The Dengue Saga: The Known Nemesis

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While the world currently faces a deadly threat in the form of SARS-CoV-2, other diseases that previously wreaked havoc never really disappeared in the face of the newer threat.

They are pretty much present as they were before the coronavirus pandemic.

In 2019, the Philippines declared a national dengue epidemic due to the deaths reaching 622 people that year.

June is Philippines’ Dengue Awareness month as is stated in the Proclamation No. 1204 on 21 April, 1998 and is most likely made so because rainy season in the Philippines starts on this month.

The virus is transmitted by mosquitoes, like the Aedes aegypti species shown above.| Photo from The Centers for Disease Control and Prevention website
The virus is transmitted by mosquitoes, like the Aedes aegypti species shown above.| Photo from The Centers for Disease Control and Prevention website

The International Anti-Dengue day is observed every 15 June annually since starting in Jakarta in 2011 with the goal of increasing public awareness, mobilizing resources for its prevention/control and to demonstrate the Asian region’s commitment in tackling the disease.

For starters, we will be tackling the basics of Dengue and steps in its prevention.

The Centers for Disease Control and Prevention describes dengue fever as a disease caused by the Dengue Virus.

The virus, CDC says, is mosquito-borne, which means that it is transmitted by mosquitoes, most especially the Aedes aegypti species.

It is good to note that dengue is not the only disease these mosquitos carry, it just so happened that dengue is more common locally than let’s say, malaria, zika or yellow fever.

According to the World Health Organization, people infected with the dengue virus are asymptomatic or have only mild symptoms like uncomplicated fever. Others have more severe illness and in a small proportion it is life-threatening. The incubation period or the time it takes for the symptoms to appear is three to 14 days (average of six to seven).

So it’s often a good gauge in assuming a possible dengue infection when a patient comes from an endemic area and got symptoms of dengue – less than 14 days it would be likely to consider dengue, more than 14 days then its unlikely (although more diagnostic factors need to be done in order to be certain).

Children more commonly experience symptoms similar to the common cold or gastroenteritis (vomiting and diarrhea) and have a greater risk for severe complications though initial symptoms are generally mild and often includes high fever.

Various medical sources (Johns Hopkins Medicine, CDC, WHO) agree that the following dengue’s characteristic symptoms include

  • Sudden onset fever
  • Headache
  • Muscle and joint pains (the alternate name of dengue fever is breakbone fever which comes from this symptoms) sometimes abdominal pain
  • Varied forms of rash
  • Mouth and nose bleeding (uncommon)

The CDC has identified the course of infection as divided into three phases: febrile, critical and recovery Phases.

Febrile phase

Febrile phase comes with High Fever (usually 40oC), headache, muscle and joint pains with nausea and vomiting. Perhaps familiar with many is the development of redness or rashes – but there are actually variations that may help identify which day the illness is (although this is not definitive and would still vary) Flushed skin similar to blushing may appear in the first two days, and may also be present in the trunk area as well as the arms. Measles like rash (morbilliform type in medical terms) may appear in days 4 to 7. Even smaller but frequent rashes (petechiae) may also appear at this point, together with bleeding in mucous membranes (nosebleeds and bleeding gums)

The fever in dengue is biphasic, which means that it may disappear and then reappear one or two days later.

Critical phase

As fever resolves, people undergo the critical phase of the disease. In this phase, Plasma exits the blood vessels due to leakage, which typically happens for one to two days. This leads to a decreased blood supply in the circulation and vital organs but increased fluid accumulation in the chest and abdominal cavities – sometimes leading to pleural effusion (fluid in the lung cavity) and ascites (fluid in the peritoneal cavityin the abdomen)

The decrease in circulation leads to shock. And the fluid accumulation most often causes damage to the blood vessels leading to severe bleeding (hemorrhage). Thus the terms Dengue Shock syndrome and Dengue Hemorrhagic Fever, which essentially go hand in hand, oftentimes happen in this phase.

While it does sound very worrisome, severe cases happen rarely. Dengue with prompt treatment is self-limited with a mortality rate of less than 1%. Only when dengue becomes untreated will the mortality rate spike up to 20%.

Recovery phase

In this phase, fluid that leaked in the critical phase is reabsorbed back into the bloodstream. This usually lasts 2-3 days. Itching of the skin and development of another rash (maculopapular, vasculitic type) is usually a sign of recovery accompanied by slow heart rate. Physicians treating dengue patients with IV fluids who were previously dehydrated usually stop the infusion by the time the patient has stabilized because the body is capable of resorbing lost fluid itself and continuing IV fluids might result to fluid or volume overload which could be detrimental to the brain and cause seizures. 

Most people with dengue recover without any ongoing problems.

Dengue Treatment and Prevention

Treatment of dengue is better left to the physicians, which more often than not, is based on maintaining proper fluid balance in the body to prevent dehydration or fluid overload (a lot of measuring and math, take it from me) and alleviating symptoms that come with dengue fever as there is currently no known antiviral drugs that is specific for the dengue virus itself with a dengue vaccine only partially effective.

As said earlier, dengue is not threatening with prompt treatment. A patient who can drink and pass urine, and is otherwise healthy with no warning signs can be managed at home with oral rehydration therapy and frequent follow ups. While those who have underlying health conditions, warning signs, or might not be able to follow up frequently might need to be cared for in the hospital for good measure.

According to the DOH Health Advisory for Dengue (2016), dengue with warnings signs is described as a previously well person with acute febrile illness of one to seven days plus any of the following: abdominal pain or tenderness, persistent vomiting, clinical signs of fluid accumulation (ascites), mucosal bleeding, lethargy or restlessness, liver enlargement, increase in haematocrit and/or decreasing platelet count.

While treating dengue is important, treatment can be altogether prevented if dengue is fought in its source. WHO has recommended an Integrated Vector Control program consisting of five elements:

  • Advocacy, social mobilization and legislation to ensure that public health bodies and communities are strengthened
  • Collaboration between the health and other sectors (public and private)
  • An integrated approach to disease control to maximize the use of resources
  • Evidence-based decision making to ensure any interventions are targeted appropriately
  • Capacity-building to ensure an adequate response to the local situation.

The primary method of controlling dengue is eliminating its vectors, the mosquitos, and this is done by disrupting it’s habitats. Open sources of water should rid of and if this is not possible, insecticides and biologic control agents should be considered but ultimately should be made sure that it does not cause more harm than good (as is what happens when there are projects that use this and end up doing more damage – via introducing invasive species of mosquito eating fish or poisoning the environment with too much insecticides and creating even more health hazards)

Personal protection can be in a form of clothing that fully cover the skin, mosquito nets and insect repellant lotion, although decreasing an individual’s risk do little to mitigate the overall frequency of an outbreak due to urbanization and climate change. It is largely in the hands of the government to do massive mitigation efforts in accordance to guidelines that will ultimately provide the most benefit in fighting of the dengue threat.

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