Sharp Drop in Dengue Cases in Delhi

• 27 Oct 2018

Recently dengue cases have been reported in Delhi but so far the cases are lowest in the last four years.

• Delhi witnessed its worst outbreak in 2015, with over 15,000 cases and 60 deaths.

Dengue

• Dengue is a mosquito-borne viral disease that is widespread throughout the tropics, with local variations in risk influenced by rainfall, temperature and unplanned rapid urbanization.
• Dengue virus is transmitted by female mosquitoes mainly of the species Aedes aegypti and, to a lesser extent, Aedes albopictus.
• This mosquito also transmits chikungunya, yellow fever and Zika infection.
• Severe dengue (also known as Dengue Haemorrhagic Fever) was first recognized in the 1950s during dengue epidemics in the Philippines and Thailand.
• Today, severe dengue affects most Asian and Latin American countries and has become a leading cause of hospitalization and death among children and adults in these regions.
• There are 4 distinct, but closely related, serotypes (separate groups within a species of microorganisms that all share a similar characteristic) of the virus that cause dengue (DEN-1, DEN-2, DEN-3 and DEN-4).
• Recovery from infection by one provides lifelong immunity against that particular serotype. However, cross-immunity to the other serotypes after recovery is only partial and temporary. Subsequent infections by other serotypes increase the risk of developing severe dengue.

Dengue in Delhi

• The DEN-3 strain has been there in the capital for three years, which is one of the reasons for fewer cases this time. If the same type remains in circulation for over a period of time, a large proportion of the population develops immunity to it.
• The reappearance of one of the serotypes that has not been around for a while can lead to a spurt in cases. So, monitoring the strains throughout the season to identify the serotype is required.
• If there is any migration from a state having a different type of strain, it can spread among the public and can lead to a complex situation.
• According to experts, awareness among people is extremely important to control the disease.