Epidemiology of dengue vector causing the disease, measures for control

By Our Correspondent
October 21, 2021

Islamabad : Islamabad Capital Territory is being hit badly by dengue fever with over 2,330 confirmed cases so far reported along with nine deaths while in the last five days, 688 patients have been confirmed positive for the infection though on the basis of epidemiological pattern, the spread of the disease can be termed as normal.

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It is a normal epidemiological pattern of dengue fever disease that fluctuates and appears after a gap of a year or two. Over 2300 confirmed cases of dengue fever have been reported from Islamabad and it is mainly due to the present most conducive environment prevailing in the region for the breeding of dengue mosquitoes. There are millions of mosquitoes that develop from larvae within seven days of cycle, as eggs are hatched in batches of around 25 each while each female mosquito has an ability to lay 200 to 250 eggs at a time. The most favourable temperatures are 25 to 30 degree centigrade while humidity is 30 to 60 per cent.

Dr. Muhammad Najeeb Durrani who is an epidemiologist and member Global Outbreak &Alert Response Network (GOARN) expressed this while talking to ‘The News’ on spread of dengue fever and its control.

The bite of ‘aedes aegypti’ mosquito does not cause disease if the mosquito is not infected by an infected traveler around as the mosquitoes first get infected themselves then become a source of spreading the infection in the area, he said.

Studies reveal that the dengue fever mosquitoes both ‘aedes aegypty’ and ‘aedes albopictus’ are vectors for causing dengue fever as the female mosquitoes carry one of the four types of dengue virus from the dengue patient to the healthy person and transmit the disease.

Dr. Durrani who has served as District Health Officer ICT said Islamabad is a zone where around half a million people visit and leave in a week and disease is prevalent in most districts of Punjab and KPK. People from endemic areas travel daily to Islamabad and play an important role in the spread of the disease.

He explained that the disease affects more in areas that are under developed and hence the spread is faster in the rural areas as compared to the well developed sectors in Islamabad. Solid waste remains a very important risk factor and it is evident that the rural areas have no system for swift solid waste disposal that is why majority of patients are from rural set ups, he said.

Rain water is retained in small disposable containers, plastic bags, plastic or metal broken cups, utensils, bottle lids all present in trash that forms solid waste, causes female mosquitoes to reach and lay eggs, he said.

He added that the teams in health department provide rapid epidemiological case response in affected areas by IRS (Insecticide Residual Spray) to 48 houses around a patient’s home including the patient’s residence and also perform fumigation in the area besides conducting an awareness campaign in the community through lady health workers through door to door campaign on how to prevent themselves from the bite of the dengue mosquito and adopt other measures to restrict growth of the mosquitoes inside and around their homes.

The response is given to each and every case as reported on dashboard from the hospitals but the health department alone is not capable of preventing or controlling the epidemic without participation of all the communities and active role played by nation building departments like Education, Administration, Police, Railways, Iesco, Auqaf, local government, Revenue, communications department and most importantly media, said Dr. Durrani.

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