Billones, Kim Irving L. Miclat, Frances Leah D. Tan, Hannah Michaela F. HUB42 BIOL 126 (Medical Microbiology)

Outline  Introduction  Epidemiology  Updates on Diagnosis  Prevention and Control  Intervention Strategies  Issues and Problems

Introduction

Description  Dengue (DF) and Dengue Hemorrhagic Fever (DHF), caused by one of four closely related, but antigenically distinct, virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4), of the genus Flavivirus, are primarily diseases of tropical and sub tropical areas.  Infection with one of these serotypes provides immunity to only that serotype for life

Aedes aegypti, a domestic, day-biting mosquito that prefers to feed on humans, is the most common Aedes species to cause this disease. Infections produce a spectrum of clinical illness ranging from a nonspecific viral syndrome to severe and fatal hemorrhagic disease. Description (cont.)

derived from the Swahili "Ka-Dinga pepo” - a sudden cramp like disease caused by an evil spirit. The first reported epidemics of dengue fever occurred in in Asia, Africa, and North America The virus was identified in the 1940's when it became a concern to the armies fighting in Pacific and Asia. History

Japanese scientists first identified the virus in 1943 and were quickly followed by U.S. researchers. By 1956 the four serotypes of the virus were identified and every outbreak of the disease, since it has been due to a virus belonging to one of the four serotypes. History (cont.)

In Southeast Asia, epidemic DHF first appeared in the 1950’s, but by 1975 it had become a leading cause of hospitalization and death among children in many countries in that region. It had a resurgence in the 1990's and remains a major public health problem in many areas and the current situation has been designated a global pandemic. History (cont.)

sudden onset of fever The fever is high, °C. accompanied with severe headache (mostly in the forehead), pain behind the eyes, body aches and pains, rash on the skin and nausea or vomiting. The fever lasts for 5-7 days. In some patients, fever comes down on 3rd or 4th day but comes back. Signs and Symptoms

The characteristics of dengue that make it different from other causes of fever are the pain behind the eyes, severe pains in the muscles, severe joint pains, and skin rashes. Signs and Symptoms (cont.)

Dengue viruses (DEN-1, DEN-2, DEN-3 and DEN-4) - flaviviruses Enveloped, spherical viruses, 40-60nm diameter Etiology

Aedes aegypti, yellow fever mosquito. The mosquito can be recognized by white markings on legs and a marking of the form of a lyre on the thorax. The mosquito originated from Africa but is now found in the tropics worldwide. Aedes_aegypti_CDC- Gathany.jpg Vectors

Epidemiology

 The disease is now endemic in more than 100 countries in Africa, the Americas, the Eastern Mediterranean, South-east Asia and the Western Pacific.  South-East Asia and the Western Pacific are most seriously affected.  It is estimated that there may be 50 million cases of dengue infection worldwide every year.

Dengue fever was typically acknowledged as a childhood disease, as it is the main cause of pediatric hospitalization in Southeast Asia.

Updates and Diagnosis

Diagnosis  Clinical Diagnosis  Laboratory Diagnosis

Clinical Diagnosis  Clinical features frequently depend on the age of the patient  Older children and adults may have either a mild febrile syndrome or the classic incapacitating disease with high fever or abrupt onset, sometimes with two peaks, sever headache, paint behind the eyes, muscle and joint pains, nausea and vomiting, and rashes

Laboratory Diagnosis CBC Antibodies Titer Serological Tests

Advances in Diagnosis  Molecular Detection  Dengue Virus Serotyping

Prevention and Control

 Anti-Dengue campaign  “S-es”  Seek and destroy mosquito breeding places. These include all containers that collect stagnant water (bottle caps, dish racks, cans, empty bottles and used tires).  Self-protection. This includes covering windows and doors in the house with fine- meshed screens, using mosquito nets, and rubbing insect repellent lotions or sprays onto exposed areas of one’s skin.

 Seek medical treatment immediately. High fever lasting 2-7 days, rashes and/or bleeding, severe headache, pain behind the eyes, muscle, joint, or bone pain are some symptoms that could indicate dengue. The DOH advises the public to go to a Dengue Express Lane in a hospital, where proper diagnostic tests for dengue would be administered to a patient.  Say “no” to indiscriminate fogging. The DOH says that no fogging operations should be done in an area unless there are known dengue cases present.

Intervention Strategies

eliminate the places where the mosquito lays her eggs Pet and animal watering containers and vases with fresh flowers should be emptied always bring an insect repellant lotion Keep your surrounding clean

Issues and Problems There is no vaccine that directly kills the virus. Dengue patients are neglected. The vectors are very hard to eliminate. The people are not very cooperative with the efforts of the government to eliminate dengue.

References htmhttp://sprojects.mmi.mcgill.ca/tropmed/disease/dengue/history. htm Gathany.jpghttp://en.wikipedia.org/wiki/File:Aedes_aegypti_CDC- Gathany.jpg surged-to-68-doh/ surged-to-68-doh/ view.php?pdf= ngueFactSheet.pdf