– Individuals with malaria parasites produce specific odors on the skin. We found that dogs that have a sensitive scent can be trained to detect these scents. It also applies to clothes used by infected people, said Steven Lindsay of the Department of Life Sciences at Durham University in the United Kingdom and principal investigator behind a new malaria study.
He recently presented his findings at the annual meeting of the American Society for Tropical Medicine and Hygiene.
I felt the socks
Many hundreds of Gambian students participated in the new research. First, they underwent general health checkup, then tested for parasite malaria. After that they took a pair of socks to use at night. The next day, the researchers collected the socks and spread them into the condition of infecting children with malaria. Only child-socks infected with malaria were collected without the symptoms and socks of fresh children. The socks were then sent to England. Here they were frozen, while flea dogs were trained.
The smelling test was meant to distinguish between socks for girls saturates from malaria and healthy children. They should be sneezed in each pair of socks and frozen if they think they have found malaria mites. If they do not smell something they have to go ahead.
The result of the test showed that dogs managed to detect 70% of the socks of children infected with malaria and 90% of the healthy ones.
The parasite of malaria is mutated
Researchers say that the impact accuracy is impressive and that dogs were able to identify socks for children with a lower incidence of infection than required by the World Health Organization (WHO) rapid tests.
Generally, the diagnosis of malaria is done using blood samples and microscopy. They may be time-consuming and need special skills. You can also use quick blood tests, but these are quite expensive. They have a high level of precision.
The researchers knew this was a so-called proof of conceptstudy, to prove that malaria can be diagnosed by dogs. They also believe that the accuracy of dogs can be as good as blood tests. Lindsey justifies this because malaria parasites in children are not always the same type as the various stages of the disease. The smell they create in human skin changes.
He points out that the tests currently used may also be short, as malaria parasites are mutated. Thus, parasites may not have the specific protein that is necessary for the clinical trials to occur
In addition, researchers believe that the ability of dogs to inhibit certain malaria-related scents may be an inspiration in the development of emerging and artificial electronic muscles that can smell disease.
The guard dogs of malaria at the border
Lindsey believes that dogs can help when health authorities want to control villages for malaria operators who have no visible symptoms. With the existence of a carrier, you can transfer malaria parasites to local mosquitoes. The only way we can prevent today is to try or treat everyone in a village.
Researchers behind the survey therefore believe that the dogs they kill will work well at border crossings in countries where malaria is almost eliminated. Lindsey draws on the eastern African island of Zanzibar, where the eradication of the malaria parasite was difficult due to the constant flow of immigrants.
Gunnar Hasle is an infectious disease specialist and operates the Reiseklinikken in Oslo. He says the preliminary 70% success rate is very low.
"This means that the method is useless to see if a person with a fever has malaria, as it is unacceptable to conclude errors at 30 percent.
It also highlights 90% of those who are healthy and 10% have an erroneous message about malaria.
"It's an unacceptably high number if the method is to be used to smell a large number of healthy people," he says.
Blood testing in the clinic, dogs at the border
Hasle also states that odor signs have been used for hundreds of years. It is possible, among other things, to achieve diabetes, breathing acetone odor or removing nail polish. In addition, it is possible to smell hepatic insufficiency because the spirit has a sweet smell.
"He also tried to get dogs to diagnose lung cancer," said Hasle, referring to a survey from 2012. The result was about the same as in the malaria test.
He believes it is totally impossible to use dogs to diagnose clinics and that it will be difficult to train enough dogs to meet the need
– Any health facility in tropical regions should have access to diagnosis of malaria. Then it is much easier to do quick tests that you can use after a minimum of training than to get trained dogs.
He believes, however, that he can help in some cases and support the researchers' minds to use flea dogs as guardians of malaria.
"Sniff dogs can be used for bulk testing to migrate to an area that has eliminated malaria," he concluded.