Towards the end of August 2016, the Health Ministry of India had issued an alert warning the population about increased cases of chikungunya and dengue, and has urged city officials to take preventative measures to avoid major outbreaks.
India is not a stranger to such tropical infections especially dengue. Every year, the country is subject to spikes in infections, usually after the rain season in August and September, and fades when the cold winter weather sets in by the month or November. This is because the vector of dengue is the mosquito Aedes aegypti, which eggs are laid in stagnant waters and need an aquatic environment in order to survive until developing into a terrestrial organism. The whole process takes 8 to 10 days depending on temperature and the level of nutrients available to the larvae during its aquatic stage.
What is alarming is the increase in the number of cases when compared to previous recorded years. Between 2006 and 2012, the annual average of dengue infections stood at 20,474 cases. In the year 2014 however, the number of cases jumped to 40,571, increasing further in 2015 with 100,000 cases and 220 deaths. Although the number of deaths remains relatively low with regards to population size, the economic impact is substantial for the Indian government as it is estimated that the annual cost of dengue amounts to $1.11 billion, with about half, $548 million, directly attributed to medical treatments alone. Moreover, when analysing data from the Indian Ministry of Health and Family Welfare, statistics demonstrate a 1,000 percent increase in the states of Haryana and Madhya Pradesh, an increase of 957 percent in West Bengal, over 300 percent in Andhra Pradesh, and a 154 percent increase in the capital, Delhi.
A number of microbiologists and health institutes studying the patterns of infections in the country such as the National Institute of Virology in Maharashtra have published a number of studies demonstrating that dengue is no longer a seasonal concern, but is indeed endemic (active throughout the year) in most major cities spread across 16 states.
Until recently, the lack of a viable vaccine has forced health authorities to focus efforts on fighting the vector, the Aades aegypti mosquito, rather than the pathogen itself. Vaccines aimed at preventing dengue have been under development since the 1940’s, with a breakthrough in 2015 – 2016 where the first preventative treatment by Sanofi Pasteur, Dengvaxia, was approved by regulatory bodies in Mexico and the Philippines, as well as Brazil, El Salvador and Paraguay. A draw back of the vaccine is that it is only recommended for people between the ages of 9 to 45 years, and extended till 60 years of age in Paraguay. In April this year, the World Health Organization’s Strategic Advisory Group of Experts (SAGE) on Immunization has recommended the use of such a vaccine only in regions where dengue is highly prevalent.