The CDC urges clinicians to remain alert for symptoms and ask patients about any recent travel as cases increase worldwide.
Experts recommend that Georgians take precautions against mosquito bites, but they stress that dengue fever is unlikely to start spreading here. Georgians are much more likely to be infected with West Nile virus, which caused 81 infections in the state between 2018 and 2022.
Dengue fever is the most common mosquito-borne infection in the world, but in the United States, most dengue cases are associated with travel to tropical and subtropical regions, such as the Virgin Islands, Puerto Rico, and South America. So far this year, there have been nearly 1,500 locally acquired cases of dengue fever in the United States, almost all in Puerto Rico.
Mosquito-borne diseases are transmitted to humans through the bites of infected mosquitoes. They are not transmitted from person to person.
Dengue is mainly transmitted through the bite of an infected mosquito, the Aedes aegypti mosquito, or yellow fever mosquito, a type of mosquito that is very rare in Georgia. But the Aedes albopictus mosquito, or Asian tiger mosquito, which is very common in Georgia, can also transmit dengue in other parts of the country.
Experts say Georgians are at greater risk of dengue fever when travelling.
Gonzalo Vazquez-Prokopec, an expert in ecology and vector control in Emory’s Department of Environmental Sciences, said the growth in dengue cases is fueled by the warm temperatures brought by last year’s El Niño — a weather pattern marked by warmer-than-average ocean temperatures.
The post-pandemic surge in travel is also playing a role in the increase. “Human mobility, whether short or long distance, plays a significant role in the spread of viruses,” he said.
If a mosquito bites a person infected with dengue, it can transmit the virus to other people. This means that local epidemics become possible when people import the virus.
But with such a low number of Georgian travellers infected with dengue, the potential for local spread of the disease in Georgia remains very low, particularly because the type of mosquito (Aedes aegypti) that spreads dengue is rare in Georgia.
Credits: Steve Nowland
Credits: Steve Nowland
There is no specific medication to treat dengue fever, and there is no vaccine for adults or people who have never been infected with dengue fever.
Only one in four dengue cases have symptoms. While some infections cause only mild symptoms, others can cause headaches, high fever, joint pain, and recovery can take weeks. About 5% of people infected with dengue will develop severe dengue, which can lead to shock, internal bleeding, organ failure, and even death.
Vazquez-Prokopec said travelers to areas where dengue fever is spreading should take precautions to avoid mosquito bites. Travelers should also take steps to avoid getting bitten when they return home. Many people infected with dengue fever have no symptoms and don’t even know they have it.
Elmer Gray, an entomologist with the University of Georgia Cooperative Extension Service, said features taken for granted in high-income countries help reduce and prevent exposure to disease-carrying mosquitoes and can help prevent continued spread. Air conditioning, window screens and drainage systems all reduce mosquito breeding and exposure.
Malaria was once a common disease in the United States, but it was eradicated in the early 1950s through the use of insecticides, drainage ditches and window screens. The last locally acquired malaria case in Georgia was at least two decades ago, a probable case in 1999, according to the DPH. In Florida, there were seven locally acquired malaria cases last year.
Gray, who is a public health specialist whose research focuses on mosquitoes and other insects such as black flies, said West Nile virus, a virus spread locally by mosquitoes in Georgia, continues to pose a threat to Georgians. He said there were 19 cases of West Nile virus in Georgia last year, and two of those died from complications related to the virus. No human cases have been reported yet this year, but it is still early, with the season typically peaking in August and September.
In Georgia, West Nile virus is most commonly transmitted by the southern house mosquito, which is very common throughout the state. In most cases, a healthy immune system can fight off West Nile virus. But in rare cases, usually involving the elderly, people with weakened immune systems, or very young children, the disease can progress to symptoms such as fever and rash. In extremely rare cases, the virus can cause encephalitis (swelling of the brain) and death.
Eastern equine encephalitis (EEE) is another mosquito-borne disease that has emerged in Georgia. It is extremely rare, with four cases reported in the state between 2018 and 2002. Mosquito species known to carry EEE are found primarily in coastal and swampy areas of the state.
Georgia is home to 63 species of mosquitoes. And when it comes to fighting mosquitoes of all kinds, vigilance is key, experts say.
It remains to be seen how much mosquitoes will plague metro Atlanta this summer. Mosquitoes love the heat, but they also need standing water to complete their life cycle. This dry spell of scorching temperatures means a decrease in overall mosquito populations, especially those that prefer warm, humid conditions.
But weather conditions can change quickly.
“So here we are in July, people are out at dusk, which is when most mosquitoes are active,” Gray said. “If we have dangerous mosquitoes in metro Atlanta, it’s because something is missing. There’s a dumpster, an abandoned swimming pool, a tire (with standing water). Take a few precautions. Light-colored, loose-fitting clothing, EPA-approved repellents. A few precautions can go a long way.”
Tips to avoid mosquito bites:
1. Wear light-colored clothing. Mosquitoes are more attracted to people wearing darker colors because they are more noticeable.
2. When you’re outdoors in a mosquito-prone area, insect repellent is the most effective measure. There are several EPA-approved repellents, such as picaridin, oil of lemon eucalyptus, and IR3535. Gray prefers products that contain DEET because they’ve been tested and proven safe for children as young as 2 months old. To treat children, an adult should first apply the repellent to their hands, then rub the repellent onto the child’s exposed skin, but never onto the child’s hands, as small children have a habit of putting their hands in their mouths.
3. Mosquitoes need standing water to breed, so eliminate sources of standing water in yards and landscapes.
4. Mow grass and trim vegetation around yard edges to reduce areas where adult mosquitoes hide during the heat of the day.
5. Mosquitoes are most active at dawn and dusk, so stay indoors during these times to avoid bites.
6. If you’re sitting on your porch or patio, a box fan can deter mosquitoes.
Source: Elmer Gray, entomologist with the University of Georgia Cooperative Extension Service