Dogs can help sniff out malaria, finds new study

Dogs can detect malaria by sniffing people’s socks. Study says the animals appear able to identify people infected with the disease even if they are not showing symptoms


Dogs possess a sense of smell many times more sensitive than even the most advanced man-made instrument. Just how powerful is a dog’s nose?

Powerful enough to detect substances at concentrations of one part per trillion – a single drop of liquid in 20 Olympic-size swimming pools.

With training, dogs can sniff out bombs and drugs, pursue suspects, and find dead bodies.

And more and more, they’re being used experimentally to detect human disease – cancer, diabetes, tuberculosis, and now, malaria – from smell alone.

New research shows that dogs can diagnose the infection quickly, accurately, and in a non-invasive way. Steven Lindsay, a public health entomologist at the Department of Biosciences at Durham University in the United Kingdom, is the lead investigator of the new study.

Lindsay summarised the findings at the American Society of Tropical Medicine and Hygiene (ASTMH) Annual Meeting, which this year took place in New Orleans, LA.

“People with malaria parasites generate distinct odors on their skin, and our study found dogs, which have an incredibly sensitive sense of smell, can be trained to detect these odors even when it’s just on an article of clothing worn by an infected person,” said Lindsay.

The research is was presented on (Monday, 29 October 2018) at the American Society of Tropical Medicine and Hygiene Annual Meeting in New Orleans, USA.

Professor Steven Lindsay, said, “While our findings are at an early stage, in principle we have shown that dogs could be trained to detect malaria infected people by their odour with a credible degree of accuracy.”

He added, “This could provide a non-invasive way of screening for the disease at ports of entry in a similar way to how sniffer dogs are routinely used to detect fruit and vegetables or drugs at airports.”

“This could help prevent the spread of malaria to countries that have been declared malaria free and also ensure that people, many of whom might be unaware that they are infected with the malaria parasite, receive antimalarial drug treatment for the disease,” Lindsay explained.

The research was funded by the Bill & Melinda Gates Foundation. It was carried out by Durham University, the charity Medical Detection Dogs, the London School of Hygiene & Tropical Medicine (LSHTM) and the University of Dundee (all UK), the Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, and the National Malaria Control Programme, The Gambia.

Researchers from the MRCG and the LSHTM used nylon socks to collect foot odour samples from apparently healthy children aged five to 14 in the Upper River Region of The Gambia in West Africa.

Using a simple finger-prick test the children were also screened to determine if they had the malaria parasite Plasmodium falciparum in their blood.

The sock samples were transported to the Medical Detection Dogs charity in Milton Keynes, UK where two dogs, a Labrador-Golden Retriever cross called Lexi and a Labrador called Sally, were trained to distinguish between the scent of children infected with malaria parasites and those who were uninfected.

In total 175 sock samples were tested including those of all 30 malaria-positive children identified by the study and 145 from uninfected children.

The dogs were able to correctly identify 70 per cent of the malaria-infected samples. The dogs were also able to correctly identify 90 per cent of the samples without malaria parasites.

Lindsay stressed that the study was a proof of principle and more needed to be done, including testing the approach with real people rather than socks, and in different regions where there are different strains of malaria parasite.

Source: Medical News Today