Mosquito-borne infection known as dengue is a growing global concern. According to the World Health Organization (WHO), there is a resurgence of epidemic dengue fever and an emergence of dengue hemorrhagic fever (DHF) or severe dengue.
The WHO estimates 50 to 100 million dengue infections and 500,000 severe dengue cases that require hospitalization worldwide each year. Majority of those affected by the virus are children and about 2.5 percent of the cases are fatal.
The global health institution also reported that severe dengue is a leading cause of death in children in some Asian and Latin American countries. The number of reported cases continues to rise as close to half of the world’s population or over 2.5 billion people in the world today are at risk of contracting the dengue virus.
Factors leading to global spread
Dengue is endemic in many parts of the tropics and subtropics. The Philippines being a tropical country is naturally at risk to the dengue virus. It means that dengue occurs every year in tropical countries with high incidence of rainfall which provides the disease-carrying mosquitoes a good breeding environment.
It is believed however, that the four dengue viruses (DENV 1, DENV 2, DENV 3, DENV 4) originated in monkeys and independently jumped to humans in Africa or Southeast Asia between 100 and 800 years ago. World War II was also thought to be crucial in the transmission of the Aedesmosquitoes to other countries where the disease is not endemic.
Severe dengue or DHF was first documented in the 1950s in epidemics in the Philippines and Thailand. Before 1970, only nine countries had experienced severe dengue epidemics. Today, dengue has become endemic in more than 100 countries in Africa, the Americas, the Eastern Mediterranean, South-east Asia and the Western Pacific with South-east Asia and the Western Pacific regions the most seriously affected. The risk of infection is higher in the urban areas of these regions. Statistics however show that cases of dengue infections are on the rise as well in the rural areas. Population growth, uncontrolled urbanization, inadequate water systems/supply, increase in air travel, and accumulation of non-biodegradable and other hard to dispose materials which collect water and provide breeding ground for mosquitoes are some of factors attributed to the increase and spread of the disease.
In the Philippines, the [[Department of Health]] (DOH) recently admitted that it has failed to limit the number of dengue cases to less than their initial target of 80,000 for the year 2012.
4S anti-Dengue campaign by the DOH
The Dengue Surveillance Report for January 1 to August 18 showed that dengue cases in the country already reached 80,745 this year. This figure is 14.14 percent higher than the number of cases recorded last year for the same period. The highest number of reported infections was in the National Capital Region with 16,087 cases. This was followed by Central Luzon with 12,401 cases and Calabarzon with 11,839 cases. A dramatic increase in dengue cases in other provinces was also reported. An increase of 219 percent was recorded in the Zamboanga Peninsula from 883 to 2,825 cases. Dengue cases in Western Visayas showed 194 percent increase from 2,121 to 6,242 cases; while the Davao region showed 151 percent, from 2,352 to 5,917 cases. In Northern Mindanao, there was 146 percent increase from 1,316 to 3,248 cases. The Bicol Region registered a 130 percent increase from 835 to 1,926 cases. Hospitals are encouraged by the DOH to create “dengue express lanes” because of this continuously growing number of dengue patients.
According to the DOH report, more than 50% of those infected with the dengue virus were male and about 40% were children between 1 to 10 years old. The report showed only 496 deaths due to dengue but this could be higher if all dengue cases especially in the rural and urban poor areas are reported and documented.
These figures are expected to go up especially with the recent flooding in the National Capital Region and nearby provinces and with the onset of the El Nino phenomenon. Stagnant waters, crowded relocation centers and waters in storage containers when there is a shortage in water supply will again give these mosquitoes opportunities to multiply.
How to fight dengue?
Until now, there is no treatment, cure or vaccine for dengue. A vaccine is currently under clinical testing in Thailand but it may take five to ten years before it can be used against the disease. Prevention and cleanliness is still the best way to fight dengue – prevent mosquito bites and eliminate potential breeding grounds of mosquitoes.
Infographic on Dengue by the DOH, PCOO
Most dengue cases are not serious and patients recover after around a week. Persons infected with dengue need to have plenty of rest, drink lots of fluids and take pain killers without aspirin and consult a doctor. A person who gets infected by a dengue virus will get immunity against that particular serotype. Unfortunately, a person who gets infected again by other dengue serotypes has a higher risk of developing severe dengue or DHF and Dengue Shock Syndrome (DSS) which can be fatal. Early diagnosis especially in severe dengue cases which require hospitalization would help a lot in the patient’s recovery and can reduce the possibility of death from more than 20 percent to less than 1 percent.
A person with dengue experiences high fever (40°C/ 104°F) accompanied by two of the following: severe headache, pain behind the eyes, muscle and joint pains, nausea, vomiting, swollen glands or rash. These symptoms usually last for 2 to 7 days. Infants and very young children do not exhibit all these symptoms in the initial stages, making dengue detection difficult right away. It is recommended that babies and young children with high fever for two days or more be brought to the doctor so they can be tested and diagnosed accurately.
Severe dengue according to WHO is a potentially deadly complication of dengue fever. Warning signs that include severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums, fatigue, restlessness, blood in vomit occur 3 to 7 days after the first symptoms and after a decrease in temperature (below 38°C/ 100°F). The next 24 to 48 hours of the critical stage can be fatal. Intravenous fluid replacement and blood transfusions are usually done to prevent deterioration and shock. If untreated, shock can lead to death within 24 hours, but if treated quickly with intravenous fluid replacement and blood transfusions, patients can recover.
Image from Flickr.com. Graphics from doh.gov.ph website. Some rights reserved.