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Tuesday March 19, 2024

Dengue fever outbreak may take more time to go unlike past

By Muhammad Qasim
October 19, 2019

Rawalpindi: Seasonal close of on-going dengue fever outbreak that proved to be the most severe in nature in the history of the twin cities of Islamabad and Rawalpindi this year may take more time as compared to the outbreaks in the past and there may be chances that the infection would continue to haunt population in the region even after November.

To date, the three teaching hospitals in town including Holy Family Hospital, Benazir Bhutto Hospital and District Headquarters Hospital have received well over 9,300 confirmed patients of the infection while according to Deputy Director at Pakistan Institute of Medical Sciences Dr. Waseem Ahmed Khawaja, the PIMS has received well over 5,500 confirmed cases of dengue fever this year.

The number of confirmed cases of dengue fever in the twin cities this year has already becomes four times the number of patients reported in the outbreaks in 2015 and 2016 which were considered as the most severe in nature. With over 4,000 confirmed cases in 2015 and around 4,500 cases in 2016, the outbreaks came to seasonal close in the mid of November after fall in temperature.

Heavy influx of confirmed cases of dengue fever in the region this year is due to huge larval density of mosquitoes ‘aedes aegypti’, the vector that causes dengue fever as epidemiologically, cases of dengue fever increase proportionally with the larval density, said a top official serving at the allied hospitals.

Pleading anonymity, he said the localities which have been severely hit by dengue fever outbreak this year have larvae of dengue fever vector in abundance. The outbreak may not lose its intensity for another two months or so because of greater population of mosquitoes, he said.

During the outbreaks of 2015 and 2016, the allied hospitals received around 20,000 patients at their dengue outpatient departments in over 95 days of outbreaks while this year, the hospitals have already received well over 62,000 patients at their dengue OPDs in just 65 days, from August 14 to date.

Many health experts are of the view that the outbreak this time is much intense and so far nothing significant has been done to control spread of the infection. In fact, we have got late and now it may not be possible to eliminate larvae and mosquitoes entirely from the environment, said the official.

He added that the seasonal close of the epidemic depends upon fall in temperature but this time, the problem is greater larval density particularly in indoor environment. The teams of health departments in the twin cities are finding larvae from inside homes in much abundance, he said. We witnessed deaths from dengue fever in November during the dengue fever outbreaks in 2015 and 2016 which were four times less severe in nature as compared to the on-going outbreak, he added.

It is worth mentioning here that the mosquito that causes dengue fever lays the first eggs of the year at the beginning of May and the mosquito density is maximal in early July, late August and in September though the egg laying activity remains intact until November. The optimal temperature for ‘aedes aegypti’ larvae is 28 degree centigrade and above this the rate of development is high and below 18 degree centigrade, the growth gets prolonged.

Experts say that in indoor environment, the larvae may find temperature between 18 degree centigrade and 28 degree centigrade even in December and individuals have to take extraordinary measures this time to avoid dengue fever.