The prevalence of Dengue fever in India is escalating due to the delayed onset of monsoon, according to a recent study. This article will discuss why dengue spreads, the various methods currently employed to control it, and touch upon the vaccination status as of now.
Dengue Transmission and its Climate Dependency
An increase of 1.69% in dengue transmission by the Aedes aegypti mosquitoes from 1951-1960 to 2012-2021 was observed in the study. Several factors affect Dengue transmission in different geography – rainfall, humidity, and temperature being key. Aedes aegypti is most prevalent in the southern peninsula, eastern coastline, north-eastern states, and the northern plains while Aedes albopictus dominates the eastern and western coastlines, north-eastern states and the lower Himalayas. The study also foresees the expansion of Aedes aegypti into the Thar Desert regions and Aedes albopictus into the upper Himalayas, due to future climatic changes.
About Dengue Fever: Causes, Symptoms, and Diagnosis
Dengue, caused by the Flavivirus, is a tropical disease transmitted via Aedes mosquitoes. Four distinct virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4) are known to cause dengue. Symptoms include sudden high fever, severe headaches, pain behind the eyes, severe bone and joint pain amongst others. Diagnosis is done through a blood test. As of now, there is no specific treatment for the infection.
The Growing Incidence of Dengue
Global incidence of Dengue has seen a dramatic increase in recent times. According to the World Health Organization (WHO), a majority of cases remain underreported. WHO estimates around 390 million dengue virus infections per year, of which approximately 96 million show symptoms. As per the data shared by the National Center for Vector Borne Diseases Control, India recorded 63,280 dengue cases as of September 2022.
Controlling Dengue Using Bacteria
World Mosquito Program researchers have successfully controlled dengue in Indonesia using mosquitoes infected with Wolbachia bacteria. These mosquitoes were released into the city where they bred with local species until nearly all mosquitoes had Wolbachia bacteria. After 27 months, researchers found a 77% reduction in dengue incidence in areas where the Wolbachia-infected mosquitoes were released.
The Status of Dengue Vaccination
The first approved dengue vaccine, CYD-TDV or Dengvaxia, was approved by the US Food & Drug Administration in 2019. Suitable for individuals aged 9 to 16, who have previous laboratory-confirmed dengue infection and live in endemic areas. Indian Immunologicals Limited (IIL) is making notable efforts to develop India’s first Dengue vaccine, with permission already granted for Phase-1 trials. They are developing this vaccine in collaboration with the National Institutes of Health in the US.
Civil Services Exam Question Based on Disease Transmission
To highlight the relevance of disease transmission knowledge, we cite an example from the UPSC Civil Services Examination Previous Year Question. The question asked which diseases could be transmitted through tattooing, among Chikungunya, Hepatitis B, and HIV-AIDS. The correct answer was Hepatitis B and HIV-AIDS as both can be transmitted via blood, while Chikungunya is primarily spread through mosquito bites. It showcases that understanding disease transmission is integral, not only from a public health perspective but also from a competitive exam viewpoint.