Zika Virus: What Happened When : Shots - Health News The warning is believed to be the first of its kind for the continental U.S. from the Centers for Disease Control and Prevention. Read about this update and see a full timeline of the Zika outbreak.

Zika Virus: What Happened When

Katherine Du/NPR
Katherine Du/NPR
Katherine Du/NPR

Editor's note: As of Oct. 1, we're no longer updating this timeline.

Since it was first discovered in Uganda in 1947, Zika virus was known mostly as a short-lived and mild illness. In 2015, that all changed. An outbreak in Brazil has been linked to cases of a serious birth defect, microcephaly, and a potentially crippling disease, Guillain-Barre syndrome.

As the mosquito-borne illness spreads across the Americas, scientists are trying to figure out which illnesses the virus is truly responsible for and why more people are getting sick.

We've put together a timeline to track the global response to Zika virus and scientists' understanding of how it affects people, with the most recent events at the top. (Find NPR's ongoing coverage here.) Check back, as we're regularly updating this list.

The Timeline Of Zika Virus


    Angel Valentin/Getty Images
    Employees with the municipal government collect garbage from a vacant building in front of a housing project August 7, 2016 in the Puerta de Tierras section of San Juan, Puerto Rico. This is part of an island-wide effort organized by grassroots groups and local mayors to try to stop the spread of the ZIKA virus in Puerto Rico.
    Angel Valentin/Getty Images

    The Puerto Rico Department of Health reports an increase in cases of Guillain-Barre syndrome, a rare autoimmune disorder triggered by some infections, including the Zika virus.

    Meanwhile, a separate report out of Maryland indicates that an infected person can share the virus through sex — even if they did not have symptoms.


    Johan Ordonez/AFP/Getty Images
    A paramedic takes a blood sample from a pregnant women at the maternity of the Guatemalan Social Security Institute (IGSS) in Guatemala City on February 2, 2016. Guatemala increased the monitoring of pregnant women because of the risk of infection by Zika virus.
    Johan Ordonez/AFP/Getty Images

    In a major expansion of an earlier advisory, the Food and Drug Administration recommends that blood banks across the U.S. screen all blood donations for the Zika virus. The recommendation previously only applied to areas with active Zika virus transmission.

  • 08/19/2016: ZIKA HITS THE BEACH

    Alan Diaz/AP
    "We believe we have a new area where local transmissions are occurring in Miami Beach," Florida Gov. Rick Scott said Friday about the Zika situation in the state.
    Alan Diaz/AP

    Florida officials announced that mosquitoes have started spreading Zika in another part of the Miami area — Miami Beach. The CDC has advised pregnant women to avoid going there, and suggested that couples concerned about exposure to the virus postpone travel to Miami-Dade County. To date, Florida mosquitoes are known to have infected 36 people with the virus.

  • 08/16/2016: FROM FLORIDA TO TEXAS

    Joe Raedle/Getty Images
    A plane sprays pesticide over parts of the city of Miami in the hope of controlling and reducing the number of mosquitos, some of which may be capable of spreading the Zika virus on August 12, 2016 in Miami, Florida. The CDC has advised pregnant women to avoid the Wynwood neighborhood of Miami where the majority of the 25 cases of people with the Zika virus have been found.
    Joe Raedle/Getty Images

    After a Texas resident returned from a trip to Miami, the traveler tested positive for Zika virus. Health officials believe the traveler picked up the virus in Florida, which would make it the first case linked to travel within the continental U.S.


    Screenshot from Google Maps
    The area in Miami that is being affected by Zika.
    Screenshot from Google Maps

    The CDC advises pregnant women to avoid traveling to Wynwood, the Miami neighborhood where mosquitoes are transmitting Zika virus. Pregnant women who live there should take measures to prevent mosquito bites and be tested for Zika during the first two trimesters. It's believed to be the first time the CDC has told people to avoid travel to an area in the continental U.S. due to an outbreak of infectious disease.

  • 08/01/2016: 10 MORE CASES IN MIAMI

    Joe Raedle/Getty Images
    Robert Muxo, a Miami-Dade County mosquito control inspector, inspects a property for mosquitos or breeding areas as the county fights to control the Zika virus outbreak on July 30 in Miami. There have been a reported four individuals that have been infected with the Zika virus by local mosquitoes which makes them the first known cases of the virus being transmitted by mosquitoes in the US.
    Joe Raedle/Getty Images

    The Florida health department has found 10 more people who likely got Zika virus from local mosquitoes, bringing the total to 14. Gov. Rick Scott asked the CDC to send an emergency response team to help with the investigation and mosquito control, including inspections of pools and other standing water where mosquitoes breed.


    John Raoux/AP
    U.S. Surgeon General Vivek Murthy, left, looks at a container of mosquitos that could potentially carry the Zika virus with U.S. Department of Health and Human Services Secretary Sylvia Burwell, center, and Orange County Mayor Teresa Jaccobs while on a preparedness visit to Orange County Mosquito Control, Monday, July 25, 2016, in Orlando, Fla.
    John Raoux/AP

    "This morning we learned that four people in our state likely have the Zika virus as a result of a mosquito bite," Florida Gov. Rick Scott said at a press conference. "This means Florida has become the first state in our nation to have local transmission of the Zika virus."


    Chris O'Meara/AP
    Tatiana Sepulveda takes donated blood from Adrien Quiles in 2009 at the Tampa General Hospital in Tampa, Fla.
    Chris O'Meara/AP

    Fearing local transmission of the virus, the Food and Drug Administration has asked two South Florida counties, Miami-Dade and Broward, to cease collecting blood donations until they can test each one for the virus.


    Le Club Symphonie/Cultura RF/Getty Images
    Zika can spread through sexual transmission.
    Le Club Symphonie/Cultura RF/Getty Images

    Until recently, the CDC only considered men capable of transmitting the virus during sex. But since a man in New York City contracted Zika after having sex with an infected woman, the agency now recommends that heterosexual and homosexual couples — especially those with pregnant partners — use condoms or abstain from sex to reduce the possibility of transmission if one of the partners lives in an area with Zika or has recently traveled to one. In another adjustment, the CDC now recommends that clinicians offer a Zika virus blood test to pregnant women up to two weeks after symptoms set in, as well as to at-risk pregnant women who have had no symptoms.


    Rick Bowmer/AP
    Nadja Mayerle with the Salt Lake City Mosquito Abatement District looks at a mosquito Tuesday, July 19 in Salt Lake City. Health authorities in Utah are investigating a unique case of Zika found in a person who had been caring for a relative who had an unusually high level of the virus in his blood. Exactly how the disease was transmitted is still a mystery, though the person has since recovered.
    Rick Bowmer/AP

    The relative of an elderly man in Utah seems to have contracted Zika from taking care of him. The patient had an unusually high amount of virus in his blood, about 100,000 times what's expected. That could be why, in this rare case, the virus passed through nonsexual contact with a sick person. Another possibility for spread was reported last week, with the first report of a woman passing the virus to a man through unprotected sex. Health officials maintain that infected mosquitoes are by far the main way Zika virus spreads.


    Lauren Victoria Burke/AP
    Senate Minority Leader Harry Reid of Nev. speaks to reporters on Capitol Hill in Washington, Thursday, July 14, 2016, to discuss unfinished business before Congress prior to its recess. Congress is about to leave for a seven-week vacation without giving the Obama administration any of the $1.9 billion it's seeking to battle the Zika virus.
    Lauren Victoria Burke/AP

    After months of debate, Congress missed its deadline to decide about funding the fight against Zika virus. Now, its members are on a seven-week break. The American Medical Association said in a statement that it's "disappointed by Congress' failure to pass legislation before adjourning."

  • 07/14/2016: OVER THE PEAK?

    Katie Park/NPR
    Data for Brazil covers 10 states that report public cases. Total data excludes some countries that do not report suspected cases. A "suspected" case is diagnosed by a clinician based on symptoms; most have not been confirmed through laboratory testing.
    Katie Park/NPR

    The worst might be over, according to epidemiologists writing in the journal Science. But though cases of Zika virus appear to be declining golbally, the epidemic is far from over. The virus could be a threat in the U.S. for many summers to come.

  • 06/23/2016: STUCK IN CONGRESS

    Mark Wilson/Getty Images
    Sen. Debbie Stabenow (D-MI), speaks about the Senate's recent failed vote for funding to fight the Zika virus, on Capitol Hill June 29, 2016 in Washington, DC. Also pictured are Sen. Heidi Heitkamp (D-ND), (L), Sen. Kirsten Gillibrand (D-NY), (2nd-L), and Sen. Mazie Hirono (D-HI), (R). (Photo by Mark Wilson/Getty Images)
    Mark Wilson/Getty Images

    House lawmakers passed a bill that would give $1 billion to the Zika virus response, about half of what President Obama requested. It will now move to the Senate, where Democrats have declared opposition to the Republican proposal. If more money isn't allocated, funding would be shifted from Obama's health care law and from Ebola virus research and response. The deadline to approve funding is mid-July. Funding is intended to support efforts at home and abroad to research Zika vaccines and tests and to control mosquito populations.


    Puerto Rico has started screening blood donations for Zika virus.
    Thomas Fredberg/Science Photo Library/Getty Images

    In April, health officials in Puerto Rico started screening blood donations for Zika virus. Out of about 13,000 donations tested since then, 68 have tested positive with a new, highly sensitive assay. Those donations have been removed from the blood supply. One blood center in Houston has voluntarily begun testing blood donations as well. CDC Director Tom Frieden said the blood screening in Puerto Rico offers a concerning glimpse of how the virus is spreading in the territory. "It's possible that thousands of pregnant women in Puerto Rico could become infected with Zika. This could lead to dozens or hundreds of infants being born with microcephaly in the coming year," he said.

  • 06/16/2016: BIRTH DEFECTS IN THE U.S.

    Dr. Sawczuk, president of the Hackensack University Medical Center, and Dr. Al-Khan, director of the Center for Abnormal Placentation, watch as Dr. Piwoz, chief of the Pediatric Infections Diseases at the Sanzari Children's Hospital, speaks during a news conference at the Hackensack University Medical Center. Doctors say a baby born to a mother with the Zika virus appears affected by the disease.
    Frank Franklin II/AP

    The CDC has started reporting birth defects among babies born in the U.S. to women with evidence of past Zika virus infection. They'll also report on birth defects in cases of pregnancy loss. As of June 9, there have been three of each. Two cases of babies born with microcephaly were previously reported in Hawaii and New Jersey. Brazilian officials have confirmed more than 1,400 cases linked to Zika virus.

  • 06/15/2016: GLIMMER OF HOPE

    Luis Robayo/AFP/Getty Images
    Seven months pregnant Maribel Gomez installs a mosquito net over her bed on February 17, 2016, in Cali, Colombia.
    Luis Robayo/AFP/Getty Images

    Scientists in Colombia tracking thousands of pregnant women found that if a woman was infected with Zika during the third trimester, her baby wasn't likely to be born with severe birth defects. As they wrote in The New England Journal of Medicine, none of the 600 women who experienced Zika symptoms during the third trimester gave birth to babies with brain abnormalities.


    Yasuyoshi Chiba/AFP/Getty Images
    General view of the Olympic Aquatics Stadium at the Olympic Park which will host the swimming events during Rio 2016 Olympic Games in Rio de Janeiro, Brazil, on June 7, 2016.
    Yasuyoshi Chiba/AFP/Getty Images

    WHO says that "cancelling or changing the location of the 2016 Olympics will not significantly alter the international spread of the Zika virus." The announcement came a day after 150 scientists wrote this in an open letter to the organization: "It is unethical to run the risk" of delivering the virus via attendees to poor countries where the virus could become endemic. Who is right? NPR's Michaeleen Doucleff finds that according to one estimate, there would be at most 16 cases of Zika among Olympic attendees.


    Democratic members of Congress join together to call on Republicans to postpone the Memorial Day holiday recess on the steps of the House of Reps at the U.S. Capitol May 26, 2016 in Washington, DC. The Democratic leaders highlighted the need for "action on the Zika virus, the opioid epidemic, the Flint water crisis and the president's nomination of Judge Merrick Garland to the Supreme Court.
    Chip Somodevilla/Getty Images

    While Congress continues to fight over whether and how much to fund Zika preparedness, state and local health departments scramble to fill the gaps. "It is not a question of whether babies will be born in the United States with Zika-related microcephaly. It is a question of when and how many," says Ron Klain, former White House Ebola response coordinator. Rep. Tom Cole of Oklahoma tells All Things Considered that the current House funding package, which is one-third of the president's request, is enough for now.

  • 05/26/2016: EYE ABNORMALITIES

    Fundus camera image of the retina and optic nerve in the human eye.
    Ralph Jr/Getty Images/Science Source

    Researchers in Brazil studying 40 infants born with microcephaly found that 22 had eye abnormalities, including some in small optic nerves and a very sensitive part of the retina responsible for color vision. They write in JAMA Ophthalmology that mothers with symptoms of Zika during the first trimester were more likely to give birth to children with eye abnormalities.


    Carrie Feibel/Houston Public Media
    Mosquitoes in traps are transported back to the county's laboratory for analysis.
    Carrie Feibel/Houston Public Media

    There are 56 species of mosquitoes flying around Harris County, Texas. But entomologists there hunt only for the big three — the ones that carry West Nile virus, St. Louis encephalitis, dengue, chikungunya and now Zika. Dozens of scientists and technicians are already setting traps and testing species to see which viruses are present and where it makes sense to spray pesticides. In New Jersey, inspectors are scouting out the bugs in marshes.


    Centers for Disease Control and Prevention
    This map represents the CDC's best estimate of the potential range of Aedes aegypti in the United States.
    Centers for Disease Control and Prevention

    That brings the U.S. total to about 280 U.S. women affected by Zika, including more than 120 in U.S. territories. NPR's Michaeleen Doucleff explains where in the country pregnant women should take precautions. The CDC says there's no sign people have gotten Zika from mosquitoes in the continental U.S.

  • 05/20/2016: ON AFRICA'S DOORSTEP

    Aerial view of Praia, the capital city of Cape Verde
    Wikimedia Commons

    The virus continues its trip around the globe. The World Health Organization confirms that the strain of the virus found in Cape Verde, off the northwest coast of Africa, is the same one that's circulating in the Americas. It was probably imported from Brazil. Dr. Matshidiso Moeti, WHO regional director for Africa, says the virus is now "on the doorstep of Africa."

  • 05/16/2016: SUDDENLY PARALYZED

    Meredith Rizzo/NPR
    Luther checks out the waterfront near his home in National Harbor, Md.
    Meredith Rizzo/NPR

    Scientists agree that the Zika virus can, in rare cases, trigger a disease called Guillain-Barre syndrome. We follow two people who went through the sudden traumatic illness. While there's a high recovery rate, patients with GBS often require intensive hospital care to survive weeks of paralysis.


    Three-month-old Esther Kamilly has her head measured by Brazilian and U.S. health workers from the United States' Centers for Disease Control and Prevention (CDC) at her home in Joao Pessoa, Brazil, Wednesday, Feb. 24, 2016, as part of a study to determine if the Zika virus is causing babies to be born with a birth defect affecting the brain.
    Andre Penner/AP

    Scientists say they may know how the virus damages the brains of infected fetuses. By testing mice, they found that the virus is particularly attracted to brain cells, which it can infect and turn into virus-making factories. But those particular cells are also the ones responsible for building a large portion of the brain.

  • 05/05/2016: 1 YEAR OF ZIKA IN BRAZIL

    Rozilene Ferreira de Mesquita, center, holds her son, Arthur Ferreira da Conceicao as she listens to a doctor during a visit to Hospital das Clinicas da Universidade Federal de Pernambuco for Arthur on Monday March 14, 2016 in Recife, Brazil. Arthur was born with microcephaly, which the Zika virus is being linked to.
    Matt McClain/The Washington Post/Getty Images

    One year ago, Brazil confirmed its first case of Zika virus. "As far back as 1952, [scientists] speculated that Zika and other newly discovered African viruses might have effects on the central nervous system or produce congenital changes in the foetus if pregnant women were infected. But that was pure speculation. For all practical purposes, Zika looked like a medical curiosity that posed little, if any, threat to public health," says a World Health Organization report on what's been learned in the past year. An accompanying timeline traces the virus's path since 1947.

  • 05/02/2016: 1 MILLION FREE CONDOMS


    The New York City Department of Health announces that it will donate 1 million free condoms to Puerto Rico, in an attempt to reduce the spread of Zika there through sex. There are over 3.5 million people in Puerto Rico.

  • 03/29/2016: FIRST U.S. DEATH DUE TO ZIKA

    An American flag and Puerto Rican flag fly next to each other in Old San Juan a day after the Puerto Rican Governor Alejandro Garcia Padilla gave a televised speech regarding the governments $72 billion debt on June 30, 2015 in San Juan, Puerto Rico. The Governor said in his speech that the people will have to sacrifice and share in the responsibilities for pulling the island out of debt.
    Joe Raedle/Getty Images

    A 70-year-old man died in Puerto Rico of complications due to the Zika virus, health authorities announced. After a rare immune reaction to the virus that prevented his blood from clotting, he experienced internal bleeding and died in February.


    A CDC flier hangs taped to a door in McAllen, Texas. Health departments, especially in areas along the Texas-Mexico border, are preparing for the expected arrival of the Zika Virus, carried by the aegypti mosquito, which is endemic to the region. The CDC announced this week that Zika is the definitive cause of birth defects seen in Brazil and other countries affected by the outbreak.
    John Moore/Getty Images

    Anxiety about the potential spread of Zika is growing in Gulf Coast states. In places like Houston, it's causing some tough choices for pregnant women and those considering conceiving. A special clinic has opened to counsel women who have traveled to Zika-affected areas.


    Centers for Disease Control and Prevention
    The Zika virus is spread by mosquitoes, but can be sexually transmitted as well.
    Centers for Disease Control and Prevention

    A Dallas man passed the virus to his partner after a trip to Venezuela. The case confirmed something researchers suspected for a long time: that vaginal sex isn't the only way the virus can get around.


    Mario Tama/Getty Images
    Mother Daniele Santos feeds her baby Juan Pedro, 2-months-old, in their living room on Feb. 3, 2016 in Recife, Pernambuco state, Brazil.
    Mario Tama/Getty Images

    Yes, the Zika virus is causing birth defects in the infants of some women who were infected during pregnancy. After months of hesitation, a CDC review published Wednesday in the New England Journal of Medicine concludes there's a causal relationship.


    Luis Robayo/AFP/Getty Images
    Aedes Aegypti mosquito larvae are photographed in a lab in Cali, Colombia in January.
    Luis Robayo/AFP/Getty Images

    President Obama will sign a bill that would offer incentives to drug companies to develop vaccines and treatment for the Zika virus. "In some ways, it's akin to passing out umbrellas in advance of a hurricane," says White House press secretary Josh Earnest. Congress is "two months late and $1.9 billion short," he says, referring to its failure to come through with emergency funding requested by the Obama administration.


    Ramon Espinosa/AP
    People in Pinar del Rio, Cuba, make their way through a fumigation fog that's meant to kill the mosquito that transmits the Zika virus.
    Ramon Espinosa/AP

    Top officials with the Obama administration announce that they'll redirect $589 million toward the Zika virus response. Most of that money was to be used to deal with the Ebola virus.


    Courtesy of Kristi L. Hall
    Mariel Mohns and Mustafa Rasheed are working in a University of Wisconsin lab that's trying to figure out how Zika virus could be damaging fetuses.
    Courtesy of Kristi L. Hall

    When a disease breaks out, scientists from wealthy countries tend to swoop in, take samples and then head back to the lab, rarely sharing their results with anyone for months, if ever. But, as NPR's Nurith Aizenman reports, scientists working on the current Zika outbreak are trying to nip "parachute research" in the bud by sharing more, and sharing faster. A lab at the University of Wisconsin, Madison is publicly sharing its findings in real time, including ultrasounds from infected monkeys.


    Felipe Dana/AP
    A baby born with microcephaly in Brazil is examined by a neurologist.
    Felipe Dana/AP

    The World Health Organization says there's scientific consensus that the Zika virus is responsible for causing birth defects. In northern Brazil, epidemiologists with the CDC finish gathering blood samples from 600 families. They want to know what the risk is to a woman infected with Zika that her child will have birth defects.

  • 03/30/2016: HINTS FROM A CASE REPORT

    Johan Ordonez/AFP/Getty Images
    A pregnant woman gets an ultrasound to monitor for the birth defect microcephaly, in Guatemala City in February.
    Johan Ordonez/AFP/Getty Images

    After a vacation to Mexico, Guatemala and Belize, a couple from Washington, D.C., learned that their fetus had severe brain abnormalities. They decided to end the pregnancy. The case, published in The New England Journal of Medicine, gave hints at how Zika infects a fetus — and at how women may be able to find out earlier whether babies will have birth defects.

  • 03/25/2016: SEX ADVICE FROM THE CDC

    Torn packaging of wrapper containing a condom
    Rafe Swan/Getty Images

    Couples are wondering what to do if they want to get pregnant but are worried about the Zika virus. Here's what the Centers for Disease Control and Prevention says about how to minimize the risk of microcephaly in future pregnancies:

    — If you're a man and you were diagnosed with Zika virus (or you even just had symptoms of the virus) wait at least six months before having unprotected sex with a female partner. If your female partner is already pregnant, use condoms or abstain from sex until the baby is born.

    — If you're a woman who was diagnosed with Zika or had the symptoms, wait at least two months before trying to get pregnant.

    — The CDC also advises that people who had even a chance of being exposed to the virus during travel or through sex wait at least a couple of months before trying to get pregnant.

    It's still not confirmed that infection with Zika virus causes microcephaly, but there's increasing evidence that it can.

  • 03/18/2016: 3-IN-1 TEST APPROVED

    Danica Coto/AP
    In this Feb. 24, 2016 photo, an employee with the U.S. Centers for Disease Control and Prevention (CDC) tests human blood samples for Zika at the CDC's dengue lab in San Juan, Puerto Rico. One of the CDC's main goals is to test every single pregnant woman in Puerto Rico for Zika and prevent people from contracting the virus.
    Danica Coto/AP

    A test called the Trioplex determines in one go if a person has dengue, chikungunya or Zika virus in the blood. It's been used in San Juan, Puerto Rico, to test pregnant women in the territory. Now that the Food and Drug Administration has granted emergency use authorization, it can also be used by qualified labs in other parts of the U.S. But as Shots has reported, this kind of test (RT-PCR) is conclusive only if a patient is tested within a week of infection with Zika virus.

  • 03/15/2016: 1 IN 100

    Catherine Osborn/for NPR
    Dr. Regina Coeli holds 4-month-old Enzo Thamires in an examination room of the Oswaldo Cruz public hospital in the Brazilian city of Recife.
    Catherine Osborn/for NPR

    Looking back at a Zika outbreak in French Polynesia, researchers writing in The Lancet estimate that the risk of having a baby born with microcephaly was about 1 per 100 in women infected with Zika virus during their first trimester of pregnancy. The usual rate of microcephaly there had been about 1 in 5,000 newborns. "There's something different about the way these babies cry," writes Rob Stein after a visit to a hospital in Recife, Brazil.

  • 03/10/2016: HOW BEST TO TEST FOR ZIKA

    A medical researcher works on results of tests for various diseases, including Zika, at the Gorgas Memorial laboratory Panama City, Friday, Feb. 5, 2016.
    Arnulfo Franco/AP

    It's pretty simple to figure out if someone has an active Zika infection with a blood test. But people tend to clear the virus out of their bodies quickly, and that's when it can get complicated. Shots picks apart what the current host of tests can accomplish. In San Juan, Puerto Rico, the CDC is unrolling a test called the Trioplex that can determine in one go if a person had dengue, chikungunya or Zika virus.


    Human blood in storage

    Shipments of blood from the continental U.S. arrive in Puerto Rico. The U.S. Department of Health and Human Services is funding the shipments so that patients in Puerto Rico in need of blood transfusions don't have to worry that they'll accidentally get Zika from an infected donor.


    Seven months pregnant Maribel Gomez stands next to a mosquito net placed over her bed on February 17, 2016, in Cali, Colombia. Cali's Health Secretariat massively delivered mosquito nets to pregnant women and installed guppy fish bowls as a preventive measure against Aedes aegypti mosquito, vector of Zika, Dengue, and Chikungunya.
    Luis Robayo/AFP/Getty Images

    Preliminary results from a study of 42 pregnant women in Brazil suggest Zika can cause a whole spectrum of complications — not just microcephaly — in the fetuses of women infected while pregnant. In another study, Colombian researchers found that three newborns tested positive for Zika, one diagnosed with microcephaly and two with abnormal brains, Nature News reports. The research isn't peer-reviewed or published, so we can't vouch for it. Studies of babies in Brazil have made similar findings, but these cases may be the first Zika-related birth defects in Colombia. NPR's Nurith Aizenman has reported: "If there really is a link, Colombia is where the next surge in birth defects could be."


    Victor Moriyama/Getty Images
    A Biologist releases genetically modified mosquitoes in the city on Feb. 11, 2016 in Piracicaba, Brazil. Technicians from the Oxitec laboratory are releasing genetically modified mosquitoes Aedes Egypti to combat Zika virus.
    Victor Moriyama/Getty Images

    Republican congressmen question the need for $2 billion requested by the Obama administration to fight Zika. At the same hearing, Dr. Jeanne Sheffield, director of the division of maternal-fetal medicine at Johns Hopkins University School of Medicine, says it's likely that about a month after infection with Zika, women can conceive without worrying about the virus's effect on the fetus. "It's about the only good news here," she says. Public Health Canada recommends couples wait at least two months after infection with Zika virus to conceive. Also: WHO summarizes its latest guidance for pregnant women. The FDA adds corneas, bone, skin, heart valves, stem cells, cord blood, placenta, semen and oocytes to the list of donated human materials that need to be screened for Zika virus before being transplanted in a patient.


    Researchers are working furiously to determine whether the Zika virus now spreading in Latin America is responsible for a spike in cases in Guillain-Barre syndrome, a condition that can cause temporary paralysis. Scientists studying patients from a 2013 outbreak in French Polynesia argue that a link can already be established. NPR's Nurith Aizenman visits patients with Guillain-Barre syndrome in Colombia, where scientists are also trying to confirm the link.


    Catherine Osborn for NPR
    Lindomar Pena, a virologist at a lab in Recife, Brazil, holds a box of vials used to store samples of the Zika virus in huge freezers.
    Catherine Osborn for NPR

    NPR's Rob Stein comes eye to eye with frozen tubes of Zika virus held by a researcher in Recife, Brazil. He also follows CDC investigators as they go door to door looking for new moms. They're trying to figure out if the virus is really causing microcephaly, a birth defect that leaves babies with abnormally small heads and damaged brains.


    The U.S. territory is reporting at least 117 cases of Zika virus, including five pregnant women. The island's government is working to get screens on more windows. Emergency crews hunt for the mosquito that reproduces in piles of old tires, open containers and even flower vases — before the rainy season hits. "We have to do what we didn't do for 30 years in 45 days," Dr. Johnny Rullan, Puerto Rico's former secretary of health, tells NPR.

  • 02/29/2016: 36 PLACES

    People gather on Copacabana beach, a landmark tourist destination in Rio, on February 26, 2016 in Rio de Janeiro, Brazil. The Zika virus outbreak, which may be linked to a surge in microcephaly cases in the country, is threatening tourism in Brazil which expects to profit from hundreds of thousands of foreign visitors travelling to Rio de Janeiro during the Rio 2016 Olympic Games.
    Mario Tama/Getty Images

    Caribbean islands St. Vincent and the Grenadines and St. Maarten join the list of destinations where Zika virus transmission is ongoing. That makes 36 countries and U.S. territories with a CDC Zika virus travel notice — just in time for spring break.


    Christ the Redeemer statue is shown in this aerial view Friday, Oct. 9, 2015, in Rio de Janeiro. The 2016 Olympic Games will be held in Rio de Janeiro.
    David J. Phillip/AP

    The Summer Olympics will be held Aug. 5-21 in Rio de Janeiro. If you'll be pregnant then, the CDC recommends not going. For those who choose to go anyway, it offers a list of precautions and health phrases in Portuguese, like "fwee pee-KAH-doo poor pare-nee-LONE-goo," or "I have been bitten by mosquitoes."


    A pregnant woman gets an ultrasound at the maternity of the Guatemalan Social Security Institute (IGSS) in Guatemala City on February 2, 2016. Guatemala increased the monitoring of pregnant women because of the risk of infection by Zika virus.
    Johan Ordonez/AFP/Getty Images

    Nine women are confirmed to have been infected with Zika while pregnant. Of the nine cases, two babies were born healthy, and one was born with severe microcephaly. Two women had miscarriages, two had abortions, and the remaining two pregnancies appear to be continuing normally. The women had all traveled to places where Zika virus transmission is ongoing, including Mexico, Puerto Rico and American Samoa. The CDC recommends that all pregnant women who have recently traveled to such places be screened for the virus. Ten more possible cases of Zika virus in pregnant women are currently being investigated.


    Resident Rafaela Silva dos Santos holds her baby Sofia Valentina as she watches an argument between police and residents nearby, in the mostly demolished Vila Autodromo favela community, on February 24, 2016 in Rio de Janeiro, Brazil. Dos Santos said she fears her baby will contract the Zika virus as another member of the community was diagnosed with Zika two weeks ago.
    Mario Tama/Getty Images

    Breast-feeding is really important for mothers and children. There's no evidence that a mother — even one who is sick with Zika — can transmit the virus to a child through her milk, according to new guidance from WHO.


    Florida Gov. Rick Scott asked the CDC for more Zika tests.
    Steve Cannon/AP

    Health officials in Florida report 32 cases of Zika virus, all acquired during travel. That includes three pregnant women. Gov. Rick Scott requested 250 more Zika antibody tests from the Centers for Disease Control and Prevention. "I would like to bet money on the fact that we will see locally acquired cases," Dr. Amy Vittor, an internist and public health researcher who studies tropical diseases at the University of Florida, tells NPR's Greg Allen. But the state is unlikely to see the scale of the Zika outbreaks now sweeping through the Caribbean and Latin America, in part because residents have far less exposure to mosquitoes. A British company, Oxitec, awaits FDA approval to test how well genetically modified mosquitoes can reduce the populations of Aedes aegypti in the Florida Keys.


    Vladimir Solano for NPR
    These people have just walked across the bridge from Venezuela to Colombia, where the Colombian immigration authorities are on duty. Many people live on one side and work on the other, crossing so frequently they don't have to register with officials each time.
    Vladimir Solano for NPR

    Tourism officials in Puerto Rico worry that the Zika virus could cause a slump in tourists. But in Colombia, the worry is more about people coming into the country — people from Venezuela crossing the border for medical care on the other side, and potentially bringing the virus with them.


    The Centers for Disease Control and Prevention confirmed two cases of Zika virus in U.S. women who had no risk factors for the illness except one: They had slept with their male partners, who had recently traveled to countries with ongoing transmission and who reported having Zika-like symptoms. Twelve other possible cases of sexual transmission from men to women are being studied. The CDC recommends that men who could have been exposed to Zika either use condoms during sex with a pregnant partner or abstain from sex for the rest of the pregnancy.

  • 02/19/2016: THE OTHER ILLNESS

    In this Feb. 11, 2016 photo, Zuleidy Balza, left, sits with her mother Zulay Balza who's recovering from Guillain-Barre syndrome at the Erasmo Meoz Hospital in Cucuta, Norte de Santander state, Colombia. Balza was diagnosed with Guillain-Barre Syndrome.
    Ricardo Mazalan/AP

    Media coverage has centered on the virus's potential effect on babies, but it may also be causing an illness in adults. Guillain-Barre syndrome is a condition where a person's immune system starts to attack nerves. It can be triggered by exposure to a number of viruses and bacteria and can cause temporary or permanent paralysis. Colombia has seen about 100 cases suspected of being linked to Zika, three times more than the usual rate.


    Becky Sullivan/NPR
    Patients wait to get care at the clinic. Over the last several months doctors here say they've seen about 150 pregnant women who have been exposed to Zika.
    Becky Sullivan/NPR

    "Some men in Brazil see a child with special needs as a woman's problem and promptly leave their partner," reports NPR's Lulu Garcia-Navarro. One psychologist predicts that some children with microcephaly will be abandoned and end up in state institutions. In Colombia, where the Zika virus hit later, maternity wards are bracing for the possibility that they, too, will see an increase in microcephaly in coming months.


    A Biologist works with genetically modified mosquitoes on February 11, 2016 in Campinas, Brazil. Technicians from the Oxitec laboratory located in Campinas, 100km from Sao Paulo, are releasing genetically modified mosquitoes Aedes Egypti to combat Zika virus.
    Victor Moriyama/Getty Images

    One state in Brazil stopped using a chemical to treat drinking water, after a report from Argentina suggesting that it — and not the Zika virus — could be the cause of microcephaly. Another rumor is that genetically modified mosquitoes are behind Brazil's recent problems. But international health experts say the evidence continues to pile up against Zika. For now, the virus is guilty until proven innocent.


    Blood donation

    The U.S. Food and Drug Administration recommends that blood banks not take donations from people who have traveled in the past four weeks to places with active Zika virus transmission. Researchers meeting at the National Academy of Sciences name some top priorities: to improve testing methods; develop animal models of the disease; and understand which animals might still host the virus once the current outbreak wanes in humans.


    Inti Ocon/AP
    In this Jan. 28, 2016 photo, a Health Ministry worker fumigates insecticide inside a classroom to combat Aedes aegypti mosquitoes that transmit the Zika virus in Managua, Nicaragua. Worries about the rapid spread of Zika through the hemisphere has prompted officials several Latin American countries to suggest women stop getting pregnant until the crisis has passed.
    Inti Ocon/AP

    The Aedes aegypti mosquito is the dog of the mosquito world. "It loves us. It loves our cities. It loves our blood. It functions very well with us," says Marten Edwards, an entomologist at Muhlenberg College. Many countries are stepping up use of insecticides, as seen at left in Managua, Nicaragua. The CDC's Dr. Tom Frieden told lawmakers Wednesday that studies are underway to test which insecticides work best. And as NPR's Goats and Soda blog found in a review of repellents, people could also consider stocking up on perfume from Victoria's Secret.


    Moises Castillo/AP
    A blood samples from pregnant women are analyzed for the presence of the Zika virus, at Guatemalan Social Security maternity hospital in Guatemala City, Tuesday, Feb. 2, 2016. According to Guatemalan health authorities, the country does not have any confirmed case of pregnant women infected by Zika virus.
    Moises Castillo/AP

    "There really hadn't been any work done in about 40 years on Zika virus in animals," says Dr. Michael Diamond, an infectious disease specialist at Washington University in St. Louis. "We need vaccines, we need therapies, we need diagnostics. We need to know how this virus works."

  • 02/08/2016: $1.8 BILLION

    Dr. Anthony Fauci, director of NIH/NIAID, listens as Dr. Anne Schuchat, Principal Deputy Director of the CDC, speaks. President Obama is asking Congress for more than $1.8 billion in emergency funding to help fight Zika. The money would be used to expand mosquito control programs, speed development of a vaccine, develop diagnostic tests and improve support for low-income pregnant women.
    Pablo Martinez Monsivais/AP

    That's how much the Obama administration says it plans to ask Congress for to fight the Zika virus. Dr. Anne Schuchat with the Centers for Disease Control and Prevention says the organization has shipped antibody tests to state health departments to test pregnant women who traveled to Zika-affected areas. "But it's important to say we don't have unlimited quantities right now," she says. And "the test isn't perfect."


    The Centers for Disease Control and Prevention puts its emergency operations center on the highest level of activation to respond to the Zika outbreak. Officials say they're confident they could quickly contain any outbreaks in the United States. David L. Heymann, chairman of the World Health Organization emergency committee on the virus, tells NPR the main focus now is on clarifying the link between Zika and babies born with small heads and brains.


    Marvin Recinos/AFP/Getty Images
    An Aedes aegypti mosquito is photographed in a laboratory at the University of El Salvador, in San Salvador, on February 3, 2016. Health authorities continue their efforts to eliminate the mosquito, vector of the Zika virus, which might cause microcephaly and Guillain-Barre syndrome in unborn babies.
    Marvin Recinos/AFP/Getty Images

    Brazilian health officials say they have detected live virus in the urine and saliva of people sick with the virus. In the past, researchers isolated live virus from urine and semen. While authorities in Brazil recommended that women not kiss or share silverware with strangers, U.S. health authorities caution that the discovery of virus in bodily fluids does not mean it can spread through exchanging them. Still, the CDC suggests that men who have recently returned from areas where Zika is active use condoms during sex, especially with a pregnant partner. Mosquito bites remain the primary transmission route.


    CDC/Cynthia Goldsmith
    This is a transmission electron micrograph (TEM) of Zika virus, which is a member of the family Flaviviridae. Virus particles are 40 nm in diameter, with an outer envelope, and an inner dense core. The arrow identifies a single virus particle.
    CDC/Cynthia Goldsmith

    Health officials in Dallas County, Texas, say a local patient acquired Zika virus in the U.S. through sex with a person who had recently returned from Venezuela. Shots reports that the virus is thought to have been transmitted through sex before, though rarely.


    Mario Tama/Getty Images
    Health workers fumigate in an attempt to eradicate the mosquito which transmits the Zika virus on January 28, 2016 in Recife, Pernambuco state, Brazil. Two two-man teams were fumigating in the city today. Health officials believe as many as 100,000 people have been exposed to the Zika virus in Recife, although most never develop symptoms.
    Mario Tama/Getty Images

    Dr. Margaret Chan, director-general of the World Health Organization, declares the strong association between Zika virus and microcephaly a public health emergency of international concern. She says it will take international coordination to improve mosquito control and speed up the development of tests that detect the virus.


    Luis Robayo/AFP/Getty Images
    An Aedes Aegypti mosquito is photographed on human skin in a lab of the International Training and Medical Research Training Center (CIDEIM) on January 25, 2016, in Cali, Colombia. CIDEIM scientists are studying the genetics and biology of Aedes Aegypti mosquito which transmits the Zika, Chikungunya, Dengue and Yellow Fever viruses, to control their reproduction and resistance to insecticides.
    Luis Robayo/AFP/Getty Images

    "Out of an abundance of caution," the Centers for Disease Control and Prevention advises pregnant women to postpone traveling to areas with active Zika virus transmission. Pregnant women who choose to travel, it says, should take steps to avoid being bitten by mosquitoes.


    Mario Tama/Getty Images
    Alice Vitoria Gomes Bezerra, 3-months-old, who has microcephaly, is held by her mother Nadja Cristina Gomes Bezerra sits on January 31, 2016 in Recife, Brazil. In the last four months, authorities have recorded close to 4,000 cases in Brazil in which the mosquito-borne Zika virus may have led to microcephaly in infants.
    Mario Tama/Getty Images

    Countries across Latin America and the Caribbean urge women to put off pregnancy to reduce the risk of babies being born with microcephaly. NPR's Lulu Garcia-Navarro reports from a clinic in Brazil offering women seeking fertility treatment the option to freeze their eggs or an embryo at no additional cost because of the new guidelines due to the Zika outbreak. The virus's link to birth defects reignites debate about abortion in several countries.


    Marvin Recinos/AFP/Getty Images
    A patient suffering from the Guillain-Barre neurological syndrome recovers in the neurology ward of the Rosales National Hospital in San Salvador, on January 27, 2016. Health authorities have issued a national alert against the Aedes aegypti mosquito, vector of the Zika virus which might cause microcephaly and Guillain-Barre syndrome.
    Marvin Recinos/AFP/Getty Images

    The Pan American Health Organization warns of a possible connection between Zika virus and an increase in neurological syndromes. "Although neither event establishes a causal relation with Zika virus, the hypothesis cannot be discarded," the PAHO report says. During a past outbreak in French Polynesia, 42 patients were confirmed to have Guillain-Barre syndrome out of about 9,000 suspected cases.


    Mario Tama/Getty Images
    Dr. Vanessa Van Der Linden, the neuro-pediatrician who first recognized the microcephaly crisis in Brazil, measures the head of a 2-month-old baby with microcephaly on January 27, 2016 in Recife, Brazil. The baby's mother was diagnosed with having the Zika virus during her pregnancy.
    Mario Tama/Getty Images

    The Pan American Health Organization asks member nations to report unusual patterns in the health of newborn babies. Researchers at the Osvaldo Cruz Institute in Brazil report detecting signs of the virus in the amniotic fluid of two pregnant women whose fetuses were diagnosed via ultrasound with microcephaly.


    Lourdes Garcia-Navarro/NPR
    Marilla Lima had Zika virus while pregnant. Her 2 1/2-month-old son, Arthur, has microcephaly — a birth defect characterized by a small head and severe brain damage.
    Lourdes Garcia-Navarro/NPR

    A sharp increase in the number of babies born with small heads is reported in a part of Brazil that noted an outbreak in Zika virus infections months before. The state of Pernambuco used to register 10 cases of microcephaly per year. In 2015, there were over 140 cases.


    Alyson Hurt/NPR/Centers for Disease Control and Prevention, Pan American Health Organization
    Alyson Hurt/NPR/Centers for Disease Control and Prevention, Pan American Health Organization

    Named after the forest in Uganda where it was discovered in 1947, the Zika virus has sickened people on multiple continents since then. But past outbreaks have not been connected to birth defects or to increased rates of a neurological condition called Guillain-Barre syndrome.

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