Chikungunya fever (CHIK) is an infection caused by the Chikungunya virus (CHIKV). The virus is spread through the bite of an infected mosquito, similar to West Nile and dengue viruses. The Chikungunya virus was first identified during an outbreak in 1952 in southern Tanzania, although it is suspected to have been present in Africa and Asia for much longer. It is not currently found in the United States.
Chikungunya fever outbreaks have been reported in Africa, southern Europe, Southeast Asia, India, and islands in the Indian and Pacific Oceans. In December 2013, a cluster of CHIK cases were reported from St. Martin, an island in the Caribbean. This is the first known occurrence of local CHIKV transmission in the Americas.
So fat the cases in the US have been to people who had been traveling to the Caribbean. But if someone who is infected is bitten by a mosquito in the US then the disease can be spread by local mosquitos.
Chikungunya virus is spread by two mosquito species: Aedes aegypti(primarily) and Aedes albopictus, both found in Florida. While the virus is not currently found in the state, introductions are possible if a CHIKV infected visitor or returning traveler is bitten by Florida mosquitoes in the early stages (the first week) of their illness. Infected mosquitoes can then spread the virus to other people they bite.
The same actions to prevent other mosquito borne illness such as dengue and West Nile virus disease are effective for preventing CHIK. While traveling in areas where CHIK, dengue or other mosquito borne diseases are present remember to:
- use EPA approved repellants such as DEET
- wear comfortable clothing that protects skin from mosquito bites
- select hotels or other residences with intact window and door screens
Signs and Symptoms
An infected person will typically become ill three to seven days after the mosquito bite, but symptoms can begin anywhere from two to 12 days post-bite. These symptoms can last 3-10 days. Up to 28% of people who are infected will not have any symptoms (asymptomatic), although they can still be infectious to mosquitoes for a short time if bitten. Persons at greatest risk for severe illness include newborn infants, those over 65 years of age, and those who have other health conditions. Treatment is symptomatic or supportive.
Symptoms may include:
- Sudden high fever (usually >102º F) which may be continuous or intermittent
- Severe joint pain that commonly involves the hands and feet
- Joint swelling
- Back pain
- Rash usually 2-5 days after fever starts
- Other symptoms may include headache, body ache, nausea, vomiting, and redness around the eyes. In unusual cases, infection can involve the brain, eyes, heart, kidney and other organs.
- Fatal infections are rare, however many patients have chronic joint pain, arthritis, loss of energy and depression lasting weeks to years.
Chikungunya and Dengue
It is important to note that a person can be infected with CHIK and dengue viruses at the same time as they are both carried by the same types of mosquitoes. Therefore, it is important that providers consider both dengue fever and CHIK when evaluating suspect cases with travel to areas where both viruses are present. Testing is the only way for a health care provider to definitively differentiate CHIK and dengue fever.