Zika in Miami – The First Cases in the U.S. Where Mosquitoes are the Transmitters

July 29, 2016 – It was only a matter of time before mosquito transmitted Zika reached the southern continental United States. The first four cases of local transmitted Zika have been confirmed by officials in Miami-Dade County. The infected area of the city appears to be just north of the downtown. The suspected source is mosquitoes that hitched a ride on boats coming from Central and South America. The symptoms of the four confirmed infected people have been mild. None have required hospitalization.

To date the continental United States has confirmed more than 1,300 Zika cases all from people coming back from traveling to areas where the Aedes aegypti mosquitoes reside. But Aedes aegypti can be found in much of the lower continental U.S. (see map below). Recently the Department of Health in Oklahoma reported their presence in the southwestern part of the state. Oklahoma, however, has not recorded a Zika case (there have been 13 so far in the state) where the mosquitoes were identified as the agents of transmission.

Aedes aegypti has always resided in Central and South America where the climate has suited the species. But climate change is causing changes in species distribution. And that means diseases spread by mosquitoes normally confined to the tropics are heading poleward as conditions become more receptive for the carriers of these infectious agents.

Aedes aegypti isn’t just a Zika threat. The mosquito population also spreads dengue fever and chikungunya. It doesn’t however have anything to do with West Nile Virus which is spread by a different mosquito, the Culex.

The best preventive for all the diseases spread by mosquitoes is to avoid getting bitten. That means covering exposed skin and using DEET or other recommended insect repellents that are age appropriate. Some repellents should not be used on children.

Aedes aegypti is a mosquito that enjoys urban environments where it can find standing water in which to breed. If you have old tires or flower pots that are rain filled you can eliminate these breeding sources by dumping the water out or storing these objects out of the rain.

In its latest announcement, the U.S. Center for Disease Control (CDC) states that as of July 21, 2016, the Zika virus has spread to 50 countries reporting active transmission through mosquito hosts. And although most people who get Zika from a mosquito bite will be asymptomatic or have only mild symptoms, the virus remains a significant threat to pregnant women. The CDC’s latest count on pregnant women with Zika infection in the continental United States is 378 and climbing.

With the Rio Olympics a week away, the CDC is advising people traveling to Brazil to see their doctor prior to going and should they become sick (common symptoms are fever, rash, joint pain and red eyes) after being bitten by a mosquito see their doctor upon return and mention where they traveled. The CDC has stated that “anyone who is traveling to the Olympics is at risk for Zika.”

If it is any consolation, the CDC states that travel to the Olympics represents only a small fraction of overall global travel, 0.25% of total air travel to areas where Zika is prevalent. And for families or individuals traveling to the Games who are contemplating a future pregnancy, the CDC advises women to not try to conceive for a period from 8 weeks to 6 months after returning. Men who have symptoms of Zika should not consider having their partners become pregnant for 6 months.