Chikungunya Virus (CHIKV)

What is the Chikungunya virus (CHIKV)?

CHIKV is a viral disease transmitted to people by the bites of infected mosquitoes. Mosquitoes become infected by feeding on infected persons. CHIKV is transmitted primarily by the yellow fever mosquito but may also be transmitted by the Asian tiger mosquito.

Where does CHIKV occur?

Prior to 2013, chikungunya virus cases and outbreaks had been identified in countries in Africa, Asia, Europe, and the Indian and Pacific Oceans. In late 2013, the first local transmission of chikungunya virus in the Americas was identified in Caribbean countries and territories. Local transmission means that mosquitoes in the area have been infected with the virus and are spreading it to people. The virus then spread throughout most of the Americas.

Who gets CHIKV infections?

People of all ages can become infected with CHIKV and suffer a debilitating illness, but only 20% of the people that are infected will suffer any illness symptoms. Infants, senior citizens, and people already suffering from other underlying illnesses are at greater risk of a severe illness. To date no locally-acquired cases have been reported among Virginia residents. There is a risk of infected travelers transmitting CHIKV to local Asian tiger mosquitoes which are the most common nuisance mosquito in urban areas of Virginia.

What are the symptoms of chikungunya (CHIK) infections?

Most people infected with CHIKV have a fever that may be accompanied by joint pain or swelling in multiple joints, body aches, headache, nausea, back pain, and rash. Joint pain most commonly occurs in joints of the hands, feet, wrists, and ankles, or in more proximal joints like the elbows and knees. Joint pain may be severe. The initial illness may last for up to 10 days, but joint pains often last longer. Some patients may recover, then experience a relapse of joint pain two to three months after the initial illness. The joint pain may become chronic and last for several years after the acute illness. Fatalities are uncommon, but are more likely to occur in elderly patients or people with underlying health conditions.

How soon after exposure do CHIK symptoms occur?

CHIK symptoms may begin as early as 1 day or as late as 12 days after an infective mosquito bite, but symptoms usually begin 3 to 7 days after exposure.

How are CHIKV infections spread?

CHIKV is spread in a person-to-mosquito-to-person cycle. People infected with CHIKV may be infective to other mosquitoes that bite them as early as 1 to 3 days after their infectious mosquito bite. Infected persons may remain infective to mosquitoes for as long as 7 days after their illness onset. People that are infected with CHIKV but do not develop illness symptoms may still pass the virus on to mosquitoes that bite them. Infected persons cannot transmit CHIKV directly to another person.

Does past infection with CHIKV make a person immune?

It is thought that a prior CHIKV infection will provide lasting immunity to the virus.

What should I do if I think I have CHIK infection?

If you feel sick and have recently traveled to an area with a CHIKV outbreak, seek evaluation from your healthcare provider and tell him/her about your recent travel. Your doctor may order a laboratory test to determine whether you have CHIK or some other infection with similar symptoms. Information on countries experiencing CHIK outbreaks is available at the CDC page on areas at risk for chikungunya.

What is the treatment for a CHIKV infection?

There is no specific treatment available for CHIK. Healthcare providers primarily provide supportive care and work to relieve the symptoms of the illness.

How can CHIKV transmission to others be prevented?

If you have CHIKV infection, you should avoid mosquito bites during the first week of illness to help prevent further spread of the virus. When outdoors in mosquito-infested areas avoid mosquito bites by dressing properly and/or using insect repellents; wear long pants, shoes, socks and long sleeves, and apply insect repellents to exposed areas of skin. Home doors and windows should be screened to prevent entry of mosquitoes. Asian tiger mosquitoes lay eggs exclusively in containers of water that are outdoors around the home. Elimination of larval habitats around your home and on neighboring properties is the most effective way to reduce the number of Asian tiger mosquitoes around a home. Remove or routinely dump water-containing items such as buckets, bird baths, canoes, bowls, etc..

How can I learn more about CHIKV Infections?

• If you have concerns about CHIKV infection, contact your healthcare provider.
• Call your local health department. A directory of local health departments is located at the VDH Local Health Districts page.
• Visit the Centers for Disease Control and Prevention website at the CDC page on chikungunya.
• You may also contact the Virginia Mosquito Control Association if you have questions about local mosquito control programs.

October 2018