What We Know So Far
- Zika, a virus transmitted by mosquitoes and linked to thousands of cases of birth defects, has been spreading across South and Central America at an alarming rate.
- There is no vaccine or cure.
- For most infected people, Zika symptoms are mild, if they appear at all. But pregnant women who are exposed seem to have a higher risk of having a child with microcephaly, or an abnormally small head.
- The WHO has declared Zika-linked microcephaly a global health emergency. But public health experts also caution that there is no definitive proof that the Zika virus is responsible for the birth defects.
- Colombia, Ecuador, El Salvador, and Jamaica have advised women to delay pregnancy.
- Brazil has warned pregnant women against attending the Rio Olympics, but the International Olympic Committee is downplaying dangers for most spectators, noting that the games will be held during Brazil’s winter season, when mosquitoes are less of an issue.
CDC: Few Pregnant Travelers Have Zika
Few pregnant travelers screened for Zika were infected by the virus — only about 3% even in women with symptoms — U.S. health officials said on Friday.
From January to March, Zika virus tests were given to 4,500 U.S. travelers returning from Zika-afflicted regions, with more than 3,300 of them pregnant women. Only 28 pregnant women overall had Zika, said the CDC report. Most of them reported symptoms of the virus such as a purple rash, fever or red eyes. Only seven pregnant women lacking any symptoms were actually infected.
The report called the numbers reassuring, yet said that “health care providers should continue to offer testing to pregnant women with potential exposure to Zika virus, even if they do not have symptoms,” because of the severe birth defect risks linked to the tropical virus.
Overall, 182 people out of more than 1,500 with symptoms turned out to be infected. Researchers are still assessing whether asymptomatic infection with Zika poses less of a birth defect risk.
CDC: Zika Definitely Causes Microcephaly
Zika virus definitely causes microcephaly and other brain birth defects, federal health officials declared on Wednesday, calling for heightened vigilance against the disease for pregnant and fertile women.
“Our hope is now we can be more definitive in communicating that Zika causes birth defects in babies, so that people take our health messages more seriously” said Sonja Rasmussen of the U.S. Centers for Disease Control and Prevention during a telephone briefing for reporters.
In October, Brazilian health officials raised alarm over sharp increases in cases of microcephaly, a severely shrunken brain and skull birth defect, and are now investigating thousands of suspected cases. The mosquito-borne and sexually-transmitted virus has spread to 33 countries and territories in the Americas in the last year, according to the World Health Organization.
In a New England Journal of Medicine report, Rasmussen and her colleagues compared published studies in Zika-infected fetuses and microcephalic children against scientific criteria for declaring a definitive link between a disease and a birth defect. The rarity of the severe form of microcephaly — termed “fetal brain disruption syndrome” — seen in infected infants seals the connection, they concluded.
World Health Organization chief Margaret Chan had declared a strong suspicion of a link earlier this year after declaring a public health emergency over the birth defects, but researchers had kept the possibility of some other culprit open in recent months.
Now, “there is no longer any doubt that Zika causes microcephaly,” said CDC chief Thomas Frieden, at the briefing.
“We don’t have all the answers,” Rasmussen cautioned at the briefing. Estimates of the risk of a birth defect range from 1% to 30% in a pregnant woman infected by Zika, for example, a range that researchers would like to better define.
“Not every pregnant woman infected with Zika results in birth defects,” she said.
Zika Arrived In Brazil In 2013, A Year Before The Outbreak
Air travelers may have delivered Zika to Brazil in 2013, genetics researchers suggested on Thursday, well before the 2014 World Cup soccer tournament that is sometimes blamed for the international spread of a virus tied to severe birth defects.
Over the past year, in the wake of the Brazilian outbreak, Zika has spread to 38 nations and territories. However, a new study in the journal Science that looked at genes from seven Brazilian victims of the virus — including a dead newborn with microcephaly — suggests Zika spent at least a year in Brazil undetected, apparently without triggering a burst of birth defects. The first surge of cases of microcephaly, a shrunken head and brain, did not appear until 2015, and have since grown to 863 cases and counting.
Read the whole story from Dan Vergano
CDC: Men Should Wait Six Months After A Zika Infection Before Attempting A Pregnancy
As many as 138,000 women in Puerto Rico face unintended pregnancies amid a Zika outbreak there, federal health officials warned on Friday, calling for increased access to contraception on the island.
“Pregnancy by itself is a risky situation,” said U.S. Centers for Disease Control and Prevention official Denise Jamieson, speaking at a briefing for reporters. “Zika just adds another risk.”
So far, 39 countries and regions are experiencing outbreaks of Zika virus, following a 2015 outbreak in northeastern Brazil. Since October, Brazil has linked 863 cases of microcephaly birth defects — a shrunken brain syndrome in infants — to infections with the virus during pregnancy. Although carried by mosquitoes, the virus is also sexually transmitted. There are six U.S. cases confirmed.
As part of the Friday announcement, CDC made its first recommendations for the time limits that couples should wait before attempting a pregnancy after an active Zika infection, marked by rash, fever and headaches: Women should wait eight weeks after the onset of symptoms, while men should wait longer — six months — before having unprotected sex and attempting conception. That’s because the virus takes longer to clear from semen than the bloodstream after an infection.
Because Zika virus most often infects people without symptoms — perhaps 80% of the time — the CDC also counsels men and women who have visited Zika-affected regions to avoid unprotected sex or attempting pregnancy for eight weeks after their travel. The recommendation covers vaginal, anal and oral sex for all genders to prevent infection.
“CDC is learning more about Zika every day,” Jamiesen said, pointing out the recommendations remain interim ones for now. The health agency based them on the longest observed linger times for the virus in blood and semen, and then multiplied those numbers by three to make its recommendations.
The agency still recommends that men who have been infected by Zika with pregnant partners either abstain from sex or use a condom for the duration of the pregnancy. —Dan Vergano
WHO Predicts 2,500 Cases Of Microcephaly In Brazil
Brazil may eventually suffer more than 2,500 cases of microcephaly tied to the Zika virus outbreak, World Health Organization chief Margaret Chan said on Tuesday, with cases now confirmed in Panama and more under investigation in Columbia.
“The more we know [about Zika], the worse things look,” Chan said at a briefing in Geneva, Switzerland. “In less than a year, the status of Zika has changed from a mild, medical curiosity to a disease with severe public health implications.”
Since 2015, Brazil has confirmed 863 cases of microcephaly, a severe birth defect marked by shrunken skulls and brains, in about 39% of suspected cases that have been investigated so far. WHO expects that confirmation rate to continue, and to spread to the 38 countries and territories now part of the outbreak.
A pattern has emerged in the outbreak, Chan added, with a paralytic ailment called Guillain-Barre syndrome striking Zika victims within three weeks of the start of the virus arriving in a new region. “Detection of microcephaly and other fetal malformations come later, as pregnancies of infected women come to term.”
So far 12 nations have reported these early cases of Guillain-Barre. Cabo Verde, an island nation off the northwest coast of Africa, also reported its first suspected case of microcephaly linked to Zika on Tuesday. Cases of spinal inflammation and meningitis-like brain symptoms have also been linked to the outbreak.
If the outbreak spreads beyond Latin America, and the birth defect pattern holds, “the world will face a severe public health crisis,” Chan said. “The first explosive spread [of Zika] may be over before a vaccine is available.”
Zika Mosquito May Spread To New York And L.A. This Summer
Summer months will see the kind of mosquitoes that carry Zika virus arrive in New York and Los Angeles, climate scientists estimated in a map released on Wednesday. (See high-res version here.)
Although U.S. winter temperatures are too cold for these Aedes aegypti mosquitoes outside south Florida and south Texas, summer temperatures should see them spreading north, according to researchers from the National Center for Atmospheric Research and NASA’s Marshal Space Flight Center.
Read the whole story from Dan Vergano here.
Microcephaly Strikes 1 In 100 Pregnancies After Early Zika Infection, Study Finds
A Zika infection in the first trimester of pregnancy triggers microcephaly in about 1 in 100 births, suggests a study of the 2013 Zika outbreak in French Polynesia published on Tuesday.
Read the whole story from Dan Vergano here.
Genetically Modified Mosquitoes Gain Test Approval For Key West
The U.S. Food and Drug Administration gave approval on Friday to testing genetically altered mosquitoes on a Key West island, in a bid to cut risks of dengue and Zika virus.
The preliminary finding of “no significant impact” on human or animal health from an experimental release of the transgenic mosquitoes on Key Haven Florida, home to about 400 people, leaves 30 days for public comments.
The experimental mosquitoes, already tested in Brazil and Grand Cayman island, are all males that possess a “lethality” gene. Their release cuts mosquito numbers by passing the lethal gene to their offspring, who die unless they are fed tetracycline. Made by the biotech firm, Oxitec, the transgenic “OX513A” mosquitoes have been shown to cut numbers of wild Aedes aegypti mosquitoes that carry Zika and other diseases by around 82%.
“Oxitec will not conduct the field trial of its OX513A mosquito until the FDA has had the opportunity to review public comments,” said the agency.
Some 155,000 people in Florida had previously signed a petition opposed to the experimental mosquitoes. However, last week, lawmakers at a hearing pushed the FDA to approve the insects’ release immediately without public comment, something the agency said it would not like to set aside.
42% Of Americans Think Zika Is Fatal, Survey Finds
Even though the Zika virus is only very rarely fatal, 42% of Americans surveyed said it was “very likely” or “somewhat likely” to kill its victims, pollsters reported on Thursday.
The suggestion of widespread Zika misunderstanding comes months into the tropical virus leaping into public view, with the U.S. Centers for Disease Control and Prevention issuing travel advisories in January suggesting that pregnant women skip trips to outbreak regions.
People also aren’t getting the message that the virus only rarely cause symptoms, the Annenberg Public Policy Center survey finds, with 44% thinking it does. In reality, only about 1 in 5 infections causes symptoms, typically a rash and fever.
That same portion of the people surveyed, 44%, mistakenly thought that the Aedes aegypti mosquito spreading the virus is found in all 50 U.S. states. Just over half say they are concerned about catching the virus. In reality, the mosquito is largely confined to Texas, Florida, and Gulf Coast states.
“Where is the misunderstanding coming from? We don’t know yet,” survey research director Ken Winneg of the Annenberg Center told BuzzFeed News. The survey team is analyzing where readers are learning about Zika to figure out the misunderstandings, collected in March 2 to March 7 phone queries, as part of a running series of surveys looking at news coverage of the outbreak.
About 68% of the 1,019 people surveyed say they are familiar with news reports about Zika. The survey results have a roughly 4% +/- margin of error in its reporting.
To Fight Zika, Feds To Pull Money From HIV And Flu Vaccine Research
Zika-fighting efforts threaten to drain funds needed to develop HIV and flu vaccines, prevent dengue, and monitor Lyme disease, federal officials said on Thursday, blaming a funding battle with Congress for the slowdown.
“We are going to have to slow down, or stop things,” Anthony Fauci of the National Institutes for Allergies and Infectious Diseases (NIAID) said at a briefing for reporters.
The Obama administration and Congress are locked in a budget fight over $1.9 billion requested last month to pay for the federal response to the Zika outbreak.
Last month, House Appropriations committee member Chris Stewart of Utah unveiled a bill calling for federal health agencies to spend roughly $1.2 billion in remaining funds set aside to respond to 2014’s Ebola outbreak on Zika instead, a position supported by the spending committee’s leadership. The Senate has not acted on the Obama request, and Senator Roy Blunt of Missouri, a member of the Senate spending committee, last month questioned adding to the federal deficit by acceding to the Obama administration’s Zika request, when Ebola funds remain unspent.
However Ebola, “is not over,” Centers for Disease Control and Prevention chief Thomas Frieden testified at a hearing.
Both Fauci and Frieden pled for the Zika funding at the Wednesday briefing, which updated efforts to test insecticides in Puerto Rico and research on a Zika vaccine. Scientists working on a universal flu vaccine and respiratory virus vaccines, as well as a HIV vaccine, Fauci said, will have to be shifted to Zika virus vaccine efforts soon.
“No dengue work is going on right now,” Frieden said, one example of work halted as CDC has turned its efforts to monitoring the Zika virus outbreak, now observed everywhere from Brazil to Mexico and throughout the Caribbean. Zika might infect “thousands” of pregnant women this summer, Frieden. “Time is of the essence.”
In Puerto Rico, he added, the CDC is testing insecticides in 19 different location and finding some widely-used ones are ineffective against resistant Aedes aegypti mosquitoes that carry Zika virus. Mosquitoes have widely evolved resistance to many insecticides in a patchwork fashion, making finding the most effective ones essential before the rainy season in the Caribbean starts in the next few months.
“Puerto Rico remains a great place to visit, as long as you’re not pregnant,” Frieden said.
Zika Connected To Brain Swelling In Cruise Ship Patient
An elderly cruise ship passenger suffered dangerous brain swelling after a Zika infection, a French medical team reported on Wednesday, adding to suspicions the virus targets brain tissues.
Zika virus has been connected to cases of severe brain birth defects such as microcephaly in infants, as well as a paralytic ailment, Guillain-Barre Syndrome, in adults. The report of brain swelling in an 81-year-old man is a first report of the virus targeting the elderly.
In the New England Journal of Medicine report, researchers said the man arrived comatose at the hospital 10 days after a month-long cruise to New Caledonia, Vanuatu, the Solomon Islands, and New Zealand, paralyzed on his left side and in his right arm. Put on life support, he developed a distinctive rash over the next two days.
MRI scans revealed swelling of his brain and membranes covering his brain, a case of “meningoencephalitis” typically caused by bacterial or viral infections. A test of his spinal fluid came back negative for viruses or bacteria, however, except for Zika virus. All of the places his cruise had visited, except New Zealand, had reported Zika outbreaks within the last two years.
Case reports are typically seen by researchers as indications of areas where more research is needed, not the final word on the effects of a disease.
“Clinicians should be aware that [Zika virus] may be associated with meningoencephalitis,” nevertheless, concluded the researchers led by Guillaume Carteaux of the Assistance Publique–Hôpitaux de Paris in Créteil.
The elderly patient recovered after two days on life support and discharged from the hospital 17 days later. He still has some weakness in his left arm.
Most Severe Birth Defects Tied To Zika Infection In First Trimester
Zika infections during the first trimester of pregnancy look particularly dangerous, U.S. health officials said on Tuesday, in a survey of severe birth defects in Brazil.
The U.S. Centers for Disease Control & Prevention weekly report concentrated on Pernambuco, Bahia, and Paraíba states in northeastern Brazil, where microcephaly reports skyrocketed last year. It looked at 574 cases of microcephaly, a severe birth defect marked by shrunken skulls and brains in infants, in those three states, where the Zika outbreak peaked from February to May last year.
In those states, the analysis correlated fever and rashes during those months as “consistent with Zika virus infection during the first trimester of pregnancy with the increased birth prevalence of microcephaly.”
CDC directer Thomas Frieden suggested in February that Zika may do more damage during the first trimester to infants, similar to rubella. The overall microcephaly rate in 20 Brazilian states examined in the CDC report was 2.8 cases per 10,000 births, more than four times higher than the rate reported in Brazil before the outbreak.
Brazil is currently investigating thousands of suspected microcephaly cases, with 641 confirmed as being tied to a Zika infection overall. Cases of microcephaly tied to the mosquito-borne virus outbreak were reported in Colombia and in Rio de Janeiro, in southern Brazil, last week.
“Pregnant women should protect themselves from mosquito bites by wearing long sleeves and long pants, applying insect repellent, and when spending time indoors, ensure that rooms are protected by screens or mosquito nets,” concludes the report.
World Health Organization chief Margaret Chan on Tuesday also suggested that sexual transmission of Zika virus may be more common than previously suspected, raising concern about its transmission early in pregnancy. The CDC has recommended that men use condoms during their female partner’s entire pregnancy as a precaution.
Study: 29% of Pregnant Women With Zika Passed On Birth Defects
A study of pregnant women in Rio de Janeiro adds to evidence that Zika virus triggers severe birth defects and miscarriages, an international team reported on Friday.
The New England Journal of Medicine study reports stillbirths, brain defects, and fluid accumulation in fetuses of the infected women. The study compared 42 infected pregnant women with 16 uninfected ones, who were otherwise healthy and lived in similar neighborhoods.
Examinations revealed birth defects, including microcephaly, in 29% of the infected women’s fetuses. Similar testing found none among the uninfected women. “Despite mild clinical symptoms, [Zika virus] infection during pregnancy appears to be associated with grave outcomes,” the study said.
Women infected during the first trimester of pregnancy had most of the birth defects, but one woman infected as late as her 27th week also had a fetus with central nervous system abnormalities. Microcephaly, the shrunken skull and brain birth defect seen in clusters during the Zika outbreak, was just one of a range of brain-tissue-related birth defects seen among the infected women. Two suffered stillbirths late in their pregnancy, and two identified early in the study miscarried before they could be examined by ultrasound.
“In the present scenario, over a period of a few months, we identified a
fetal death rate of 4.8% — nearly twice the rate in an HIV-infected pregnant cohort followed for a decade — in addition to the serious fetal developmental problems,” the physicians concluded. —Dan Vergano
Colombia Reports First Cases Of Zika-Related Birth Defects
Colombia’s public health officials are reporting the country’s first confirmed cases of birth defects — one case of microcephaly and two cases of severe brain abnormalities — tied to the arrival of Zika virus, a science journal reported on Friday.
“All three tested positive for the presence of Zika virus,” according to the report in Nature. The diagnoses were made by the Colombian Collaborative Network on Zika (RECOLZIKA), established to monitor the effects of an outbreak that arrived in that nation in September.
Public health experts have warned that birth defects would likely start appearing in other nations as the Zika virus spread from northeastern Brazil. The Colombian birth defects might portend a wave that follows nine months behind the arrival of the virus. Zika has spread to 47 countries in the last year, according to World Health Organization officials.
Colombia and Brazil are monitoring birth defects with international assistance to help estimate the true risk of birth defects from a Zika infection during pregnancy, still a matter of conjecture at this point in the outbreak. —Dan Vergano
Google Gives UNICEF $1 Million For Zika Prevention
On Thursday, Google announced that it is granting UNICEF $1 million for its Zika-prevention efforts, as well as building a set of visualization tools to track potential outbreaks.
“A volunteer team of Google engineers, designers, and data scientists is helping UNICEF build a platform to process data from different sources (i.e., weather and travel patterns) in order to visualize potential outbreaks,” the company said on its blog. “Ultimately, the goal of this open source platform is to identify the risk of Zika transmission for different regions and help UNICEF, governments and NGO’s decide how and where to focus their time and resources.”
The $1 million grant to UNICEF will go toward developing diagnostics and vaccines, as well as curbing the population of mosquitoes that transmit the Zika virus, the company said.