 mosquitoes so far this year, about four times the total for all of 2021.

“Sudia takes those traps and — using a microscope and tweezers — divides mosquitoes into vials and sends 50-bug batches to OSU for testing,” explained the announcement.

In Clark County, the county’s Mosquito Control District has been working to lessen the mosquito population since April and continues to treat areas with high numbers of mosquitoes across the county.

As they work to control the mosquito population, public health officials are suggesting for people to take steps to avoid mosquito bites and remove mosquito habitats on their property.

“The species of mosquitoes that are currently active in Clark County lay their eggs in the damp soil along rivers during late spring and early summer,” said Clark County in an announcement. “As mountain snow melts and water levels rise, those areas become covered with water and the eggs hatch.”

Considering last year’s dry spring and summer, lower water levels meant fewer mosquito eggs hatching and a smaller population of adult mosquitos. That changed this year with the increased rainfall, echoed county officials.

“All of those conditions culminating at the same time created this year’s perfect storm,” said Mario Boisvert, Clark County Mosquito Control District manager.

So, how are officials tackling the mosquito issue in Clark County?

The district used a helicopter to treat more than 1,600 acres of mosquito breeding grounds with larvicide, according to the announcement.

It added, “Now, technicians are setting traps to identity areas with large populations of adult mosquitoes and using trucks to treat those areas. And the Mosquito Control District is working to address more than 300 requests for service submitted over the last three weeks.”

Technicians with the district are also treating thousands of catch basins across the county to prevent the hatching of a species of mosquitoes that can carry West Nile Virus. They also trap the mosquitoes in these areas to test them for this specific virus.

Clark County notes that it has never had a positive test for the virus because of a mosquito sample, but the virus has been detected in mosquitoes in other parts of the state.

Multnomah County has also never returned positive results for the West Nile virus. Last year, ecologists identified West Nile virus in 75 batches of mosquito samples taken across eastern and southern Oregon, said the press release.

“A lot of people say there are no mosquitoes in Multnomah County,” said Emilio DeBess, the public health veterinarian for the Oregon Health Authority. “That’s because Vector Control does an amazing job controlling mosquitoes.”

What can you do to protect yourself?

Clark County officials share these tips:

  • Install or repair screens on windows and doors
  • When possible, stay indoors during dawn and dusk when mosquitoes are most active
  • When practical, wear long-sleeved shirts, long pants, shoes, socks, and hats outside, especially in wooded or wetland areas
  • Place mosquito netting over infant carriers when outdoors
  • Use EPA-registered insect repellents, including those with DEET, picaridin, IR3535 or oil of lemon eucalyptus. Use especially at dawn and dusk. Read the label and carefully follow the instructions for applying repellents, especially when applying on children

Property owners are urged to do the following:

  • Drain standing water from old tires, flowerpots, buckets, plastic tarps, and wheelbarrows
  • Change water in bird baths, ponds, wading pools, pet bowls and animal troughs at least twice a week
  • Repair leaking faucets and sprinklers; clean clogged gutters
  • Properly maintain swimming pools
  • Check for containers or trash in hard-to-see places, such as under bushes