Chikungunya Fever on the Island of Réunion


The island of Réunion, a French Overseas Department in the Indian Ocean is experiencing an extensive outbreak of Chikungunya fever, a viral infection carried by mosquitoes, Aedes aegypti. Since the outbreak was first recognised in March 2005, French Authorities estimate that 157 000 cases of the illness have occurred. This represents more than 20% of the entire population of 750 000. This appears to be part of a larger upsurge in Chikungunya activity in the Indian Ocean area – there were large outbreaks in the Comoros Islands, the Seychelles and Mauritius at the beginning of 2005.

Chikungunya fever is commonly found in East Africa, Southeast Asia and in the Indian sub-continent.  Illness generally follows 4-7 days after the bite of an infected mosquito and presents with sudden onset of fever with joint and muscle pain (that can at times be very severe) with headache and conjunctivitis. The joints of the wrists, ankles, hands and feet are most commonly affected.  Rashes on the chest and abdomen are common and in the current outbreak on Réunion almost a quarter of patients had bleeding from the nose or gums.  Fortunately, it tends to be a mild illness and most patients recover fully; in Réunion, fewer than 1 in 20 patients needed to be hospitalised.  There have, however been 77 deaths reported in elderly Chikungunya patients who had other medical conditions.  It is not clear if Chikungunya was the cause of death in these patients and this possibility is currently being investigated.There is currently no vaccine against the virus responsible for causing Chikungunya. Travellers to affected areas are advised to take sensible precautions against mosquito bites (advice on protecting yourself from mosquito can be found on HPSC's website In addition, the particular mosquito responsible for this outbreak had a tendency to appear during daylight hours so precautions should be used throughout daylight hours as well.   

Although the risk of serious disease is low, certain groups are at higher risk, including:

  • Pregnant women
  • People with weakened immune systems (such as patients living with cancer or HIV/AIDS) and
  • People suffering from severe chronic illness (such as heart, lung or kidney disease and diabetes).

Until this outbreak is over, such people should postpone all non-essential travel to the affected areas of Réunion, Comoros Islands, the Seychelles and Mauritius.