In the past week, the Centers for Disease Control has acknowledged that the Zika virus is being locally transmitted between humans and mosquitoes in southern Florida. Initially four human cases were diagnosed but, because many cases are asymptomatic, public-health officers then went door-to-door asking residents to donate a urine sample. In this way, 11 more cases were discovered.
The Florida governor has declared a public health emergency and asked the CDC to bring in teams specially trained to stop an emerging outbreak of mosquito-borne disease. The CDC people are good at what they do but if it were easy to stop this virus, it would not be causing so many problems.
This is a serious public-health issue for South Florida. But what about here in Central Kentucky? Should we be worried? Should we start taking extraordinary measures to prevent mosquito bites? Should we cancel that outdoor event we’ve been planning? Should we hide indoors the rest of the summer? What, exactly, should we do?
Best answer: Keep calm, don’t overreact and enjoy what’s left of summer. Zika is not likely to cause a mosquito-borne outbreak in Kentucky in 2016.
The mosquito transmitting Zika in Florida is Aedes aegypti, the yellow-fever mosquito. Until the mid 1980s it was the species that caused most of the mosquito bites on people in our area. Since then, though, it has largely been replaced by Aedes albopictus, the Asian tiger mosquito.
In the 1980s, 80 percent of the mosquitoes we caught in Lexington were yellow-fever mosquitoes, but over the last two years we have only found four out of over 26,000 mosquitoes caught. The significance of Asian tiger mosquitoes replacing yellow-fever mosquitoes here is that Asian tiger mosquitoes either do not transmit Zika or are much less efficient at it.
Lacking the principal vector, we do not expect a significant outbreak of Zika in Kentucky this year. Moreover, in the next week or two, mosquito populations will begin to slowly decline, along with any threat of a Zika outbreak.
To be sure, there will be more travel-related cases along with a few sexually transmitted ones. Anyone traveling to Zika areas needs to be careful while there and practice safe sex when they return. But the risk of contracting Zika from a mosquito bite in Kentucky this season is extremely low.
What does this mean to you?
First, use common-sense mosquito-avoidance techniques. Use a repellent. Empty containers holding water. Avoid being outdoors from 4 p.m. to around 9 p.m., when these species are most active.
Second, don’t overreact. Don’t use insecticides unless necessary and they are no more necessary in Central Kentucky this year than in any previous year.
Third, have faith in your state and local public-health departments. Kentucky has top-notch and highly dedicated people in the Department of Public Health in Frankfort and in Lexington and Louisville. We began preparing for Zika last October. We have developed a system of rapid-response teams that is being copied by surrounding states. Trust the experts here.
Finally, stay informed. Zika has proven to be difficult to predict as it has mutated. It may well jump to another mosquito more common here. If we start seeing significant caseloads in Georgia, for instance, we’ll have to go on alert here.
Remember that Zika is a very mild virus — many people, perhaps most, never know they were infected. Symptoms are about as serious as a cold and go away on their own after a few days.
Of course, pregnant women have a completely different set of concerns and they should take extra precautions, particularly related to travel. But for most of us, Zika is just not going to be a serious public-health threat this year.
Next year may well be a different story. For now, though, let’s keep Zika in perspective. We all have a long list of things to worry about. For most of us, Zika should not be high on that list right now.
Grayson C. Brown is director of the Public Health Entomology Laboratory at the University of Kentucky.