– People with malaria parasites produce special scents on the skin. We found that dogs that have a sensitive sense of smell can be trained to detect this odor. This also applies to the clothes used by people who are infected, said Steven Lindsay in the Department of Biosciences at Durham University in England and the principal researcher behind the new malaria study.
He recently presented his findings at the annual meeting of the American Society of Tropical Medicine and Hygiene.
Sniff on socks
Several hundred Gambia school children participated in the new survey. First, they underwent a general health examination, then they were tested for malaria parasites. After this they got a pair of socks for overnight use. The next day, the researchers collected socks, dividing them into malaria infection status for children. They only collected socks for children who contracted malaria without symptoms and fresh children's socks. The socks were then sent to England. Here they freeze while sniffing dogs are trained.
The sniff test is to distinguish between socks for children who are saturated and healthy. They have to sniff each pair of socks and freeze if they think they found malaria mites. If they don't smell something, they must continue.
Test results showed that the dogs managed to identify 70 percent of the socks of children infected with malaria, and 90 percent were healthy.
Malaria parasites mutate
The researchers said that the accuracy of the impact was impressive and that dogs were able to identify socks for children with lower infection status than those required by the World Health Organization (WHO) rapid test.
In general, malaria diagnosis is made using blood samples and microscopy. This can be time consuming and special skills are needed. You can also use a quick blood test, but this is quite expensive. They have a high level of accuracy.
The researchers realized that this was what was called proof of conceptstudy, to show that malaria can be diagnosed by dogs. They believe more that the accuracy of a sniffing dog can be as good as a blood test. Lindsey confirmed this because malaria parasites in children do not always have the same type when they pass through various stages of the disease. The smell they create on human skin then changes.
He pointed out that the tests currently used might also be short, because the malaria parasites mutate. Thus, parasites may not have the special protein needed for clinical trials to show infection
Furthermore, researchers believe that the ability of dogs to sniff to detect certain odors associated with malaria can be an inspiration in the development of artificial and artificial electronic noses that can smell disease.
Malaria guard dog on the border
Lindsey believes that sniffing dogs might help when health authorities want to check villages for malaria carriers who have no visible symptoms. By becoming a carrier, you can transfer malaria parasites to local mosquitoes. The only way we prevent today's spread is to test or cure everyone in the village.
Researchers behind the survey believe that sniffing dogs will work well at border crossings, in countries where malaria is almost eradicated. Lindsey is interesting on the island of Zanzibar, East Africa, where the elimination of malaria parasites has been difficult due to the flow of immigrants.
Too little accurate
Gunnar Hasle is an infectious disease specialist and operates Reiseklinikken in Oslo. He said that the initial hit rate of 70 percent was too low.
"This means that this method is not useful to find out if someone with fever has malaria, because it is unacceptable to conclude an error of 30 percent.
He also showed 90 percent of them were healthy, and that 10 percent got the wrong message about malaria.
"This is a very high number if this method is used to kiss a large number of healthy people," he said.
Blood tests in clinics, dogs on the border
Hasle also stated that indications of odor have been used for hundreds of years. It is possible, for example, to succeed in diabetes, by breathing the smell of acetone, or nail polish remover. Furthermore, it is possible to smell heart failure, because the spirit has a sweet smell.
"It has also tried to get dogs to diagnose lung cancer," Hasle said, referring to a survey from 2012. The results were almost the same as in malaria trials.
He believes that it is not possible to use dogs to diagnose clinics and it will be difficult to train enough dogs to meet those needs.
– Every health unit in the tropics must have access to diagnose malaria. So it's much easier to get a quick test that you can use after training is minimal than getting a trained dog.
He continued to believe that they could help in several cases, and supported the thinking of the researchers using sniffing dogs as guardians of malaria.
"The dog sniff can be used for mass screening of immigration to areas that have eradicated malaria," he concluded.