Pennsylvania Releases Zika Action Plan

by | May 13, 2016

By Don Sapatkin

With mosquito season weeks away, Pennsylvania officials on Thursday announced how they would confront the Zika virus, including responses to infections picked up in the Caribbean, a scenario that has not mattered so far because there have been no mosquitoes present to carry the virus.

The plan covers situations all the way up to widespread transmission in multiple counties, although officials believe that is unlikely. Also, the state does not yet have the funding in place to fulfill the plan, which involves stepped up the trapping and killing of mosquitoes.

New Jersey expects to release its own Zika response plan soon, a spokeswoman for the state Department of Health said.

Both states are working to upgrade their laboratories so they can screen blood samples for the virus. Testing currently is done by the U.S. Centers for Disease Control and Prevention, which has a backlog of four to five weeks.

Pennsylvania hopes to be able to turn tests around within one to two weeks, Health Secretary Karen Murphy said in a conference call with reporters.

A faster time will not affect a patient's treatment, as the virus typically produces mild flulike symptoms or none at all. But Murphy said a shorter wait could reduce anxiety among pregnant women, since birth defects have been associated with infections during pregnancy.

Under the plan, multiple positive test results would trigger a series of other actions, from local fliers and tips sent through social media to more intensive surveillance of both mosquitoes and humans living nearby.

The mosquito responsible for nearly all the infections in Central and South America does not thrive in the mid-Atlantic region. But another species, which has transmitted the virus in limited circumstances, is among the most common here, especially in Philadelphia and its inner-ring suburbs.

That mosquito, Aedes albopictus, bites during the day and is particularly challenging to control because it lives in such close proximity to humans that spraying from planes and placing larvicide in sewers has limited effect.

The main control targets must be the "containers" that it prefers: birdbaths, dog bowls, wheelbarrows, lost cups and clogged gutters. The mosquito travels less than a half-mile in its lifetime.

If mosquitoes carrying the Zika virus are found in any significant numbers, an eradication campaign would become very personal, said John Quigley, secretary of the Pennsylvania Department of Environmental Protection.

"We will literally have to go house to house, yard to yard," Quigley said.

"It is very much a ground-troop-oriented approach. And that is why it is so important that the public help us," he added, by getting rid of standing water where mosquitoes breed.

In theory, someone who was infected with Zika during travel in an area where it is common could be bitten by a mosquito after returning home, and that mosquito could pass it on to another human.

That is unlikely to any significant extent, officials say, because small numbers of travel-related human cases would mean small numbers of infected mosquitoes. It also takes time for enough of the virus to grow inside the mosquitoes to make their bites infectious, and albopictus has been a poor transmitter of similar viruses such as dengue.

A handful of infections have also been transmitted through sex or blood.

Travel-related infections from mosquito bites have been confirmed in 18 Pennsylvania residents. Twelve have been confirmed in New Jersey.

According to the Pennsylvania plan released Thursday, if a cluster of positive tests in travelers had come back after June 1, the official start of mosquito season, they would have triggered additional trapping and testing of mosquitoes within 100 yards in each direction, plus eradication measures for larvae and possibly pesticide for adult mosquitoes.

A single suspected case transmitted by local mosquitoes would bring a more robust response, at three times the distance. Confirmed cases would also lead to public communications and possible door-to-door surveillance.

"We really cannot say what kind of transmission we are going to see," Murphy said, "which is why we are preparing."

(c)2016 The Philadelphia Inquirer