Why is the Zika Epidemic Happening Now?

Author: Mosquito Squad of Greater Washington DC

The latest Zika outbreak has alarmed both travelers, and homebodies as new cases of Zika have popped up in Washington DC, Virginia, and Maryland. The Zika virus has spread like wildfire across the Americas, thanks to the menacing mosquito.

As Zika transmission continues to increase, there is much confusing and frightening information out there. We at DC Mosquito Squad want to help keep you informed and safe, so we are answering a series of the most pressing questions about the Zika virus here on our website.

Why is Zika causing a major epidemic?

Zika seems to have popped up out of nowhere, but it has been around for decades. So, why hasn’t it caused this kind of global health emergency in the past? Why has it suddenly become such a significant problem? Here’s what you need to know.

The history of Zika

The virus was first identified in 1947 in the Zika forest in Uganda. It has existed in Africa and Southeast Asia since then, but it kept a low profile. The outbreaks were small and isolated, with just 14 documented cases before 2007. Then, in 2007, the first major outbreak occurred on Yap island in Micronesia, with 49 confirmed cases. The virus became more prominent in other Pacific Islands, and in 2013, French Polynesia had a large outbreak. NPR reports that researchers estimated 20,000 people were affected. However, after the outbreak, the virus seemed to disappear. They haven’t seen a confirmed case in French Polynesia since April 2014.

The outbreak we are facing today is the largest yet, and it has spread to 30 countries and territories, since it began in Brazil in May 2015. It’s not clear how the virus spread to Brazil, but according to Reuters, the Brazilian government believes it was carried by a tourist from Africa or Oceania visiting Brazil for the World Cup in 2014.

Before 2013, it only affected small populations

Part of the reason that Zika has gone unnoticed for so many years is that wasn’t studied. According to Science Magazine, there may have been earlier outbreaks of the virus in Africa and Asia, but they were not a focus for researchers. As a result, there wasn’t any testing to look at the possible side effects of the virus.

When the virus began to spread through the South Pacific, populations were small, so the rare side effects were not prominent enough to be noticed.

Links to Guillain-Barrê syndrome and microcephaly had not been previously detected

Zika itself was not previously considered a major threat compared to other mosquito-borne viruses like Dengue or Chikungunya. Only one in five people develop symptoms, which include fever, rash, joint pain, and swollen eyes, all of which are usually mild. The serious side effects like Guillain-Barrê syndrome and microcephaly just weren’t on the radar.

It wasn’t until the 2013 outbreak in French Polynesia that doctors began to notice a link between Zika and Guillain-Barrê syndrome, which can cause paralysis. The New York Times reports that during the French Polynesia outbreak, there were 42 confirmed cases of Guillain-Barrê, which is eight times more than normal.

When Zika exploded in Brazil last May, it took months before a potential link to microcephaly to was detected. The Economist reported that the first red flag came when doctors in the Brazilian state of Pernambuco reported a huge increase in microcephaly cases in October. More than 3,500 cases were reported throughout the country in the next four months, as compared to less than 200 in the five years before 2015.

Even still, researchers are not 100% certain that there is a causal link between Zika and these two side effects. It will take time for studies to be completed to prove causation, but that doesn’t mean that proper precautions shouldn’t be taken.

The virus spreads more rapidly in Latin America than in Africa or Asia

According to Vox, several factors have contributed to the epidemic spread of Zika in Latin America. As we’ve seen, Zika wasn’t really on the radar of international health organizations before Brazil’s outbreak, so authorities were caught off guard and were unprepared when it struck. Also, because the virus hasn’t previously affected the Americas, no one has the necessary immunity to fight it – so populations were incredibly susceptible.

Possibly the biggest reason for the rapid spread is that the Aedes genus (the mosquito which spreads Zika), is found all over Latin America. There isn’t the much existing infrastructure to fight the spread, because many people live in underdeveloped communities without air conditioning or window screens to prevent mosquitoes from entering the home. These areas often lack ready access to clean water and tend to be prime breeding grounds resulting from poor sanitation and stagnant water.

Climate change and international travel may be partially to blame

Zika isn’t the only virus that began to terrorize new regions. Other mosquito-borne tropical illnesses like Dengue and Chikungunya have been spreading to regions where they have never existed before. Researchers are not yet sure why this is occurring, but they speculate that climate change and international travel could be part of the problem.

Last year was the hottest year on record, and EcoWatch reports that Brazil saw temperatures rise by 3-5 C. The warming of the Pacific can be partially attributed to El Niño, but scientists believe that climate change is also playing a role.

Brazilian studies have shown that Aedes mosquitoes are now found in 80% of the country, which is four times more than a decade ago. As a result, mosquito-borne viruses are being spread to areas that were previously too cold to support them.

Also, human travel contributes significantly to the spread of viruses. Aedes mosquitoes only travel a few hundred meters. Humans, however, travel vast distances within their home countries, as well as internationally. When an infected human travels to a different region and is bitten by a mosquito in that region, the virus spreads.

There is still much to learn about Zika, but it is clear that it should be taken as a serious threat. The World Health Organization has declared Zika a global health emergency, and international scientists, doctors, and researchers are working to find a way to contain it.

If you’re planning international trips, it’s important to protect yourself from mosquitoes when traveling as well as follow the CDC travel advisories. Be sure to check our blog regularly for updates about Zika, and contact DC Mosquito Squad today to prepare to fight this epidemic in your backyard.