Here is everything you need to know about Zika, including whether or not to cancel your travel plans to affected countries.
What is Zika, anyway?
The Zika virus is an arbovirus, closely related to yellow fever, dengue and chikungunya. The virus causes mild symptoms and usually does not result in severe illness requiring hospitalization, and it is rarely deadly. In fact, if it weren’t for two specific conditions strongly suspecting of being related to Zika, this outbreak would not be worthy of much attention at all.
A health ministry worker fumigates for Aedes aegypti mosquitoes where carnival celebrations will be held in Panama City, Tuesday, Feb. 2, 2016.
IMAGE: AP PHOTO/ARNULFO FRANCO
The Zika virus was first identified in 1947 in the Zika Forest of Uganda. However, it likely jumped from another species to humans, and then began spreading in human populations, according to Andrew Read, an entomologist and senior scholar at Penn State University.
“Zika is not naturally a human pathogen as far as we know,” Read told Mashable in an interview. “And so it’s jumped from something and is now spreading in humans.”
The spread of Zika is aided by the broad distribution of the mosquito that transmits it, since the mosquito’s range stretches from South America to the U.S. border with Canada, as well as the lack of immunity among populations in the Western Hemisphere.
Based on evidence-to-date, Zika cannot be spread person-to-person and is not airborne, though much is unknown about whether it can be contracted sexually. There is one well-documented case in which Zika was sexually transmitted in 2008, and on Tuesday, the Centers for Disease Control and Prevention (CDC) in Atlanta confirmed to a case reported in Dallas County, Texas.
“CDC has confirmed through laboratory testing the first U.S. case of Zika virus infection in a non-traveler in the continental United States,” the agency said in an email. “According to a Dallas County Health Department investigation, a person who recently traveled to an area with Zika virus transmission returned to the United States and developed Zika-like symptoms. The person later tested positive for Zika, along with their sexual partner, who had not traveled to the area. In this instance there was no risk to a developing fetus.”
The CDC recommended the use of condoms to prevent the transmissions of sexually transmitted infections.
Does the virus affect adults?
Yes. The Zika virus itself typically causes only mild symptoms, lasting from several days to a week, according to the Centers for Disease Control and Prevention (CDC) in Atlanta. The most common symptoms are fever, rash, joint pain and conjunctivitis (red eyes). Only about one in five people infected with the virus actually show symptoms.
More ominously, the virus is strongly suspected of causing microcephaly, a rare and potentially deadly birth defect, as well as an adult neurological disorder called Guillain Barré Syndrome. Microcephaly is characterized by babies born with incomplete brain development and unusually small head sizes, while Guillain Barré Syndrome can cause paralysis, muscle weakness and other debilitating symptoms in adults.
Daniele Ferreira dos Santos holds her son Juan Pedro as he undergoes visual exams at the Altino Ventura foundation in Recife, Pernambuco state, Brazil, Thursday, Jan. 28, 2016.
IMAGE: AP PHOTO/FELIPE DANA)
In recent months, the number of microcephaly cases in Brazil — which usually hovers around 250 per year — has soared to at least 4,180, as of late January.
“The evidence is growing and it is getting strong.”
During a press conference in Geneva on Monday, Margaret Chan, the director-general of the WHO, said the link between Zika virus infection and microcephaly as well as neurological disorders “is strongly suspected though not yet scientifically proven.”
The suspicions were enough for the emergency committee to act, she said.
“The evidence is growing and it’s getting strong,” Chan said regarding the link between Zika infections and the debilitating, and in some cases deadly, outcomes.
“There is urgent need to do a lot more work,” Chan said.
The virus’ spread may have been aided by El Niño-related heavy rains and flooding in parts of Brazil, since standing water makes for ideal breeding grounds for the virus-carrying Aedes aegypti mosquito.
If I go to Brazil tomorrow, but don’t plan to get pregnant for like 10 years, what are the risks?
A Sucre municipality worker fumigates for Aedes aegypti mosquitoes that transmit the Zika virus in the Petare neigborghood of Caracas, Venezuela, Monday, Feb. 1, 2016. Venezuela is reporting a jump in cases of a rare, sometimes paralyzing syndrome that may be linked to the Zika virus. (AP Photo/Fernando Llano)
The CDC’s travel advisories only apply to pregnant women (women of childbearing age who plan to become pregnant are advised to speak with their doctor before traveling). The advisories are designed to prevent American travelers from being exposed to the virus due to the concern that it could cause a poor pregnancy outcome, such as microcephaly.
The advisories present a conundrum for other tourists, though, who don’t fall into the CDC’s category. The risk is that you could contract a Zika infection, and experience a rare bout of Guillain Barré Syndrome, which can cause paralysis that takes a year or more to recover from.
However, the risks of such an outcome are low. The disturbing thing about this outbreak is that there are a great deal of unknowns, ranging from how many cases of microcephaly there are in South and Latin America to the precise ways that a pregnant woman can pass the virus on to her unborn child.
Researchers are just starting to ramp up their efforts to understand, detect and prevent this virus through diagnostic screening and vaccine development.
The CDC advises that all travelers to countries with active Zika virus transmission take actions to limit their exposure to mosquito bites, including by wearing long sleeve clothing, using insect repellent and staying in hotels with air conditioning.
Science writer David Quammen, who wrote an authoritative account of newly emerging diseases, said people should be cautious about traveling to areas where the virus is actively being transmitted. However, he cautioned against panic.
“This is potentially a pretty widespread problem and people are justified to get cautious and adjust their lives and change some plans,” he said.
Should I cancel or postpone my travel plans to Brazil or another country on the CDC’s travel advisories list?
That is up to you and your doctor. While the risk of contracting Zika and having a severe complication are likely quite low, the actual risks are not yet known. It’s this lack of knowledge about how many cases of the illness there are, as well as how many instances of microcephaly and Guillain Barré Syndrome, that argue in favor of a cautious approach to non-essential travel.
What are the chances the Zika virus will spread to the U.S.?
The likelihood of Zika virus transmission occurring within the U.S. is considered to be relatively high, for two main reasons. First, the mosquito that spreads the virus is already present in large numbers across much of the U.S., particularly in the Southeastern states.
Second, travelers from countries where Zika transmission is occurring, be it Colombia, Brazil or Costa Rica, can bring it back to the U.S. and begin a chain of transmission.
However, large outbreaks are not currently anticipated in the U.S. due to better mosquito control measures and urban infrastructure compared to Latin and South American cities, where urban waste and standing water are more abundant. The CDC has said relatively small, contained outbreaks of Zika are expected, much as has occurred with dengue and chikungunya.
Is there a vaccine for Zika? If not, how soon might one be developed?
There is no vaccine for Zika, largely because the virus was not considered to be a significant threat to humans since it first emerged several decades ago. The National Institutes of Health has issued a call to the research community that it is looking to fund vaccine development, though that may take several years to pay off.
According to Read, a key factor that will help determine how long and challenging the road to a vaccine will be is whether there is more than one strain of the virus that is circulating, as occurs with dengue, or if it is more like yellow fever, with a single strain involved.
Instead of a vaccine, for now, the best way for the ongoing outbreak to be controlled is through management of mosquito populations.
Brazil and other governments have embarked on mosquito mitigation programs, trying to eliminate as many breeding sites as possible. However, the dense urban population and lack of proper waste disposal methods make mosquito control particularly challenging in urban areas, including in Rio de Janeiro, where Brazil plans to host the Summer Olympics in August.
What is not yet known about Zika?
The short answer? A lot.
In fact, doctors have more questions than answers about this outbreak and the apparent increase in microcephaly and Guillain Barré Syndrome cases.
There are few, if any, Zika experts out there, since the virus was not considered a major public health threat until this latest outbreak. Public health officials are trying to rapidly assess the level of risk to pregnant women in affected countries, including if the risk of infection-related microcephaly is highest at particularly stages in the pregnancy.
Doctors are also trying to devise accurate and fast diagnostic tests to detect Zika cases. Political divisions between Central and South American countries could inhibit efforts to fight the illness, since some countries, such as Venezuela, are not gathering and sharing public health information.
“In Venezuela, for instance, we have absolutely no reliable information on what’s been going on there” regarding Zika’s spread, said Nuno Antunes, an analyst at Decision Resources Group, a healthcare consultancy in Massachusetts, who focuses on Brazil, among other Latin and South American nations.
Even in Brazil, there are questions about the accuracy of the microcephaly numbers, with some experts questioning the health ministry’s figures for pre-Zika microcephaly cases.
Is it just me, or are we having a new disease outbreak to deal with every year now?
No, it’s not just you. To Quammen as well as others, this illness is yet another example of a growing human population encountering new pathogens that take advantage of today’s interconnected world.
“The reality is always that it hasn’t come out of nowhere, there is a broader ecological context” to an emerging virus like Zika, he said, mentioning SARS, the Middle East Respiratory Syndrome, or MERS, and other emerging viruses in recent years.
“All of these things are connected, they are ecological and evolutionary,” he said.
Read also said that new human pathogens including viruses and bacteria are emerging more rapidly, and spreading more rapidly, now than they did decades ago.
“They are actually emerging at a faster rate than they used to,” he said. “It makes you wonder what else is out there.”
“It makes you wonder what else is out there.”
“We disrupt mosquito habitats a lot more now and we have [more] travel now,” Read said.
Increasingly crowded cities, including in Rio, make us particularly vulnerable to illnesses that our immune systems are unfamiliar with.
“We are walking around with a big target on our backs, and these things reflect the fact that more and more in the future viruses and antibiotic-resistant bacteria are going to find more ways to hit that target,” Quammen said.