What is Zika virus?
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.
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 toldMashable 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.
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.
Does the virus affect adults?
Yes it does. 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.
If I go to Brazil tomorrow, but don’t plan to get pregnant for like 10 years, what are the risks?
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.
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.
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.
“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.