Kolkata has seen a rapid rise in dengue cases this year as it emerged as a major city with the highest number of dengue cases. It recorded three times more dengue cases than Mumbai and Chennai. Dengue cases in Kolkata rose by 199% reaching a total of about 3321 cases and Delhi is at a close second with 2068 cases of the mosquito-borne disease, which has wreaked havoc across the country this year.
It has been proved that the dengue disease is sensitive to weather. The biological characteristics of Aedes mosquitoes are directly influenced bexpeditesy ambient temperature and rainfall. High temperature increases biting or feeding frequency; development process from larval to adult stage; hastens incubation of dengue virus in mosquitoes.
Therefore, the reason behind the intensification of dengue disease is attributed to the weather in Kolkata that prevailed during this year's monsoon. Kolkata remained deficient in rainfall during the season and a high temperature under clouded sky, not only boosted the incubation of dengue virus in mosquitoes but also let the water loggings, a perfect breeding ground, not evaporate. This gave birth to dangerous Aedes mosquito in the city that led to higher dengue transmission rate and a larger mosquito population in a short period of time.
Most projections of global climate change indicate global warming and increasing intensity and frequency of extreme weather events such as extreme temperature, drought, heavy rainfall, and flood. This is likely to intensify the outbreaks of dengue disease. It has been estimated that the population at risk of dengue will increase from 3.5 billion to around 5-6 billion in year 2085, if projected climate change takes place. Nevertheless, few studies have projected the change in incidence of dengue fever resulting from the dengue sensitivity to climate and weather patterns.
Photograph by Rameshshng
