India's dengue fever cases almost 300 times higher than official annual tally

A new study has revealed that the annual number of dengue fever cases in India is 282 times higher than officially reported.

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 (CRME) in Madurai, Tamil Nadu, found that the disease inflicts an economic burden on the country of at least 1.11 billion dollars each year in medical and other expenses.

Donald Shepard, PhD, lead author of the study and a health economics professor at Brandeis University, said that they found that India had nearly 6 million annual clinically diagnosed dengue cases between 2006 and 2012-almost 300 times greater than the number of cases that had been officially reported.

The researchers said that they 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.

India is believed to have more cases of dengue than any other country in the world, and except for a slight dip in 2011, the incidence rate has grown steadily there in recent years. In 2013, India's National Vector Borne Diseases Control Program reported that the country had experienced

an annual average of 20,474 dengue cases and 132 dengue-related deaths since 2007, but infectious disease experts believe those official numbers likely reflect only a small fraction of actual cases. India had a major dengue outbreak in 2013, with more than 55,000 reported cases, triggered largely by the heaviest rains in two decades. Standing water provides a breeding ground for disease-carrying mosquitoes.

The study was published in the American Journal of Tropical Medicine and Hygiene.