What to Know About First Local Zika Outbreak in Continental US

— -- For the first time in the continental U.S. the Zika virus has been spread locally through infected mosquitoes.

Florida Gov. Rick Scott announced the first local Zika outbreak today, saying that four people have been infected. For months health experts have warned that a small local outbreak of the disease was likely to occur and that local and state health departments should be ready.

Here's what you need to know about the latest Zika outbreak.

Where is the outbreak located?

The affected area is believed to be north of downtown Miami and to be about one square mile in size.

The area is under close surveillance and according to officials at the press conference today, door-to-door outreach is underway there. State and local officials have also been contracting with local companies to eliminate mosquito habitats through increased spraying, including of aerial liquid larvicide.

What about the mosquitoes that carry Zika? What should I know about them?

To date, there have been no mosquitoes found in Florida that have tested positive for Zika. Over 19,000 mosquitoes have been screened for Zika in Florida. The specific species of mosquito thought to transmit Zika, Aedes aegypti, prefers urban environments to wetlands, is more active during the day, and doesn’t travel far distances. Florida officials are confident that they’ll be able to control and reduce mosquito populations based on their success responding to outbreaks of Dengue and Chikungunya mosquito-borne illnesses. They advise residents to continue to wear repellent, eliminate standing water, and wear long-sleeved clothing to decrease the chance of getting mosquito bites.

What should pregnant women know?

Pregnant woman can travel to Florida and have a low risk of transmission. However, pregnant women should still take the following precautions to prevent mosquito bites:• Wear long sleeves and pants. • Use insect repellent with at least 30 percent Deet. • Avoid areas with standing water. • Stay in places with adequate window screens and air conditioning.

Pregnant women can see their health providers to receive a Zika prevention kit, which includes condoms, bug spray, and other precautionary tools.

What are the risks for those who are not pregnant?

About 80 percent of infected persons who contract Zika will be asymptomatic, yet around 20 percent of infected persons may show symptoms. Most cases have consisted of mild symptoms such as fever, joint pain, and rash. These symptoms usually go away in seven to 10 days. Reports have shown that there may be a rare association with Guillain-Barre syndrome in people that have been affected by Zika. Guillain-Barre is a rare syndrome in which the body’s immune system can attack nerves and cause a temporary, reversible paralysis. The syndrome often takes places after an infectious illness normally caused by certain viruses.

What precautions are being taken for the blood donation?

Given the concern for blood donation transmission in the recent local cases, the Florida government has provided $620,000 in funds to support blood donation testing. In the meantime, pregnant women will receive blood from counties without known cases of Zika.

Dr. Shyam Sivasankar is an emergency medicine resident at the Stanford University-Kaiser Permanente program. He is a resident with the ABC News medical unit. Dr. Shakira Sanchez-Collins is an Internal Medicine/Urban Health Resident at Johns Hopkins Hospital who is currently working at ABC News in the medical unit.