A landmark trial could pave the way for the potential eradication of pest mosquitos across the globe after a bacteria was successful in sterilising up to 80 per cent of the disease carrying insects.
The trial, the first of its kind conducted in the southern hemisphere, revealed the selected bacteria was successful in sterilising and eradicating the Aedea aegypti mosquito – the same insect responsible for carrying Zika, yellow fever and dengue – from trial sites in Northern Queensland.
The international trial was a collaboration between the CSIRO, University of Queensland (UQ), Verily Life Scienes, QIMR Berghofer Medical Research Institute and James Cook University (JCU) and involved the release of three million Aedea aegypti mosquitos sterilised with Wolbachia bacteria at three trial sites in Queensland’s north.
The mosquitos were assessed over a 20-week period in late 2018 where they would search out wild females to mate where the bacteria would prevent the production of any offspring.
In one instance, one year following their release, scientists indicated one of the trial sites was almost devoid of mosquitos.
CSIRO chief executive Dr Larry Marshall says the study was a breakthrough in mosquito control and could support the suppression and eradication of the pests in the future.
“Over 40 per cent of humans suffer from mosquito-spread diseases, so it’s an opportunity for Australia to develop environmentally-friendly mosquito control tools to tackle current and future mosquito incursions,” Marshall says.
“By working with Australian and international partners, we can tackle two of Australia’s greatest challenges at once – health and security – with breakthrough research translated into effective global export solutions.
“CSIRO is leveraging great Australian science to create new technologies to make this approach more cost effective and suitable for the climates of less developed countries that suffer most from mosquito-borne viruses, strengthening and protecting our region.”
UQ Associate Professor and CSIRO scientist Nigel Beebe says the trial has paved the foundations for future suppression of the species.
“During the trial, we saw over 80 per cent of the mosquito population suppressed across our three trial sites,” Beebe says.
“When we surveyed the sites the following year, we were very encouraged to see the suppression still in effect, with one of our most productive towns for Aedes aegypti almost devoid of this mosquito with a 97 per cent reduction across the following season.
“One year on, the mosquito population at the second trial site remained substantially suppressed, while the population fully recovered at the third site.
“We are currently investigating the differences observed in the following mosquito season as they are incredibly informative in further developing this technology and in modelling how we could remove this exotic virus-transmitting pest in other locations worldwide.”
Already, techniques from the trial are being used to support mosquito suppression programs in French Polynesia as well as in the Hunter region of northern New South Wales.
Aedes aegypti mosquitos are one of the world’s most dangerous pests given they are found on every continent apart from Antarctica and can spread diseases and infecting millions every year.
The trial included the need to produce 20 million mosquitos, which was performed at JCU’s Cairns campus.
The process used, known at Sterile Insect Technique, has been common in insect suppression since the 1950s however few trials had considered, or executed, the technique on mosquitos.