Mosquito-borne fevers rampant in biggest port

Madagascar is used to fighting mosquitoes, but not the kind responsible for the fever outbreak that is crippling the eastern port town of Toamasina, where experts warn that conventional vector control will not be enough.

Since the beginning of this year nearly all Toamasina's 200,000 residents have reportedly come down with a fever as a result of either dengue or chikungunya fever. Both diseases are spread by the Aedes aegypti mosquito.

"We are sending a joint World Health Organisation (WHO) and Ministry of Health team there [Toamasina] on Sunday to better understand the behaviour of the mosquito. It is a different mosquito to the one transmitting malaria, which they are used to," the WHO country representative, Dr Leonard Tapsoba, told IRIN.

Known locally as 'malaria season', the rainy season with its pools of stagnant water means breeding conditions for mosquitoes are optimal.

The symptoms and treatment of chikungunya and dengue fever are very similar, making it difficult for health practitioners to distinguish between the two, Tapsoba said. "There is only symptomatic treatment, so the only response is vector control. They [officials] have started fumigation and cleaning, but we also need to better understand the mosquito."

According to Tapsoba, the malaria mosquito breeds and is active at night and indoors, while "the dengue mosquito is active during the day and outdoors, so traditional measures like impregnated [insecticide-treated] bed nets and normal measures are not enough."

An awareness campaign has been launched, urging the population to participate in a mass clean-up drive. "This is a fight by the community - they have to remove any potential water reservoir that the mosquito can use as a breeding ground - but because people have jobs, and it breeds during the day, this is very difficult," he said.

Agence France-Presse quoted Dr Clarette Dinh-Van, a general physician operating a private clinic in Toamasina, as saying, "In the last three months, between 80 and 90 percent of Toamasina residents have had a fever."

Health officials are still uncertain as to whether the outbreak can be attributed to a mosquito-borne disease called chikungunya, Swahili for 'that which bends up', which has been spreading across the Indian Ocean islands, or dengue, "because surveillance is picking up all types of fever and Madagascar does not have the specific viral lab capacity to identify the cause," Tapsoba noted.

Tapsoba said blood samples have been sent to France for testing and dengue has been confirmed. One case of chikungunya was also registered.