The Sting That Kills

IN the past two years, Tarun Goswami has seen eight malaria attacks, three of them of the fell malignant variety, at home in a south Calcutta neighbourhood. His wife was struck down twice, his seven-year-old son survived two malignant attacks and suffered a benign one, his septuagenarian mother was laid low once and the maidservant was down with malignancy some time ago. Now Goswami, a journalist with a leading Calcutta-based newspaper, is himself recovering from an attack. "There's fear psychosis in the neighbourhood," he says. "Every home has a malaria patient, and two have died in the past two weeks."

Nature's most loathed insect never really disappeared from Calcutta. But the dreaded Anopheles stephensi which encourages the growth and multiplication of the plasmodium falciparum—the only malaria parasite which can kill—is again wreaking havoc in this decaying city of 11 million people. The under-reported and deceptive official figures already have an ominous buzz: of the 70,000 blood samples tested at crumbling government hospitals and clinics since January, some 30 per cent contained the malaria parasite. Some 6 percent of these samples contained plasmodium falciparum, the pathogen which causes malignant malaria. The official death toll: seven. "This is a seasonal outbreak when the breeding of anopheles mosquito reaches a peak," says Dr Sujit Ghosh, chief health officer of the Calcutta Municipal Corporation (CMC).

The reality is grimmer. At one government hospital alone, Sambhunath Pandit in south Calcutta, 18 patients have died of malignant malaria between August and last Monday. Another 314 patients lay shivering in the wards; the outpatient department detected 1,256 cases and sent them home with medication. At the School of Tropical Medicine (STM), India's only tropical diseases institute, doctors reported that nearly 50 per cent of the samples which tested positive for malaria—as high as 70 per cent of an average of 150 samples a day last week—contained  plasmodium falciparum.

At CMC's 26 detection centres in the city, the presence of the killer pathogen jumped to 45 of 4,346 samples this month from a low of just one out of 3,609 samples in June. Clearly, reports from other hospitals suggest that the number of malignant malaria deaths had crossed 35. "This year, we're witnessing an increased severity of the disease," agrees Dr Amitava Nandi, STM's head of the department of protozoology.

At the root of the alarming rise in this fell variety of urban malaria is the failure to stamp out the Anopheles stephensi, one of the 10 species of mosquitoes—there are 3,200 species worldwide—from Calcutta. Unlike their relatively harmless Culex quinquefasciatus species which breeds in filthy water and comprises 85 per cent of the city's mosquito population, the Anopheles stephensi breeds in clean and stagnant water in domestic containers, unused latrines, flower pots and vases, aircoolers and overhead water tanks, among other places.

The mosquito, according to a study in the Indian Journal of Malariology, builds up its population in domestic water containers "mainly in and around buildings, including skyscrapers," enter bedrooms and fly out to adjacent huts and cattlesheds after imbibing blood to rest before laying eggs. Another study in Tropical and Geographical Medicine, a Netherlands-based journal, reveals the resilience and changing behaviour of the mosquito: after the National Malaria Eradication Programme went on a DDT spraying spree inside tenements in Calcutta in the '50s, the Anopheles stephensi stopped resting inside buildings after biting. "Spraying insecticides here and there will not solve the problem," says Debashish Biswas, vector control officer of the CMC.

But the sluggish municipality initially sent its 400-odd vector control staff on a DDT and anti-larval spraying and air fogging overdrive to kill mosquitoes—both highly polluting and largely ineffective to combat the Anopheles stephensi. There are some 1.75 lakh registered civic holdings in the city buildings, factories et al—and a host of construction sites which are breeding grounds. Late last week, the municipality marshalled its troops to visit some of these buildings, checking overhead tanks and reservoirs for larvae and distribute leaflets. "The key in such a situation," says Dr Dilip Barman, chief of the Sambhunath Pandit Hospital, "is to protect yourself with a mosquito net."

 Otherwise, the mosquito will continue to kill. If the fever is not treated in time with a carefully calibrated combination of chloroquin and primaquin—the two drugs which kill the parasite and stop its transmission—plasmodium falciparum can kill by attacking the brain, lungs, kidney, intestinal tract and blood cells. In these times of unchecked and unplanned urbanisation, urban malaria is here to stay—nearly 100 people died in a malignant malaria outbreak in Mumbai in 1995. But an improved civic consciousness of a largely apathetic citizenry and focused strategies by the municipalities can prevent our cities from becoming malarial hot zones.