Battle against malaria: Fighting mosquitoes that killed 24,000 Indians in 2015
Subhash Pai, 46, was hospitalised last week in an upscale Gurgaon hospital after he collapsed in office. Doctors suspected a heart attack but what he had was malaria infection.
Pai is among millions of Indians afflicted by the mosquito-borne disease every year. However, what his case highlighted was the growing mutation of malarial parasites to evade every known frontline drug.
And mosquitoes developing resistance to all types of insecticides are the other big roadblock that’s threatening India’s goal to eliminate malaria – zero indigenous cases in by 2030.
In its least-publicised initiative, the Indian Space Research Organisation (Isro) is providing remote-sensing technology to detect, map and classify mosquito breeding areas in the country, the latest in India’s war against the mosquito-borne disease that is believed to have killed an estimated 24,000 people in the country in 2015. The number of officially recorded deaths for the year is, however, 384.
Malaria is a parasitic disease that spreads between humans through the bite of infected female anopheles mosquitoes. Once the parasite enters the human bloodstream, it invades the liver and then the red blood cells. Initial symptoms include fever, headache, sweats, chills and vomiting, and at this stage, the immune system usually fights and controls the infection.
If malaria is severe, the parasite disrupts the blood supply to vital organs, including the brain, causing seizures, coma and death.
Pai was diagnosed with infection of plasmodium falciparum, one of the four species of human malaria parasites that includes plasmodium vivax, plasmodium malariae and plasmodium ovale. A decade ago, 65% of all infections were caused by P vivax and 35% by P falciparum two decades ago. Now the ratio is reversed (see box).
The P falciparum parasite causes the more deadly cerebral malaria that, when untreated, may lead to loss of consciousness and even coma. It’s responsible for 99% malaria deaths worldwide.
Pai’s malaria was undiagnosed and untreated because he had asymptomatic malaria, with no symptoms or fever, headache, bodyache or chills associated with the disease.
“We now rarely see the textbook malaria symptoms of high recurrent cycle of fevers and chills, so all cases of fever lasting more than three days are routinely screened for malaria,” said Dr Anupam Sibal, group medical director, Apollo Hospitals.
Asymptomatic cases have so far been limited to the north-eastern states and Odisha where malaria occurs the year round, but now sporadic cases are being reported across India.
“It usually occurs in endemic areas where people often develop partial immunity that controls the infection but does not kill the parasite, but now we’re getting sporadic cases in people who haven’t travelled to these areas,” said an official from the National Vector-Borne Disease Control Programme which tracks diseases spread by mosquitoes, sandflies and other vectors.
Over the past two decades, the world is shifting from vector-control to a parasite-control strategy to fight malaria. Early diagnosis and treatment using anti-malarial drugs lowers the parasitic load in the body and makes the patient less infectious.
“Malaria rapid diagnostic tests (RDTs) that detect malaria parasites in human blood and give results within 15 minutes are being used to test all cases of fever for malaria in the remotest parts of the country,” said a health ministry official.
A study last year by the Indian Council of Medical Research’s Regional Medical Research Centre in Dibrugarh, Assam found P falciparum infection as high as 84.44% in the population surveyed, followed by P vivax in 10.56% people, and mixed infections (P falciparum and P vivax) in 5% of the people. Among the P falciparum cases, 38.16% persons were asymptomatic.
Studies from Africa show that asymptomatic malaria is a chronic disease that should be treated because it raises risk of anaemia, maternal and neonatal mortality, bacterial co-infection, and cognitive impairment
In India, 80% of malaria cases occur among 20% of its population living in 200 high-risk districts of Andhra Pradesh, Chhattisgarh, Gujarat, Jharkhand, Karnataka, Madhya Pradesh, Maharashtra, Odisha, West Bengal and the seven northeastern states.
With fewer than half of those infected reaching hospital, the infections and deaths are a lot higher than recorded. The WHO’s world malaria report estimates India had around 13 million malaria cases.
The first chloroquine-resistant P falciparum was reported near the India-Myanmar border in 1973 and chloroquine-resistant P vivax in Mumbai in 1995. Both strains are now all pervasive, which led to the national programme to offer fast-acting artemisinin combination therapy (ACT) for treatment since 2010. People not responding to ACT have to be reported to district malaria officer.
New tools are being added globally. From 2018, Ghana, Kenya and Malawi will pilot the world’s first malaria vaccine in babies and children who account for more than 95% of the world’s malaria deaths.
Between 2000 and 2015, 17 countries eliminated malaria, said the World Malaria Report 2016.
These countries did it with the same tools as India -- rapid diagnostic tests, ACT drugs and use of long-lasting insecticidal nets. India’s real challenge is taking medicines and tools to all those who need it and bust myths, which threaten to derail efforts.
The Dibrugarh study found that while those surveyed had heard of malaria, 22% thought it was caused by unsafe drinking water, leeches and unsafe blood during transfusions.
Malaria is curable and elimination is possible if India scales up its act. The Rs 10653.16 crore five-year National Strategic Plan for Malaria Elimination (2017-22) launched last week will be as effective as the last-mile delivery.