C.D.C. Is Monitoring 279 Pregnant Women With Possible Zika Virus Infections

[Guest Nicole]

Doctors are monitoring 279 pregnant women with confirmed or suspected Zika virus infections in the United States and its territories, federal health officials said Friday.

Of those women, 157 are in the 50 states and the District of Columbia, and 122 are in territories, including Puerto Rico. Public health officials are gathering data on the health consequences of the infection, including the rate at which fetuses develop abnormally shrunken heads and brain damage, a birth defect called microcephaly.

Also on Friday, the World Health Organization confirmed that the strain of Zika virus in Cape Verde, just off the western coast of Africa, is the same strain that is spreading in Brazil. Almost 200 pregnant women in Cape Verde have been infected, and the virus has been blamed for three cases of microcephaly there.

The rising numbers of pregnant American women testing positive — Friday’s figure is more than double the previous count of 113 — reflect a new case definition used by the Centers for Disease Control and Prevention rather than a surge in cases, according to Dr. Margaret Honein, the chief of the agency’s birth defects division.

No cases transmitted by mosquito have yet been reported in the 50 states. The number of infected pregnant women in this country began rising dramatically in February, probably reflecting the spread of the Zika virus from Brazil to more countries visited by Americans.

Most of the 279 women are still pregnant, Dr. Honein said, and fewer than a dozen have experienced “adverse outcomes,” such as stillbirths, microcephaly or other congenital problems.

A “relatively small number” of the infections clearly resulted from sexual transmission rather than mosquito bites, she added. But in most cases, it was difficult to determine how the women became infected because they had lived in or had traveled to areas where mosquitoes carrying the virus were biting.

The C.D.C. previously reported only pregnant women with symptoms like rash, fever or bloodshot eyes. But “we’ve learned a lot in the last four months,” Dr. Honein said.

At least four published studies have cited cases in which women with no memory of having symptoms gave birth to children with birth defects.

The new case definition includes all women who have had a positive test for Zika virus, or a likely positive for antibodies to it.

Antibody tests are not as accurate as tests for the virus itself because previous infections with dengue fever or shots to prevent yellow fevercan create false positives.

“C.D.C. wants to make sure we are monitoring all women at risk for poor outcomes,” said Dr. Denise J. Jamieson, a co-leader of thepregnancy and birth defects team at the agency.

Each Thursday, the agency will update the number of infected pregnant women in the United States, officials said.

The outbreak in Cape Verde, a Portuguese-speaking country with close links to both Brazil and West Africa, has been a puzzle for months.

The intense outbreak in the island nation started last October, just as Brazil’s surge in microcephalic babies was detected. But confirmation that it was caused by the Brazilian strain, rather than the much older African one, did not come until the Pasteur Institute in Dakar, Senegal, sequenced the genomes of the infecting viruses.

Cape Verde’s outbreak is now fading, said Dr. Matshidiso Moeti, the W.H.O.’s regional director for Africa, and there has been no outbreak in Senegal, which she called Cape Verde’s “door out to other countries.”

Although that might suggest that Africans have some immunity, “it’s never good news to hear that a virus with neuropathic effects is on your doorstep,” said Dr. Bruce Aylward, the W.H.O.’s chief of emergency response.

“We don’t know what the level of population immunity is in Africa, and we don’t know if it will mitigate some of the impact,” he said. “So we have to work against a worst-case scenario.”

Although laboratory capacity in Africa has been built up in the wake of the 2014 Ebola outbreak, the continent is still very poor and the response to the W.H.O.’s appeal to donors for a $50 million Zika fund has been “anemic,” Dr. Aylward said.

A recent study in Clinical Microbiology Reviews looked at 80 sets of blood tests for the Zika virus in countries around the world between 1947, when the virus was discovered in Uganda, and 2014, when it was detected in French Polynesia — the last major outbreak before it reached South America.

Some samples are small, some tests used methods that would confuse Zika with related viruses, and the results range wildly: For example, 12 percent of 261 Ugandans tested in the 1940s were immune to the virus, while nearly 60 percent of 2,457 Senegalese tested in the 1970s were.

The authors concluded that the Zika virus was probably endemic to all of sub-Saharan Africa, although there was no way to know how many people had immunity at any given time.

Although Dr. Aylward said it is still not known whether immunity to the African strain confers protection from the Brazilian one, Scott C. Weaver, the director of the Institute for Human Infections and Immunity at the University of Texas Medical Branch in Galveston and an expert on the Zika virus, said he would be “very surprised if there weren’t complete cross-protection between the two.”

Genetically, the two strains are very closely related, he said. By contrast, strains of yellow fever have much more variation, and yet he did not know of a single instance in which the yellow fever vaccine, which is based on one strain gathered years ago, failed to protect against the other strains.

Testing in animal models, including immune-deficient mice, has just begun, he said, but he could not name any laboratory trying to prove that infection with one strain of Zika protects against later infection with another.

“We assume there’s cross-protection, and we’re interested in other questions,” he said, including whether microcephaly is typically caused by Zika alone.

At the White House on Friday, President Obama pressured Congress to give him $1.9 billion for the fight against Zika.

Americans should tell their Congressional representatives to “get on the job,” he said.

“This is something that is solvable — it is not something that we have to panic about, but it is something we have to take seriously,” Mr. Obama said in the Oval Office after a briefing from top health officials.

Congress should not take its scheduled Memorial Day vacation without passing the legislation, he said.

His advisers have said the president would veto a House measure that provides only $622 million. The administration was “encouraged” by the Senate’s $1.1 billion version but is not promising to sign it.

Referring to the funding Mr. Obama has requested, “anything short of that will be insufficient,” said Eric Schultz, the deputy White House press secretary.

Source: http://www.nytimes.com/2016/05/21/health/pregnant-women-zika-virus-cdc.html?_r=0