Earlier this week, a mosquito (Aedes albopictus) that can carry chikungunya and dengue fever viruses has been spotted north of the Swiss Alps in the canton of Aargau. In response, the Swiss health ministry plans to make chikungunya, which was described for the first time in Tanzania in 1952, a mandatory reportable disease from next year.
Earlier this year, the chikungunya virus infected more than 160 people in the Ravenna region in northern Italy, resulting in one fatality. This outbreak of chikungunya is thought to have been the first outside the tropics. The mosquito is also present in southern France and parts of Spain, as well as the United States.
Symptoms of chikungunya appear between 4 and 7 days after being bitten and are usually high fever and headache accompanied by arthritis affecting multiple joints which can be debilitating. Chikungunya virus is enzootic in many countries in Asia and throughout tropical Africa, but is generally not fatal.
Health experts said that the situation was not alarming, but that European countries must work together to control mosquito populations.
The UK and Northern Europe should be safe from chikungunya for the time being – but it is difficult to predict for how long. Who would have imagined six or seven years ago that the UK would face not one but three epizootic diseases simultaneously? During the past three months, that is exactly what happened – the UK has experienced foot-and-mouth disease, Bluetongue and avian influenza outbreaks. Who would have imagined that there would have been two outbreaks of foot-and-mouth disease within the space of six years, when the previous outbreak was 40 years ago?
Clearly, the threat from epizootic diseases has no geographical limits, and is rapidly becoming a world-wide issue. As Dr Joseph Domenech, the chief veterinary officer of the Food and Agriculture Organization of the United Nations, said recently ‘no country can claim to be a safe haven with respect to animal diseases’. This is particularly significant because many of diseases such as chikungunya or West Nile fever are zoonotic.
The emergence of Bluetongue virus in Northern Europe and the UK is an indication of the potential for climate change to extend the geographical range of insect-borne diseases. Effects of climate change on health are also a priority for the World Health Organisation, which recently announced that the theme for World Health Day in 2008 would be ‘protecting health from climate change’.
The CAB Abstracts database includes key scientific literature from more than 160 countries in 50 languages on both “exotic diseases” and other more common animal diseases, whose prevalence may change as the result of climate change. There are over 800 records on chikungunya. This information is invaluable for anyone involved in creating regional control policies that need to be specifically tailored to regional variations in disease risk. Data on surveillance, control and research relating to animal diseases and diseases of public health significance across the world are available.