Friday, February 23, 2024

Threat from dengue

Dengue, a mosquito-borne viral disease, has over the last few years become a major public health concern in India, with 94,198 cases reported till September this year besides over one hundred deaths mostly due to comorbidity. The reason that dengue has occurred earlier than usual and also more severe than in previous years is attributed to high heat and humidity, due to the effects of climate change, conditions that favour mosquito survival. After the recent unusual heavy monsoon thundershowers across north and south India including the north east, may states were inundated with flood and rainwater. By first week of September, water levels in the rivers receded over time but led to other problems. Various diseases such as conjunctivitis (eye flu) and dengue have been on the rise. While conjunctivitis is being seen as a short-term problem, the severe rise in dengue cases has kept administrations on their feet. When an area becomes flooded, the populations and territories of many vectors, especially mosquitoes, may initially vanish, but when the water subdues after rainfall, they return to these areas as receding flood water can provide ideal breeding sites for them, stated a study published this year by the Cambridge University Press. The receding of water also means rapid multiplication of Dengue Virus(DENV). Dengue is a viral infection caused by the dengue virus (DENV), transmitted to humans through the bite of infected female Aedes aegypti mosquitoes. Aedes mosquitoes are small, dark-colored mosquitoes that have white lyre-shaped markings and banded legs. They usually bite people inside their homes or indoors in general and lays eggs during the daytime in water. Aedes mosquitoes prefer to breed in areas of stagnant water. However, wet shower floors and toilet tanks are considered the most dangerous areas as they allow mosquitoes to breed in the residence. Aedes mosquitoes normally bite during the day, especially 2 hours after sunrise and just before sunset. This mosquito can bite people without being noticed because it approaches from behind and bites on the ankles and elbows. About half of the world’s population is now at risk of dengue with an estimated 100–400 million infections occurring each year. According to medical handouts, both symptomatic and asymptomatic persons are viremic and can transmit DENV to mosquitoes that bite them during this approximately 7-day period. This viremic period is known as the “period of infectivity”. In sick persons, viremia typically coincides with the presence of fever. Dengue fever usually occurs after an incubation period of 4-10 days after the bite of the infected mosquito. Dengue incubation period takes about 4-7 days, can last up to 14 days. Those tested positive for dengue should quarantine themselves for at least 5-7 days so that the virus does not spread. Number of dengue cases especially in Dimapur may not have touched the peak as witnessed during July-August to mid-September but fresh infections are still reported. The problem is that the state government appears more determined to reject any assumption of dengue outbreak as an epidemic rather than fighting the spread of dengue. The manner with which the government took great pains to disprove it as an epidemic seemed as if this would improve the worrying situation where several have died. Had the government’s response to the first reported outbreak of dengue in Dimapur, Mon and Chümoukedima etc been adequate, then perhaps dengue outbreak could have been better managed.

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