The dengue outbreak, which had at last count infected nearly 25,000 people — close to 4,000 of them in Delhi alone — this year, could in fact be much bigger than these numbers. Huge underreporting of the incidence of the disease is hampering the response and exposing many to danger, experts say.
According to the Ministry of Health and Family Welfare, 20,000 confirmed cases of dengue were reported every year on average between 2006 and 2012. There were 75,808 cases in 2013, and 40,571 in 2014.
However, a landmark 2014 study by the government’s National Institute of Health and Family Welfare (NIHFW), New Delhi, found that India could have had “an annual average of 5,778,406 clinically diagnosed dengue cases, or 282 times the reported number per year” between 2006-2012.
The study reported that the “National Vector Borne Disease Control Programme captures only 0.35 per cent of the annual number of clinically diagnosed dengue cases in India”.
A year earlier, in 2013, an assessment by a team of 18 researchers from seven countries, published in the British journal Nature, said “India alone contributed 22-44 million dengue infections” in the world — which suggested that the Ministry’s estimate could be off by a 1,000 times.
“The government numbers are just the tip of the iceberg,” said Dr Soumya Swaminathan, Director General of the Indian Council of Medical Research (ICMR). She added that nobody really knew the real burden of dengue, and the truth lay somewhere between the 282-times-more and the 1,000-times-more estimates.
ICMR will launch a programme to estimate the actual burden of the disease, Swaminathan said, adding that the involvement of citizens and an “eco-bio-social approach” was the only way to win the battle against dengue.
Dr Srinath Reddy, president of the Public Health Foundation of India (PHFI), agreed that “the official numbers of dengue cases is a gross underestimate”, and said “India’s surveillance systems are just not configured to capture the full spectrum of dengue from the large number of patients who remain asymptomatic to the ones who get hospitalised”.
The NIHFW study, by nine researchers including former institute director Dr Deoki Nandan, and published in The American Journal of Tropical Medicine and Hygiene, estimated the total direct annual medical cost of the dengue burden at $ 548 million (Rs 3,600 crore), and the total economic cost to be in the order of $ 1.11 billion. This year’s Budget allocation for the Health Ministry was about $ 4.81 billion.
According to the World Health Organisation (WHO), some 3.9 billion people in 128 countries are at risk of dengue globally. “Unknown to most, India is today the epicentre of the global epidemic of dengue, harbouring the largest number of dengue infections in the world,” said Dr Navin Khanna, a dengue researcher at the International Centre for Genetic Engineering and Biotechnology in New Delhi. Dengue, Khanna said, had become hyper-endemic in the country, whose incidence had “increased 30 fold in the past five decades”.
Some of the discrepancies in data could be due to the fact that the government records only laboratory confirmed cases as dengue, with a very large majority of cases going unreported, and seen as routine viral infections.
The underreporting has major implications on the way dengue is treated, since repeat infections, usually due to a different strain of the virus, can be far more debilitating as compared to the primary infection.
Sheer numbers make it imperative that public health measures aimed at controlling the breeding of mosquitoes are adopted. “There is no way a hospital system can be designed to cater to such gigantic numbers,” Kakkar said. An expert from WHO’s India Programme office warned that “dengue is the fastest growing disease in the world and climate change will only exacerbate the problem”.
(The author is a science writer)
Global Incidence of Dengue
Research published in the journal Nature in 2013 puts India in the deep red zone of the world dengue map. The report estimated India’s annual contribution to the global incidence of the disease at at least 22 million.
ALARM BELLS, UNEASY BUZZ
“Government numbers are just the tip of the iceberg,” says Dr Soumya Swaminathan, Director General of ICMR. She adds that no one really knows the real burden of dengue, and that ICMR would launch a programme to estimate actual numbers. The involvement of citizens and an “eco-bio-social approach” is the only way to win the battle against dengue, she says.
Dr Srinath Reddy, president of the Public Health Foundation of India (PHFI), agrees that “the official numbers of dengue cases is a gross underestimate”, and says that “India’s surveillance systems are just not configured to capture the full spectrum of dengue from the large number of patients who remain asymptomatic to the ones who get hospitalised”.
“This is not a cover-up by the government, but underreporting is hampering our response,” says Dr Manish Kakkar, an expert on infectious diseases at PHFI.
“Unknown to most, India is today is the epicentre of the global epidemic of dengue, harbouring the largest number of dengue infections in the world,” says Dr Navin Khanna of the International Centre for Genetic Engineering and Biotechnology.