- The Washington Times - Wednesday, December 27, 2017

Zika has largely “burnt out” in the Americas, health experts say, with the disease that just a year ago spawned dire travel warnings, changed vacation plans and almost forced a federal government shutdown now dissipating with a whimper.

The number of cases has dropped dramatically in the continental U.S., from more than 200 mosquito-bite infections in 2016 to just four — two in Texas and two in Florida — this year.

The U.S. territories, which were swamped with nearly 36,000 locally transmitted cases last year, saw slightly more than 600 this year — a drop of 98 percent.

Scientists say the virus’ swift march through the Americas in 2015 and 2016 provides the best explanation for the drop-off, since the blitz produced a robust immune response. Also, 4-in-5 people who contract the virus don’t show symptoms, so they probably didn’t even know they had it.

Some hot spots in South America and Mexico still report elevated transmission, but the disease has lost the fear factor that sparked government warnings to women and their partners planning or in the midst of pregnancy to drop some countries and U.S. neighborhoods from their travel plans.

The Centers of Disease Control and Prevention said it wasn’t surprised to see a downturn in 2017, particularly in Puerto Rico, since a swath of the population is no longer susceptible to the disease.

“However, mosquito-borne disease outbreaks are difficult to predict. There will be future outbreaks, including large ones, as well as years with reduced transmission, but it is impossible to know when or where these transmission patterns will occur,” said agency spokesman Benjamin Haynes. “CDC expects that local spread of Zika virus will continue in many places that experienced large epidemics in 2016, including Puerto Rico, but new large epidemics are not likely in these locations in the near term.”

It’s quite a turnaround from one year ago, when the Zika panic gripped the U.S. and Florida Gov. Rick Scott, facing dozens of mosquito-borne cases, shuttled to Washington to demand a federal contribution for an overdue response to the virus linked to microcephaly — a condition in which babies born to infected mothers have abnormally small heads.

After months of wrangling and a near-government shutdown, Congress approved $1.1 billion in Zika-fighting aid.

The federal government has used up all but a tiny fraction of the money, but with case counts way down, policymakers have moved on to new fights and the Trump administration hasn’t asked for any more cash, saying the normal budget is good enough.

At-risk states along the Gulf Coast say they put the 2016 supplemental funding to good use — from bolstering mosquito surveillance to protecting the blood supply — and that they have enough resources to handle the threat moving forward, barring an explosion of cases.

“Many of these activities, now that they are in place, can be absorbed by routine and expected yearly funding,” said Samantha Hartmann, spokeswoman for the Louisiana Department of Health.

Louisiana officials said big awareness campaigns on Zika will expire, but the state is in a good place overall as it monitors Aedes aegypti mosquitoes.

Counterparts in Texas say they have “the funds needed for our current activities,” while those in Florida said “the current funding is sufficient to cover our planned response.”

Michael Kaufman, an associate professor of entomology at Michigan State University, said he thought the congressional response to the Zika scare last year “was a bit over-reactive,” though the money likely sped up efforts to contain the virus in hard-hit Puerto Rico and created awareness about the threat of insect-borne diseases.

For instance, Texas officials proactively urged Houston residents to clear away standing water where mosquitoes could breed after Hurricane Harvey flooded the region.

The two locally contracted cases out of Texas this year involved people who appeared to have been bitten in counties near the Mexican border but didn’t know it until later, when lab tests revealed evidence of an infection.

In October, Florida officials said a mosquito appeared to carry the disease from someone who had been infected in Cuba to a partner, meaning transmission didn’t extend beyond their household.

A month later, they said a person in Miami-Dade County tested positive for the virus but hadn’t traveled to a Zika-affected nation or have a sexual partner who had been to one of those areas.

The CDC’s website counts only three cases — not four — nationwide, though the agency said the discrepancy could be due to the lag time in reporting the cases up the chain, from the state to federal level.

Experts say despite Zika’s slowdown, the disease is relatively new to the Western Hemisphere, so it’s difficult to predict what will happen in coming years. Mosquito-borne diseases such as dengue have been known to go quiet and then flare up again, especially in the summer and fall months.

“This means if that if you think you might become pregnant around that time you want to have a conversation with your obstetrician about ways to protect yourself against mosquito bites,” said Peter J. Hotez, dean of the National School of Tropical Medicine at the Baylor College of Medicine in Houston. “Unfortunately we will not have a Zika vaccine in time for any summer 2018 outbreaks if they should occur.”

Earlier this month, the National Institutes of Health said an investigational Zika vaccine proved to be safe and produced an immune response in first-phase testing. The trial vaccine uses the “protein shell” of inactive particles from the virus to trigger antibodies, without actually infecting recipients of the shots.

“We feel cautiously optimistic that this will be a reasonably prime candidate as a vaccine for Zika,” said Anthony Fauci, NIH’s director for infectious diseases.

Dr. Fauci said if there is another outbreak in the coming year, scientists may be able to use that population to gather data on its immune-producing properties faster. In that case, researchers may submit the vaccine candidate for licensure by the end of 2018 or start of 2019.

Otherwise, the process could take until late 2019 or 2020.

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