Uttam Maharjan

Dengue, also called breakbone fever, has taken almost epidemic proportions across the country. Out of 77 districts, 56 districts, including the three districts in the Kathmandu Valley, have so far been afflicted by the vector-borne disease. Dengue is caused by the bite of an Aedes egypti mosquito, which belongs to the family Culicidae. The disease is related to other diseases like Zika virus, Mayaro virus, West Nile virus, Japanese encephalitis, yellow fever and chikungunya. Dengue occurs in three forms: dengue fever, dengue haemorrhagic fever and dengue shock syndrome. There are five serotypes of the dengue virus, which belongs to the genus Flavivirus in the family Flaviviridae, out of which mild forms – type 1 or 2- are attacking the country at present.
Dengue usually occurs in the tropical areas like the country's Terai belt. However, this year the disease has occurred even in the hilly districts, catching the health authorities unawares because they have not imagined that such a tropical disease will also make a foray into the hilly districts. It has been found that mosquitoes travel to high altitudes like mountains; moreover, they complete their life cycles even in cold areas, which is a matter of concern. High rainfall this year has also contributed to the spread of dengue in alarming proportions.
Recent studies have shown that vector-borne diseases like dengue and malaria are found in areas where they were unknown in the past and have disappeared from areas where they once were found in abundance. It is all due to climate change.
An outbreak of dengue first occurred in the country in 2004 AD. Another outbreak occurred in the five districts of the country in 2006 AD. Dengue also made its presence felt in 2010 AD and 2011 AD. In 2011 AD, 79 confirmed cases of dengue were reported in 15 districts. Last year, six dengue cases were reported in the Kathmandu Valley. As dengue did not assume dangerous proportions then, the health authorities did not pay serious attention to the disease. But this year, over 5,000 dengue cases have been detected across the country.
The incidence of dengue is more frequent in lowlands than in highlands. The main culprit behind the high incidence of the disease in the country is climate change, which has led to higher temperatures all over the world. In a hot climate, it is easier for mosquitoes to breed rapidly. A rise in temperatures also facilitates the replication of the dengue virus.
The outbreak of dengue has been exacerbated by the movement of Aedes egypti mosquitoes as well as people infected by the disease from the tropical areas to other areas of the country. Further, the behaviour of Aedes egypti differs from other mosquitoes in that it lays eggs in clean and stagnant water and it bites people usually during the day.
The worst part of dengue is that no vaccine or medicine has been developed till now. Only ten per cent of those affected by the dengue virus show symptoms and have to undergo treatment. Dengue patients are given only supportive treatment. Very few patients suffer from complications due to haemorrhage. If bleeding occurs, leading to a drop in a platelet count, a blood transfusion will have to be administered to them. Therefore, the only reliable method for controlling dengue seems to lie in controlling the Aedes egypti mosquitoes by destroying their eggs and larvae. If the mosquitoes are not wiped out this year, they will lay eggs and increase next year also, making it even more difficult to control the disease. As fogging kills only adult dengue-causing mosquitoes, not eggs or larvae, it is imperative to initiate 'search and destroy campaigns' across the country.
Dengue being a new challenge, both the people and the health authorities seem to be ill-prepared to fight the disease. Lack of awareness has stood as a big impediment to tackling the disease. In the meantime, several myths surrounding the disease have swirled around such as the Aedes egypti mosquitoes cannot fly over two feet or the mosquitoes bite people only below the knees.
The government has sprayed several areas of the Kathmandu valley with anti-mosquito foam. Awareness campaigns have also been launched in the Valley. In fact, the nature of dengue is such that it cannot be controlled through the efforts of the government alone. Community participation holds the key to controlling the disease. As clean and stagnant water is favourable for the Aedes egypti mosquitoes to lay eggs, efforts need to be accelerated both at individual and communal levels to make the environment hostile to the breeding of the mosquitoes.
As per the experts, a hot climate induced by climate change is to blame for the rising incidence of dengue in the country. The country contributes very little to the carbon footprint. The country can even take advantage of carbon trading due to its low carbon emissions. Still, countries like ours which have a very little contribution to global carbon emissions have to bear the consequences of climate change. So, climate change has affected all the countries in the world, whether they contribute to carbon emissions greatly, moderately or negligibly.
As six people have died of dengue till now and the disease has assumed near-epidemic proportions, infecting not only common people but also high-profile people like ministers and doctors, the government needs to embark upon anti-dengue campaigns across the country in synergy with the health personnel and communities.

(Former banker, Maharjan has been regularly writing on contemporary issues for this daily since 2000. He can be reached at uttam.maharjan1964@gmail.com)