Planning to Visit the Philippines?DENGUE EPIDEMIC, WHAT YOU NEED TO KNOW. By Alfonso B. Villamora Just like the insects from the science fiction movie "Starship Troopers", diseases hosted by mosquitoes are starting to fight back against human intervention.
For the past several months, I have been monitoring the worsening dengue epidemic situation in the Philippines with great interest. The daily newspaper headlines in that country say it all, "Dengue kills teener, downs 58 in Ormoc", "Dengue kills 2, downs 452 in Cordillera", "Dengue on the rise in Bicol", and several more. The news are very alarming. Dengue fever is stalking homes across the Philippines leaving a trail of death that has claimed the lives of dozens of victims, mostly children.
It is also very alarming because the occurrence of this epidemic is no longer just confined to certain geographic locations. Before, it was widely believed that dengue does not occur at high elevations of over 5,000 feet such as the Cordilleras. More recent studies confirmed that the dengue-carrying mosquitoes now thrive in Baguio and Benguet because of the global warming phenomenon.
According to the latest report by the Philippine Department of Health (DOH), 20 children (2-12 years old) died of dengue and 417 have been diagnosed since January in the Ilocos Region; 6 deaths in La Union with 198 reported cases ; Pangasinan had 6 deaths also with 113 reported cases. In Laguna, 1,450 suspected cases of dengue have been reported since July this year. While in Aklan, a total of 45 have been admitted at the Aklan Provincial Hospital.
In Bicol, Dengue has claimed the lives of two children and has inflicted 110 others.
The number of cases is expected to rise with the onset of the rainy season.
What is dengue?
Dengue is a mosquito-borne infection which in recent years has become a major international public health concern. It is found in tropical regions around the world, predominantly in and around urban areas. A more lethal complication, dengue haemorrhagic fever (DHF), was first recognized in the 1950s and is today a leading cause of childhood deaths in many countries. There are four distinct viruses which cause dengue, and infection by one does not offer protection against subsequent infection by the other three. Indeed, there is good evidence that infection by a second dengue virus increases the risk of more serious disease resulting in DHF.
The spread of dengue is attributed to expanding geographic distribution of the four dengue viruses and of their mosquito vectors, the most important of which are Aedes aegypti and Aedes albopictus (the Asian tiger mosquito). A rapid rise in urban populations is bringing ever greater numbers of people into contact with the vector mosquito, while poor sanitation in many urban centers and lack of adequate resources for water storage and waste disposal provides more opportunities for mosquito breeding.
Characteristics
Dengue fever is a severe, flu-like illness that affects infants, young children and adults but rarely causes death. The clinical features of dengue fever vary according to the age of the patient. Infants and young children may have an undifferentiated febrile disease with rash. Older children and adults may have either a mild fibrile syndrome or the classical incapacitating disease with abrupt onset of high fever, severe headache, pain behind the eyes, muscle and joint pains, and rash.
On the other hand, dengue haemorrhagic fever is a potentially deadly complication that is characterized by high fever, nausea and vomiting, dehydration, hemorrhagic phenomena – often with enlargement of the liver and in severe cases, circulatory failure. The illness commonly begins with a sudden rise in body temperature, the face is red and hot, and accompanied by the other symptoms listed for dengue fever. The fever usually lasts for 2-7 days and can be as high as (40-41°C), possibly with convulsions. For mild cases, all sign and symptoms will disappear after the fever subsides. In severe cases, the patient may suddenly deteriorate after a few days of fever; the body temperature drops, followed by signs of circulatory failure, and may rapidly go into a critical state of shock and die within 12-24 hours if untreated.
Transmission
Dengue viruses are transmitted to humans through the bite of infected Aedes mosquito. Once infected, a mosquito remains infective for life, transmitting the virus to susceptible individuals during mosquito bites. Humans are the main amplifying host of the virus, although studies have shown that monkeys in some parts of the world may become infected and perhaps serve as a source for virus for uninfected mosquitoes. Infected humans circulate the virus in their blood at approximately the same time as they have fever, and other Aedes mosquitoes may acquire the virus if they feed on an individual at this time.
Treatment
There is no specific treatment for dengue fever.
Immunization
Vaccine development for dengue and DHF is difficult because any of the four different viruses may cause disease, and because protection against only one or two dengue viruses could actually increase the risk of more serious disease. Nonetheless, progress is being made and commercial vaccines could become available in several years.
Prevention and Control
At present, the only method of controlling or preventing dengue and DHF is to combat the vector mosquito. In Asia, Aedes aegypti breeds primarily in man-made containers like bottles, cans, used tires and other items that retain water. So, good clean-up campaigns around the neighborhood will eliminate almost all of these breeding places. The application of insecticides will also help in eliminating mosquito populations.
Should you postpone your trip to the Philippines until after the epidemic is over? Well, not necessarily but just be cognizant of the places you are visiting. The dengue epidemic is throughout the Philippines, so it might save you some headaches (no pun intended) if you do some pre-planning. Get in touch with the Department of Health in the town or city you are planning to visit and obtain the information you need.
The author is a Lieutenant Commander in the US Navy and a staff at the Navy Environmental and Preventive Medicine Unit No. 5 in San Diego, California.
