Topic 2: Viral Hemorrhagic Fevers

Viral hemorrhagic fevers (VHFs) are animal and human illnesses caused by five distinct families of viruses. They include Ebola virus, Lassa fever virus and dengue fever virus. In most cases the virus is transmitted through air, with the exception of the dengue fever virus which is transmitted by Aedes mosquitoes and ticks. Dengue fever is a global problem in more than 110 countries.

Causes

The dengue fever virus is an RNA virus and has four different strains. The virus is transmitted by Aides mosquitoes. The mosquitoes usually are found in the tropics and sub-tropics and below an elevation of 1,000 meters. Infection with the virus has a higher probability during early morning and evening hours especially during the rainy seasons. After the mosquito feeds on a with dengue fever infected person, the mosquito becomes infected with the virus. After 8 – 11 days the virus has spread to the saliva gland in the mosquito and is subsequently released into the mosquito’s saliva. When this mosquito bites a non-infected person, that person will be infected with the dengue fever virus. The mosquito has a life expectancy of 45-60 days.

Symptoms

The characteristic symptoms of dengue fever are sudden fever, headache, muscle and joint pains, and a rash. The course of infection is divided into 3 phases: febrile, critical and recovery. The febrile phase can last from two to seven days. The critical phase last between 2 and 3 days. During this phase the patient looses large amounts of body fluids into the chest and abdominal cavity. Dengue shock syndrome and dengue hemorrhagic fever occur in less than 5% of all cases of dengue. However, a patient suspected with dengue fever infection should meet a doctor for treatment. What to do when being infected with dengue fever

1. Drink a lot of pure water and follow the doctor's instructions

2. Take Paracetamol for fever and discomfort; ibuprofen and aspirin should be avoided.

3. Wipe the body of the patient with wet cloth to reduce the fever.

4. Eat the light meal as much as you can.

5. Avoid eatingred or black food or drinks as it may be mistaken for blood when vomiting.

6. See a doctor regularly for symptom monitoring and treatment.

Preventing infection with dengue fever

1. Use a mosquito net when sleeping

2. Sleep in a room with mosquito wire screen.

3. Stay in areas with adequate air flow and lighting.

4. Water storage should be closed tightly.

5. Destroy the mosquitoes’ breeding places

6. Add chemical treatment to water storage or other small water sources which cannot be covered to prevent mosquito breeding.