Genetically modified mosquitoes could help reduce the incidence of dengue

Photo courtesy of Oxitec

A laboratory in the UK has taken a novel approach to helping reduce the spread of dengue: developing a genetically modified male mosquito whose offspring should in theory never reach maturity.
Dengue is only spread through bites from the female of its primary vector, the Aedes aegypti mosquito. Oxford-based Oxitec has added two extra genes to male mosquitoes. These males are released into the wild where females mate with them. Their offspring inherit the extra genes, which are intended to cause them to die before reaching adulthood. They are also born with a marker to identify them under a special light.
The approach is based on the premise that a reduction in the mosquito population will contribute to a reduction in the spread of the disease. Current field trials in Panama aim to build on ongoing trials in Brazil (and earlier trials in Malaysia and the Cayman Islands), assessing the safety and effectiveness of this approach in different environments.

Understanding the local context
Oxitec is collaborating with local partners in some areas of the world hardest hit by dengue. We spoke to Dr. Andrew McKemey, Head of Field Operations at Oxitec, about the technology and how they are working with local organizations to stop the spread of dengue.

Photo courtesy of Oxitec

The company’s work in Brazil, for example, began through collaboration with Dr. Margareth Capurro at the University of São Paulo. Today, Oxitec and the University are working with social nonprofit organization Moscamed to reduce the Aedes aegypti population in cities in the state of Bahia in eastern Brazil. “We are working with local collaborators and they are really key to what we do because we have to think about the cultural context in the different countries we are working in,” Dr. McKemey told us.
Transparency and engagement vital
The Oxitec insects are receiving a lot of attention on the international stage, from the research community and NGOs in particular. “We are doing something new, so there is a lot of attention and we have to be totally transparent,” notes Dr. McKemey.

Photo courtesy of Oxitec

At a local level, transparency is key to success too. It is vitally important that the people in the villages where the modified mosquitoes are released fully understand the work Oxitec is doing. Dr. McKemey explains their approach to working with the local community: “We have extensive community engagement programs with all our projects. We go door-to-door, hold town hall meetings, visit schools, all kinds of things. In Brazil, where they are really into their carnivals, we had people dressed as mosquitoes handing out leaflets.”
Resistance reflects dengue experience
Most places where Oxitec is working have a significant problem with mosquitoes and people are keen to see them brought under control. In places like Malaysia and Brazil, where dengue is a very apparent problem, people are very supportive.

Photo courtesy of Oxitec

However, in places such as the Cayman Islands – where Oxitec did its first work – dengue isn’t endemic. “Technologies such as this are more about stopping dengue coming in and gaining a foothold,” Dr. McKemey notes. “There isn’t as much first-hand experience of what dengue means, so there can be more resistance from locals who don’t foresee the problems.”
Alleviating concerns
“One of the most common concerns,” he continues, “is about the ecosystem. But Aedes aegypti originated in Africa so in most places around the world – and all the places we are working – it’s not indigenous.”

Photo courtesy of Oxitec

Another concern is that some modified mosquitoes could feed on waste containing tetracycline (an antidote for the effect of the additional genes), enabling the offspring to survive and pass on their GM traits.
To date, Oxitec has studied over 100 generations of its GM mosquitos, but the longer-term safety and efficiency of this approach still remains to be proven. The continuing field tests – including the ongoing releases in Brazil and Panama, and the planned releases in Florida Keys, which will be described in our next post – will answer some of the questions raised.

Gravitraps: One way to catch mosquitoes effectively

Because they are so vast in number, catching mosquitoes isn’t an easy (or cheap) task. In Singapore, the National Environment Agency has come up with one low-cost means of stopping mosquitoes – Gravitraps.

These cylinders, containing hay-infused water, attract female Aedes aegypti mosquitoes searching for a place to lay their eggs. If the mosquito lays eggs before getting caught in sticky tape, then a barrier of wire mesh prevents any hatchlings making it into the outside world.

The challenge – as outlined by The American Journal of Tropical Medicine and Hygiene in their 2013 study – is setting the right number of Gravitraps in the right place at the right time. The scientists placed Gravitraps in mid-rise apartment blocks in 11 dengue cluster areas in Singapore. Investigators checked them over a 16-week period, and Aedes aegypti mosquitoes were caught in all but one of the clusters. To be effective, they recommend that a large number of Gravitraps, at least five per apartment block, be deployed.

Being an inexpensive option for public health boards is an upside of the Gravitraps, according to the researchers. And results from trials in Singapore have been positive: they’ve been rolled out across housing estates earlier this year, and in construction sites – as featured on the news in March 2014.

Natural disasters led to increase in dengue in Solomon Islands

Flash floods across the Solomon Islands – an island nation that is home to around 600,000 people – led to a score of deaths, and thousands of islanders being displaced in April 2014. But homelessness is not the government’s only concern: the number of dengue cases has risen sharply. Dr. Lester Ross, the Solomon Islands’ Permanent Health Secretary reported that the last week of April alone had seen 163 new cases of dengue. Continue reading Natural disasters led to increase in dengue in Solomon Islands

Why we are all accountable for dengue’s economic burden

At 2.5%, the mortality rate for dengue may not be as high as other vector-borne diseases, but its impact can be just as devastating. The economic burden of the disease is undermining individuals, communities, and countries.

“Dengue is a high cost burden that’s undermining the population,” Amanda McClelland, Emergency Health Senior Officer at the International Federation of Red Cross and Red Crescent Societies (IFRC) explained when we spoke with her. “We see people in the villages getting dengue regularly and it costs them a lot: they’re losing money in wages and spending money on treatment.”

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Image courtesy of the IFRC

According to the IFRC advocacy report Dengue: Turning up the volume on a silent disaster, those affected often need to either sell their belongings or take out a loan to pay for medical treatment. The loss of income, decrease in productivity, and cost of medical expenses erodes the resilience of the affected household.

Despite its devastating impact, dengue has failed to grab the attention of the world’s media. Even in Asia Pacific where it is widespread, it only grabbed 9.1% of media attention for selected disasters in 2010.

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Image courtesy of the IFRC

“A lack of media attention means two things for us,” Amanda revealed. “Firstly, we can’t get the message out to the population so people’s awareness of dengue is low and that means they’re not able to take simple precautions to protect themselves and their families. And the lack of visibility also affects donor motivation and support for long-term prevention activities.”

Increased support from donors would casino online allow the Red Cross Red Crescent to sustain delivery of integrated community health services – including training and community engagement – that are needed for the environmental sanitation and hygiene promotion that protects people from the disease. “A lot of interventions are not expensive – it’s basic behavior change promotion and social mobilization – but extra donor money for that is always valuable,” Amanda added.

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Image courtesy of the IFRC

When there was a large scale five-country outbreak in the Americas last year, the IFRC released $1m from its disaster fund for the outbreak response but then couldn’t fund vital long-term prevention activities. This is often the case despite long-term programs, like one from the Sri Lanka Red Cross for example, producing excellent results. “In Sri Lanka volunteers were able to keep up community support,” shared Amanda, “encouraging environmental sanitation and the wearing of protection, and ensuring people knew when to go to the hospital for treatment.”

The lack of donor motivation is mirrored by a different focus in government investments; and the IFRC recognizes the important role governments have to play in controlling the disease. It is calling on them to strengthen their capacity to respond to the dengue caseload and harness integrated community health services.

Governments also have a wider role to play: in helping to improve disease surveillance, establish the true burden of dengue, support drug research, and sustain focus on the vital work that community workers and volunteers provide.

Amanda believes that all governments – including European governments – could increase their focus and participation on dengue as this is now an issue affecting everyone. “With the economic crisis, the emphasis on public health and vector control in some countries like Greece and Spain has gone down. That has had an impact even on malaria, so we would envisage that that would have an impact on dengue caseloads as well,” noted Amanda.

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Image courtesy of the IFRC

Break Dengue wants to see the economic burden on families reduced. By helping the IFRC turn up the volume, we hope to encourage donors and governments, as well as other stakeholders, to invest in helping combat this disease.

ASEAN Dengue Run raises community awareness

Image: Runners in the ASEAN Dengue Day run in Vietnam

The race is on to raise dengue awareness at the ASEAN Dengue Day run in Vietnam

ASEAN Dengue Day: Running for dengue awareness

Greater public awareness is critical to combatting Dengue, one of the fastest growing infectious diseases in the world with the Asia-Pacific region bearing some 75% of the global burden. So in 2011, the Association of Southeast Asian Nations established ASEAN Dengue Day, a region-wide advocacy event held on June 15 each year to demonstrate a commitment to the cause.

Break Dengue sat down with Dr. Hoang Quoc Cuong, the vice director of the training center of the Pasteur Institute in Ho Chi Minh City and organizer of the very first ASEAN Dengue Run, held in the Dong Thap Province of Vietnam as part of ASEAN Dengue Day this year. See what he has to say.

ASEAN Dengue Day is now in its fourth year, but this is the first Run?

First of many I hope. Since ASEAN and the World Health Organization (WHO) chose June 15 as ASEAN Dengue Day, we have held an annual regional meeting in one of the member countries, but organizing the run gives a tremendous boost to the main goal of raising public awareness. This is especially important in southern Vietnam, where the number of dengue cases has nearly doubled in the past five years, resulting in a significant number of deaths.

Since ASEAN and the World Health Organization (WHO) chose June 15 as ASEAN Dengue Day, we have held an annual regional meeting in one of the member countries, but organizing the run gives a tremendous boost to the main goal of raising public awareness. This is especially important in southern Vietnam, where the number of dengue cases has nearly doubled in the past five years, resulting in a significant number of deaths.

How many people took part?

It was a great turnout. As it is just a “fun run” of just 3 kilometers, more than 5,000 people were able to take join. Even the Deputy Health Minister, Nugyen Thanh Long was there. Most of the competitors were from the Dong Thap Province and included students from the University of Dong Thap and the medical college, as well as people from the young union, the police force and the army. Dengue Day was a Sunday this year, so we also saw many local people take part, running alongside representatives from other provinces.

So you count it as a success?

Oh yes, we want to keep the run as an annual event because it really brings dengue control and prevention home to people in the heart of the community. Our most important achievement was to spread the message that each family should spend at least 10 minutes each week killing larvae and mosquitoes. We hope to make it even bigger next year. Perhaps we’ll see 10,000 people take part!

How did you promote the event?

We hosted a press conference a week before the run at the Pasteur Institute, which attracted more than 50 journalists from all over the country. We also have a Facebook page with over 5,000 likes already. I think social media can be the most important marketing channel for this kind of event.

Are you winning the war against dengue in Vietnam?

I’ve worked in dengue prevention for more than five years. From my personal experience, dengue control is very difficult in southern Vietnam, and the vector control program in place over the past 50 years has seen very limited success. The most important factor is the communication strategy. Communication and education need to be used ahead of other control measures, especially in Vietnam. Then, perhaps, we could start thinking about applying legal measures to reduce larvae and mosquito density in the community, like the laws aimed at reducing tobacco use.

Does working together with other regions affected by dengue benefit the project?

I personally think that the war against dengue needs to involve all affected countries, targeting all generations on both a regional and global scale. We need to make as much of a social impact as possible.

Are there any new initiatives being used to spread awareness?

Yes, we plan to create more initiatives together with Sanofi Pasteur to combat dengue in this country and other ASEAN countries and we are also calling for more support from other agencies and resources.

The Tiny Enemies: teaching children about dengue

In May of this year, children across Vietnam learned how to reduce dengue transmission through a comedy play about a little girl’s adventures with giant mosquitoes. Hover over the image below to find out how “The Tiny Enemies” helped raise dengue awareness among 30,000 Vietnamese children.

Football fever and the World Cup: what it means for dengue

463615439 This year Brazil hosts the 20th FIFA World Cup, attracting up to half a million international visitors. For the areas around nine of the World Cup stadiums, records show that the main dengue season will have passed before the World Cup is held in June and July, although the risk remains in the northeast.

Still, the mass gatherings of fans may increase the potential for dengue transmission and supporters could introduce new genotypes to which local immunity is low.

It has been suggested that the Brazilian authorities should implement aggressive vector control in April and May, particularly around the northern stadiums, to decrease the number of dengue-transmitting mosquitoes. However the matches play out, the World Cup is at least an opportunity to evaluate the uptake of new public health information systems on dengue so they can be enhanced in the future and potentially applied in other countries.

Madeira: Europe’s dengue epidemic

Image of Madeira, location of first Europe dengue epidemic

2012 brought Europe its first dengue epidemic, in Madeira a region of Portugal

When people think of dengue fever, the words ‘Europe dengue outbreak’ probably don’t come to mind. Latin America and Southeast Asia are usually the first to be hit and are go-to references for the disease. It’s not surprising given that most of the countries where the disease is endemic are located in tropical regions.

But dengue managed to extend its reach, and a Europe dengue epidemic hit Portugal’s, Madeira, in 2012. The archipelago suffered a major outbreak between September 2012 and March 2013.

A 2013 report from the European Centre for Disease Prevention and Control (ECDC) shows the full extent of the epidemic: 2,168 probable cases, 1080 confirmed. Thankfully, no fatalities.

Dengue fever cases are rare in Europe. A case was recorded in Germany in 2010 (the disease had been acquired in Croatia) and there was a reported case in Nice, France, but Madeira’s was the biggest outbreak in Europe for some time.

Geographically, Madeira is off the coast of North Africa but as regular flights connect the archipelago with mainland Europe – and given the ability of the disease to travel – swift action was needed to contain the outbreak.

78 patients were diagnosed in other European countries with dengue infection after returning from Madeira

The report says Madeira is well connected with tropical countries where dengue is a major problem so there is no room for complacency.

Update: Learn more about Brazil’s first dengue vaccination program

When doctors first sounded the alarm in 2012, EU specialists arrived from the ECDC on a mission to set up a dengue surveillance system and help local authorities to mount a response against the disease.

Looking back on the Europe dengue outbreak, long under control, the ECDC says ongoing monitoring of the disease and mosquitoes needs to be put in place. It calls for greater efforts to control mosquitoes and encourages in-depth planning for handling even more serious epidemics in the future.

The take-home message for people in Europe is clear. In a globalized world where air travel is commonplace, “tropical” diseases can move between continents with ease.

Dengue is everyone’s problem.

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Can governments stop dengue with legislation?

Hand scope boat What’s the best way to combat dengue? Prevention is better than cure, but how can we prevent the spread of the disease?

In the Pakistani province of Sindh, the regional government has taken a hard line against dengue. Last year it introduced its Sindh Prevention and Control of Dengue Regulation 2013, which obliges everyone – from public officials to ordinary members of the public – to take responsibility for dengue. Failure to comply with the legislation can result in severe penalties.

It’s a radical approach, driven by concern over nearly 5,000 cases of dengue reported in the province during 2013. But is the threat of legal action enough to make people use insecticide or empty pots that could turn into mosquito breeding grounds. Will fear of a fine make doctors report suspected dengue cases within an hour?

Sindh is not the only province to use legislation to fight dengue: Punjab province takes its anti-dengue regulation so seriously that failure to comply with it is a non-bailable offence.

It’s a trend that can be seen all over the world: in Venezuela, there are calls to fine hospitals that fail to report cases of dengue. In 2012, Sri Lanka’s government introduced the National Dengue Prevention Act, although its critics claim that it doesn’t go far enough.

166151276 It’s hoped that the law can prove a powerful tool to combat dengue. But while legislation is important, can it really work without also educating people about dengue?

What do you think?

Dengue in the USA

178373271 Dengue isn’t a disease that only happens somewhere else. Public healthcare officials in Texas had a stark reminder of this in late 2013, when research showed that dengue has been present in the city of Houston since 2003.

So why didn’t anyone notice dengue at the time? Well, according to research published in Vector-Borne and Zoonotic Diseases even though Houston is an ideal environment for dengue-carrying mosquitoes, officials didn’t seem to think it was going to affect them. No one was looking out for dengue, so it took the city by surprise.
Healthcare officials in the US are going to have to change their attitude. There have already been isolated dengue outbreaks in Florida and Hawaii, and mosquitoes are expanding their reach. Some scientists blame a change in the climate for the presence of dengue-carrying mosquitoes in California’s Central Valley and San Francisco Bay. In 2013 there were even reports of dengue in New York. But there is no apparent logic to dengue’s return, and scientists are struggling to understand why some cities are worse hit than others.

Whatever the reasons, the emergence of dengue is a wake-up call for public health officials in the USA. This isn’t someone else’s problem anymore.