Chikungunya is a viral disease spread by mosquitoes, especially Stegomyia aegypti (Aedes aegypti) and Aedes albopictus. The latter known as the Asian Tiger Mosquito is common in Seychelles. Both are also implicated in the spread of dengue fever. The name of the disease comes from a Swahili word which means "that which contorts or bends up", referring to the contorted posture of patients.
There have been recent outbreaks in Madagascar, Comoros, Mauritius and La Reunion. The movement of the disease has been linked to the movement of infected people because human to mosquito to human transmission sustains the epidemics.
Environmental health experts note that since the beginning of 2003, Chikungunya epidemics have seemed to move from Eastern Java towards the east coast of Africa. In particular, they say a sudden surge of outbreaks in the islands have occurred at the end of 2004 and beginning 2005, after the Tsunami of December 2004. This could be simply a coincidence or perhaps linked to environmental changes after the Tsunami.
Climate change may increase the threats of Chikungunya, dengue and other diseases spread by mosquitoes in several ways. One way is by increasing the temperatures under which many diseases and mosquitoes flourish, and another by altering rainfall patterns so that more water may become available in the environment for mosquitoes to breed.
Climate variations such as El Niño, along with global warming, have fueled much interest over the last decade in understanding the impact of climate on the spread of disease agents. Studying links between climate and disease may reveal clues into causes of the rise, spread and variations in epidemics.
The spread of these infectious diseases is also assisted by environmental degradation, international travel and the globalization of trade. For example, the Asian Tiger Mosquito breeds in water collected in car tires and has spread to various countries in imported tires. It is reported as being dispersed world wide as eggs being carried in the ballast water of ships. Ballast water is implicated in the spread of other alien invasive species.
Urban living has provided numerous and effective breeding sites for mosquitoes. The Asian Tiger Mosquito is well known to favor urban habitats, and with Seychelles being considered the most urbanized country in Africa the threat becomes even more real.
The high level of public health protections in Seychelles, such as good housing, sanitation and solid waste disposal, may limit the future distribution and impact of infectious mosquito-borne diseases regardless of climate changes. In addition, as the Ministry of Health and Social Affairs has said, members of the public have to ensure that breeding grounds for mosquitoes are eliminated as well as taking care not to travel to infected countries.
By Nirmal Jivan Shah, published on the People Newspaper, Seychelles, on 4 August 2005