Dengue fever, a fast-spreading mosquito-borne viral disease, is making waves across the globe, especially in tropical and subtropical regions. With its ability to cause anything from mild flu-like symptoms to severe, life-threatening conditions like dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), this tiny virus is a mighty adversary. Dengue prevention strategies are key in minimizing its impact.

As millions grapple with its impact, understanding the unique features of the dengue virus and how to protect ourselves is more critical than ever. Let’s learn the general symptoms, transmission mechanisms, control methods and also some less known facts about the dreadful fever.

Unique Features Of Dengue Virus

There are several special features of the virus, which makes it unique  and different from all other viruses. Some of the characteristic features include:

1. Four Distinct Serotypes

DENV-1, DENV-2, DENV-3, and DENV-4: Dengue virus has four serotypes. Infection with one provides lifelong immunity towards that serotype but not for the others. Subsequent infection by a different serotype increases the probability of severe dengue like dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Dengue prevention strategies must consider these serotypes to be effective.

2. Antibody-Dependent Enhancement (ADE)

Secondary Infection Increases the Risk: Antibodies from initial infection enhance the entry of a different serotype into host cells. This phenomenon, in other words, antibody-dependent enhancement, may cause severe disease during secondary infections, which results in DHF or DSS.

3. Transmission through Aedes Mosquitoes

Mode of Transmission: Dengue is transmitted mainly through mosquitoes, especially Aedes aegypti. These mosquitoes are actually urban pests and breed in standing water. The virus is not transmitted directly from person to person but through the mosquito vector.

4. RNA Virus

Single-Stranded RNA Genome: The dengue virus belongs to the Flavivirus genus and has a single-stranded RNA genome that is subjected to mutations and variations, resulting in different strains for each serotype. Keeping up with these variations is crucial for dengue prevention strategies

Signs and Symptoms of Dengue

Symptoms of dengue typically begin 4-10 days after an infected mosquito bite and may include:

• High Fever: up to 40°C (104°F) lasting 2-7 days.

• Severe Headaches and Eye Pain: typically located behind the eyes with severe headaches.

• Joint and Muscle Pain: This symptom is excruciating and, for this reason, described as “breakbone fever.”

• Nausea and Vomiting: Common gastrointestinal disturbances are also a feature.

• Rash: A maculopapular rash that can be seen over the trunk and limbs can be an accompanying sign.

• Mild Bleeding: In more serious cases, symptoms manifest as nosebleeds or easy bruising.

• Fatigue and Weakness: Fatigue can still be a persistent symptom following fever.

Severe dengue can also lead to other serious complications, including persistent vomiting, severe abdominal pain, internal bleeding, and shock, placing the patient’s life at risk. Dengue prevention strategies should also include educating the public on the recognition of these symptoms.

Transmission of Dengue

Dengue is principally transmitted through the bite of an infected female Aedes aegypti and Aedes albopictus mosquito. These mosquitoes like to live in and around people’s houses in urban areas and breed in any water container holding stagnant water. Dengue transmission peaks during the rainy season when the incidence of stagnant water increases. These mosquitoes bite largely during the daytime when they are most active.

Prevention of Dengue Fever

Dengue prevention strategies aim at controlling mosquito populations and reducing exposure to mosquito bites.

Mosquito control

• Breeding site elimination: Regularly empty stagnant water found in containers, pots, and other places that serve as a breeding place for mosquitoes.

• Controlling via the use of larvicides: Larvicides can be applied to water bodies to reduce mosquito populations.

• Fogging and Insecticides: Effective tools for outbreak control; they work best if applied correctly.

Personal Protection

• Clothing: Long-sleeved shirts, long pants, and socks can lessen the amount of skin exposed.

• Repellents: DEET, picaridin, or oil of lemon eucalyptus work effectively.

• Mosquito Netting and Screens: These help to reduce your exposure to mosquito bites.

Vaccination

Dengvaxia is a live attenuated recombinant vaccine; such vaccines have the virus in an attenuated form, meaning the vaccine contains a weakened virus that cannot cause a disease but is still capable of stimulating the immune system to recognize and combat the virus. The Dengvaxia induces immunity against all four strains of dengue, namely DENV-1 to DENV-4. This vaccine is available but only recommended in people who have had dengue before, as this may worsen the disease in others.Dengue prevention strategies involving vaccination must be carefully planned to target appropriate individuals.

Community Involvement

Effective dengue control will need the community to be actively involved through public awareness on prevention methods of the breeding of mosquitoes, collective efforts geared toward elimination of breeding sites, among others. 

Dengue continues to be a major health problem but is not curable. However, its impact can be lessened through prevention and early detection. Measures should be taken, both personally and systematically, to eliminate the breeding of the vector, and enhance personal protection.

Important Facts Regarding Dengue:

• Risk Increases with Secondary Infection: When an individual who has previously contracted dengue fever becomes infected with a different serotype of the virus, the likelihood of developing severe complications increases due to a phenomenon known as antibody-dependent enhancement (ADE).

• Dengue Can Affect the Liver: In more severe situations, dengue may lead to liver impairment, which includes raised liver enzymes, hepatitis, or even acute liver failure.

• Dengue Infection Can Alter Blood Clotting: When severe, dengue can negatively affect blood clotting and cause internal bleeding with classic symptoms of dengue hemorrhagic fever including nosebleeds, bleeding of the gums, and blood in vomit or stool.

• Dengue Can Give Rise to Severe Eye Manifestations: In the worst of cases, dengue can also give rise to eye complications such as dengue-related maculopathy, resulting in problems in seeing or even temporary blindness. Dengue prevention strategies should consider these rare but severe complications.

Role of MIS

Microbe Investigations Switzerland offers the testing and validation services for  products applied in mosquito control to help eliminate dengue. Contact MIS for more information on our wide service range on testing and validation.