For the past 20 years, Dr Shobhona Sharma, a professor in the Department of Biological Sciences at the Tata Institute of Fundamental Research, has been studying the biology of malarial parasite and our immunity to it. She spoke to Hindustan Times and put the surge in malaria cases in the right perspective.
Mumbai is being called the malaria capital of India. Is the tag justified?
Mumbai is definitely not the malaria capital. There are various pockets in Orissa, Madhya Pradesh, Chhattisgarh and northeastern states where the number of malaria cases is much higher.
Mumbai is not even an endemic area. It is a hypoendemic zone for malaria. According to the World Health Organisation, an area is considered endemic when more than 10 per cent of the area's children get malaria annually.
Children in India are not as prone to malaria as in Africa. Even if we consider the criteria for an endemic area to be 10 per cent of the total population being affected, Mumbai does not qualify as one. Here less than three per cent of the population is infected annually. In pockets of Orissa and Chhattisgarh, four to five per cent of the population suffers from malaria and at times it crosses ten per cent.
Is the corporators demand to declare malaria an epidemic justified?
There is a significant rise in number of malaria cases but I don't think we can call it an epidemic. Malaria is not a new disease. It is a seasonal phenomenon. It is not like chickungunya, which surfaced after a gap.
Vivax malaria, the milder strain of malaria, has become fatal. Has the parasite become more virulent?
There are countless variants of the vivax and falciparum parasites. Scientists have been trying to identify the virulent genes of the strains but have not succeeded yet. So, we can't say whether the parasite has become more virulent.
How do you explain the new malaria symptoms such as diarrhoea and cough?
We don't have scientific evidence to explain the change. It is speculated that excessive immune response may be involved. Some of us think it could be linked to the excess and indiscriminate intake of antibiotics and painkillers. These formulations may accumulate in our bodies and cause strain on the immune reaction and/or on organs (liver and kidney). This may explain why people are getting so sick when they contract an infection.
What would be the best way to combat malaria?
Fogging only drives away mosquitoes temporarily. The best measure is to sleep under a mosquito net. The mosquitoes that transmit malaria bite mainly at night.