Dengue is the most common mosquito-borne viral disease of humans that in recent years has become a major international public health concern. Globally, 2.5 billion people live in areas where dengue viruses can be transmitted. The geographical spread of both the mosquito vectors and the viruses has led to the global resurgence of epidemic dengue fever and emergence of dengue hemorrhagic fever (dengue/DHF) in the past 25 years with the development of hyperendemicity in many urban centers of the tropics.
Transmitted by the main vector, the Aedes aegytpi mosquito, there are four distinct, but closely related, viruses that cause dengue. Recovery from infection by one provides lifelong immunity against that serotype but confers only partial and transient protection against subsequent infection by the other three. There is good evidence that sequential infection increases the risk of more serious disease resulting in DHF.
DHF was first recognized in the 1950s during the dengue epidemics in the Philippines and Thailand. By 1970 nine countries had experienced epidemic DHF and now, the number has increased more than fourfold and continues to rise. Today emerging DHF cases are causing increased dengue epidemics in the Americas, and in Asia, where all four dengue viruses are endemic, DHF has become a leading cause of hospitalization and death among children in several countries.
Symptoms of Dengue Fever
Symptoms, which usually begin four to six days after infection and last for up to 10 days, may include
Sudden, high fever
Severe headaches
Pain behind the eyes
Severe joint and muscle pain
Nausea
Vomiting
Skin rash, which appears three to four days after the onset of fever
Mild bleeding (such a nose bleed, bleeding gums, or easy bruising)
Sometimes symptoms are mild and can be mistaken for those of the flu or another viral infection. Younger children and people who have never had the infection before tend to have milder cases than older children and adults. However, serious problems can develop. These include dengue hemorrhagic fever, a rare complication characterized by high fever, damage to lymph and blood vessels, bleeding from the nose and gums, enlargement of the liver, and failure of the circulatory system. The symptoms may progress to massive bleeding, shock, and death. This is called dengue shock syndrome (DSS).
People with weakened immune systems as well as those with a second or subsequent dengue infection are believed to be at greater risk for developing dengue hemorrhagic fever.
Diagnosing Dengue Fever
Laboratory Diagnosis
The diagnosis of dengue fever normally involves testing of the patient’s blood. Clinical lab findings would include “low levels of white blood cells (leukopenia) and platelets (thrombocytopenia) and, often, an elevated level of the enzyme serum aminotransferase.”
A normal person’s blood platelet count is from 150,000 to 450,000. When a dengue patient’s blood platelets drop to 80,000 and below, there is potential risk of haemorrhaging. It is important for the patient to be admitted in the hospital for constant blood platelet monitoring.
Test kits for early detection
Normal routine tests for dengue viral infection are centered on the detection of specific dengue virus antibodies which are only produced several days after the initial clinical signs appear. That means one should wait for four to six days for a primary infection.
However, dengue test kits that detect antigens, instead of antibodies, are now locally available. These test kits have the ability to confirm early infection – as early as on the first day of symptoms – by detecting the dengue virus antigen NS1 in the patient’s blood. According to the test kit’s manufacturers, results are immediately available in one day. This fast method can possibly prevent epidemics in the country.
Treatment and possible future vaccine
As of now, there is no specific medication or vaccine that can treat dengue. Treatment is focused on relieving the patient’s dengue symptoms. Paracetamol can be given to bring down the fever. However, aspirin, ibuprofen, and mefenamic acid are discouraged because such medicines can increase the risk of bleeding.
Intravenous fluids and electrolytes are administered to the patient to treat dehydration and electrolyte imbalances. Blood transfusion may also be necessary if the patient experiences signs of bleeding. A person diagnosed with dengue needs lots of rest to recover his strength.
“Some vaccine companies would more or less finish their first clinical trial by 2012, others by 2014,” National Center for Disease Prevention and Control (NCDPC) director Dr. Yolanda Oliveros mentioned in 2009. There are medical practitioners who are currently talking of developing vaccines and drugs to help fight dengue. NCDPC is putting together efforts to study the use of some indigenous materials in fighting dengue.
Prevention and Control
The DOH makes use of tri-media (television, radio, newspapers) and the internet to propagate information and advisorieson dengue. These dissemination methods help reach more people around the country.
Efforts are continuously focused on the 4S strategy against dengue.
1. Search and destroy possible breeding places of dengue-causing mosquitoes like flower pots, vases, discarded plastic bags, bottles, old tires, cans, earthen jars, coconut husks, roof gutters, water drums, and other containers that mighthold clean stagnant water. Preventing dengue can be easier achieved by doing your part in keeping the environment clean. Change water in vases frequently. Make sure all water containers are kept covered.
2. Self-protection measures include wearing long sleeves or long pants. It is also best to avoid dark-colored clothes like dark shades of blue and black, as dark clothing has been observed to attract mosquitoes. Apply mosquito repellant on the skin to deter mosquito bites. Mosquito repellant lotions and liquid sprays are available on the market; however, parents are cautioned against using strong repellants on small children because of potentially harsh chemicals. There are organic mosquito repellant alternatives such as all-natural citronella bug spray. You can also use mosquito coils, electric vapour mats and mosquito spray during the daytime. Screens and mosquito nets are also good deterrents against mosquitoes.
3. Seek early consultation because dengue is crucial. See a doctor immediately if you show early signs and symptoms of dengue.
4. Say no to indiscriminate fogging. In the past, fogging was considered as a temporary solution against dengue-carrying mosquitoes. At present, fogging is only advisable and recommended when outbreaks and epidemics are positively determined in a particular area. Fogging can only kill the adult infected mosquito; it cannot get rid of the larvae, locally known as kiti-kiti. Indiscriminate fogging will only drive away other mosquitoes to other places to find new breeding grounds.
By: Ms Madel Buensuceso | Nurse | Samal, Bataan
