Chikungunya fever is a mosquito-borne viral disease caused by the chikungunya virus. The name “chikungunya” derives from a word in the Kimakonde language, meaning “to become contorted”, and describes the stooped appearance of patients suffering from joint pain. Outbreaks have occurred in countries in Africa, Asia, Europe, the Americas and islands in the Indian and Pacific Oceans.
The disease is characterised by fever and debilitating joint pain. Other common signs and symptoms include muscle pain, headache, nausea, fatigue and rash. Symptoms are generally self-limiting and last for a few days. Chikungunya fever is rarely fatal and most patients recover fully, but in some cases joint pain may persist for several months, or even years.
Mode of transmission
Chikungunya virus is most commonly transmitted to humans through the bites of infected female Aedes mosquitoes. When a patient suffering from chikungunya fever is bitten by a vector mosquito, the mosquito may be infected and it may spread the disease by biting other people. The vector Aedes aegypti is not found in Hong Kong but the other vector, Aedes albopictus, is widely distributed locally. These mosquitoes can be found biting throughout daylight hours and there may be peaks of activity in the early morning and late afternoon.
Chikungunya virus can also be rarely transmitted from mother to newborn around the time of birth.
The incubation period ranges from 2 to 12 days, commonly 3 to 8 days.
Travellers returning from countries where the disease is endemic or an outbreak has occurred should seek prompt medical advice if develop symptoms of the disease. Currently, there is no specific antiviral drug treatment for chikungunya fever. Treatment is directed primarily at relieving the symptoms, including using anti-pyretics, analgesics and replacement of fluids.
At present, there is no effective vaccine against chikungunya fever. The best preventive measure is to eliminate pockets of stagnant water that serve as breeding sites for mosquitoes, and to avoid mosquito bites.
General measures on preventing mosquito-borne diseases
Help prevent mosquito proliferation
Pregnant women and children of 6 months or older can use DEET-containing insect repellent. For children who travel to countries or areas where mosquito-borne diseases are endemic or epidemic and where exposure is likely, children aged 2 months or above can use DEET-containing insect repellents with a concentration of DEET up to 30%. For details about the use of insect repellents and the key points to be observed, please refer to 'Tips for using insect repellents'.
For more information about control and prevention of mosquito breeding, please visit the website of the Food and Environmental Hygiene Department (FEHD) at http://www.fehd.gov.hk/english/pestcontrol/handbook_prev_mos_breeding.html