Can ticks and mosquitoes infect you with COVID-19?

Unprecedented numbers of people are out on our hiking trails, seeking relief from quarantine with healthy outdoor activity. In pursuit of that outdoor fun, many people are in fact taking serious risks, including jumping off cliffs into our dangerous waterfalls (where there is a death about once every two years, see story at left) and hiking on trails that are overcrowded. 

But one thing we don’t have to worry about, it appears, is getting infected with COVID-19 by a tick or mosquito. 

Philip Armstrong is a virologist/medical entomologist with the state Department of Environmental Sciences at the Center for Vector Biology & Zoonotic Diseases, which is at the Connecticut Agricultural Experiment Station in New Haven.

His office had contacted us, as they often do, with information about testing of mosquitoes for infectious diseases. I asked him about COVID-19 and he reassured me that the coronavirus can’t be transmitted by insects. 

“There are no biting insects or ticks that can transmit COVID-19,” he said in an email last week. “This is a respiratory virus that is discharged in saliva and mucus by sneezing, coughing, breathing or talking. It is not a blood-borne virus and therefore, it doesn’t get picked up by mosquitoes  or ticks during blood feeding.

“The virus must also be able to replicate in the mosquito or tick before being transmitted. There are very select viruses that are adapted to this specialized mode of transmission and a respiratory virus like COVID-19 is not one of them.”

That doesn’t mean, however, that you should relax your normal vigilance when you’re out in the woods. Ticks didn’t suddenly become less dangerous because there is a global pandemic. 

“Ticks and mosquitoes transmit a number of other pathogens that are of concern,” Armstrong said. “The bigger risk at this time of year (May-July) are the tick-borne diseases when the tiny deer tick nymphs are most active. 

“These ticks transmit the agents of Lyme disease, babesiosis, anaplasmosis and Powassan encephalitis.  

“Mosquito-borne diseases like West Nile virus and eastern equine encephalitis (EEE) virus occur later in the summer (July-September).”

As Armstrong is clearly a person who is keen not to be bitten and infected, I asked him what he recommends as protection for anyone who spends time outdoors.

“To prevent your exposure to ticks and mosquitoes:

• Cover-up!  Wear long pants and long-sleeved shirts. Clothing material should be light-colored and tightly woven.

• Tuck pant legs into socks to prevent tick bites.

• Wear insecticide-treated (permethrin) clothing.

• Use an EPA-approved insect repellent on exposed skin surface and apply according to directions.

• Perform frequent tick checks when outdoors and at home.”

The Environmental Protection Agency (EPA) list of approved repellents can be found at www.epa.gov/insect-repellents.

Permethrin is not a completely benign insect repellent. According to the National Pesticide Information Center, the jury is out on whether it can cause cancer. 

There is an explanation of how it works on the center’s website. “Permethrin affects the nervous system in insects, causing muscle spasms, paralysis and death. Permethrin is more toxic to insects than it is to people and dogs. This is because insects can’t break it down as quickly as people and dogs. Cats are more sensitive to permethrin than dogs or people because it takes their bodies a long time to break it down.”

If that makes you nervous, you might want to look into repellents made with picaridin, which is a distant cousin to black pepper. The government generally doesn’t think picaridin will cause cancer in humans. It also doesn’t kill insects; it just makes it hard for them to smell and find human prey. 

If you’re outdoors all the time, you might need the more intense protection of permethrin. For a hike in the woods, you can try the picaridin. No matter what, take a soapy shower and shampoo your hair when you get home, and do a thorough tick check.