KARACHI: Country is in an urgent need to evolve a surveillance mechanism with specific reference to Weather and Climate Effect on the growth of Aedes Egypti, the dengue fever-causing type of mosquitoes Dr Erum Khan, a senior researcher associated with the Department of Pathology and Microbiology, Aga Khan University talking to APP said weather conditions, mainly humid with average temperature ranging between 38 degree centigrade to above 40 degrees, has particularly emerged to be a triggering factor for Dengue Fever in Karachi.
“This is mainly during past two years, ” she said mentioning that high humidity shortens incubation and blood-feeding intervals besides favouring adult mosquito longevity and thus dengue transmission.
In reply to a question she said Aedes gonotrophic cycle is shorter at temperature above 32 degree C, while Pupae development period reduced from four days at 22 degree C to less than one day at 32-34 degree C.
“Extrinsic incubation period reduced from 12 to 7 days at temperatures ranging between 32-35 degree C while even relative humidity is in itself a determinant in A. egypti egg development and adult population size,” said Dr Erum.
In the given situation, the expert suggested that the government needed to modify its strategy and must pre-plan to address intensity of cases, that could be gauged through weather conditions of any area during past two years.
Dr Khan reiterated that on basis of weather conditions of any given area, including Karachi, proactive preventive measures vis a vis fumigation besides home based interventions can be adopted.
The researcher mentioned that currently dengue is endemic in all continents except Europe while incidence of Dengue Hemorrhagic Fever (DHF) is common in Asia and Americas.
“Yet, we find that countries like Singapore, Malaysia etc where Dengue is endemic have evolved cost effective strategies based on pragmatism so as to cause little inconvenience or threat to the people,” she said.