CHIKUNGUNYA
What mosquitoes transmit chikungunya virus?
In the Americas, both Aedes aegypti, the yellow fever mosquito, and Aedes albopictus, the Asian tiger mosquito, are responsible for transmission of chikungunya virus.
Aedes aegypti
Aedes albopictus
Where do they live?
Both the yellow fever mosquito and the Asian tiger mosquito are found throughout much of the United States. They are also globally distributed in tropical and subtropical areas. The mosquito life cycle is defined by four major life stages: 1) the egg, 2) larva, 3) pupa, and 4) adult.
The adult is the life stage people are likely the most familiar with. In the adult stage, mosquitoes fly around, and the females try to feed on our blood.
However, people may be less familiar with the larvae and pupae, or the immature stages of the mosquito. The immature stages live in the water. The yellow fever mosquito and the Asian tiger mosquito, more specifically, live in artificial and natural containers around or near human dwellings. These containers can potentially be anything that holds water including a tree hole, bird bath, clogged rain gutter, children’s toys, garbage, tires, and a range of other items.
Unlike many other nuisance mosquito species, as adults, both the yellow fever mosquito and the Asian tiger mosquito are primarily looking to feed on human blood during the day, when people are the most active. It is important to note that only the female mosquito feeds on blood.
What can I do to prevent infection?
KEEP EMPTY
Eliminating Immature Mosquito Habitats
The immature stages of these two species inhabit containers that are found around our home. Eliminating larval development sites is an excellent way to prevent the mosquitoes from completing their life cycle. This is a practice known as source reduction.
To do this, simply go around your home and identify any containers that are holding water. Trash items can be discarded. For containers that will regularly refill with water, dumping out the water every five days will prevent immature mosquitoes from being able to reach adulthood. As an extra step, scrub the interior surfaces of the container with a sponge to dislodge any remaining mosquito eggs and rinse them off. If you have tires on your property, check with your local mosquito control or waste program. There may be programs in place to dispose of the tires on your property. For decorative ponds that cannot be emptied out regularly, consider stocking it with mosquito fish (ex: Gambusia affinis, Gambusia holbrooki) or utilizing a biological control agent, such as products with the active ingredient Bti (Bacillus thuringiensis subspecies israelensis).
Using Repellents
In addition to regularly engaging in container elimination and/ or sanitation practices, using repellants when outdoors and wearing long sleeves and pants can prevent mosquitoes from feeding on you. When using repellents, make sure to choose from the list of CDC-recommended repellents.
Protecting Your Home
Preventing mosquitoes from entering the home is also important to preventing mosquito bites. This includes ensuring that all windows are covered with screens and that the doors to the home remain closed. Essentially, all entry points to the home should be sealed or covered by a screen. These screens should be checked regularly to ensure that there are no holes that would allow a mosquito to slip through. Damaged screens can be repaired or replaced to prevent mosquitoes from entering the home.
What are the symptoms of a chikungunya virus infection?
The most common symptoms of chikungunya virus infection are fever and joint pain, but this may also be accompanied by headache, muscle pain, joint swelling, or a rash. Symptoms will usually begin 3-7 days after being bitten by an infected mosquito.
What does the chikungunya virus transmission cycle look like?
A mosquito can become infected with chikungunya virus after feeding on an infected person. Once she finishes taking the bloodmeal, she cannot immediately transmit to another person. The virus incubates and multiplies within the mosquito. During this time, she will lay her eggs and eventually look for another bloodmeal. It is during these future bloodmeals that she may be capable of transmitting chikungunya virus to a new host.
It is important to note that the yellow fever mosquito and the Asian tiger mosquito are capable of transmitting chikungunya virus much sooner than dengue and Zika virus. In other words, there is a shorter amount of time between when the mosquito feeds on the infected person’s blood and when she can then transmit the virus to a new person. This creates a cycle of transmission between humans and mosquitoes.
