– People with malaria parasites produce specific odors in the skin. We have found that dogs that have a sensitive sensual smell can be trained to detect these odors. It also applies to clothes used by infected people, said Steven Lindsay of the Department of Biosciences at Durham University in the UK 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.
Sniffed on socks
Several hundred students from the Gambia participated in the new poll. First, they went through a general health check, then tested for malaria parasites. After that they received a pair of socks for use overnight. The next day, researchers squeezed their socks and divided them into malaria infection for children. They only collected socks for children infected with malaria without the symptoms and socks of fresh children. The socks were then sent to England. Here they were frozen while the dogs were trained.
The sniffing test was about to distinguish between socks for babies saturated with malaria and healthy ones. They should smell each pair of socks and freeze if they think they have found malaria mites. If they did not smell anything, they should go further.
The result of the test showed that dogs were able to identify 70% of socks of infected children with malaria and 90% of healthy ones.
The parasite of malaria moves
The researchers say that the impact accuracy is impressive and that dogs were able to identify socks for children with lower infection status than required by the World Health Organization's (WHO) rapid tests.
Generally, diagnosis of malaria is done using blood and microscopy samples. It can be time consuming and special skills are required. You can also use fast blood tests, but these are quite expensive. They have a high level of precision.
Researchers were aware of the fact that it was so-called proof of conceptto show that malaria can be diagnosed by dogs. In addition, they believe the dog's precision can be as good as blood tests. Lindsey justifies this because malaria parasites on children are not always the same type as those who go through different stages of the disease. The smell it creates in the human skin then changes.
He points out that the tests used today may also be short as the malaria parasites move. Thus, parasites can not have the specific protein needed for clinical tests to show infections
In addition, researchers believe that dogs' ability to detect certain odors associated with malaria can be a source of inspiration for the development of emerging and artificial electronic nozzles that can smell disease.
Dogs on malaria guard at the border
Lindsey thinks that sniffing dogs can be helpful when health authorities want to check out villages for malaria carriers who have no visible symptoms. Being a carrier, you can transfer malaria parasites to local mosquitoes. The only way we have to stop spreading today is to test or heal everyone in a village.
Researchers behind the survey therefore believe that odor dogs will work well at border crossings in countries where malaria is almost eradicated. Lindsey headed for the island of east Zanzibar, where the elimination of the malaria parasite was difficult due to a constant influx of immigrants.
Too little accurate
Gunnar Hasle is an infectious disease specialist and operates Reiseklinikken in Oslo. He says the 70% success rate is too low.
"This means that the method is useless to find out if a person with a fever has malaria because it is not acceptable to resolve the errors to 30%.
He also shows that 90% of the healthy and 10% receive an incorrect malaria message.
"It is an unacceptably large number if the method has to be used to smell a large number of healthy people," he says.
Blood test at the clinic, dogs at the border
Hasle also states that the odor indications have been used for hundreds of years. It is possible, among other things, to succeed in diabetes, by breathing acetone odor, or removing nail polish. In addition, it is possible to smell hepatic insufficiency, because the spirit has a sweet smell.
"It has also been attempted to make dogs to diagnose lung cancer," Hasle said, referring to a 2012 poll. The result was roughly the same as in the study on malaria.
He believes that it is entirely impossible to use dogs to diagnose clinics and that it will be difficult to prepare enough dogs to meet the need
– Any tropical health unit should have access to malaria diagnosis. Then it's much easier to get quick tests that you can use after a minimum of training than to get trained dogs.
However, he thinks he can help in some cases and supports the researchers' mindset of using naked dogs as malaria guards.
Sniff dogs can be used for mass immigration examination in an area that eradicated malaria, "he concluded.