Recently there has been a spike in Dengue cases throughout the world, especially in the tropical and subtropical areas of Central America, South America, Asia and Oceana. The International Federation of Red Cross Asia Pacific has been responding to Dengue outbreaks in 14 countries in Asia including India, Sri lanka, Bangladesh, Vietnam and Philippines. Dengue has risen to over 200,000 cases in the Philippines, 64,000 cases in Bangladesh and 40,100 cases in Sri lanka just this year according to the statistics reported. 

In the Maldives, there has been an increased number reports of Dengue this year. According to HPA weekly Dengue report of August 6th 2019, there has been 3,310 cases of Dengue reported so far this year and has said to have increased compared to the past two years during the same period. Number of Dengue cases has also increased from June to July this year in almost all of the atolls. Records collected by HPA also show that the highest number of dengue cases came from H. Dh. Atoll, Dh. Atoll, L. Atoll, Male’ and Hulhumale’. 

Transmission

Dengue is a mosquito-borne disease. It is transmitted by infected female mosquitos, mainly of the species Aedes aegypti and Aedes albopictus. The Aedes mosquito is easily identifiable by the distinctive black and white stripes on its body. These mosquitoes prefer warmer and more humid climates and have a need for clean, stagnant water to lay their eggs.  They feed during the day time through biting and may bite during the night at well-lit areas. These mosquitos also transmit Chikungunya, Yellow fever and Zika infection.

Infection

Dengue is a viral infection caused by four types of viruses of the Flaviviridae family; DENV-1, DENV-2, DENV-3 and DENV-4. Surviving from an infection of one of these viruses gives lifelong immunity to that particular virus type only and subsequent infections by other dengue virus types can increase the risk of developing Severe Dengue. Severe dengue is the more lethal form of dengue, separately known as dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS). Even though it much less common, Severe dengue can occur in both adults and children and according to Wolrd Health Organization(WHO), is a leading cause of serious illness and death among children in some Asian and Latin American countries. 

Symptoms

Dengue is a febrile disease. Meaning is it associated with an elevation of body temperature. Dengue should be suspected when a high fever (40°C/104°F) is accompanied by 2 of the following symptoms: severe headache, pain behind the eyes, muscle and joint pains, nausea, vomiting, swollen glands or rash. Symptoms usually last for 2–7 days, after an incubation period of 4–10 days after the bite from an infected mosquito.

Dengue hemorrhagic fever (DHF)  is characterized by increased vascular permeability, decreased blood volume (hypovolemia) and abnormal blood clotting mechanisms. DHF is a potentially deadly complication with symptoms similar to those of dengue fever, but after several days the patient becomes irritable, restless, and sweaty. The Dengue Shock Syndrome (DSS) is characterized by bleeding that may appear as tiny spots of blood on the skin (petechiae) and larger patches of blood under the skin (ecchymosis).

Prevention and control

There are no specific treatment of Dengue and the treatments usually given are based on dengue-like symptoms, therefore it is important to seek medical care as soon as any symptoms are noticed.  

The Dengue vaccine, CYD-TDV in its live attenuated form, has been shown in clinical trials to be effective and safe in persons who have had a previous dengue virus infection, but carries an increased risk of severe dengue in those who experience their first natural dengue infection after vaccination. World health Organization (WHO) recommends countries to do a pre-vaccination screening, based on sensitivity and specificity of available tests and of local priorities, dengue epidemiology, country-specific dengue hospitalization rates, and affordability of both CYD-TDV and screening tests, before any vaccination programs. So that only persons with evidence of a past dengue infection would be vaccinated. 

The most effective way of controlling and preventing dengue is to eliminate the transmission of dengue viruses through mosquitoes. Here are some ways you can help prevent and control dengue;

• Turnover or cover any objects that can collect water
• Cover overhead water tanks tightly to prevent mosquitoes from entering
• Clean and drain any stagnant or standing water at least once a week 
• Clean roof gutters by ensuring outlet remains open
• Use of insect repellant preferably twenty minutes after sunscreen application
• Wearing long sleeves and light-colored clothing
• Use of household insecticides, Aerosols, mosquito coils and vaporizers
• Ensure that house doors and window screens work properly
• Ensure bottles or plastic containers or any material that can collect water are properly disposed or recycled
• Improving community participation and awareness for sustained vector control

This article was reviewed by Dr. Ahmed Faisal, MMed (Pediatrics).

 

References

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http://www.adkhospital.mv/en/page/teamtalk/the-fight-against-dengue-should-go-on

https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue

http://www.denguevirusnet.com/dengue-haemorrhagic-fever.html

 

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