As malaria cases fall, a look at Tamil Nadu’s strategies for elimination

Reports from the World Health Organization and the Commonwealth Malaria Report have indicated that India is set to eliminate malaria by 2030. The number of deaths from malaria has significantly fallen, with better surveillance and access to diagnosis and medicines, the reports add.

Malaria, the WHO says, is a life-threatening disease spread to humans by some types of mosquitoes. It is mostly found in tropical countries. It is preventable and curable. The infection is caused by a parasite and does not spread from person to person. Malaria can be prevented by avoiding mosquito bites and with medicines. Treatments can stop mild cases from getting worse.

How T.N. tackles its cases

In Tamil Nadu, for the past two years, only around 340 cases were reported, says Director of Public Health T.S. Selvavinayagam. This turnaround was made possible due to steady surveillance, he adds. “When fever is reported the entire area is brought under surveillance. All institutions must be notified of fever surveillance. This enables the Health Department to get details of where the fever has occurred, who is affected and in which location,” he explains. 

Dr. Selvavinayagam goes on to detail: “Once we identify the location where there has been a fever case, the environmental factors are identified. These could be water stagnation or issues with water storage containers. Then we expand the periphery of surveillance and we continue to monitor intensively, undertake anti-vector activities etc. We rapidly search for hidden cases as we know what the precipitating factor is. The idea is to explore the hidden cases and bring them to light.”

The Health Department then  takes up routine anti-malarial activities. “We continue to monitor the area for years together if it is a high risk area,” he says.

The female Anopheles mosquitoes that spread malaria breed in fresh water, coastal and dirty water. Four types of malaria are commonly found in the country:  Plasmodium vivax, plasmodium falciparum, plasmodium ovale and plasmodium malariae.

“In Tamil Nadu we see two varieties of malaria commonly – vivax and falciparum. The latter is imported,” says former DPH K. Kolandaisamy. “Uncovered  overhead tanks, wells, riverine areas and quarries are breeding sources,” he explains. Other areas include coconut groves and places of religious congregations such as Rameswaram.

Strategies to eliminate malaria

Malaria elimination strategy includes taking a peripheral blood smear of the patient. “A health inspector should carry with them a needle and a slide box to collect the blood smear; a ladle, and a torch,” says Dr. Kolandaisamy. The last two items would help the inspector identify the disease-causing mosquitoes. They should also have a chloroscope to check for chlorine in water body, he adds.

All fever is tested for suspicion of malaria. If the malaria is suspected to be imported (travel-related), we ask for travel history to help control the spread of the disease, Dr. Kolandaisamy says.

Healthcare workers are deployed to spray insecticides. Years of surveillance and publicising the requirement to cover overhead tanks and wells has resulted in eliminating mosquito breeding spots, the doctor says.

Malaria is introduced into the State by travellers however, says the public health expert. The Falciparum variety of malaria spreads through travel. The challenge lies in identifying the source of the infection, he points out.

“The biggest challenge is lack of health and sanitary inspectors. The number of posts have been reduced. These are ‘invisible jobs’ of the public health sector. This invisible force, if not maintained, could increase the burden on staff and lead to a surge in the disease, Dr. Kolandaisamy avers.

Malaria in India

Between 2001 and 2020malaria cases declined from 2.09 million to 0.19 million, recalls S. Sabesan, senior epidemiologist.  The Plasmodium falciparum cases (considered the deadliest) declined from 1.0 to 0.12 million cases during the same period. The SPR (slide positivity rate) declined from 2.31 to 0.19 The SFR (slide falciparum rate) declined from 1.11 in 2001 to 0.12 in 2020 he says.

Chhattisgarh, Jharkhand, Maharashtra, Mizoram, Odisha, U.P. and West Bengal continue to contribute a high number of cases. 

In the southern region, cases are relatively high in Andhra Pradesh, says Dr. Sabesan, who was formerly director Gr. Scientist at the Indian Council of Medical Research-Vector Control Research Centre.

Over the past few years however, he says, the number of cases has risen again, indicating that the earlier focus on surveillance has reduced. Dr. Sabesan warns that this could hamper the goal of eliminating malaria and calls for better surveillance and control strategies across the country.

Malaria, he says, can be eliminated if the government strictly adheres to: environmental sanitation; conducts surveillance within the State and country; takes up interstate joint vector control surveillance; involves companies in public-private-partnerships for manufacture of nets and repellents and appoints trained public entomologists who can assess vector strength and offer timely guidance to prevent the revival of mosquito breeding and the spread of the disease. “We need an integrated approach. In urban areas we must target both malaria and dengue as the breeding habitat of the mosquitoes are similar. In rural areas we must also target Japanese encephalitis,” he adds.

While India is no longer in the WHO’s High Burden to High Impact initiative for malaria as of 2024, it still has some way to go to reach its target to eliminate malaria from the country by 2030, he points out.