Travellers to the Indian Ocean are being warned about an increased risk of the crippling Chikungunya virus.
The island of Reunion was hit by an outbreak of the Chikungunya virus
The Health Protection Agency said there were 93 cases in people from the UK by August this year, compared to an average of six in previous years.
Cases of the mosquito-borne virus have been recorded on Indian Ocean islands and on the Indian mainland, the HPA's annual conference was told.
Travellers are advised to take standard precautions against mosquito bites.
These include using insect repellents and wearing long trousers and long sleeved shirts, particularly during daylight when the Tiger mosquitoes which carry the virus tend to be most active.
Since March 2005 the number of cases of Chikungunya have been increasing in the islands of the Indian Ocean, particularly the island of Reunion.
The World Health Organisation estimates around 110,000 people were affected in an outbreak on the island between March 2005 and February 2006.
The virus is spread by the bite of a mosquito and causes a non-fatal self limiting illness characterised by a high fever with headache, severe joint pains, and a rash with nausea and vomiting.
Symptoms usually appear between four to seven days after being bitten and can persist for several weeks.
There is no vaccine against Chikungunya. Treatment consists of relieving symptoms by using painkillers, taking plenty of fluids and resting.
Acute symptoms last from a few of days to a couple of weeks, whilst some patients have reported incapacitating joint pain for up to several months.
Sir William Stewart, chairman of the HPA, said: "Although previously centred on the islands of the Indian Ocean - Mauritius, Madagascar and the Seychelles, cases in this region are declining whilst cases from mainland India are increasing.
"This is due to an ongoing outbreak occurring on the mainland, with over a million suspected cases to date.
"Therefore it is important that travellers to the region follow the usual health advice on how to avoid being bitten by mosquitoes and other insects."