(CBSDFW.COM) – Forget catching a frisbee or fetching a ball; 2-year-old springer spaniel Freya has a new game to play: hunt the malaria.
Scientists have found that dogs can be trained to sniff out the malaria parasite in lab-based experiments. They say dogs could one day be trained to detect the disease in people, even picking out an infected person from a crowd of otherwise healthy individuals.
The experimental study was presented Monday at the American Society of Tropical Medicine and Hygiene Annual Meeting in New Orleans, United States.
Early stage trials were conducted at British charity Medical Detection Dogs, founded in 2008 to train specialist dogs to detect human diseases.
In a demonstration for the media, Freya was led by her trainer into a room where four sock samples, worn by malaria-infected children from Gambia in West Africa, were presented in containers for her to sniff. When she detected the scent of the parasite she sat down to receive a reward.
“These socks had just been worn for 24 hours, a very short space of time. But what we found was that dogs are able to detect a difference in the socks that have been worn by children who are infected with the malaria parasite and children who are malaria-free,” Dr Claire Guest, co-founder of Medical Detection Dogs, told Reuters.
“When you’re training a dog to find an odor you have to train them the rules of the game – some odors are ‘yes’ and some are ‘no’. And once you’ve taught them those rules you then start with the disease you want them to find. And the game is: find that odor, sit in front of it and I’ll give you a reward.”
All children appeared healthy but some were carrying Plasmodium falciparum – the malaria parasite – which was determined by a finger-prick test. In total 175 sock were used, including 30 from malaria-positive children. The controlled lab-based trials found the dogs had a success rate of about 70 percent when spotting the malaria-infected samples and 90 percent success rate for identifying samples without malaria.
Researchers believe the odor given off by the malaria parasite is attracting the mosquitoes which then spread the disease. Curiously, it’s this same odor the dogs are likely to be smelling.
“Recent studies have shown that parasitized red blood cells grown in dishes produce odors. And it’s these odor that are probably coming out that mosquitoes can detect,” said Professor Steve Lindsay, Principle Investigator of the study from Durham University.
“The dogs are picking up the odors so quickly and easily that if you actually had people carrying malaria parasites they’d probably have a really big odor signal. And it may be possible to pick someone out from a crowd that’s infected with malaria parasites.”
It’s still early days for the research, and the teams now want to conduct much larger trials to see if dogs can directly sniff out malaria in people, not just clothing samples. Dogs, they say, could offer a quick, non-invasive means to stop malaria parasites crossing boarders by positioning specially trained malaria-sniffing dogs at ports of entry.
According to the World Health Organization, since 2000 six at-risk countries have been certified malaria free. Despite this they have warned that global progress against malaria is stalling and could be reversed if momentum in the fight to wipe it out was lost.
The disease infected around 216 million people worldwide in 2016 and killed 445,000 of them. The vast majority of malaria deaths are in babies and young children in sub-Saharan Africa.
(The-CNN-Wire™ & © 2018 Cable News Network, Inc., a Time Warner Company contributed to this report. All rights reserved.)