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Chikungunya Fact Sheet

by cdc.gov

Posted January 7, 2009

CDC Fact sheet on chikungunya Click Here

Chikungunya fever is a viral disease transmitted to humans by the bite of infected mosquitoes. Chikungunya virus was first isolated from the blood of a febrile patient in Tanzania in 1953, and has since been cited as the cause of numerous human epidemics in many areas of Africa and Asia, and most recently in a limited area of Europe.

What causes chikungunya fever?

Chikungunya fever is caused by a virus which belongs to the genus Alphavirus, in the family Togaviridae.

How do humans become infected with chikungunya virus?

Humans become infected with chikungunya virus by the bite of an infected mosquito. Aedes aegypti, a household container breeder and aggressive daytime biter which is attracted to humans, is the primary vector of chikungunya virus to humans. Aedes albopictus has also played a role in human transmission.

What can people do to prevent becoming infected with chikungunya virus?

The best way to prevent chikungunya virus infection is to avoid mosquito bites. There is no vaccine or preventive drug currently available. Prevention tips are similar to those for other viral diseases transmitted by mosquitoes, such as dengue or West Nile:

Use insect repellent containing DEET, Picaridin, oil of lemon eucalyptus, or IR3535 on exposed skin. Always follow the directions on the package.

Wear long sleeves and pants (ideally treat clothes with permethrin or another repellent).

Have secure screens on windows and doors to keep mosquitoes out.

Get rid of mosquito sources in your yard by emptying standing water from flower pots, buckets and barrels. Change the water in pet dishes and replace the water in bird baths weekly. Drill holes in tire swings so water drains out. Keep children's wading pools empty and on their sides when they aren't being used.

Additionally, a person with chikungunya fever should limit their exposure to mosquito bites to avoid further spreading the infection. The person should use repellents when outdoors exposed to mosquito bites or stay indoors in areas with screens or under a mosquito net.

What is the basic chikungunya virus transmission cycle?

Mosquitoes become infected with chikungunya virus when they feed on an infected person. Infected mosquitoes can then spread the virus to other humans when they bite them. Monkeys, and possibly other wild animals, may also serve as reservoirs of the virus. Aedes aegypti, a household container breeder and aggressive daytime biter which is attracted to humans, is the primary vector of chikungunya virus to humans. Aedes albopictus (the Asian tiger mosquito) has also played a role in human transmission is Asia, Africa, and Europe. Various forest-dwelling mosquito species in Africa have been found to be infected with the virus.

What type of illness does chikungunya virus cause?

Chikungunya virus infection can cause a debilitating illness, most often characterized by fever, headache, fatigue, nausea, vomiting, muscle pain, rash, and joint pain. "Silent" chikungunya virus infections (infections without illness) do occur; but how commonly this happens is not yet known. Chikungunya virus infection (whether clinically apparent or silent) is thought to confer life-long immunity. Acute chikungunya fever typically lasts a few days to a couple of weeks, but as with dengue, West Nile fever, o'nyong-nyong fever and other arboviral fevers, some patients have prolonged fatigue lasting several weeks. Additionally, some patients have reported incapacitating joint pain, or arthritis which may last for weeks or months.

What is the incubation period for chikungunya fever?

The incubation period (time from infection to illness) can be 2-12 days, but is usually 3-7 days.

Can pregnant women become infected with chikungunya virus and pass the infection to their child?

Pregnant women can become infected with chikungunya virus during all stages of pregnancy and have symptoms similar to other individuals. Most infections will not result in the virus being transmitted to the fetus. The highest risk for infection of the fetus/child occurs when a woman has virus in her blood (viremic) at the time of delivery. There are also rare reports of first trimester abortions occurring after chikungunya infection. Pregnant women should take precautions to avoid mosquito bites. Products containing DEET can be used in pregnancy without adverse effects.

Can the virus be transmitted to a child by breastfeeding?

Currently, there is no evidence that the virus is transmitted through breast milk

What is the mortality rate of chikungunya fever?

Fatalities related to chikungunya virus are rare and appear to be associated to increased age.

How is chikungunya virus infection treated?

There is no vaccine or specific antiviral treatment currently available for chikungunya fever. Treatment is symptomatic and can include rest, fluids, and medicines to relieve symptoms of fever and aching such as ibuprofen, naproxen, acetaminophen, or paracetamol. Aspirin should be avoided. Infected persons should be protected from further mosquito exposure (staying indoors in areas with screens and/or under a mosquito net) during the first few days of the illness so they can not contribute to the transmission cycle.

Where does chikungunya virus occur?

The geographic range of the virus is primarily in Africa and Asia. For information on current outbreaks, consult CDC's Travelers' Health website (wwwn.cdc.gov/travel/default.aspx). Given the current large chikungunya virus epidemics and the world wide distribution of Aedes aegypti and Aedes albopictus, there is a risk of importation of chikungunya virus into new areas by infected travelers.