Zika virus is making headlines for the third time this week, after the governor of Florida declared a state of emergency in four counties with confirmed cases of the disease, which is thought to be linked to birth defects and neurological disorders. The news comes just a day after Texas health officials confirmed the first case of locally-acquired Zika virus in the United States, and two days after the World Health Organization declared the virus a “Public Health Emergency of International Concern.“
Governor Rick Scott signed the emergency order on Wednesday, designating Zika as an urgent health emergency in Miami-Dade, Lee, Hillsborough, and Santa Rosa counties. Florida health officials have confirmed that there have been at least nine cases of the mosquito-borne Zika virus in the state, all of which are believed to have occurred in people who’ve traveled to Latin America and the Caribbean, where the virus has been spreading rapidly.
The emergency order authorizes the state’s agriculture department to take action to combat the problem, such as spraying against mosquitoes. It also directs the Florida Department of Health to make its own decisions about what’s needed from the state and the Centers for Disease Control and Prevention.
“Although Florida’s current nine Zika cases were travel-related, we have to ensure Florida is prepared and stays ahead of the spread of the Zika virus in our state,” said Gov. Scott. “We know that we must be prepared for the worst even as we hope for the best.”
The concern is that these cases could spark a localized outbreak due to the existing mosquito population in the state, which includes the Aedes aegypti mosquito that carries Zika as well as dengue fever and chikungunya. Zika virus stays in a person’s bloodstream for about a week after they’re infected, during which time a mosquito could bite them, pick up the virus, and then bite another person and transmit it to them. This could start a localized chain of transmission in Florida that would likely be difficult to stop.
“All it takes is one of those individuals … at the stage where they have virus in their blood,” said Scott Weaver, an expert in mosquito-borne viral diseases at the University Texas Medical Branch’s Galveston National Laboratory. A single mosquito biting the affected person would be enough to spread the disease to others, Weaver told Reuters news agency.
Active transmission of Zika is currently ongoing in more than two-dozen countries, mainly in the Americas and Caribbean islands. Although it is not a new disease, Zika virus did not begin spreading widely in the Western Hemisphere until last spring, when a major outbreak started in Brazil. Since May, as many as 1.5 million people have been infected in Brazil alone, and the World Health Organization recently estimated that there could be up to 4 million Zika infections in the Americas over the next year.
It’s no coincidence that the “explosive” spread of Zika is taking place after several years of record-breaking global temperatures: scientists have been predicting for a while now that tropical diseases, including dengue, malaria, and chikungunya, will expand their reach due to global warming. Evidence from around the world shows that these predictions are already coming true.
So far, at least 48 cases of Zika have been reported in the U.S. Until this week, all cases within the U.S. had occurred in travelers infected abroad. However, on Tuesday the Centers for Disease Control and Prevention confirmed the first case of locally-acquired Zika virus in a Texas patient who contracted the disease through sexual activity. According to Dallas County health officials, the patient became infected after having sex with someone who had contracted Zika virus during a recent trip to Venezuela, one of the countries currently experiencing widespread Zika transmission.
Only about 1 in 5 people infected with Zika virus show symptoms of illness. Signs and symptoms of Zika may include a low-grade fever, rash, joint pain, reddening of the eyes, body aches, headache, eye pain, and vomiting. Illness is often mild and typically resolves within a week.
The real concern is for women who are pregnant, as it has been linked to microcephaly — a condition in which a baby is born with an abnormally small head, which can lead to mental retardation and other serious developmental problems. Around 4,200 children in Brazil have been born with the condition since mid-October, marking a huge surge in the incidence of this otherwise rare birth defect. At the same time, Brazil and several other South American countries with widespread Zika transmission have also seen a worrisome increase in Guillain-Barré syndrome — a neurological condition that can lead to partial paralysis.
South Florida hospitals are now asking pregnant women if they have traveled to areas known to have confirmed cases of the Zika virus during the admission process. Pregnant women are being advised not to travel to areas where the virus is present. If they do, they should consult with their doctor first.
With warmer spring temperatures coming soon, experts believe local transmission within the U.S. is likely, particularly along the Gulf Coast. Warmer temperatures help Zika by increasing the habitat for its mosquito vector, while speeding up the biological processes that help the virus replicate. “With higher temperatures you have more mosquitoes feeding more frequently and having a greater chance of acquiring infection,” Bill Reisen, an entomologist at UC Davis, told the Associated Press. “And then the virus replicates faster because it’s hotter, therefore the mosquitoes can transmit earlier in their life.”