DENGUE AND DENGUE HEMORRHAGIC FEVER (DHF)

Creating Awareness About Dengue in Pakistan

Contents

1. What is Dengue?

2. What is Dengue Hemorrhagic Fever?

3. How are dengue and dengue hemorrhagic fever (DHF) spread?

4. What are the symptoms of the disease?

5. What is the treatment for dengue?

6. Is there an effective treatment for dengue hemorrhagic fever (DHF)?

7. Where can outbreaks of dengue occur?

8. How to reduce the risk of acquiring dengue?

9. How can we prevent epidemics of dengue hemorrhagic fever (DHF)?

10. Important statistics

What is Dengue?

Dengue (pronounced den' gee) is a disease caused by any one of four closely related viruses (DEN-1, DEN-2, DEN-3, or DEN- 4). The viruses are transmitted to humans by the bite of an infected mosquito. It is estimated that there are over 100million cases of dengue worldwide each year.

Dengue fever is a severe, flu-like illness that affects infants, young children and adults, but seldom causes death.

What is Dengue Hemorrhagic Fever (DHF)?

DHF is a more severe form of dengue. It can be fatal if unrecognized and not properly treated. DHF is caused by infection with the same viruses that cause dengue. With good medical management, mortality due to DHF can be less than 1%.

Dengue hemorrhagic fever (DHF) is a potentially deadly complication that is characterized by high fever, often with enlargement of the liver, and in severe cases circulatory failure.

How are dengue and dengue hemorrhagic fever (DHF) spread?

Dengue is transmitted to people by the bite of an Aedes mosquito that is infected with a dengue virus. The mosquito becomes infected with dengue virus when it bites a person who has dengue or DHF and after about a week can transmit the virus while biting a healthy person.

There must be a person-to-mosquito -to- another-person pathway.

Dengue cannot be spread directly from person to person because virus is not contagious.

Replication and Transmission of Dengue Virus

1. Virus transmitted to human in mosquito Saliva

2. Virus replicates in target organs

3. Virus infects white blood cells and lymphatic tissues

4. Virus released and circulates in blood

5. Second mosquito ingests virus with blood

6. Virus replicates in mosquito midgut and other organs, infects salivary glands

7. Virus replicates in salivary glands

Where can outbreaks of dengue occur?

Outbreaks of dengue occur primarily in areas where Aedesaegypti mosquitoes live. This includes most tropical urban areas of the world. In fact, Dengue is found in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban areas.

Dengue viruses may be introduced into areas by travelers who become infected while visiting other areas of the tropics where dengue commonly exists.

World Distribution of Dengue

Symptoms & Signs Of Dengue Fever

Fever Headache Muscle and joint pain Nausea/vomiting Rash Hemorrhagic manifestations

Danger Signs in Dengue Hemorrhagic Fever (DHF) Abdominal pain - intense and sustained Persistent vomiting Abrupt change from fever to hypothermia, with sweating and

prostration Restlessness or somnolence Red spots or patches on the skin Bleeding from nose or gums Vomiting blood Black, tarry stools Drowsiness or irritability Pale, cold, or clammy skin Difficulty breathing

What is the treatment for dengue?

There is no specific medication for treatment of a dengue infection. Persons who think they have dengue should consult a physician.

Use analgesics (pain relievers) with acetaminophen and avoid those containing aspirin.

They should also rest, drink plenty of fluids.

Is there an effective treatment for dengue hemorrhagic fever (DHF)? As with dengue, there is no specific medication for DHF. It can however be effectively treated by fluid replacement therapy

if an early clinical diagnosis is made. Hospitalization is frequently required in order to adequately

manage DHF.

How to reduce the risk of acquiring dengue? There is no vaccine for preventing dengue.

The best preventive measure for residents living in areas infested with Aedes aegypti is to eliminate the places where the mosquito lays her eggs, primarily artificial containers that hold water.

Items that collect rainwater or are used to store water (for example, plastic containers, drums, buckets, or used automobile tires) should be covered or properly discarded.

Pet and animal watering containers and vases with fresh flowers should be emptied and scoured at least once a week. This will eliminate the mosquito eggs and larvae and reduce the number of mosquitoes present in these areas.

For people living in areas with dengue, the risk of being bitten by mosquitoes indoors is reduced by utilization of air conditioning or windows and doors that are screened.

Proper application of mosquito repellents containing 20% to 30% DEET as the active ingredient on exposed skin and clothing decreases the risk of being bitten by mosquitoes.

If someone in your house is ill with dengue, take extra precautions to prevent mosquitoes from biting the patient and going on to bite others in the household.

Sleep under a mosquito bed net, eliminate mosquitoes you indoors and wear repellent!

How can we prevent epidemics of dengue hemorrhagic fever (DHF)?

The emphasis for dengue prevention is on sustainable, community-based, integrated mosquito control, with limited reliance on insecticides (chemical larvicides and

adulticides). Preventing epidemic disease requires a

coordinated community effort to increase awareness about dengue/DHF, how to recognize it, and how to control the mosquito that transmits it.

Residents are responsible for keeping their yards and patios free of sites where mosquitoes can be produced.

Important Statistics

The incidence of dengue has grown dramatically around the world in recent decades. Some 2.5 billion people – two fifths of the world's population – are now at risk from dengue. WHO currently estimates there may be 50 million dengue infections worldwide every year.

During epidemics of dengue, infection rates among those who have not been previously exposed to the virus are often 40% to 50%, but can reach 80% to 90%.

An estimated 500,000 people with DHF require hospitalization each year, a very large proportion of whom are children. About 2.5% of those affected die.