2015: deadly dengue outbreaks across Asia

Image courtesy of IFRC

Hospitals across Asia struggle against soaring dengue cases

Malaysia, the Philippines, Thailand, Taiwan, Vietnam and India are some of the worst hit countries. According to the World Health Organization, Malaysia reported more than 107,000 cases and more than 293 deaths as of 21st November, up nearly 18% from 2014. The Philippines, meanwhile, reported more than 142,000 cases and 411 deaths as of October 31st, an almost 50% rise in cases compared with 2014. And Vietnam reported 58,633 cases and 42 deaths up to the end of October – a sharp rise in close to 19,000 cases in the past month. Meanwhile, Outbreak News Today reports 195 deaths in Taiwan.

India has been hit hard too. Extended warm weather has led to more than 90,000 cases as of late November, more than doubling the around 40,500 cases the country saw during the whole of 2014. New Delhi and Punjab are worst affected, with New Delhi facing its worst dengue outbreak in almost two decades. Hospitals in the capital are being asked to increase dengue bed numbers as thousands flock to get tested for the disease, according to Firstpost.

Publicity raises awareness – and fear

In Thailand, 123,168 have been infected so far this year, according to Karen News. Like New Delhi, it is the worst outbreak for more than 20 years. The Bangkok Post reports that those infected include popular actor Thrisadee “Por” Sahawong. Publicising his case has had its pros and its cons: on the upside, it shows no one is immune to the disease; on the downside, it’s creating a sense of panic as people strive to understand the facts.

Dengue has been badly overlooked by Thai people. They simply don’t know what the symptoms are, how the virus is spread and the preventive measures they can take today – along with those that might be available in the future, including vaccination.

Understanding dengue

One key obstacle in the fight against dengue is a global lack of understanding about the tropical disease and how it spreads. Below are some interesting facts that might help:

Dengue comes in four different serotypes

According to the Centers for Disease Control and Prevention in the US, dengue is caused by any of four closely related serotypes of the dengue virus: DEN-1, DEN-2, DEN-3 and DEN-4.

Infection with one serotype does not protect you against infection from the others. In fact it has quite to opposite effect: multiple infections from different serotypes put you at greater risk for deadly severe dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS).

Asymptomatic people can pass dengue to mosquitoes

Three-quarters of people who catch dengue have few or no symptoms. Despite being asymptomatic, these people may play a key role in the dengue transmission cycle. The cycle starts with a mosquito catching the virus from an infected person. Mosquitoes are more likely to come in contact with infected people who are asymptomatic and going about their normal daily routine than people who are sick and bed-ridden or hospitalized when they catch dengue.

Research at the Institut Pasteur in Cambodia, the Institut Pasteur in Paris and the French National Centre for Scientific Research (CNRS) has shown that people with no clinical signs of dengue can pass the virus onto mosquitoes. “People with few or no symptoms – in other words the majority of those infected by dengue – may actually be contributing to the spread of the virus without realising it,” Louis Lambrechts, a CNRS scientist in charge of the Insect-Virus Interactions Group at the Institut Pasteur in Paris, told Infection Control Today.

Climate impacts dengue transmission

Many different factors influence the dynamics of dengue transmission; climate being one. Mosquitoes thrive in tropical climates: hot temperatures increase the survival and development rates of mosquito eggs and the female mosquitoes’ tendency to bite, and reduce the time it takes for dengue to develop within the mosquito; humidity improves adult mosquitoes’ and eggs’ chances of survival.

Unusually hot weather has caused an increase in dengue cases [in Taiwan], the Centres for Disease Control Taiwan told The Straits Times in September. “This year saw temperatures in Tainan and (the southern region of) Kaohsiung at their highest in 30 years,” Mr Chuang Jen-hsiang, CDC’s deputy director said.

Why we are all responsible

Fighting dengue is a communal responsibility. Governments and local authorities can only do so much to keep areas free from mosquito breeding grounds. Malaysian Health Minister Datuk Seri Dr S.Subramaniam explained why the public also has a role to play in helping combat the disease in an interview with the New Strait Times: “We can take various actions to fight dengue but if the public continue to litter and dump rubbish from the window of their apartment then all the efforts would be wasted.”

We spoke to Deepak Gunti, state entomologist with India’s Integrated Disease Surveillance Programme (IDSP) and Vector-borne Disease Control Programme (NVBDCP). He highlighted the importance of eliminating the vector’s ability to breed in the home. “The mosquito will breed in the standing water in our houses – in a plant pot or a cooler,” he explains. “We have to educate people to reduce the number of places where they can breed.”

We clearly need to help people learn about dengue. Will you help us raise awareness about the disease and how to prevent it?

IVM in Action: The guppy fish project

Even when resources are stretched to the limit, one shouldn’t lose hope. Integrated vector management (IVM) is one of the measures that can be put in place to help outsmart dengue. Together, its five elements will help us in our fight against the deadly disease:
IVM makes a difference

IVM can and does make a significant difference, especially if coupled with other approaches (like surveillance or effective diagnosis). Check out the graphic below to see IVM in action in Cambodia and Lao PDR. Learn how these communities brought the five elements of IVM together and see how each element contributes to the three vital components of their more efficient, more cost effective, and more sustainable vector control:

A mobilized community that has accepted the intervention and participates in the project: maintaining guppies in targeted water containers.
Organized guppy fish breeding that provides a continuous supply to the community.
A reliable guppy distribution system that includes restocking at the household level and regular project monitoring by community volunteers.

The project was financed by ADB, and was developed and implemented collaboratively by the Ministries of Health, the WHO WPRO, the WHO country offices in Cambodia and the Lao PDR, ADB, and HLSP.

How the 5 elements of IVM bring about long-term change

Imagine a world where malaria, dengue, and other vector-borne diseases are eliminated. How do we make that dream a reality? Studies (Bugoro et al 2011; Whittaker & Chang, 2012) have shown that larval control and environmental management might provide part of the answer. They allow us to build excellent complementary solutions based around the five elements of Integrated Vector Management (IVM):

Check out the graphic below to see IVM in action in the Solomon Islands. A river mouth blocked by a sandbar was creating stagnant water pools – an ideal environment for mosquitoes to breed. Under the stewardship of the Ministry of Health and with technical support of the World Health Organization, the local communities brought the five elements of IVM together when they constructed a novel vector control solution: an 82 m pipeline that took advantage of local seawater currents to naturally flush dammed rivers and streams and stop mosquitoes from breeding.

In the Solomon Islands, this environmental intervention controlled the primary malaria vector – the Anopheles farauti mosquito – at different stages of its life cycle. Just think about how similar systems might help communities in similar environments flush out Aedes aegypti mosquito breeding sites.

In images: Laos fights against dengue

For the people in Laos, dengue is simply an everyday reality. These images, taken in the days following ASEAN Dengue Day, show them as they battle dengue.

Join the fight and help free our tribe from dengue!

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Aware communities are the key to breaking dengue in Pakistan

When I was studying for my medical entomology degree at the Health Services Academy in Islamabad, Pakistan, I contracted dengue. I found out how excruciatingly painful and harmful this disease could be. After my recovery, I became very passionate about fighting dengue, malaria, and other infectious diseases. I knew the bite of one tiny mosquito could destroy a life, and I wanted to do everything in my power to prevent that from happening ever again.
Creating awareness
To combat dengue we need to create awareness and build the capacities of local communities, so that people can learn how to help themselves. A uniform response and early detection are needed.
In 2013, I investigated an outbreak of dengue in the Swat Valley, north of Islamabad, in which over 10,000 cases of dengue were reported to the directorate of Malaria Control. The conditions were really dire and 400 people died in the outbreak, dislocating entire communities and turning many children into orphans.
To prevent the further spread of the disease, we applied fogging – spraying insecticide that is non-harmful to humans – to the affected areas. We also informed the community how they could protect themselves, for example using mosquito nets while resting. The people were very welcoming and grateful for our support and organized seminars in the community on how to recognize the larvae and treat infected water supplies.
The graph above shows how many cases were reported every day in the Swat Valley. It is clear that the campaign was a huge success, as the Swat Valley communities developed very high awareness and resistance. For 2014, the data show that dengue is no longer a day-to-day issue.

A clear drop in dengue cases in the Swat Valley, 2013-2014 (all data courtesy of Jaipal Singh)

Coordinating efforts
Although the campaign in the Swat Valley was a success, what is missing is a coordinated, national response to dengue. A lot of progress has been made in the areas around Lahore, Karachi and Islamabad, but dengue keeps spreading to those regions that lack training and the capacity to fight it.
Vietnam, Indonesia, Sri Lanka, and Malaysia – countries that have decades of experience with dengue – all use GPS technology to map and track reported cases of dengue. As soon as a case occurs, they can send a rapid response team to deal with the contamination, which is a very efficient system for preventing further spread. Pakistan has learned many lessons from previous outbreaks of dengue, but it needs to develop a coordinated, cross-sector response to outbreaks.

Community efforts to prevent the spread of malaria, dengue and other vector-borne diseases.

Initiatives like Break Dengue are so important. We need the support and the attention of the international community, which is a huge boost for everyone involved in the fight against dengue and an enormous inspiration to the young students in universities.
Many people in the Western world don’t know about dengue and don’t sympathize with the victims, but we really have to show why people should care. Building awareness is the only way forward towards prevention.
Will you help us raise awareness to fight dengue? Spread the word on Facebook and Twitter.
About Jaipal Singh MS in Medical Entomology
Jaipal Singh holds a MS degree in Medical Entomology from the Health Services Academy in Islamabad, Pakistan. He specializes in mosquito vectors of infectious diseases such as malaria, dengue, and leishmaniasis. He is associated with the Directorate of Malaria Control in Islamabad and has four years of field experience reporting and preventing infectious diseases.