By Kathy Danforth / Published May 2016
In a community association, residents may share their pool, their security, their fitness center, and their mosquitoes. While these pests may have faded into the background as a disease carrier, the Zika virus serves as a reminder of why associations and individuals should remain proactive in mosquito control. Any standing water—whether on a balcony, in a yard, or on a common area—can serve as a nursery for a new disease carrier to spread in the area, but minimizing the risk starts before the threat is publicized.
Mosquito-borne diseases can be caused by parasites or by viruses known as arboviruses. According to the Florida Department of Health (DOH), “Mosquito-borne diseases found in Florida include the West Nile virus disease, Eastern equine encephalitis, and St. Louis encephalitis. Many other mosquito-borne diseases are found in different parts of the world, and can be brought back to Florida if infected people or animals are bitten by mosquitoes while in Florida. Some examples of these diseases include chikungunya fever, dengue fever, malaria, yellow fever, and Rift Valley fever,” with Zika being added to this list. These diseases can be transmitted from animals to people, and with the warm Florida weather, they may be transmitted year-round.
In 2015 in Florida, 11 human cases of West Nile virus were acquired in Florida and one case of dengue fever. Seventy-three cases of chikungunya, 82 cases of dengue fever, and 51 cases of malaria were reported in individuals who had recently traveled in areas with infection. In 2016, no locally-acquired mosquito-borne diseases had been reported by mid-March.
The Zika virus has had 60 travel-associated cases reported in Florida in 2016. With the World Health Organization declaring a public health emergency related to the Zika virus on February 1, 2016, Governor Rick Scott declared a public health emergency in Miami-Dade, Hillsborough, Lee, and Santa Rosa counties because of the prevalence of Aedes mosquitoes (the carrier) in Florida and the disease’s potential impact.
The CDC states, “The most common symptoms of Zika are fever, rash, joint pain, and conjunctivitis. The illness is usually mild, with symptoms lasting for several days to a week after being bitten by an infected mosquito. People don’t often get sick enough to go to the hospital, and they very rarely die of Zika. For this reason, many people might not realize they have been infected.” It is estimated that only one in five people infected with the virus show symptoms.
Zika can be spread from an infected pregnant woman to her child, and also from an infected man to his sexual partner. In Brazil, an increase in the number of babies born with microcephaly, an abnormally small head with potentially severe brain damage, has been linked with Zika, causing particular concern. The virus has also been linked to Guillain-Barré syndrome (GBS). Because there is currently no vaccine or treatment, the defense falls back to fighting the disease where it is carried.
The guilty mosquitos are small and typically bite during the day, but do not have the buzz and sting that often alert people to their presence. According to WebMD, “Experts who have spent some time studying Aedes mosquitoes are amazed at how well they’ve adapted to feeding on people. Take, for instance, their habitat. They don’t have a lot of stamina in the air. Their flight range is just 300 to 600 feet. As a result, insecticidal sprays mostly don’t work on this breed, because it’s hard to catch them airborne. To feed, they have to stick close to their intended targets, again…us. They live under decks, patio furniture, and in homes that don’t have cool air—they don’t much like air conditioning. They especially love the drip trays that collect extra water under potted plants.”
The Florida Department of Health “Mosquito Control Environmental Assessment Form” includes the following possible sites to check for standing water: bird baths, potted plants, buckets, barrels, clogged gutters, wading pools, uncovered boats, covering tarps, used tires, wells, toys, pet water bowls, flat roofs, fish ponds, debris, and garbage/recycle containers.
Jim Maler with All Florida Pest Control, a Certified Florida Community Service Provider (CFCSP), advises, “Empty buckets or watering cans. If you have a rain barrel, treat it with a non-toxic product designed to kill mosquito larvae. Drill holes in your trash or recycling bins so they don’t collect water. Even though it’s a pain to disconnect them, unscrew and empty downspout extenders at least once every five days, because that’s how long it takes mosquito eggs to hatch. If you’ve got plants in containers, empty their drip trays at least once a week. The same goes for outdoor furniture covers, which may hold pockets of water after a rainstorm, and bird baths. Monitor moist areas around homes and buildings, like mulch beds, and plants that hold water, like bromeliads, and any leaves that can form a cup. Keep areas clean from debris and basically anything that can hold water.”
Maler explains that a number of plants, some containing citronellol, repel mosquitoes. Lemongrass, lemon basil, lemon balm, lemon verbena, catnip, citronella, ageratum, geranium, mums, pennyroyal, tansy, marigolds, rosemary, and lavender can help keep the insects away. Herbs such as basil, garlic, clove, eucalyptus, horsemint, tea tree, peppermint, and rosemary also will drive them off. Neem trees and wild plants such as cedar trees, mugwort, nodding onion, pineapple weed, snowbrush, sweet fern, sagebrush, wild bergamot, wormwood, and vanilla leaf also are known to repel mosquitoes and may be of use to those communities with extensive grounds.
Lake maintenance can prevent bodies of water on a property from becoming expansive breeding grounds. “The larvae eat particles in the water, so you want to avoid excess phosphorus, nitrogen, and other nutrients in the water. Associations can also stock lakes with gambusia or mosquito fish,” suggests Tadese Adeagbo with Lake and Wetland Management, Inc. Other species of fish and some animals, such as lizards, dragonflies, and flies, are also predators of mosquitoes.
“Insecticides for lakes can help prevent mosquitoes in the water,” relates Adeagbo, “so that can help control the population but will by no means eradicate mosquitoes in an area. The flying adults can find a puddle anywhere in the woods. Aquatic larvicides come in a liquid form, which dissipates faster than granular forms, which will control mosquitoes for a longer period. For real control of lake mosquitoes, there has to be consistency; if you ease up, the mosquitoes will deposit eggs. The larvicides also kill midges, which some communities are concerned about. They are small insects that don’t bite or carry disease, but they end up on screens and porches and can be problematic.
“Mosquitoes don’t like moving water, so they gravitate toward stagnant areas,” Adeagbo points out. “If you have a fountain, one with a lot of flow may be more likely to inhibit growth of the mosquito population.”
Maler explains that after checking for obvious problem areas with standing water, treatments may include a backpack fogging machine to treat landscape beds and moist areas near buildings, fogging machines on golf carts for larger areas, fly lights inside entrances, mosquito attractant machines on the exterior of buildings, and various insecticides for areas of standing water.
Of course, mosquitoes are not just an association issue. At the individual level, everyone should take additional precautions as needed to avoid mosquito bites. Adeagbo notes, “Even if you have the best mosquito program possible, there’s nothing to stop a mosquito from another location nearby from showing up. There is no end to mosquitoes in sight.”
Covering entries to buildings and covering exposed skin are recommended protections. Maler notes, “Aedes mosquitoes like to bite below the knees, so long pants and socks are important. Wear long sleeves as well. If you’re sitting on a porch or patio, use box fans to create a strong breeze around your feet and legs. Since mosquitoes don’t do well in wind, a draft helps set up a mechanical barrier, and it also helps blow away all the human odors that cue them to your warm-blooded presence.” The female mosquitoes are attracted to carbon dioxide, which humans and other animals exhale.
Protection for several hours can be provided by repellants, such as DEET, picaridin, oil of lemon eucalyptus (PMD), or IR 3535. The Florida DOH notes that concentrations above 50 percent do not significantly extend protection. More details—probably beyond your expectations—are available at www.floridahealth.gov/diseases-and-conditions/mosquito-borne-diseases/_documents/fl-resident-guide-to-mosquito-control-ifas.pdf.
And, homeowners can rest assured that individual counties will also respond to a health threat should mosquito-borne disease become prevalent. “Counties can do aerial spraying, which is a lot costlier but will kill active, flying insects,” reports Adeagbo. “We have not reached that stage currently, but the county will make that decision if the situation warrants.” However, homeowners do not want to be the first to encounter a problem, and the use of chemicals is not without possible side (or “cide,” in this case) effects. Even with the common mosquito, being a first preventer is a safer route than being a first responder. n
Jim Maler is with All Florida Pest Control, a Certified Florida Community Service Provider (CFCSP). For more information, visit www.allfloridapests.com.
Tadese Adeagbo is with Lake & Wetland Management, Inc., a Certified Florida Community Service Provider (CFCSP). For more information, visit www.lakeandwetland.com.