Dengue fever outbreaks expose weaknesses in regional health networks

Photo: Department of Foreign Affairs

Monsoon rains and a lack of adequate precautions is leading to a spike in cases of mosquito-borne dengue fever. Governments and international organisations should recalibrate their efforts to mitigate future epidemics.

By Zachary Frye

Dengue fever, an illness spread to humans through mosquitos, is spreading across Southeast Asia. Regional governments are declaring national emergencies but find it difficult to contain the disease.

The outbreak is exposing weaknesses in regional health networks. Although dengue is common in the region, health organisations and government agencies were unable to prevent an epidemic.

Moving forward, it is crucial that relevant actors coordinate precautionary measures. Only a strategy of prevention will mitigate the severity of future outbreaks.

Dengue fever is treatable, but it can also be deadly

Thailand’s Ministry of Public Health claims there were over 44,000 recorded cases of dengue fever in the country since January 1, 2019 – nearly double the number of cases at this time last year. 62 people have died.

Similar spikes can be found across the rest of Southeast Asia. Singapore has seen a fivefold increase. Cases in Laos rose from 6,400 in 2018 to over 14,000 this year. The Philippines is dealing with an 85% increase in its volume of dengue fever cases. Nearly 100,000 people have been diagnosed since January.

Although most people can fight the virus off within a week, about 1 out of 100 people die, even with early treatment.

About half of those infected with dengue do not display symptoms. The other half demonstrate a range of symptoms, including a high fever and severe joint and muscle pain.

In rare cases, it can lead to dengue hemorrhagic fever, causing severe bleeding and dehydration.

Humans can’t spread the virus, but they can transmit the disease to other mosquitos, making it more difficult to contain. There is no cure as of yet, but researchers are working on a vaccine.

What is behind the recent spike?

Cycles of dengue epidemics usually occur after changes in the virus strain lead to reduced immunity among affected populations.

Medical experts, however, are unable to give a definitive answer to what caused this year’s epidemic.

Dr Paul Tambyah, the president of the Asia-Pacific Society of microbiology and infection, argues that it’s unclear if the current spike is due to a different sub-strain of the virus or simply a result of increased breeding sites.

Others, like Dr Ooi Eng Ong from Duke-NUS Medical School, rule out increased mosquito populations as the culprit. Dr Ooi claims the virus itself may have mutated, which is different than a change in sub-strain.

“Such mutations have contributed to outbreaks in different parts of the world and may be responsible for the current rise in the number of dengue cases,” he added.

Governments and health organisations are playing catch-up

With medical experts unable to come to a consensus on the cause of the escalation, governments are left trying to mitigate its population’s risk factors without a clear understanding of what’s behind the outbreaks. 

Dengue vaccine clinical study, Ratchaburi, Thailand.
Photo: Sanofi Pasteur

Regional governments are urging their citizens to remove sources of stagnant water, dispose of waste properly, and keep their homes and living environments clean and dry.

Governments are issuing public warnings and epidemic notices, including lists of symptoms and transmission methods, urging suspected patients to seek medical attention.

While these efforts are important, cases will continue to rise unless a more comprehensive response can be implemented.

Prevention strategies will be crucial moving forward

In order to prevent the scourge of dengue, the most helpful development would be the dissemination of a vaccine. There are currently five dengue vaccine candidates in clinical development, and two of them are in the last phase of testing.

Although governments don’t have the means to ensure the safety and effectiveness of a vaccine through legislation, they can provide the right environment for further innovation.

To accomplish this, medical research needs to be prioritised in national budgets. Coordination between governments and health services providers will also be essential, both internationally and within domestic borders.

Coordinated efforts to spray international cargo holds, for example, would also help reduce cross-border transmission. Knowledge sharing among regional health leaders would also encourage proper prevention and disease management techniques.

In the short term, governments should follow the lead of Singapore in creating a Dengue Task Force. Trained teams can help decontaminate public places and buttress identification and control mechanisms.

Across the region, mosquito populations will increase during monsoon season. Stronger early-case detection can help manage potential outbreaks and keep the public informed on the hardest-hit locations.

There is little doubt that dengue presents a unique challenge to regional governments. It takes time to properly diagnose the root cause of an epidemic, and the virus won’t wait around for scientific consensus or the creation of a vaccine.

Transmission and mutation will continue until a lasting medical solution can be found. In the meantime, it is up to governments and public health organisations to lay the groundwork for a response based on prevention, not piecemeal attempts at containment.