Dengue: a real challenge

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Among the viruses causing hemorrhagic fever, two are most important,

(i) Ebola virus, (ii) dengue virus.

The 99 percent of the cause of viral hemorrhagic fever are reported world widely by Ebola virus. But now in some developing countries dengue virus is also getting increasingly severe.

The vector dependant diseases are generally driven by weather patterns as sometimes biological conditions become very supportive for multiplication of vector (mosquitoes). The dengue virus is present in Pakistan since 2003 but it remained subdued without causing an outbreak.

Until 2009, Pakistan was in drought phase marked with ever recorded hot years. Due to high temperature the vector remained naturally controlled primarily due to weather limiting factors. Pakistan entered into new phase of global warming in 2010 when it turned into a warm-humid territory for the first time. The fecundity rates (egg laying capacity) of vector insects increase in humid climate with temperature varying between 32C to 40C. The temperature above 40C usually becomes a natural controlling factor for the vectors.

The main reason of outbreak of dengue virus in Punjab, Pakistan is climate change caused by global warming. Our universities and research institutions failed to project the possible threats which are now being posed to the society as a consequence of climate change. The first cycle of global warming was experienced as drought, hot and dry weather. Now we have moved into rainy and humid cycle.

India, Sri Lanka and Thailand already have extended humid regions and thus the problem was not new to them. In Punjab, prolonged phase of warm humid climate intermixed with frequent showers was a first experience. During current year, the natural control factors (high temperature, dry and hot winds) were not available to control the vector. Even if a pre-monsoon spray had been conducted, there could have hardly been any noticeable improvement until lifestyles and living habits had been changed ensuring high level of cleanliness.

The main reason of failure in creating effective protection from dengue virus is poor research standards in our research institutions and universities who could not predict the magnitude of threat and devise protective technical pathways. Studies to formulate strategy for devising adaptations to mitigate impact of global warming have not been conducted in Pakistan.

Our universities and research institutes are conducting research to copy whatever universities of developed countries have published about 15 to 20 years before. Contrary to identifying and focusing on real factors, we continue ignoring accountability of research institutions and instead politically motivated opinions are expressed merely to blame the government for a technical failure.

Controlling the DHF by eliminating vector is expensive and many times not as effective as we would like. A three point action plan is proposed: (i) develop a vaccine by indigenous research or influence WHO to intensify its efforts for vaccine development, (ii) develop a plan based on community participation to control vector including adaptations in our collective lifestyle and habits, (iii) the population dynamics of vector mosquito should be carefully studied and weather forecast should be used to initiate protective measures at appropriate time.

MUSHTAQ AHMAD WARRIACH

Lahore

1 COMMENT

  1. This is a great article sir.. It is hard to make it understand it to the normal people but you have done a great effort!!

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