The viral illness called Chikungunya
came to the world’s attention in 2005-2006 after five decades of obscurity. During this time, there were large scale outbreaks that swept through East Africa and India, including the eastern Indian Ocean islands. In addition, for the first time, it struck a country with Western health care facilities, Reunion (a French overseas territory). Then it even presented as a mysterious illness in certain parts of Italy, and for a while the Italians did not know what hit them.
It took some detective work on the part of Italian scientists to figure out that the vector (carrier) of this debilitating disease came to town in motor vehicle tires imported from foreign countries. The Italian scientists found out that the mosquito vector carrying the Chikungunya virus was very comfortably lodged in small water droplets inside the rubber tire. This seemed to suggest that these mosquitoes were of a hardier variety than the Anopheles mosquito which helps transmits the malaria parasites.
When a disease is prevalent in India, the Indian border with Nepal becomes porous not only for free human travel but also for “emerging diseases” like Chikungunya.
Recently, laboratory-confirmed cases of Chikungunya have been reported by the Sukraraj Tropical and Infectious Disease Hospital in Teku. The first group of patients came from Dhading district, which neighbours Kathmandu.
The Ministry of Health and Population (MoHP) has also been conducting surveillance in Kathmandu, but even Kathmandu clinicians do not know much about this “new” disease. Chikungunya is a viral illness that is closely related to dengue. Both are transmitted by the vector mosquito (Aedes aegypti) and cause a similar set of symptoms.
The patient usually complains of fever, headache, back pain with a skin rash present. A remarkable distinction between this illness and dengue fever is the inflammation (arthritis) of the small joints of the hands in Chikungunya patients, which is usually not found in dengue fever.
For Chikungunya, as in dengue, there is no specific antidote, only paracetamol and other symptomatic treatment. There is also no vaccine available. Protective clothing, using insect repellents (odomas) and other measures to prevent day-time mosquito bites (as opposed to night-time mosquito bites for malaria transmission) are important means to avoid this disease. Public health measures like not letting water collect in used tires, flower pots, and plastic containers where the mosquito can breed are obviously important. The good news is that in most instances this disease, like dengue fever, is self-limiting and most people eventually recover.
Both dengue and Chikungunya may be brought to Kathmandu by migrant workers and others from the Tarai district (where both dengue and Chikungunya are thought to be more prevalent). The specific mosquito vectors are apparently in plentiful supply here, and when people afflicted with the disease come to Kathmandu, the Aedes aegypti mosquito enjoys a hearty blood meal including the virus from them. The same mosquito then happily bites another victim and transmits the virus.
Finally, the emergence of Chikungunya is a good example of rich-country travelers being sentinels for diseases from poor countries. Since 2005 thousands of travelers from South Asia have been afflicted with this disease, and as a result, investigators in well-resourced countries were able to study and provide awareness about this new emerging illness.