Shantha ThiagarajanResearchers documented the first case of sickle-cell disease (SCD) in India in the Nilgiris in 1952. More than seven decades later, the blood disorder continues to affect the hills’ tribal communities, where consanguineous marriages can increase the likelihood of children inheriting the disease when both parents carry the sickle-cell gene. Known locally as the “bone-crushing disease”, SCD can cause severe episodes of pain, chronic anaemia, fatigue, infections and damage to vital organs. In its more severe forms, it can shorten life expectancy.Yet, despite decades of research and screening, the question of how many people in the district have it remains.Two recent studies have examined the disease’s severity and the potential of artificial intelligence to help identify it. A 2026 paper says SCD in the Nilgiris and neighbouring Wayanad is generally milder than in several central Indian tribal populations. But the review, published in the Journal of Haematology and Allied Science by Kanjaksha Ghosh, former director of the National Institute of Immunohaematology at KEM Hospital, Mumbai, says much of the available research is hospital-based and may not represent the wider population. It also says large-scale studies are needed to understand how genetic factors such as fetal haemoglobin and alpha-thalassaemia, along with nutrition, infections, climate and occupation, influence severity. But it does not establish how prevalent the disease is.Nilgiris public health department data show 61,393 people from tribal communities such as toda, kota, kurumba, irula, paniya and kattunayakan have undergone screening over the past eight years under various national health mission programmes. “Of these, 340 people have been identified with SCD, while another 1,650 people, including non-tribals, have been found to have sickle cell trait,” says Dr D Somasundaram, deputy director of public health.These figures show how many cases screening programmes have identified. They do not indicate how many people remain undiagnosed or how the disease affects patients over time. The district is home to about 35,000 tribal people from communities, according to the 2011 census.In Gudalur and Pandalur taluks, the Association for Health Welfare in the Nilgiris (Ashwini), which has worked with tribal communities for decades across 320 hamlets in eight areas, with many of its field staff drawn from tribal communities themselves, has been focussing on the reproductive age group and is now implementing newborn screening.“Health education is not enough. Families need to understand how the disease is inherited and what it could mean for their children,” says Dr Mridhula of Ashwini. Doctors and social workers are battling cultural issues such as consanguineous marriages and a lack of awareness of its hereditary nature. Earlier healthcare initiatives combined outreach with treatment and counselling. Mobile medical vans would visit remote settlements in the Nilgiris once a fortnight, providing outpatient care, maternal services, vaccinations and laboratory tests. The Tamil Nadu Health System Project also provided sickle-cell screening, treatment cards, genetic counselling, hydroxyurea and emergency transfusions. The project appointed tribal peer counsellors at several healthcare centres.“Though most in the communities are aware of SCD, they lack an understanding of it,” says Dr R Laxman Bharathi of Nilgiri Adivasi Welfare Association (Nawa). “Patients come for check-ups every month, and we also follow up with them. Some non-tribal residents don’t want to participate in screening.”Common myths among tribal communities portray SCD as contagious, a divine curse or the result of black magic, certain foods or abandoning traditional ways of life, fueling stigma and discouraging people from coming forward for screening or care.While earlier screening focused on tribal settlements, with some random screening in non-tribal areas, the district public health department is now extending the programme to other communities and locations. “We are screening new pockets in the district under the new public health programme, covering the indigenous community Badaga and other populations too,” says Somasundaram. “Patients identified with SCD are being followed up in association with Nawa and Ashwini. These organisations and Ooty Government Medical College Hospital provide treatment and medication.” The medical college hospital follows 49 patients.Technology could help improve diagnosis. A 2025 study by Maria Sheeba and K Sarojini, published in the International Journal of Electronics and Communication Engineering, developed an AI system that uses red blood cell images to classify sickle-cell anaemia among Nilgiris tribal communities. Using records from 300 patients obtained through Nawa, along with 14 disease-related attributes and red blood cell images, the system achieved 98% accuracy. But the researcher says that while it could help with early diagnosis in communities, identifying cases and measuring prevalence are different tasks. An AI system cannot determine how many people have the disease unless screening reaches a representative population.Dr Bharathi says that since 2021, NAWA has screened about 11,000 people from the badaga community in the Kotagiri, Coonoor and Ooty blocks. “About 30 are getting treatment from Nawa. Some have opted to take treatment privately,” he says. He estimates that 1% of badagas have the disease and 8% carry the trait. “Among the thoraiyar community, disease prevalence is 5% and trait prevalence is 10%. Among tribal communities, the corresponding figures are 1% to 2% and 10%.”India has the world’s second-highest burden of sickle-cell births. Announced in the Union Budget 2023–24, the National Sickle Cell Anaemia Elimination Mission set a target of screening seven crore people aged up to 40 across 17 states between 2023 and 2026, to eliminate the disease as a public health problem by 2047. It identified 30 tribal blocks in 14 Tamil Nadu districts as vulnerable to SCA. The state has reported around 500 cases, with about 70% in the Nilgiris. Cases of SCD and sickle-cell trait have also been reported in the hill areas of Salem, Kallakurichi, Dharmapuri and Villupuram. Digital cards recording whether individuals are unaffected, carriers or have the disease are among its provisions, but these have yet to be issued in the Nilgiris.For the district, identifying patients is only the beginning; ensuring they get continuing care is the bigger task.Understanding sickle-cell diseaseSickle-cell disease is an inherited blood disorder involving an abnormal haemoglobin called haemoglobin S. Red blood cells become stiff and crescent-shaped, which obstructs blood flow and causes them to break down prematurely.The shortened lifespan of these cells causes chronic anaemia and affects oxygen delivery to organs.Sickle-cell trait refers to carrying one copy of the sickle-cell gene. People with the trait are typically healthy but can pass the gene to their children.
