After two days of rain, six-year-old Jenny came down with a fever. Her mother, Esther, noted that Jenny had lost her appetite and that her skin was flushed, but wasn’t particularly concerned. She gave her paracetamol, which she believed would help the temperature to subside. The fever vanished the following day but returned the next.
Seven days after the symptoms first appeared, Jenny became drowsy, breathing rapidly and with a racing pulse. Then she began to vomit blood. Esther rushed her daughter to hospital where a doctor administered blood transfusions, but it was too late. The little girl died soon afterwards.
Jenny was a victim of a virulent form of dengue, a mosquito-borne contagion that’s rapidly becoming one of the country’s health problems.
“Before, it if the rainy season, we think that dengue is rampant, but this time, dengue is all year round,” Dr. Annabell Yumang, the director of the regional office of the Department of Health in Davao Region, told the media during a weekly forum some months ago. “Every month, we now have dengue cases.”
Now, there’s this disturbing report: Between January 1, 2023 to December 7, 2023, over 500,000 dengue cases and 750 deaths were reported from eight countries in the Western Pacific Region, according to the World Health Organization (WHO).
The Philippines topped the list with 167,355 cases and 575 deaths. Vietnam closely trailed with 149,557 cases and 36 deaths. Dengue is endemic in both countries.
“The global incidence of dengue has markedly increased over the past two decades, posing a substantial public health challenge,” said the United Nations health agency in a statement.
From 2000 to 2019, the WHO documented a ten-fold surge in reported cases worldwide increasing from 500,000 to 5.2 million. The year 2019 marked an unprecedented peak, with reported instances spreading across 129 countries.
After a slight decline of cases between 2020 and 2022 due to the recent pandemic and lower reporting rate, an upsurge in dengue cases was observed globally in 2023, the WHO reported.
Several factors are associated with the increasing risk of spreading the dengue epidemic. These included the changing distribution of the vectors, especially in previously dengue naïve countries; the consequences of El Nino phenomena in 2023 and climate change leading to increasing temperatures and high rainfall, humidity among others; fragile health systems during the COVID-19 pandemic, political and financial instabilities in countries facing complex humanitarian crises and high population movements.
“These factors also challenge the response to the epidemic and the risk of further spread to other countries,” the WHO pointed out. “Weakness in the surveillance systems in many affected countries may have led to delayed reporting and response and missed identification of symptoms, contributing to increased severe dengue outcomes.”
Actually, there are two kinds of diseases caused by dengue virus (DENV). There’s the classical dengue fever known for more than 200 years and is now resurging. The other new entity, dengue hemorrhagic fever (DHF), emerged in 1953 in Manila and in 1958 in Bangkok.
More than 90 per cent of the recorded deaths are in children under 15. “Dengue is a big problem among children because it is a major cause of illness and deaths,” says Dr. Lulu C. Bravo, a professor of infectious and tropical diseases.
Approximately 5 percent of all DHF cases are fatal. Without proper treatment, DHF fatality rates reach 15 percent more. “Although dengue is rarely lethal, its contribution to disease and ill health, especially among young children, should make dengue control a primary public health concern,” says Dr. Dominic Garcia, an infectious disease specialist.
The symptoms of dengue fever are now familiar to most people situated in areas where the disease is most widespread. Dengue fever usually starts suddenly with a high fever with chills or chilly sensations. Headaches, pain on moving the eyes, backache and muscle and joint pains are also common.
“Extreme aching in the legs and joints occurs during the first hours of illness,” explains The Merck Manual of Medical Information. “The temperature rises rapidly to as high as 40 degrees Centigrade, with relative bradycardia (heart beating less than 60 beats a minute) and hypotension (abnormal condition in which the blood pressure is too low for normal functioning). Fever and other symptoms of dengue persist for 48 to 96 hours, followed by rapid dropping of fever with profuse sweating.”
A rash usually appears 3 to 4 days after the start of the fever. The illness can last up to 10 days, but complete recovery can take as long as a month. Older children and adults are usually sicker than young children.
DHF is a potentially deadly complication that is characterized by high continuous fever (40-41 degrees Celsius) lasting 2-7 days that may be accompanied by loss of appetite, nausea, vomiting, abdominal pain, and subsequent evidence of bleeding like persistent red spots on the skin, nose or gum bleeding, coffee-ground vomit, and dark stools. The patient can go into shock (referred to as dengue shock syndrome).
In moderate DHF cases, all signs and symptoms abate after the fever subsides. In the worst cases, parents are advised to watch out for these danger signs: restlessness, cold clammy skin, sudden abdominal pain, having difficulty in breathing, and behavioral change.
Most people equate DHF with influenza and similar flu-like diseases. “There is usually rash in dengue while there is none in flu,” differentiates Dr. Allan Schapira, an epidemiologist. “Fever caused by dengue tends to last almost a week, while that of flu disappears after 3-5 days.”
Dengue virus is transmitted to humans through the bite of infected mosquitoes. The primary vectors that transmit the disease are Aedes aegypti and, to a lesser extent, Aedes albopictus mosquitoes.
DENV has four serotypes: DENV-1, DENV-2, DENV-3, DENV-4. “Infection with one serotype provides long-term immunity to the same serotype and only transient immunity to the other serotypes, after which secondary infections with a different serotype increase the risk for severe dengue,” the WHO explained.
Not all Aedes mosquitoes, however, are carriers of DENV, but only those that have bitten people infected with dengue fever. It takes about 8-10 days to multiply in the female mosquito’s salivary gland before the insect can transmit the virus to human beings.
Effective vector control is key to the prevention and control of the DENV, according to the UN health agency. Vector control activities should target all areas where there is a risk of human-vector contact, such as residences, workplaces, schools, and hospitals.
Right now, the WHO promotes Integrated Vector Management (IVM) to control Aedes species. Among the IVM practices are removing potential breeding sites, reducing vector populations, and minimizing individual exposure.
IVM should involve vector control strategies for larvae and adults (that is, environmental management and source reduction), especially monitoring water storage practices, weekly draining and cleaning of household water storage containers, larvicide in non-potable water using WHO-prequalified larvicides at correct dosages, distribution of insecticide-treated nets for fever/dengue inpatients to contain spread of the virus from health facilities.
The WHO also recommends personal protective measures during outdoor activities, which include topical repellents to exposed skin or the treatment of clothing and using long-sleeved shirts and pants.
“Indoor protection can also include the use of household insecticide aerosol products, or mosquito coils during the day,” the WHO said. “Window and door screens can reduce the probability of mosquitoes entering the house. Insecticide-treated nets offer good protection to people against mosquito bites while sleeping during the day.”
Since Aedes mosquitoes are most active at dawn and dusk, personal protective measures are recommended particularly at these times of day. “Personal protection measures and mosquito control should also cover workplaces and schools since the vectors are day-biting mosquitoes,” the WHO said.
Until now, there is no specific treatment for dengue infection. However, early detection and access to appropriate healthcare for case management can reduce mortality, as can rapid detection of severe dengue cases and timely referrals to tertiary healthcare facilities.
According to the WHO, most people with dengue have mild or no symptoms and will get better in 1–2 weeks.
The UN health agency reminded that people who are infected for the second time are at greater risk of severe dengue.
Severe dengue symptoms often come after the fever has gone away such as: severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums or nose, fatigue, restlessness, blood in vomit or stool, being very thirsty, pale and cold skin, and feeling weak.
“People with these severe symptoms, admission is necessary,” said Dr. Lulu C. Bravo, a professor of infectious and tropical diseases. “The patient is subjected to regular blood test monitoring until stable. Fluids are carefully computed and monitored plus as soon as needed, blood or blood components are transfused.”
