Mosquito Borne Viruses Pose Potential Threat to Florida/Polk County

Aedes albopictus - Asian tiger mosquito
(photo by James Gathany)

Aedes aegypti adult (photo by James Gathany)

Both dengue and chikungunya are viral diseases whose vector is the yellow fever mosquito - Aedes aegypti. Chikungunya has as an additional vector, the Asian tiger mosquito (Ae. albopictus). Both Ae. aegypti and Asian tiger mosquito occur in Polk County but Ae. aegypti is much more common in the urban areas of south Florida.

Both species are container-inhabiting mosquitoes; often breeding in unused flowerpots, spare tires, untreated swimming pools, and drainage ditches. They thrive in urbanized areas, in close contact with people making them exceptionally successful vectors. Ae. aegypti bite during the day both indoors and outdoors while the Asian tiger mosquito bite mostly at dawn and at dusk.

The Florida Department of Health, recently reported that dengue fever had been confirmed in 24 people in Florida and chikungunya confirmed in 18 people. All of the infected people in Florida had traveled to the Caribbean or South America and could have become infected there, according to Walter Tabachnick, director of the Florida Medical Entomological Laboratory in Vero Beach.

The Florida Department of Health fear that individuals who become infected while traveling could pass the disease on to localized populations of either vector when they return to Florida which could result in a state epidemic.   

Localized epidemics of dengue occurred in 2013 in a small neighborhood in Jensen Beach where 24 people were infected, and in 2009 and 2010 in Key West where 28 people were infected, according to state and federal reports.

The Caribbean Public Health Agency said this week that authorities in 18 Caribbean countries or territories had reported more than 100,000 confirmed or suspected cases of chikungunya.

A key feature shared by both dengue and chikungunya is that the fever comes on sharply about a week after exposure and lasts about a week. Dengue fever classically is accompanied by a headache, eye pain, prominent muscle aches, and swollen lymph nodes. Similarly, chikungunya features prominent headache and swollen lymph nodes, but instead of the muscle pain that is so characteristic of dengue, chikungunya entails marked joint pain and arthritis. A flat red rash that is covered with small confluent bumps is common beginning on about day 3 in patients with chikungunya, especially so in children.

At the present time there is no vaccine for either of these two virus diseases. Unfortunately some infected individuals may experience symptoms for months even years after infection. There are no specific medicines for these diseases. Using medicines other than aspirin may help to lower joint pain and fever.

There are several steps individuals can take to reduce localized mosquito numbers. Because these mosquitoes are container-inhabiting mosquitoes, one of the most successful and cost-effective methods to reducing populations is by preventing containers around the home from collecting water. By turning over empty flowerpots, properly maintaining swimming pools, and removing unused tires, you can greatly reduce the number of places mosquitoes have to lay eggs. Aerate birdbaths and make sure gutters are free of blockages. Clean pet bowls every day and always empty overflow dishes for potted plants.

For personal protection from bites, apply an insect repellant (DEET, picaridin, IR3535 and oil of lemon eucalyptus), and wear long pants and long sleeves when outside. Wear permethrin-treated clothing to repel and kill mosquitoes. Make sure door and window screens are intact. For more information on mosquito management, please visit the Florida Medical Entomology Laboratory mosquito management website at: http://mosquito.ifas.ufl.edu/Mosquito_Management.htm.

For information regarding mosquito management devices for the home, see http://edis.ifas.ufl.edu/in171