Here’s how West Nile is spread — and what symptoms to look for after a mosquito bite
If you’ve been out in the back yard lately, chances are mosquitoes have left their mark.
The springtime rains have helped fuel the mosquito population, including the aedes species that bites during the day.
“As far as miserable, we’re on track for miserable,” said Mike Merchant, a Texas A&M urban entomologist. “A lot of summers, I just bequeath the back yard to mosquitoes. And this may be one of those summers.”
The aedes mosquito is out there in large numbers, but the good news is the rain has helped keep temperatures cooler and wash out pools of culex mosquitoes, which bite at night and carry the West Nile virus.
“The longer we can postpone the dry, summertime heat, the better off we are,” Merchant said.
West Nile season
Last week, Tarrant County Public Health reported its first mosquito positive sample for West Nile in Colleyville. Dallas and Denton counties have also had traps test positive for West Nile this year.
Typically, West Nile peaks toward the end of July, said Nina Dacko, Tarrant County Public Health’s Vector Control supervisor.
“These seasons are unpredictable,” Dacko said. “I don’t have a crystal ball, but my concern is if we don’t see more cases this year, I would be worried about next year.”
The fear is always that Tarrant County could see another season like 2012, when there were 280 human West Nile cases. Most years the number of cases is far less. Last year there were only 18 human West Nile cases in Tarrant County and there were only 20 in 2017.
There are variety of factors that go into West Nile, from temperatures being hot enough for the virus to replicate in mosquitoes to the bird population being susceptible to the virus. This year has also seen birds congregating in different patterns because of the wet weather.
Birds develop immunity after being exposed to West Nile, but younger birds have none. Mosquitoes contract the virus by biting infected birds and then transmit it to humans.
Joon Lee, an associate professor at the University of North Texas Health Science Center in Fort Worth, also expressed concern that DFW may be overdue for more West Nile cases.
Lee oversees a program to trap and test mosquitoes for West Nile across Fort Worth. It includes 53 traps to sample for West Nile. There are also traps in 12 selected city parks and five to monitor for dengue, chikungunya, and zika virus vector mosquitoes.
The lower number of West Nile cases the last two years is one of the “environmental conditions that occur before an epidemic or an increased level of West Nile virus activities,” Lee said in email.
How to protect yourself from mosquitoes
Even if West Nile doesn’t take off this year, it looks like a difficult season to be outdoors.
Jose Bartok, one of the owners of the Mosquito Authority, said his company uses two methods to treat yards — an external misting system and larvicide to control the population.
The misting system isn’t very effective this year, and larvicide requires treatments every 21 days to control the population.
“They are very good breeders,” Bartok said. “We need to cut the life cycle.”
The company’s staff is careful to avoid flowering plants, where beneficial insects like bees and butterflies are commonplace.
“When performed properly, those services work,” said Patrick Prather, owner of Entex Pest Solutions. “These traps are dependent on density. You almost have to treat it like mircohabitats.”
Apply insect repellent
Over-the-counter short-term fixes that work include sprays from companies like Cutter and Off. A good boxfan stationed strategically on a back porch can also provide protection, said Dacko of Tarrant County Public Health.
Applying insect repellent is also highly recommended.
Prather, who also owns Municipal Mosquito, which controls the mosquito population for 60 North Texas cities and counties, said applying bug repellant is essential.
“If you’re going outdoors, use insect repellent every time, preferably containing DEET,” Prather said.
And work to eliminate mosquito habitats around your home.
“Go find those things that are holding water,” Prather said. “The kiddie pool, the children’s toys, buckets, vases, wheels, the landscape drains. Any artificial container around the house is fully loaded this year.”