Texas' Zika Numbers Are Way Lower Than Florida's – But Why?

Jun 24, 2016

States that are home to the aedes agypti mosquito have been keeping tabs on confirmed cases of the Zika virus, which can cause severe birth defects in unborn children.

So far, states have reported primarily travel-related cases and just a few that were sexually transmitted.


Texas has roughly seven million more people than Florida. Based simply on probability, Texas would be expected to have more Zika cases – but it doesn’t. Right now, Texas has recorded 46 cases of the virus, while Florida has reported 183. There are countless possible reasons for why this could be happening. University of Florida Professor Phil Koehler suspects it’s “probably a combination of surveillance and people cooperating with the surveillance, and also the vast number of guests that we have coming in from countries that have Zika epidemics coming on.”

But the Dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, Dr. Peter Hotez, is not convinced travel patterns tell the whole story of why Florida has, or has found, more cases of Zika so far.  

“It would be difficult to just ascribe that to just differences in people coming in. You know the cities of Texas: Houston, San Antonio, Dallas, are really gateway cities,” he said.

Florida’s Health Department, however, does think that it’s travel patterns driving their high Zika numbers. But Hotez says the big factor being overlooked is, as Koehler said, surveillance.

“The way we are going to know if Zika is occurring on the Gulf coast is probably through people, and that is doing programs of active surveillance.  Going into affected communities and communities that you might think be affected, and taking blood samples and testing people for Zika. That unfortunately is very labor intensive and expensive,” Hotez said.

This could be where Florida has been stepping up its game when it comes to Zika. “There have been states of emergency for public health declared in at least 20 counties in Florida,” Koehler said. “So, that means there have been special efforts to try to find and diagnose cases as fast as they can.”

Earlier this month, Houston Mayor Sylvester Turner asked state officials to do exactly that here in Texas. He wants Texas to declare Zika “a public health emergency” in an effort to get money directed toward local efforts to fight the virus. But Dr. Hotez says it will likely take more than that. Ultimately, he says, both Texas and Florida are probably only catching a small percentage of cases right now anyway. Hotez says in order to really measure the scope of the problem, it’s going to take a lot of federal money.

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