Doctor: Zika is a delayed epidemic

Peak season for the spread of mosquito- borne illnesses has come and nearly passed without a single confirmed case of Zika transmitted in Texas.

Time to breathe a sigh of relief?

“No, quite the opposite, I think,” said Dr. Peter Hotez, dean of the national school of tropical medicine at Baylor College of Medicine and one of the world’s foremost Zika experts.

For months, Hotez has been warning that without an aggressive federal strategy to fight the spread of the virus, Zika likely would spread to Houston and other areas along the U. S. Gulf Coast. Now, the most critical period in that effort has passed, with Congress still deadlocked on approving funding.

On a conference call with reporters last week, U. S. Sen. John Cornyn of Texas touted the latest proposal by Republicans to end the monthslong partisan stalemate over

passage of Zika funding legislation. The $1.1 billion proposal — part of a broader stopgap appropriations bill to keep the federal government operating beyond Oct. 1 — comes seven months after President Barack Obama requested $1.9 billion from Congress to combat the virus.

The vote on the revised measure, which is expected this week, will coincide with the official end of the peak season for mosquitoborne illness in Houston and along the Gulf. The timing couldn’t be better, Hotez said, sarcastically, on Friday.

“The money will go to great use,” he said. “Next year.”

Most of that money would go toward developing a Zika vaccine and to eradicating mosquitoes in Florida and along the Gulf. The funding still isn’t a sure thing; some Senate Democrats have signaled they won’t support a bill that doesn’t also allocate federal aid to address the lead-contaminated public water system in Flint, Mich.

Without the federal money for ramped-up mosquito control and patient screening, Hotez worries the virus has been allowed to spread here in the Houston area for weeks, unchecked and undetected.

“The problem with Zika is it’s what I call a ‘delayed epidemic,’ ” he said. “So we’re not going to know if we’ve had local Zika transmission until seven or eight months from now, when babies are born with microcephaly. Only then will we begin to understand the scope of this thing.” No obvious symptoms

Microcephaly — a birth defect characterized by an abnormally small head and incomplete brain development — has become the most identifiable consequence of a virus that’s proved difficult to detect. It’s estimated 80 percent of Zika patients experience no obvious symptoms; many of the rest develop only a minor fever or rash and don’t bother seeing a doctor. In early August, Harris County health officials said a baby born here died from microcephaly, the first and only confirmed Zika-related death in Texas. The mother had traveled to Latin America during her pregnancy.

If doctors aren’t actively testing the patients who do come — in Texas, only those who’ve traveled out of country are routinely tested — the only way to detect Zika is through serendipity, Hotez said. That’s what happened with a patient last month in Miami, where health officials have since confirmed about 100 others have contracted the illness from mosquito bites. In the aftermath, officials have stepped up mosquito control and patient screenings.

“This same series of events is likely going on in multiple cities on the Gulf Coast, including Houston, but the stars just haven’t aligned for a serendipitous diagnosis,” Hotez said. “That’s why I say we won’t know the extent of this Zika outbreak until next April or May, when the first babies are born.” ‘Hard to believe’

Without federal money, Zika prevention efforts have been left to state and local health departments. In Harris County, that’s meant spraying for mosquitoes and encouraging residents to prevent standing water from pooling on their property. The county also has been trapping and testing mosquitoes for Zika but has yet to find the virus.

Dr. Catherine Troisi, infectious disease epidemiologist at UTHealth School of Public Health in Houston, said that offers some reason for hope. In Miami, mosquitoes have tested positive for the virus.

“Maybe it hasn’t spread here,” Troisi said. “If 80 percent of cases are asymptomatic, that means 20 percent are, and we haven’t seen those. Maybe that’s good enough.”

Area health officials aren’t banking on it. At Baylor, researchers have begun working with the National Institutes of Health on a study of people infected with Zika. A few locals who’ve tested positive for the virus already have agreed to participate, said Dr. Shital Patel, the principal investigator on the project. The goal is to study how the immune system responds to the infection and help the development of a Zika vaccine.

In Texas, state officials have confirmed about 200 cases of Zika, almost exclusively among people who’d traveled to countries where Zika is prevalent. Two people who were diagnosed had sexual contact with travelers. About 75 of the cases have been reported in Greater Houston, which is more at risk due to the number of residents who travel internationally, experts say.

“Remember, that’s how many have been diagnosed,” said Baylor’s Hotez, who estimated the actual number of travel-related Zika cases in Texas at between 2,000 and 10,000.

The way Hotez sees it, the question isn’t if Zika has spread locally, but how extensively.

“It’s hard to believe that we’re not going to have Zika transmission in Texas,” he said.