A Laurentian University researcher believes his innovation for killing mosquito eggs could go a long way toward fighting the Zika virus and other illnesses spread by the insects, such as dengue fever, all at a lower cost and with much less environmental impact than traditional control methods.



Prof. Gerardo Ulibarri recently completed a 10-month study in a remote Guatemalan community, in an area where the mosquito genus that spreads Zika and dengue is common, using Canadian-designed traps called ovillantas, made from 50-centimetre sections of old car tire and filled with a milk-based, non-toxic solution developed at Laurentian to lure mosquitoes, as well as a wooden or paper strip on which the females lay their eggs.



The strips were removed twice weekly, analyzed and the eggs destroyed using fire or ethanol. The solution was reused, as it now contained mosquito pheromone, which made it even more attractive as an egg-laying site, drawing even more females.



During the study, Ulibarri said, his team collected and destroyed more than 18,100 aedes eggs per month, using four ovillantas in seven neighbourhoods in the town of Sayaxche, Guatemala – almost seven times the number collected using standard one-litre bucket traps in the same study areas, and without the use of any chemical pesticides.



Results of the study, funded by the Canadian government through Grand Challenges Canada, appear Thursday in the F1000ResearchZika & Arbovirus Outbreaks online channel at f1000research.com/channels/arbovirus.



"One of the challenges was to see how the community would accept this Canadian technology and then help and become independent," Ulibarri said. "Let’s remember, these communities are sometimes marginalized, they do not get much help from the local government in the sense of caring for the community – they just go, they spray pesticides and that’s it – so there are a lot of people very sick all the time with dengue fever. If they are sick, they can’t work and if they can’t work, they can’t earn a living.



“The challenge was very high to do this in these remote communities where some people don’t even speak Spanish. So we took on this challenge and, with the help of the local community and health workers, it turned out to be very interesting. The results were awesome."



During the 10-month testing period in 2015, he said, there were no dengue cases in the community, and while Ulibarri stopped short of pointing to the use of only 84 ovillantas as the cause for that reduction, he saw it as a promising sign.



"There’s something going on there," he said. "That’s a problem for future studies, to establish the entomological effect of the reduction of the mosquitoes."



He’s confident, however, that the traps will "make a big dent, and even stop the spread of the Zika virus in the region, simply because there will be no vector, no mosquitoes that can transmit the disease, because we are destroying, continuously, the second generation of mosquitoes through the larva and the eggs."



There has been an explosion in cases of Zika in South and Central America, Mexico and the Caribbean since the first cases began showing up in Brazil last May.



Most people who contract the infection have no symptoms; those who do get sick experience such ill effects as fever, joint pain, rash and red eyes. However, the virus has been potentially linked in Brazil to thousands of cases of abnormally small heads in infants born to women who may have been infected while pregnant, as well as cases of Guillain-Barre syndrome, a neurological condition that can cause muscle weakness or even partial paralysis.



Targeting mosquito eggs using the ovillanta, Ulibarri said, is one-third as expensive as trying to destroy larvae in natural ponds and only 20 per cent the cost of targeting adult insects with pesticides, which also harm bats, dragonflies and the mosquitoes’ other natural predators.



"The natural predators of the mosquitoes increased – dragonflies, frogs, et cetera, and those that were helping us to destroy the aedes mosquitoes, which was very nice," Ulibarri said.



During earlier studies in Sudbury, he said, bees were spotted drinking the solution and frogs were seen swimming in the traps, eating mosquito larvae that had already hatched.



Ulibarri first began work on the project in 2006 in conjunction with the Sudbury and District Health Unit, to target mosquitoes responsible for the spread of West Nile virus in North America.



"They were spraying pesticides all over the city, trying to control the amount of mosquitoes and West Nile virus transmission," Ulibarri said. "They asked me if I could come up with an idea to reduce the amount of pesticides that were used to control the transmission."



During studies in Sudbury, he said, researchers found they could reduce the populations of certain mosquitoes by as much as 90 per cent.



"We wanted to see if this methodology could be extrapolated to other species in other parts of the world."



A year-long study using 50 traps in Petatlan, Mexico, reduced aedes populations by around 70 per cent, paving the way for the Grand Challenges Canada-funded study in Guatemala.



"Canadians have proudly funded this innovation and hundreds of others that have improved the lives of the world’s most vulnerable people," said Liam Brown, from Grand Challenges. "We’re really excited about this one. It’s a simple, affordable, effective innovation that kills the spawn of an insect that, in many parts of the world, presents some of the greatest risks to human health."



bleeson@postmedia.com

Twitter: @ben_leeson

