The Zika Virus Takes A Frightening Turn — And Raises Many Questions | KERA News

The Zika Virus Takes A Frightening Turn — And Raises Many Questions

Jan 22, 2016
Originally published on January 29, 2016 11:26 am

Something new — and quite frightening — appears to be happening with the Zika virus.

For decades Zika was a virus that turned up in monkeys and occasionally in humans in Africa and Southeast Asia. Its symptoms were mild and the number of confirmed human cases was low.

The first big outbreak was on the island of Yap in Micronesia. Three quarters of the island's population were infected — about 5,000 people. But few of them reported any symptoms.

Things began to change last year. The virus, which is spread by mosquitoes, turned up in Brazil. There have been at least half a million cases there and the virus has appeared in many other countries in Latin America and the Caribbean.

Why is this virus spreading so rapidly?

"We do still know so little about this virus and the harm that it can cause," says Albert Ko, an epidemiologist from Yale who has been working with the Brazilian Ministry of Health to investigate the Zika outbreak. "This is really a relatively new pathogen." Indeed, the virus was first identified in 1947 in a rhesus monkey in Uganda's Zika forest (which gave the disease its name).

Ko says it may be that the Americas are fertile ground for the virus — this hemisphere has the right type of mosquitoes to transmit Zika and people have no immunity to it.

Or it may be that the virus has mutated.

"This may be a new strain that's traveling very quickly but we really don't know," says Ko.

And along with the increase in numbers has come a disturbing development. In October, Brazilian health authorities noticed a surge in the number of babies born with a birth defect called microcephaly, characterized by smaller than normal heads and severe brain damage. Could the birth defect be linked to instances of Zika in the mother when she was pregnant?

The link between Zika and microcephaly, the condition where a baby's brain and head don't fully develop, still hasn't been proved definitely. But health officials are operating under the assumption that there is one. Brazil reported only 150 cases of microcephaly in 2014 before the virus arrived yet has recorded nearly 4,000 cases of the birth defect since October.

Officials in Brazil and Colombia have taken the extraordinary step of asking women to not get pregnant. The risk to pregnant women is thought to be greatest if she contracts the virus during the first trimester of pregnancy.

Marcie Treadwell is a fetal medicine physician at the University of Michigan in Ann Arbor. She says it's possible that in many more babies the virus is causing less severe forms of brain damage that will only become apparent later: "We don't know the full range of the impact of the virus."

Indeed, there are many unanswered questions. Since many people who get infected with Zika don't get sick at all, she says, "there may be a whole host of women who have had the virus while pregnant who have kids who are completely normal — or [who may] appear completely normal [but will] develop mental issues as these kids get older. We just don't know."

Currently there's no treatment for Zika. Nor is there a vaccine. All the experts can say is that pregnant women should avoid mosquitoes, says Dr. Denise Jamieson, a medical officer with the CDC in Atlanta.

She adds: "There's no intervention that we have to prevent the development of microcephaly."

About a half-dozen cases of Zika have turned up in the U.S. over the past two weeks — all in travelers returning from parts of Latin America and the Caribbean where the outbreak is raging. CDC officials predict any outbreaks in the U.S. mainland will be localized and relatively small because Americans have better access to screens and air-conditioning to protect themselves from mosquitoes.

Watch NPR Goats and Soda's Live Q&A On The Zika Virus

On Tuesday, Jan. 26 at 11 a.m. ET, NPR's Goats and Soda blog will host a live video Q&A on the Zika virus with NPR correspondents Lourdes Garcia-Navarro and Jason Beaubien. Submit your questions about the disease in a comment below, or use the hashtag #ZikaQA, and our correspondents will answer a few in our live Web stream.

Copyright 2016 NPR. To see more, visit http://www.npr.org/.

Transcript

ARI SHAPIRO, HOST:

The Centers for Disease Control and Prevention has expanded the list of countries that pregnant women should avoid because of the Zika virus. Health officials say the mosquito-borne illness may cause severe birth defects. In Brazil, where there's been an outbreak, thousands of babies have been born with brain damage. As NPR's Jason Beaubien reports, researchers say those cases may be just the beginning.

JASON BEAUBIEN, BYLINE: Something new and quite frankly frightening appears to be happening with the Zika virus right now. For decades, Zika was a virus that turned up in monkeys and occasionally in humans in Africa and Southeast Asia, but its symptoms were mild and the number of confirmed human cases was extremely low. But in 2007, there was a big Zika outbreak in the island of Yap in Micronesia. Seventy-five percent of the island's population got infected, or about 5,000 people. Still, few people reported any symptoms at all. Then in October of last year, babies started turning up with smaller than normal heads in Brazil.

ALBERT KO: We do still know so little about this virus and the harm that it can cause. This is really a relatively new pathogen.

BEAUBIEN: Albert Ko, an epidemiologist from Yale, has been working with the Brazilian Ministry of Health to investigate the Zika outbreak. The big question now is, why all the sudden is this virus spreading like wildfire? Ko says it may be that the Americas are fertile ground for the virus. This hemisphere has the right type of mosquitoes to transmit Zika and people have no immunity to it. Or, it may be that the virus has mutated.

KO: This may be a new strain that's traveling very quickly that's been able to adapt itself to the mosquito. But we really don't know. We have to do more - you know, there's more work that needs to be done.

BEAUBIEN: The CDC has issued a travel alert for pregnant women encouraging them to avoid 22 tropical countries where Zika transmission has been reported. Officials in Brazil and Colombia have taken the extraordinary step of asking women to not get pregnant. The link between Zika and microcephaly, a condition where a baby's brain and head don't fully develop, still hasn't been definitively proven but health officials are operating under the assumption that there is one. Brazil reported only 150 cases of microcephaly in 2014 before the virus arrived yet has recorded nearly 4,000 cases of the birth defect since October.

Marcie Treadwell is a fetal medicine physician at the University of Michigan in Ann Arbor. She says it's possible that in many more babies the virus is causing less severe forms of brain damage that will only become apparent later.

MARCIE TREADWELL: We don't know the full range of the impact of the virus.

BEAUBIEN: Given that many people who get infected with Zika don't get sick at all, she says...

TREADWELL: There may be a whole host of women who have had the virus while pregnant who have kids who are completely normal or that maybe appear completely normal that develop mental issues as these kids get older and we start to see some of the impact. We just don't know the range.

BEAUBIEN: Currently there's no treatment for Zika nor is there a vaccine. A half dozen cases of Zika have already turned up in the U.S. over the last two weeks, all of them in travelers returning from parts of Latin America and the Caribbean, where the outbreak is raging. CDC officials, however, predict any outbreaks in the U.S. mainland will be localized and relatively small because Americans have better access to screens and air conditioning to protect themselves from mosquitoes. Jason Beaubien, NPR News. Transcript provided by NPR, Copyright NPR.