Puerto Rico declares Zika outbreak over, CDC maintains travel warning

Aedes aegypti mosquitoes are seen at the Laboratory of Entomology and Ecology of the Dengue Branch of the U.S. Centers for Disease Control and Prevention in San Juan, Puerto Rico, March 6, 2016. REUTERS/Alvin Baez/File Photo

By Julie Steenhuysen

(Reuters) – Puerto Rico on Monday declared that the 2016 Zika epidemic is over, saying transmission of the virus that can cause birth defects when pregnant women are exposed has fallen significantly.

About 10 cases of the mosquito-borne disease have been reported in each four-week period since April 2017, down from more than 8,000 cases reported in a four-week period at the peak of the epidemic in August 2016, the Puerto Rico Health Department said in a statement.

The U.S. Centers for Disease Control and Prevention, however, has not changed its travel advice, noting that pregnant women should not travel to Puerto Rico.

The CDC said its travel notice for Puerto Rico remains in place and that it expects the virus will continue to “circulate indefinitely” in most regions where it has been introduced.

The Department of Health and Human Services declaration of a public health emergency in Puerto Rico relating to pregnant women and children born to women with the virus remains in effect, the CDC said in an emailed statement on Tuesday.

On its website, the CDC cites public health reports saying that “mosquitoes in Puerto Rico are infected with Zika virus and are spreading it to people.”

CDC acting Director Dr. Anne Schuchat said in a statement that she is “pleased that the peak of the Zika outbreak in Puerto Rico has come to a close.” However, she said, “We cannot let our guard down.”

Schuchat said CDC will continue to focus on protecting pregnant women and work closely with the Puerto Rican health department to support Zika surveillance and prevention efforts on the island, which is a U.S. territory.

A major outbreak of Zika began in Brazil in 2015 and spread rapidly to dozens of countries. There is no treatment for Zika, but private companies and governments are working on a vaccine.

In addition to Puerto Rico, the CDC has warned of a risk of Zika infection for travelers going to Mexico, Cuba, most of the Caribbean and South America, as well as parts of Africa and Southeast Asia. http://bit.ly/2m50Lf7

Locally transmitted Zika cases have also been reported in Texas and Florida.

(Reporting by Julie Steenhuysen in Chicago; Editing by Lisa Shumaker and Jonathan Oatis)

CDC says 157 pregnant women in U.S. test positive for Zika

A pair of Aedes albopictus mosquitoes are seen during a mating ritual while the female feeds on a blood meal in a 2003 image

By Ransdell Pierson and Bill Berkrot

(Reuters) – Some 157 pregnant women in the United States and another 122 in U.S. territories, primarily Puerto Rico, have tested positive for infection with the Zika virus, the U.S. Centers for Disease Control and Prevention said on Friday.

The CDC, in a conference call, said that so far fewer than a dozen of the infected pregnant women it has tracked in the United States and Puerto Rico have had miscarriages or babies born with birth defects. This was the first time the agency had disclosed the number of Zika-infected pregnant women in the United States and its territories.

U.S. health officials have determined that the mosquito-borne virus, which can also be transmitted through unprotected sex with an infected person, can cause microcephaly, a birth defect marked by unusually small head size, and can lead to severe brain abnormalities and developmental problems in babies.

The agency told reporters on the call it has dramatically increased its testing capacity for Zika in the United States as it girds for an increase in cases during the summer mosquito season.

Virtually all the Zika cases in the continental United States so far have been in people returning from countries where Zika is prevalent, such as Brazil, or through sexual transmission by travelers.

The latest report comes at a time when U.S. health officials have been clamoring for adequate funding to support mosquito protection and eradication, development of anti-Zika vaccines and better diagnostics, and long-term studies needed to follow children born to infected mothers and to better understand the sexual transmission risk.

The Obama Administration has requested $1.9 billion in emergency Zika funding. The U.S. Senate approved $1.1 billion of that request. The U.S. House of Representatives, however, voted to allocate $622.1 million financed through cuts to existing programs, such as for Ebola, which U.S. health officials have called inadequate and shortsighted.

The World Health Organization has said there is strong scientific consensus that Zika can also cause Guillain-Barre, a rare neurological syndrome that causes temporary paralysis in adults.

The connection between Zika and microcephaly first came to light last fall in Brazil, which has now confirmed more than 1,300 cases of microcephaly that it considers to be related to Zika infections in the mothers.

(Reporting by Ransdell Pierson and Bill Berkrot; Editing by Chizu Nomiyama and James Dalgleish)


Zika Spreading in Puerto Rico

A health worker prepares insecticide before fumigating a neighborhood in San Juan

By Julie Steenhuysen

SAN JUAN (Reuters) – The United States faces its first real challenge with the Zika virus on the island territory of Puerto Rico, a part of the nation that is perhaps least prepared to cope with what is expected to be its worst outbreak.

Zika is spreading rapidly in Puerto Rico and is expected to peak in late summer and early fall. By year’s end, public health officials estimate, hundreds of thousands of people will have been infected.

It is the only part of the country that is experiencing a major local outbreak, but the virus is expected to reach southern U.S. states within weeks with warmer temperatures and rising mosquito populations.

Health officials from across the United States are gathering today at the headquarters of the Centers for Disease Control and Prevention in Atlanta to outline a national strategy for combating Zika. In a measure of the concern surrounding the outbreak in Puerto Rico, CDC director Tom Frieden toured the island, meeting with top health officials and local experts last month to assess the situation first-hand.

Puerto Rico is beset with problems already hampering the response: abundant mosquitoes, high levels of insecticide resistance and economic woes that have left vector control in shambles.

“We don’t have good surveillance” here, Frieden said in an interview at the Puerto Rican health department in San Juan during his tour. “We don’t have good control measures.”

First detected in Brazil last year, the Zika outbreak is spreading through the Americas. The World Health Organization declared a global health emergency last month because of growing evidence that Zika can cause microcephaly, a rare birth defect defined by an unusually small head. In adults, the virus has been linked to the typically rare autoimmune disorder, Guillain-Barre syndrome.


Fighting Zika in Puerto Rico is complicated by the toll of a decade-long recession. Nearly half of its 3.5 million residents live in poverty, and mosquitoes are an accepted nuisance. Puerto Rico has seen repeated outbreaks of dengue and more recently, chikungunya. Both viruses are carried by Aedes aegypti, the same species of mosquito that carries Zika.

“Here in Puerto Rico, we’re really starting from square one,” said Audrey Lenhart, a CDC vector control expert in an interview at the CDC’s Emergency Operations Center in San Juan.

In its latest report, the Puerto Rican health department said there are now 350 confirmed cases of Zika infection, including 40 pregnant women.

“We have a very serious combination of problems,” said Dr. Alberto de la Vega, an obstetrician specializing in high-risk pregnancies at San Juan’s University Hospital at the Puerto Rico Medical Center.

“If you don’t have access to money to buy repellent, to sleep with an air conditioner on so mosquitoes won’t bite you, to have mosquito nets around you and you live in areas where there’s more stagnant water, obviously you have higher risks,” he said.

To mitigate the risk of microcephaly among newborns, the CDC and the Puerto Rican government are distributing Zika protection kits to pregnant women that include condoms to prevent sexual transmission from an infected partner, insect repellent, bed nets and larvicide tablets for standing water that cannot be drained.

De la Vega says many locals are resigned to the idea that everyone in Puerto Rico will be infected. He said he won’t accept that people are “surrendering like that.”


Government mosquito abatement resources are scarce, with fewer than a dozen trucks equipped with insecticide sprayers. Of the municipalities that do have trucks, most are used to kill nuisance mosquitoes that bite but do not carry disease, said Manuel Lluberas, a Puerto Rico-born entomologist who works at H.D. Hudson Manufacturing, a maker of spraying equipment.

Lluberas, who advises the WHO and the World Bank on vector control programs, said there are a few municipalities that spray insecticide once every seven to 10 days or once every few weeks. Spraying “needs to be done a lot more frequently” to be effective, he said.

Scientists at CDC’s Dengue Laboratory in San Juan have been testing insecticides on mosquitoes gathered from 17 sites on the island. Frieden said in one of the experiments, mosquitoes placed in bottles coated with a commonly effective insecticide “were happily flying around.”

Eliminating Zika will require spraying insecticide indoors on walls, under beds, behind furniture and inside closets, where Aedes aegypti hide. So far, only two insecticides – deltamethrin and bifenthrin – are approved for indoor residual spraying, and researchers have found high levels of resistance to bifenthrin in Puerto Rico.

Mosquito experts have found similar resistance in parts of Texas and California.

“You find resistance in mosquitoes in one locale, and 20 miles away they are not resistant,” said Joseph Conlon, technical advisor for the American Mosquito Control Association, which represents researchers, public health officials and pesticide makers.

Dr. Janet McAllister, a CDC entomologist, said indoor spraying campaigns will be carried out by local contractors, who will target only areas where the mosquitoes hide instead of coating entire walls, as is typically done to control mosquitoes that carry malaria. “People would not really be coming into direct contact with those surfaces,” McAllister said.

She said the CDC does not plan to use experimental methods, including genetically modified mosquitoes, such as those from Intrexon’s Oxitec now being tested in Brazil, or those infected with Wolbochia bacteria that prevent Zika transmission.

Given the urgency of the outbreak, health officials need to focus on known methods of curbing mosquitoes “rather than doing research on things that may or may not work,” she said.

(Reporting by Julie Steenhuysen; Editing by Michele Gershberg and Lisa Girion)

U.S. boosts study of Zika, birth defect link as virus seen spreading

CHICAGO (Reuters) – U.S. health officials are stepping up efforts to study the link between Zika virus infections and birth defects in infants amid predictions for widespread circulation of the mosquito-borne virus within the United States during warmer months.

The U.S. Director of the National Institutes of Health on Tuesday called for intensified efforts to study the impact of Zika infections, citing a recent study estimating the virus could reach regions where 60 percent of the U.S. population lives.

The mosquito-borne virus has been linked to brain damage in thousands of babies in Brazil. There is no vaccine or treatment for Zika, a close cousin of dengue and chikungunya, which causes mild fever and rash. An estimated 80 percent of people infected have no symptoms, making it difficult for pregnant women to know whether they have been infected.

On Monday, the World Health Organization predicted the virus would spread to all countries across the Americas except for Canada and Chile.

In a blog post, NIH Director Dr. Francis Collins cited a Lancet study published Jan. 14 in which researchers predicted the Zika virus could be spread in areas along the East and West Coasts of the United States and much of the Midwest during warmer months, where about 200 million people live.

The study also showed that another 22.7 million people live in humid parts of the country where mosquitoes carrying the virus could live year round.

Given the threat, Collins said “it is now critically important to confirm, through careful epidemiological and animal studies, whether or not a causal link exists between Zika virus infections in pregnant women and microcephaly in their newborn babies.” Microcephaly results in babies being born with abnormally small heads.

Experts say there is still much to learn about Zika infections. For example, it is not clear how common Zika infections are in pregnant women, or when during a pregnancy a woman is most at risk of transmitting the virus to her fetus.

Collins said the National Institute of Allergy and Infectious Disease is conducting studies to more fully understand the effects of Zika in humans, and to develop better diagnostic tests to quickly determine if someone has been infected. The NIAID is also working on testing new drugs that might be effective against the virus.

The blog post was followed by the announcement on Tuesday of new guidelines from the U.S. Centers for Disease Control and Prevention providing instructions for pediatricians treating infants whose mothers may have been exposed to the virus during pregnancy.

In those guidelines, the CDC makes clear that Zika virus is considered a nationally notifiable condition, and instructs doctors to contact their state or territorial health departments to facilitate testing of potentially infected infants.

The guidelines for the care of infants affected by Zika infections follows CDC guidelines for caring for pregnant women exposed to Zika virus, which were first reported by Reuters. The CDC said last week it is trying to determine how many pregnant women may have traveled to affected regions in the past several months.

(Reporting by Julie Steenhuysen; Editing by James Dalgleish)