Vaccsbook

Type of Disease

Dengue is an infectious disease caused by a virus transmitted from human to human by mosquito bites.

Type of Microbe

Dengue Fever is caused by an RNA virus of the same family as, e.g. Yellow Fever, West Nile, and Zika.

Also known as

Dengue Fever is also known as Breakbone Fever due to muscle and joint pains that develop in a some of patients.

Vaccination

A vaccine is available and prevents recurrence of disease in 60% to 90% of patients who receive it.
However, it is only given to patients who have already had Dengue, and in areas where most children have the disease by age 9. In other previously uninfected patients, it is believed to increase the severity of any initial infection.

Acquisition and Transmission

The Dengue Fever virus is transmitted by Aedes type mosquitos which bite infected humans, then transmit by biting other humans.
Whether a mother can transmit to her unborn child is unclear.
It can only be transmitted directly from human to human through blood transfusion or organ transplants

Signs and Symptoms

Most infected patients are asymptomatic or have mild symptoms.
In severe cases, symptoms are fever of up to 40C, headache, vomiting, muscle and joint pains, and a measles-like rash skin rash consisting of widespread small red raised bumps.

Timeline

Incubation (between the mosquito bite and onset of symptoms) is 3 to 7 days, occasionally up to 14 days.
The illness resolves, or rarely progresses to death, over a further 7 to 10 days; fatigue may then last for many weeks.

Contagion

After a mosquito bite, patients are considered contagious for 2 to 10 days during which time another mosquito can bite and transmit the virus to other patients.

Diagnosis

Diagnosis is usually made on the basis of characteristic symptoms in a patient where the Aedes mosquito is known to exist.
A CBC (complete blood count) may show low white count, low platelet count, but elevated hemoglobin in severe cases.
The virus can be isolated on laboratory testing, and/or by detecting antigens and antbodies.

Body Systems Affected

Dengue effects are widespread; it can affect the liver, bone marrow, blood cells, circulation/vascular system, and skin cells.

Treatment

Treatment is supportive, i.e. maintaining hydration and nutrition. As of 2020, no specific anti-viral/anti-dengue drugs are available.

Prevention

Dengue is prevented by avoiding mosquito bites, e.g. through the use of mosquito nets, and reducing the mosquito population through removing areas of open water and/or spraying with insecticides.

Complications

In its severe form, Dengue Hemorrhagic Fever results in uncontrolled loss of fluid from the circulation and circulatory collapse (shock).
After initial symptoms resolve, fatigue may last for many weeks.

Fatalities

In thse who develop severe symptoms (less than 20%), the fatality rate is 1% to 2.5%.

Epidemics & Pandemics

As of 2020, there are estimated to 100+ million infections every year; this has been increasing in the last few decades.
Localized outbreaks with up to 500,000 infecions occur yearly in various tropical and subtropical countries; a pandemic has never been identified.

Geography

Dengue Fever occurs in the tropics and sub-tropics (within latitudes of 35 degrees) where the Aedes mosquitos thrive.