Dengue fever (break-bone fever) is a mosquito-borne viral infection caused by the dengue virus (DENV).
The most plausible early report of dengue fever dates as far back as the 1700s when the epidemic swept across Asia, North America, and Africa simultaneously.
Dengue fever, however, is fast becoming a global burden with a dramatic increase in cases around the world.
According to WHO, the incidence of the fever has skyrocketed from 505,430 cases in 2000 to 5.2 million in 2019.
While the drastic increase is alarming, the report has it that the exact number of cases is under-reported since a majority of cases are either without symptoms, mild, or self-managed.
Currently, dengue fever has become most prevalent in America, the Eastern Mediterranean, South-East Asia, the Western Pacific, and in over 100 countries in the WHO region of Africa with over 3.9 billion people at risk of the infection and an estimated 100–400 million cases occurring each year.
Mode of Transmission
Humans are the primary host and source of the dengue virus.
The female Aedes species mosquitoes (Ae. aegypti or Ae. albopictus) become vectors of the dengue virus after a blood meal from viremic humans.
When the infected mosquito bites an uninfected individual, it introduces the dengue virus into his or her bloodstream and the cycle continues.
Dengue virus can also be transmitted from mother to child. An infected pregnant woman can pass the virus to her fetus during pregnancy or at birth. A higher risk of having preterm babies, babies with low birth weight, or even fetal distress exists in women who have dengue fever during pregnancy.
There are also rare cases of DENV being spread through blood transfusion, laboratory/healthcare setting exposures, and organ transplants.
Individuals who have suffered dengue infection before are at a higher risk of developing severe dengue infection.
Environmental and social risk factors include:
- High population density.
- Low human mobility rate.
- No access to reliable water sources.
- Poor water storage practices.
Many people are asymptomatic of dengue infection. However, in some cases, the following symptoms are present:
- Muscle, bone, or joint pain
- Pain behind the eyes
- Swollen glands
Prevention and Control
The only preventive measure is to protect yourself from mosquito bites using insecticides, mosquito repellents, vaporisers, coils, and most importantly always sleeping in a treated mosquito net.
Also, ensure your home and environment have no breeding place for mosquitoes.
Dengue fever becomes complicated when it develops into severe dengue fever.
Here, the blood vessels become damaged, and the number of blood platelets in the bloodstream drops. This can lead to shock, internal bleeding, organ failure, and even death.
Warning signs of severe dengue fever
- Severe stomach pain
- Persistent vomiting
- Bleeding from the nose or gum
- Blood in vomit, urine, and stool
- Bleeding under the skin, which might look like bruises
- Constant thirst
- Pale and cold skin
- Difficult or rapid breathing
- Irritability or restlessness
There is no specific treatment for dengue fever but the following approaches are helpful in relieving symptoms, especially in cases of severe infection.
- Fluid replacement: This involves constant fluid intake to replace those lost from sweating, vomiting, and bleeding.
- Use of analgesics to relieve pain.
- Supportive care and monitoring in a hospital
- Electrolyte replacement through intravenous means
- Monitoring of blood pressure
- Blood transfusion to replace blood lost during bleeding
To combat dengue infection, early detection and access to proper medical care are paramount and would greatly reduce fatality rates in severe cases.
However, a vaccine named Dengvaxia has been approved in countries with larger incidences of the infection but only individuals who have suffered the infection in the past can be protected by the vaccine.