The actual number of dengue cases in India is almost 300 times higher than officially reported, according to a study by Indian and US researchers published in the American Journal of Tropical Medicine & Hygiene.
The report found that about six million people in India got the viral disease between 2006 and 2012, which is 282 times the official annual average of 20,474 cases and 132 deaths.
The study -- led by researchers at Brandeis University’s Schneider Institute for Health Policy in Waltham, Massachusetts, the INCLEN Trust International in New Delhi and the Indian Council of Medical Research’s Centre for Research in Medical Entomology in Madurai, Tamil Nadu -- is the first to use empirical data to estimate the disease’s burden and the direct and indirect costs of dengue in India.
It found that the disease’s economic burden on the country is Rs 6,753 crore a year, roughly the same as what India spends every year on its national space programme.
“We found that India had nearly six million annual clinically diagnosed dengue cases between 2006 and 2012 — almost 300 times greater than the number of cases that had been officially reported,” said lead author Donald Shepard, professor of health economics at Brandeis University.
“Yet we believe even that number may be low, because dengue reporting is better in the area we studied in the state of Tamil Nadu than in most other Indian states due to its well-established medical surveillance system.”
Union Health Minister Harsh Vardhan, however, disagrees. “I won’t agree, I don’t think such under reporting is possible. All fevers are not dengue, only tests can confirm it,” he said.
Shepard and his colleagues in India conducted a retrospective study of dengue patients hospitalised in Madurai district in 2009-2011. They compared the data with surveillance data from 18 states and information from a panel of dengue experts to calculate a national estimate for annual dengue cases that don’t need hospitalisation.
India saw a major dengue outbreak in 2013, when 75,454 cases and 167 deaths were reported, triggered largely by the heaviest rains in two decades. Stagnant water is a breeding ground for disease-carrying mosquitoes.
Dengue, a viral disease transmitted by the day-biting Aedes mosquitoes, infects 50 to 390 million people each year in more than 100 countries, causing at least 20,000 deaths annually.
Symptoms range from mild fever and joint pain to potentially fatal internal haemorrhaging and circulatory shock, which causes organ failure. No effective anti-viral drugs yet exist to treat the illness.