As Mosquito Season Ramps Up, Harris County Virologists React With Speed

Recent data has shown Texas in the top 20% of states for mosquito-borne infections

Last May, the Centers for Disease Control (C.D.C.) reported the number of people getting infections from the insects has tripled since 2004, with Texas being one of the worst states, landing in the top 20 percent for mosquito infections.


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The C.D.C. says one of the main problems in fighting insect-borne disease is that local governments often lack the know-how to fight back.

This Centers for Disease Control map shows Texas in the top 20% of states seeing diseases from mosquitoes.

But even though Texas is one of the states hit hardest, federal officials have praised the mosquito control department in Harris County.

"Personally out of, if I were to give them a rank out of 1 to 10, I'd give them a 10," said Janet McAllister, an entomologist with the C.D.C.

So, why the 10 out of 10? We found the answer out in a couple brick buildings just off of the South Loop.

Christy Roberts is an entomologist with Harris County. Part of her job is to sort frozen mosquitoes the county has trapped into vials separated by species.

"It's just my thing,” Roberts said, “as an entomologist, everyone has their particular insect they like to look at or study and mosquitoes just happen to be mine."

Once she gets done sorting through different species, she sends the bugs, marked with numbers corresponding to trapping locations, over to the virology lab.

There, behind an airlock, Cynthia Freeman oversees the team that tests for viruses, where they take the vials and put through a centrifuge.

“A nice mosquito malt is what we call it," Freeman said.

With that mosquito malt, they can test for just about anything, including West Nile virus and Zika. One of the tests for chikungunya looks like a pregnancy test.

Freeman was testing for chikungunya, a disease which causes fever and joint pain among other symptoms, the day News 88.7 visited. Those tests came back negative.

"That's very good to hear," she said.

Cynthia Freeman demonstrates a test for chikungunya at the Harris County Mosquito and Vector Control virology lab.

Many vector control divisions in the country, including divisions in Texas, aren't able to do these tests due to a lack of funding or proper facilities.

"We're very very proud and fortunate to have a virology lab here,” Freeman said. “We are one of just a few throughout the country, so we are very unique in that regard."

Some control departments have to send samples either to hospitals or to state labs, which can take a while, and from a public health perspective, that leaves a pretty large gap between when you detect disease and when you can eradicate it — more people can get sick.

But in Harris County, once virologists find a virus in a local mosquito, they can refer back to a log of exactly where those mosquitoes were caught and have trucks sent out, almost immediately, to spray insecticide at that particular site.

Harris County only sprays insecticide where they detect disease, so nuisance mosquitoes, they don't actively try to fight them.

They are trying some new methods, though. Mustapha Debboun, the program's director, shows an experimental trap that can sort mosquito species out by itself, and it keeps track of when and under what conditions it actually caught the bug.

"That's good data,” Debboun said, “because if someone were to ask me and say, this such and such mosquito… Sometimes we can guess and say it's only a night-time mosquito or a daytime mosquito. Well this, what if this records it showing up at 10 o'clock at night, now that's data that no one has before."

Debboun said the insights they gain from the traps may help out other mosquito control divisions around the country.

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