The Zika virus, explained

Mar 04, 2016, 9:53 AM EST
Source: La Veu del País Valencià/flickr
Source: La Veu del País Valencià/flickr

In late 2015, the Caribbean Public Health Agency confirmed five cases of a new virus called Zika, prompting overworked health officials to wearily add it to a roster of mosquito-borne illnesses that already included malaria, dengue fever and the rare but extremely painful chikungunya.

Experts stressed the need to disinfect thoroughly the stagnant, often putrid sites where mosquitoes breed. An aggressive cleanup campaign, they said, could be the best way to keep Zika from becoming a public health menace.

Yet just four months later, Zika is claiming victims all over the world. The World Health Organization (W.H.O.) says that, as of February, the virus has been identified in 48 countries and territories, with the largest concentration of cases found in Central and South America.

Zika is believed to be behind a spike in certain birth defects, including microcephaly  (underdeveloped head and brain) and Guillain-Barré syndrome, a rare neurological disorder that can lead to paralysis and even death.

In February, the W.H.O. declared a public health emergency and pronounced between 3 million and 4 million people in the Americas, a region already struggling with a burgeoning economic crisis, at risk of contracting the virus by year’s end.

The Centers for Disease Control (C.D.C.) have cautioned pregnant women to avoid travel to areas hit hard by the disease, including Brazil as it prepares to host the 2016 Olympics.

The W.H.O. has suggested that athletes and would-be spectators by and large have nothing to fear, but some athletes are weighing the risks, and there is a growing chance that a sizable contingent of participants and spectators will opt to sit out the 2016 Games.

Below, Blouin News takes a closer look at the Zika virus:

Where did it come from?

Zika was discovered in 1947 in the Ugandan forest for which it was subsequently named. For decades, doctors considered it “reasonably harmless,” and there were only a handful of documented cases anywhere before 2007.

But then an outbreak in Micronesia preceded a much larger one in French Polynesia. Experts say it’s likely that the virus was unwittingly introduced to the Americas by Pacific Islanders visiting such athletic events as soccer’s 2014 World Cup, held in Brazil.

It was first detected in the Brazilian population the following year, and it is now said that one in every five people who contract it will develop symptoms, an assertion that scientists are investigating.

What are its symptoms?

One of the challenging aspects of Zika is that its symptoms can be so mild that those infected could mistake them for something else or not notice them at all. Indeed, the most common symptoms, according to the C.D.C., are fever, eye redness, joint pain and muscle ache – hallmarks of the common cold or an allergy attack.

Can it prove fatal?

Colombia has attributed three deaths there to complications brought on by Zika. The victims were found to have contracted the virus, which then developed into a severe form of Guillain-Barré.  

Although the chances of contracting Guillain-Barré are about one in 100,000, Martha Lucía Ospina, director of Colombia’s National Health Institute, has advised residents to brace themselves for more deaths linked to Zika.

How is it spread?

The virus is principally disseminated by Aedes aegypti, the same breed of mosquito behind outbreaks of dengue and yellow fever.

But health officials in a Texas town earlier this year announced a case of Zika spread by sexual intercourse. If accurate, experts say, that could account for the sudden increase in reported cases.

Is there a cure or treatment?

There is currently no cure. In fact, it’s difficult even to test for Zika since its antibodies react similarly to those found in dengue fever.

U.S. scientists are testing vaccines they say may be cleared for human trials within six months. And an Indian company claimed in February to have a vaccine ready for pre-clinical trials.

Meanwhile, the focus is on preventative measures, such as ridding the landscape of habitats hospitable to disease-carrying insects -- and even engineering a “mutant mosquito” to introduce a fatal disease into their gene pool before they have a chance to breed.

Is the U.S. at risk of an outbreak?

Experts fear it’s only a matter of time before Zika seriously hits the U.S., which has reported about 100 cases so far.

In Mexico, 11 women have been found to have contracted the virus. More troubling are CDC fears that hundreds of thousands are at high risk in Puerto Rico, which “could have major implications” for the U.S. mainland, especially Florida and Texas.

So what’s being done?

Besides the desperate search for a vaccine, there’s fund-raising for research and eradication efforts. President Obama has asked Congress to approve $1.8 billion in emergency funding to help fight a potential outbreak. And on Friday, it was announced that the White House and the CDC will invite public health officials to an April 1 summit to craft a plan of attack against the virus.

USA Today reports that Google has donated $1 million to UNICEF toward vaccine research and increasing global education about mosquito-borne illnesses and “assigned a team of engineers, data scientists and designers” to assist UNICEF in analyzing weather and travel data in search of patterns that might help zap Zika in midflight.