Dogs trained to sniff out malaria on dirty socks
Dogs can sniff out malaria from a pair of dirty socks, scientists have discovered. A study by researchers from the London School of Hygiene and Tropical Medicine (LSHTM) and Durham University found they can identify patients with the disease with 70 per cent accuracy.
It suggests dogs could become another weapon in the fight against the disease which, despite significant reductions in the number of cases in the past two decades, remains the biggest killer of children under five in Africa.
The most up-to-date figures show that in 2016 there were 216 million cases of malaria worldwide, resulting in an estimated 445,000 deaths.
It’s hoped that by detecting if people are suffering from malaria earlier, sufferers could be cured by treatments, or isolated so that other people cannot be infected.
Scientists have only recently understood that patients with malaria parasites have a unique odour or “chemical footprint,” and researchers decided to test whether dogs’ highly sensitive noses could detect this.
Several hundred children in The Gambia took part in the study, and after being checked for general health and sampled for malaria parasites, were given a pair of socks to wear overnight.
The socks were then collected and sorted according to which children were infected with malaria and which were not. Only socks from children who were uninfected or those whose blood was shown to contain malaria parasites were chosen for the trial.
The socks were then sent back to the U.K. and stored in a freezer while the dogs, pro- vided by the Medical Detection Dogs charity, were trained. Sally and Lexie, a Labrador and a Labrador-golden retriever cross, took part in the trial.
In the trial — the results of which were unveiled earlier this week at the annual meeting of the American Society for Tropical Medicine and Hygiene in New Orleans — the socks were placed on a stand and the dog sniffed each one in turn. If the dogs couldn’t detect the malaria parasites, they moved onto the next one. If there was malaria present, the dogs froze.
Sally and Lexie correctly sniffed out the socks worn by children with malaria parasites 70 per cent of the time and those without 90 per cent of the time.
“Dogs have an incredible sense of smell. Every disease smells different to a dog,” said Dr. Claire Guest, chief executive of the charity. “Malaria has its own unique odour and that’s what they were being trained to smell for.”
Researchers believe dogs could be useful in finding the last cases of malaria in communities that have almost eradicated the disease. They could also be deployed to screen travellers, just as dogs are used to sniff out drugs or other banned substances.