Dengue is hyper-endemic in the Philippines. The Geneva-based World Health Organization (WHO) has observed cyclical increases, with significant outbreaks happening every 3 to 5 years.
The Department of Health (DOH) has indicated that although the current figures have significantly decreased, the country faced a severe outbreak earlier in the decade, with yearly cases occasionally surpassing 300,000.
So, what does dengue have to do with the environment? Water, discarded plastic bottles, and dirty surroundings, that’s what.
Let’s start with water. Water serves a dual purpose in the context of dengue: stagnant water facilitates mosquito reproduction, whereas adequate hydration is essential for the recovery of patients.
According to the We Are Water Foundation, dengue is spread by Aedes mosquitoes, which deposit their eggs in clean, stagnant water located in artificial containers such as buckets, flower pots, and discarded items that accumulate rainwater, rather than in natural water bodies like rivers or lakes.
“Poor water storage practices in urban and semi-urban regions increase the number of mosquito breeding sites, thereby elevating the risk of dengue outbreaks,” the United Nations health agency reminds.
It is important to note that prior to June, the country endures intense heat from the sun due to the summer season. Many Filipinos store water in containers such as pails and barrels, which serve as attractive breeding grounds for mosquitoes that carry dengue.
As such, the We Are Water Foundation recommends that managing outdoor water in shared spaces and routinely emptying or covering containers is a crucial preventive strategy to diminish mosquito populations.
For people who are infected with dengue, it is vital to maintain proper hydration. Medical professionals indicate that the disease leads to fluid loss due to high fever, vomiting, and plasma leakage. Adequate hydration is crucial in preventing serious complications.
Health specialists clarify that those suffering from dengue experience a loss of fluids and essential electrolytes as a result of the immune system’s response to the virus, which causes plasma leakage and a reduction in circulating fluids. This condition can lead to severe complications, including shock, circulatory collapse, coma, liver and kidney dysfunction, and potentially death.
Consequently, it is imperative to ensure sufficient hydration for recovery and to avert severe complications. Recommended fluids consist of water, oral rehydration solutions (ORS), coconut water, clear broths, and fresh fruit juices. It is advisable to avoid caffeinated, alcoholic, or sugary beverages, as they may exacerbate dehydration.
In critical situations, intravenous fluids may be required to replenish plasma volume and prevent circulatory collapse. This is the reason why doctors usually suggest to have the patient a dextrose when admitted to the hospital.
Water is also related to discarded plastic bottles. When these plastic bottles are disposed of, they serve as artificial catchments for stagnant rainwater, thus providing an optimal breeding environment for mosquitoes that carry dengue.
Mosquitoes that transmit dengue possess very specific breeding habits and behavioral characteristics, which render poorly managed plastic waste particularly hazardous. Within a plastic bottle, the water is protected from rapid evaporation and wind, fostering a secure micro-environment for the larvae and pupae to grow without interruption.
As per warnings from the United Nations health agency, even an open, discarded bottle cap can retain sufficient water to effectively breed approximately – hold your breath! – 20 mosquitoes.
However, it is not solely plastic bottles that can be identified as offenders. Discarded plastic bags, sachets, food containers, and wrappers also contribute to the proliferation of dengue-carrying mosquitoes.
Aedes mosquitoes are highly adapted to human environments and prefer to reside in close proximity to people. Due to the significant accumulation of plastic waste around residences, along roadsides, and in urban areas, these insects breed near their primary food source: human blood.
Ineffective waste management results in a high density of these small water reservoirs. This directly increases the local mosquito population, accelerating the rate of dengue transmission during outbreaks.
On a broader scale, discarded plastics frequently wash into and obstruct municipal drainage systems and gutters. This leads to localized flooding on streets and creates large areas of stagnant water, exacerbating the mosquito infestation throughout entire communities.
Scientists have discovered that the eggs of Aedes mosquitoes can survive for up to six months – even when their breeding grounds go dry under natural conditions. Some of the remaining eggs can still go on when the breeding sites become filled with water again.
Medical scientists identify four distinct viruses, which are transmitted through the bite of a mosquito. Most people infected with dengue viruses have dengue fever. Patients suddenly develop a high fever. They also may have a headache around their eyes or on their forehead.
A rash, which usually appears 24-48 hours after the fever starts, begins at the trunk and then develops on the arms and legs. Patients experience muscle aches and severe bone pain (this is the reason why it is sometimes called “breakbone fever”). Two-to-six days later, nausea and vomiting may take place.
The fever usually lasts three to nine days and then goes away. One to two days after the fever goes away a second rash appears. This rash disappears in one to five days and is accompanied by a slight fever (also known as “saddleback fever”).
Dengue hemorrhagic fever (DHF) is a potentially deadly complication, which requires medical attention. Patients will experience the following: high fever (40 to 41 degrees Centigrade), headache, loss of appetite, vomiting, cough, and feel very tired. This lasts two to five days. Then they feel cold and have clammy hands and feet. They also have a flushed face. In most instances, they sweat a lot, are very restless, and irritable. Oftentimes they have little red spots on the forehead, arms, and legs.
Usually, patients get better in two to three 3 days. Sometimes, they do not and their blood pressure goes down and they develop shock (shock syndrome). Medical experts say deaths occur in 5%-40% of children that develop shock. DHF may be fatal in 40%-50% of untreated patients; however, with appropriate treatment the mortality can be brought down to 1%-5%.
Most dengue patients are children. A research study conducted by the Department of Health (DOH) sometime in 1991 pointed out that the majority of the patients are between the ages 5 and 9 years old.
“It is a big problem among children because it is a major cause of illness and deaths,” says Dr. Lulu Bravo, a distinguished pediatric infectious diseases physician and a Professor Emeritus at the University of the Philippines Manila.
But the risk of dying is higher among teenagers. “This is a common observation and maybe it’s related to the fact that DHF has a more severe illness with bleeding and shock after an initial infection,” explains Dr. Bravo. “The appearance of a second infection triggers a more severe reaction and high response of antibodies. Thus, minor illnesses are expected during the first encounter, usually in the younger age group.”
According to Dr. Bravo, dengue death is due to the body fluids leaving the blood vessels and accumulating in body cavities or spacing, thus causing shock. It may be also due to severe bleeding either internally into the intestines, in the brain, or in other organs of the body.
“The outcome could be fatal within hours of severe bleeding or in many cases children are pulled out of shock by adequate management of fluids and blood or blood products replacement,” Dr. Bravo says.
