Last week, Delhi High Court upbraided the city’s three municipal corporations for their failure to control viral diseases — malaria, dengue and chikungunya. The court’s strictures came in the wake of an off-seasonal spurt in the three mosquito-borne diseases in the city.
Mosquitoes are known to usually strike during the monsoon season and the two months after it. But 113 people in Delhi have suffered malaria since January, the highest in four years. The city recorded nearly 150 cases of chikungunya and 80 cases of dengue during the dry months, when the incidence of these diseases is usually negligible. Given that these diseases had assumed epidemic proportions in Delhi last year, their off-seasonal occurrence should be a matter of urgent concern.
In May, Chief Minister Arvind Kejriwal asked officials of Delhi’s municipal corporations to keep a tab on mosquito breeding, ensure no water-logging, undertake fogging operations and reduce garbage in neigbourhoods. But the off-seasonal incidence of the viral diseases shows that the officials have been caught off guard again. The civic authorities have blamed the diseases on the June rains. But the recent history of mosquito-borne diseases points to a more serious problem.
The parasite has been breeding far too rapidly and indifferent monitoring by the municipal authorities is no match for its fecundity. Scientists advocate combining the traditional method of vector control, surveillance and monitoring with other approaches — the use of anti-dengue and anti-chikungunya vaccines, for example. But last year, the government did not allow the French pharma company, Sanofi Pasteur, to introduce its anti-dengue vaccine, Dengvaxia, in the country.
At the same time, efforts to develop indigenous vaccines against the mosquito-borne diseases have lacked a sense of urgency. Scientists at the International Centre for Genetic Engineering and Biotechnology (ICGEB), for example, had to struggle for funds for more than 10 years before developing a prototype of a dengue vaccine last year. But the institute has not held clinical trials and, by all accounts, it could be at least eight years before the vaccine will be available to the public.
Experience worldwide shows that a combination of diligent vector monitoring and research holds the key to eliminating mosquito-borne diseases. Lessons can be drawn from Sri Lanka’s successful battle against malaria. The country’s vector control programme combined surveillance with research on the changing breeding habits of the anopheles mosquito. The Sri Lankan government also ensured coordination between different agencies mandated to control the disease. Dengue and chikungunya have arguably made vector control a more difficult proposition in India. But, as in Sri Lanka, authorities in India would do well to begin by getting their fundamentals right.