Chikungunya << `chihk ` uhn GUHN yah >> is a disease caused by a virus transmitted by mosquitoes. Scientists first recognized the disease during an outbreak in Tanzania in 1952. The name means that which bends up in the language of the Makonde people of Tanzania. It refers to the effects of the intense joint pain caused by the disease, which can make people walk bent over. Epidemics of chikungunya have occurred in Africa, India and islands in the Indian Ocean, the Philippines, Southeast Asia, and Indonesia. A new outbreak of the disease began in 2004 and has spread into southern Europe and the Americas.
Scientists classify the chikungunya virus as a kind of alphavirus. Chikungunya and other alphaviruses cause joint pain and fever. Alphaviruses can sometimes cause encephalitis, a dangerous inflammation of the brain.
Symptoms
of chikungunya illness include fever, rash, and incapacitating (disabling) joint pain and swelling. Infection may also be accompanied by headache, conjunctivitis (inflammation of the lining of the eye), and gastrointestinal symptoms, problems of the stomach and intestines. Symptoms fade after 1 to 2 weeks, and people usually recover after some time. Some patients experience mild joint pain for months after the initial illness. This lingering pain occurs primarily in patients over 60 years of age.
Chikungunya is rarely fatal. Most deaths occur among the elderly or in adults with other health conditions. Infants infected at birth may have neurological (brain and nervous system) complications that lead to long-term disabilities.
Transmission and spread.
The chikungunya virus is transmitted from human to human through the bites of mosquitoes—that is, a mosquito that bites an infected person may then spread the virus through its bite. The illness begins from 2 to 12 days after the infecting bite. In Africa, such animals as rodents, birds, and monkeys could serve as reservoirs, harboring the virus in their bodies.
Outbreaks of chikungunya have historically been confined to Africa and Asia. In 2004, an outbreak started in Kenya. The disease then spread to islands in the Indian Ocean and to India, where it had not been reported in 32 years. On the island of Réunion, nearly one-third of the population became ill. An infected traveler from India started an outbreak in Italy in 2007. This outbreak was the first chikungunya outbreak to occur in Europe. In 2013, the disease was detected spreading on the island of St. Martin, its first outbreak in the Western Hemisphere. The outbreak spread through the Caribbean and into North and South America.
Scientists think the rapid global movement of the disease in the 2000’s is due to a mutation in the chikungunya virus. A mutation is a change in an organism’s genetic (hereditary) material. The mutation seems to enable the virus to reproduce more efficiently in certain mosquitoes, increasing the chance of transmission to humans.
Prevention and treatment.
There is no direct treatment for chikungunya. Pain medication and rest provide relief for some of the symptoms. Patients may be treated with anti-inflammatory drugs to reduce joint pain and rash.
People can limit the risk of infection through basic mosquito control measures. For example, people in affected areas should limit skin exposure and wear mosquito repellant as necessary during the day, when the mosquitoes that transmit chikungunya are known to bite. A vaccine against chikungunya is available for adults.
