Health Department lab techs extract DNA from mosquitoes as first line of defense against West Nile

Wet spring, summer means mosquitoes galore
Posted at 11:28 PM, Jul 27, 2019

DENVER -- Deep inside the state health department's labs at Lowry, technicians are busy testing vials of mosquitoes for West Nile virus.

"You can put up to 65 mosquitoes in here," said Ralen Johnson, holding up a single vial.

The molecular technologist said the mosquitoes come from counties all across Colorado.

Promise made to father

Rose Gallegos, who lives just west of Ruby Hill Park, is thankful the testing is taking place.

Her father, Jesse, died from a severe, neuroinvasive form of the disease, in 2013.

"It was brutal," she said.

Mr. Gallegos was bitten on his foot in 2008.

He had come home from work and sat down to relax on his front porch.

"All of a sudden, I felt like something bit me," he told Denver7, during a 2011 interview.

Two weeks later, he was in the hospital.

He had contracted encephalitis, became paralyzed and died five years later.

"Knowing that a mosquito took my father down is horrible," Rose Gallegos said, "I promised him that I would be an advocate for the rest of my life, to warn people that West Nile is not to be played with."

Early Warning

The state's microbiology manager, Sarah Totten, PhD., told Denver7 that the most important part of their West Nile lab work is "to be able to tell which part of our state is being impacted by the virus."

"The beauty of that testing," she said, "is that we're able to identify that West Nile virus prior to humans becoming ill."

"The first thing we do is get the word out so that people can take personal responsibility to protect themselves," said Emily Travanty, PhD., deputy director of the health department's Disease Control & Environmental Epidemiology Division, "and then the division also partners with mosquito control districts to look at how to address the (mosquito) population scale."

Johnson adds saline to the vials of mosquitoes, shakes them up, and then places them in a centrifuge.

Once separated into liquids and solids, she places the liquid in a programmable machine that extracts DNA.

That machine extracts DNA from the samples, and determines whether the mosquitos were "positive" for West Nile.

Does wet spring increase risk?

With our wet spring and early summer, some people wonder if that puts Coloradans more at risk for West Nile.

"Unfortunately, we cannot really predict what kind of season we're going to have, in terms of illness," said Dr. Jennifer House, a veterinarian.

She said one in five victims will experience symptoms, which can include aches and pains and chills.

"Ten percent of those who experience symptoms will get the neuroinvasive disease," House said.

Gallegos told Denver7 that's why it's important to wear long sleeves and slacks at dusk and dawn, and to use products containing deet, until the first freeze.

One one person has tested positive for West Nile in Colorado this season.

Health officials believe the patient contracted the virus out of state.

So far, none of the mosquitoes tested at the state labs have been positive, but health officials say a batch tested at a lab in Pueblo did turn up positive.

People in Pueblo should take take extra precautions to protect themselves.