Zika concern rising, but region 'should be just fine'

"The good news is that Pennsylvania should be just fine," said Herbert Cushing, chief medical officer at Temple University Hospital and an infectious disease expert. "The mosquito that spreads this, the Aedes aegypti species, is not here. It's along the Gulf Coast of the United States but doesn't come much further north than that."

Still, anyone traveling to Brazil or other tropical locations, including Central America, should take precautions, such as using insect repellent and otherwise avoiding getting bitten by mosquitoes, Cushing added.

The virus, first detected in the late 1940s in Africa, didn't draw much notice until last year, when scientists linked an outbreak in Brazil to a small number of cases of birth defects known as microcephaly. It also may cause rare cases of temporary paralysis in adults and miscarriages in pregnant women.

Eighty percent of Zika infections cause no symptoms at all and most of the rest are so minor that public health officials have so far refrained from the common cautions about dangers to the elderly or people with compromised immune systems.

"It is very mild compared to influenza and other diseases like Dengue or Chikungunya, so there is not that much risk for the general population," Raymond Pontzer, an infectious diseases specialist at the University of Pittsburgh Medical Center, said during a conference call with reporters on Friday.

The World Health Organization has said that Zika is spreading so quickly that it could infect up to four million people in the next year. There is no vaccine or treatment for the virus. While mosquitoes are the primary culprit, there has been one report of possible spread of the virus through blood transfusion and another through sexual contact, according to the federal Centers for Disease Control and Prevention. Still, neither is considered a likely way to get the disease.

At least 31 Zika cases have been confirmed in the continental U.S. since last year, including one in North Jersey. All of them were acquired overseas.

A woman visiting Bergen County from Colombia contracted Zika in her home country and became ill while visiting in late November. She made a full recovery.

Pennsylvania has sent blood samples from at least six people for testing to the CDC, which currently has the only lab in the nation capable of testing for the virus, Loren K. Robinson, a deputy secretary of the state Department of Health, told reporters on Friday.

The New Jersey Department of Health does not comment on unconfirmed cases, a spokeswoman said.

Since the disease has been spread elsewhere by a mosquito that doesn't survive in the Philadelphia region, even in summer, entomologist Randy Gaugler said his biggest concern was about a species that he studies and is common locally, Aedes albopictus, the Asian tiger mosquito.

"In the laboratory it can transmit [Zika]. We don't know about in the field," said Gaugler, director of Rutgers University's Center for Vector Biology.

Neil O. Fishman, an infectious diseases expert at the University of Pennsylvania, thought it was unlikely that local mosquitoes would cause widespread disease.

"We haven't seen that with Dengue and we haven't seen that with Chikungunya," he said.

West Nile virus, which arrived about 15 years ago and spread quickly, is carried by a different mosquito, Fishman said.

West Nile caused a vast expansion in mosquito monitoring and control around the country.

Every species has different behavior and migratory patterns; some bite at night, others during the day.

But if Zika does arrive in the region, surveillance would "probably be loosely based on what we do for West Nile," said Robinson, the Pennsylvania health official.

For now, public health officials in the Philadelphia region are downplaying local worries. But they urge pregnant women to postpone travel to areas with ongoing outbreaks. Anyone who has visited the two dozen affected countries and is experiencing the flulike symptoms of Zika - mild fever, headache, joint or muscle pain, red eyes, skin rash, and vomiting - should see their doctor, according to the city's public health department.

Rather than worrying about a virus thousands of miles away, local doctors have other suggestions for residents.

"The flu kills 30,000 people a year in this country," Cushing said. "So this is a good opportunity to remind people that if you're going to do one thing to protect your health this year, go out and get your flu shot."

Michael Weisberg, a University of Pennsylvania professor who studies the scientific method, is leading an alumni trip to the Amazon next month. He is advising passengers to take precautions against bug bites.

"Ironically, the one person who may not travel with us is my wife," said Weisberg, who chairs the philosophy department. "We are considering having a second child and out of an abundance of caution, she may not join the trip."

dsapatkin@phillynews.com215-854-2617@DonSapatkin

Staff writer Sam Wood contributed to this article.

Most of what is known about the mosquito-borne Zika virus comes from its explosive spread in Central and South America. The Philadelphia region is different.

Who should be worried?

For now, public health officials say they are mainly concerned about pregnant women who recently traveled to any of the affected countries. A small number of cases there have been linked to birth defects. Women who are pregnant have been advised to postpone travel to those areas. Pregnant women who recently returned from infected areas should consult their health-care provider.

Could the mosquitoes responsible come here?

The species that caused the epidemic in the tropics, Aedes aegypti, does not live near Philadelphia.

Could other species spread it?

Aedes albopictus, which is common locally, is theoretically able to carry the virus, but there are no known examples outside of laboratory conditions. If it does, then the virus could spread locally.

Whether albopictus, the Asian tiger mosquito, would be an efficient vector - able to easily transmit the virus from one animal to another when it feeds on blood - is unknown.

Could the virus mutate?

A mutation that allows Zika to be carried by other mosquito species is possible. The likelihood is unknown.

Could it be transmitted in other ways?

Widespread person-to-person transmission is very unlikely. Viruses like dengue, which has been carried by the same mosquitoes for years, are not passed from one human to another.

Transmission via blood transfusion and sexual contact have been reported but not confirmed.

What are the symptoms?

They are similar to the flu, although Zika typically is milder. Four out of five infections cause no symptoms at all.

How can I protect myself from Zika?

Unlike many developing countries, the United States has established mosquito-eradication programs; most houses have window screens; and many homes and workplaces are air-conditioned.

If Zika arrives in the region, expect public-health officials to give the same antimosquito guidance that they do for West Nile virus, only louder: Get rid of standing water, where the insects lay their eggs: birdbaths, old tires, cans, gutters. Repair broken screens. Wear long pants and shirts when mosquitoes are active, and use insecticide containing DEET.

What's the big deal?

Residents of the Americas do not have immunity to the virus. Birth defects as well as temporary paralysis in adults are rare but serious. Perhaps the biggest concern is that so much about Zika is unknown.

- Don Sapatkin