Beyond malaria, mosquito can give you dengue fever

In our part of the world, the mosquito buzz is a familiar, though hateful, tune that we hear rather frequently.

As individuals, we do all that is possible to protect ourselves and loved ones from the deadly bite that a mosquito can inflict. And when we suspect that we’ve subscribed to the fever that comes as a result, the next line of action is to seek urgent medical attention.

At governmental level and with support from international donors, all efforts have been deployed towards ridding endemic areas of mosquitoes. From subsidising drugs for combination therapies  for those who have been exposed to mosquito bite, to the distribution of free insecticide-treated nets; as well as sensitisation campaigns in all relevant media, it is obvious that no one should treat mosquito bite with levity.

The fear is not without scientific backing. French scientists had captured what happens in your body right from the moment you are exposed to a mosquito bite, to the moment you start seeing the physical effects by way of illness.

The scientists are of the view that when a mosquito bites, it doesn’t just draw blood, but in fact probes around under the skin to find a blood vessel, usually for several minutes at a time.

Led by Valerie Choumet, researchers at the Pasteur Institute in Paris say some people, especially in Africa and Asia, are bitten several times every day. Each time a mosquito bites an individual, the researchers say, the blood-sucking mosquito drinks for an average of four minutes!

While on their murderous biting spree, the scientists warn, mosquitoes suck so hard that the besieged blood vessels start to collapse. “Some of these cells rupture, spilling blood into the surrounding spaces,” the scientists say.

When this happens, the mosquito naturally gets excited, drinking from the pool of blood created.

Worse still, the researchers say, malaria-carrying mosquitoes would spend longer time probing around for blood vessels, “which suggests that the malaria-causing parasite, Plasmodium, may be controlling the insect’s nervous system.”

Enter dengue fever

But beyond the mortal fear that malaria fever — a consequence of Anopheles mosquito bite — inspires, a worse disease looms large but it has not attracted as much due attention as has malaria fever.

According to the World Health Organisation, dengue is a mosquito-borne viral infection found in tropical and sub-tropical regions around the world. WHO notes that the incidence of dengue has grown dramatically around the world in recent decades; and over 2.5 billion people — more than 40 per cent of the world’s population — are now at risk from dengue

WHO says further that the infection causes flu-like illness, and occasionally develops into a potentially lethal complication called severe dengue, or Dengue Haemorrhagic Fever.

Scientists lament that about half of the world’s population is now at risk of developing dengue fever, while severe dengue is regarded as a leading cause of serious illness and death among children in some Asian and Latin American countries.

Bad enough, the number of dengue fever cases has been on the increase in recent times, as it spreads to new areas and explosive outbreaks are occurring. Worse still, researchers say, more than one-third of the world’s population live in areas at risk for transmission, and this includes Nigeria.

As worrisome as it is, physicians say, there is no specific treatment for dengue or severe dengue, but early detection and access to proper medical care lowers fatality rates below one per cent. To prevent dengue, they say, we need effective vector control measures.

Dengue fever in-depth

Epidemiologist, Mr. Segilola Araoye, explains that dengue fever is a painful, debilitating mosquito-borne disease caused by any one of four closely related dengue viruses. “The viruses are related to the viruses that cause West Nile infection and yellow fever,” he says.

Experts say dengue is transmitted by the bite of an Aedes mosquito that has been infected with a dengue virus. The mosquito itself becomes infected when it bites a person who has the dengue virus in his blood. As the infected mosquito feeds on more people, it spreads the virus directly from one person to another.

Araoye says that as is the case with many diseases, doctors can only diagnose dengue viral infection with a standard blood test to check for the virus or antibodies to it.

General practitioner, Dr. Tunde George, says there is no vaccine for dengue; nor are there specific medications to treat a dengue infection.

“Because dengue fever is caused by a virus, there is no specific medicine or antibiotic to treat it. For typical dengue fever, the treatment is purely concerned with relief of the symptoms. This makes prevention the most important step, and prevention means avoiding mosquito bites,” George enthuses.

Experts warn that the risk of being bitten by Aedes mosquito is highest during the early morning, several hours after daybreak, and in the late afternoon before sunset, though mosquitoes may feed at any time of the day.

And would you know, mosquitoes generally thrive in heavily populated residential areas.

Again, physicians say, Aedes mosquitoes typically live indoors and are often found in dark, cool places such as in the closets, under the beds, behind the curtains, and in bathrooms. The best bet, therefore, is to regularly frisk these areas by keeping them clutter- and moist-free; while also allowing for fresh air in the home.

Written by Solaade Ayo-Aderele