QIMR Berghofer scientists in Brisbane have helped map the most complete genetic picture of the potentially deadly Aedes aegypti mosquito.The international breakthrough could help stop the spread of debilitating mosquito borne viruses.

Blah, Blah, Blah

On Open House QIMR Berghofer researcher, Dr Gordana Rasic delightfully calls the difficult parts “blah, blah, blah” when explaining to non-scientists how it is done.

Dengue fever link

Aedes aegypti, which is commonly known as the “dengue mosquito” in north Queensland, transmits dengue fever, Zika virus, chikungunya and yellow fever.

“It’s one of the most widespread disease-carrying mosquitoes around the world, putting at risk more than half the global population, which amounts to billions of people,” QIMR Berghofer researcher Gordana Rasic said.

Dengue Facts

More than 3.9 billion people in over 128 countries are at risk of contracting dengue, with 96 million cases estimated per year. The World Health Organisation fact sheet on Dengue says

• The infection causes flu-like illness, and occasionally develops into a potentially lethal complication called severe dengue.
• The global incidence of dengue has grown dramatically in recent decades. About half of the world’s population is now at risk.
• Dengue is found in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban areas.
• Severe dengue is a leading cause of serious illness and death among children in some Asian and Latin American countries.
• There is no specific treatment for dengue/ severe dengue, but early detection and access to proper medical care lowers fatality rates below 1%.
• Dengue prevention and control depends on effective vector (mosquito) control measures

International collaboration

Dr Rasic and Igor Filipovic, from QIMR Berghofer’s Mosquito Control Laboratory, are the only Australian scientists involved in the study that has been published today in the prestigious journal Nature.The collaboration involved 71 scientists from seven countries and was led by researchers from The Rockefeller University and Howard Hughes Medical institute in the US.The project mapped the genome of the Aedes aegypti mosquito, providing an almost-complete blueprint of its genes.

“ Unsure if all the puzzle pieces were there and how they fit.”

Chance to prevent disease

“This is a resource that will significantly improve our chances of controlling these mosquitoes and preventing the diseases they transmit,” Dr Rasic said.

“The group identified many new genes, such as those that affect who mosquitoes target to bite, and what genes make them resistant to insecticides.

“Our role at QIMR Berghofer was to find the genes that make the Aedes aegypti such efficient transmitters of dengue.

A puzzle with missing pieces

“For more than a decade, we’ve been hampered by a lack of a true understanding of the genetic makeup of these mosquitoes, which is when the first parts of the genome were mapped.

“It was like working with a really big puzzle and we weren’t sure if all the pieces were there and how they fit.

“We have now connected the pieces, which will accelerate the work of all scientists working on this mosquito.”

“Half global population at risk.”

Zika outbreak spurred work

The international collaboration was formed just over two years after the outbreak of Zika virus in South and Central America in 2016 and the World Health Organisation’s (WHO) declaration of a Public Health Emergency.

“We joined forces to work on it because no single researcher could have done it alone,” Dr Rasic said.

Urgent common goal

“The progress was very rapid and testament to how well scientists can work together when they have an urgent common goal.

“The Aedes aegypti is not just an overseas problem, these mosquitoes are responsible for all dengue transmission in mainland Australia.

Mosquito nets

Repellent-treated mosquito nets help a family sleep safe and sound, prevent deadly malaria, and provide powerful defence against one of the biggest global health problems. For $20 you can donate one to a family through World Vision Australia.

Nasty disease carrying pest

“They also threaten to invade Brisbane from their existing strongholds in central and Northern Queensland, and our ports and airports are under constant risk of these mosquitoes arriving from overseas.

“They’re a nasty pest and disease carrier and we were really excited to be part of such an important project that opens avenues for new ways to prevent the spread of deadly viruses.”

QIMR Berghofer’s Mosquito Control Lab is the largest and best-resourced in the southern hemisphere, allowing it to be a key partner in international mosquito control studies.

Quick Facts

• The Aedes aegypti mosquito is commonly known around the world as the Yellow Fever mosquito.
• There are no drugs available for combating mosquito-borne diseases such as dengue, Zika and chikungunya.
• The only dengue vaccine available offers very limited protection.
• Queensland Health has confirmed four dengue outbreaks in the state since 2017.
• According to the World Health Organisation (WHO), mosquitoes are one of the deadliest animals in the world and cause millions of deaths every year.
• According to the WHO, the worldwide incidence of dengue has risen 30-fold in the past 30 years, and more countries are reporting their first outbreaks of the disease.
• Chikungunya is in over 60 countries in Asia, Africa, Europe and the Americas.
• There have been only four WHO Public Health Emergencies announced since inception in 2005: swine flu 2009, polio 2014, Ebola 2014, Zika 2016.
• Zika virus outbreaks have been recorded in Africa, the Americas, Asia and the Pacific.

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Malaria

Approximately 70% of the world’s malaria burden is concentrated in 11 countries: 10 on the African continent, plus India. In 2017 there were 219 million malaria cases and 435 000 malaria deaths worldwide. Most of the deaths are of children under 5 years old.

WHO’s latest World malaria report shows that after an unprecedented period of success in global malaria control, progress has stalled. The report contains the latest available data on malaria policies, interventions and trends in all endemic countries.

Just add water test

On Open House we spoke to Dr Lee Alissandratos from the ANU Research School of Chemistry who has developed a simple “just add water” field test to diagnose malaria. The diagnostic kit, which can be easily transported and stored at room temperature, would be ideal for non-specialists in remote and resource-limited communities.

“Early detection of microorganisms that cause diseases, such as malaria, is critical in the global fight to control and eradicate some of the most devastating diseases around the world,” says Dr Alissandratos, who is a CSIRO Synthetic Biology Future Science Fellow.

• Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. It is preventable and curable.
• In 2017, there were an estimated 219 million cases of malaria in 90 countries.
• Malaria deaths reached 435 000 in 2017.
• The WHO African Region carries a disproportionately high share of the global malaria burden. In 2017, the region was home to 92% of malaria cases and 93% of malaria deaths.