Chikungunya Fever

Chikungunya fever is a viral disease transmitted to humans by the bite of infected mosquitoes. Chikungunya virus was first noted in Africa, & has since been cited as the cause of numerous human epidemics in many areas of Africa & Asia, & most recently in a limited area of Europe. India, the Indian Ocean countries have had very large outbreaks.


Humans become infected with chikungunya virus by the bite of an infected mosquito. Aedes aegypti, a household container breeder & 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.


Chikungunya virus infection can cause a debilitating illness, most often characterized by fever, headache, fatigue, nausea, vomiting, muscle pain, rash, & 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 & 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.


The incubation period (time from infection to illness) can be 2-12 days, but is usually 3-7 days. Fatalities related to chikungunya virus are rare & appear to be associated to increased age.


There is no vaccine or specific antiviral treatment currently available for chikungunya fever. Treatment is symptomatic & can include rest, fluids, & medicines to relieve symptoms of fever & 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.
The geographic range of the virus is primarily in Africa & Asia. Given the current large chikungunya virus epidemics & the world wide distribution of Aedes aegypti & Aedes albopictus, there is a risk of importation of chikungunya virus into new areas by infected travelers.


Prevention is by avoiding mosquito bites. Repellents are important.