Written by: Casey Parker
A mosquito-transmitted virus, known as Zika, gained a great deal of attention from the public and health officials after a large outbreak in Brazil during 2015 and 2016. Since this outbreak, Zika has spread through Central and South America and made its way into the United States. According to the Florida Department of Health, as of December 2, 2016, there were 244 cases of locally acquired Zika infection in Florida. In U.S. territories, like Puerto Rico and the Virgin Islands, there were more than 33,000 local cases this year, according to the Center for Disease Control and Prevention (CDC).
The presence of Zika in Brazil was a hot topic due to the Olympic Games hosted in Rio de Janeiro. There was a great deal of concern because not only would there be half a million people traveling to Brazil to attend the games, but also 10,500 competitive athletes. Some athletes opted not to attend the Olympics due to the threat of Zika. One aspect that I feel many people failed to consider was the seasonality of mosquitoes. In the US, August is probably one of the hottest parts of the summer and a peak time for mosquito populations. However, in Brazil, August is their winter. The mosquitoes that transmit Zika are far less active during cooler months. This greatly decreased the risk of Zika transmission during the game. Many teams took great precaution to make sure their athletes were at the lowest level of risk possible. Thankfully, there were no reported infections of Zika in Brazil during the Olympics among athletes or visitors, according to the World Health Organization.
Zika presents a unique issue to the field of public health. Mosquito-transmitted diseases are nothing new. Many of us may be familiar with malaria, west nile virus, and dengue. So why has Zika gained so much attention? Well, a variety of factors make Zika-infection very alarming. First off, approximately 80% of people infected with the virus do not exhibit symptoms. In addition, Zika can be sexually transmitted, which is very unique in the vector-borne disease world. After the outbreak started in Brazil, increased rates of microcephaly (children with abnormally small heads) were detected. Eventually, it was determined that Zika and microcephaly were linked along with other birth defects. The CDC is also investigating the link between Zika and Guillain-Barre Syndrome, an uncommon sickness where an individual’s nervous system is attacked by their immune system. So in addition to being transmitted in a variety of ways, by a mosquito, from mother to child, through sex, and even through a blood transfusion, Zika is causing congenital birth defects along with other serious medical conditions in those infected.
The symptoms of Zika include fever, rash, joint pain, conjunctivitis (red eyes), muscle pain, and headaches. These symptoms are very similar to dengue and can be almost indistinguishable. Some even describe the symptoms as being mild. Through my experiences with individuals, I have realized that many people think that if they are not a pregnant woman, they do not have to be concerned about Zika. This is simply not the case. Researchers are learning more and more every day about this virus and how it acts in our bodies. The potential for additional health problems is not out of the question. Additionally, someone infected with Zika could sexually transmit it to another person, or a mosquito could bite an infected person, become infected, and eventually infect another person. Therefore, this is an issue that everyone, not just pregnant women, should be concerned about.
So what can we expect from Zika in the US in 2017? This is a very hard question to answer at this time. However, one article attempted to predict what next year will look like through a worst-case-scenario model (that did not account for sexual transmission). In the discussion, they state “From the numerical results, it appears that the number of Zika cases projected in the US is low” (http://www.zika-model.org/files/projectedZikaContinentalUS.pdf). Many factors can influence this model, so it is hard to predict what will actually happen. Based on confidence intervals that were also produced in this paper, they project that Florida will have the highest number of infections and symptomatic cases. Everyone should be prepared by knowing how to prevent mosquito development and how to protect themselves.
The mosquitoes that transmit Zika are day-time biting mosquitoes and they often develop in containers that may be holding water around your home. They also prefer to feed on humans over any other organism. Due to the fact that these species do not fly very far, preventing the mosquitoes from developing around your home is one of the best things you can do to reduce the risk of Zika transmission. All water around the home should be dumped out on a weekly basis in warmer months, if possible. In addition, the use of window screens, wearing protective clothing, and using repellents when working outdoors are all excellent ways to reduce the chances of being bit by a mosquito.
For additional information on Zika and daily updates on the number of Zika cases in Florida, please visit the following websites:
Edited by: Kelli Selwyn
Casey Parker is a Ph.D Student in the Department of Entomology and Nematology, and a first-year Master of Public Health Candidate in the Public Health Practice Concentration.