Animals in Medicine – update

Here’s an update from (I think) 30/3/16:

Scientists in East Africa plan to exploit rats’ highly developed sense of smell to carryout mass screening for TB among inmates of crowded prisons in Tanzania and Mozambique. ..Apopo, with funding from the Unites States Agency for International Development plans to train more rats to carry out prison screening, which it expects to be faster and more reliable than existing methods. Apopo says the rats undergo a rigorous training process that begins when they are 4 weeks old. they are introduced to various stimuli and learn how to interact with people. The rats learn to recognise the presence of TB in samples of sputum, mucus that it coughed up from the patient’s lower airways and rewarded when they succeed. “We believe our unique technology will prove itself as an effective mass-screening tool,” says Apopo’s US director, Charlie Richter. “WE then aim to expand the programme to all prisons, shanty towns factories and other settings in Tanzania.”

No, not in the usual role of vivisection, or drug testing, but something far more fascinating. This is from the i paper a few weeks ago:

Charles is an African giant pouched rat. He’s also a pioneer, one of 30 of his species that live and work in Morogoro, a few hundred miles west of Tanzania’s largest city, Dar es Salaam, on a programme to sniff out tuberculosis. … About 9 million cases are diagnosed each year worldwide. Antibiotics can cure it but it is still fatal if untreated. This is where Charles comes in. He and his fellow rats sniff cough-and-spit samples provided by suspected TB patients. The rats aren’t infallible, but they do detect about 70% of cases. This morning Charles has sniffed 100 samples, missing one that has been identified as positive by the public clinic but identifying 12 new suspect cases, which will now go for secondary testing.

Around the world, other animals, mostly dogs, are being used to screen human samples for disease; the TB-sniffing rats .. are the only animal disease-detectives in routine use. When medics first hear about the programme, they are often sceptical, says Christophe Cox, chief executive of Apopo, the Belgian-based organisation behind the project. But then they are shown the case detection data. the rats are saving lives every day.

The first “Lancet letter” (as they’re known in the dog-cancer detection community) came in 1989. Writing in the medical journal, a pair of dermatologists reported how a patient’s dog had constantly sniffed at a mole on her leg. Tests showed it was a malignant melanoma. It was removed, and she remained well.

The second Lancet letter was published in 2001. John Church, a British doctor, and his colleague reported the case of a 66-year-old man whose pet labrador, Parker, kept pushing his nose against the man’s leg, sniffing at a rough patch of skin that had bee diagnosed as eczema. It was found to be a basal cell carcinoma, which was swiftly removed.

The  Lancet letters got some, including John Church, thinking: might animal noses be quicker, or more accurate and/or cheaper than some high-tech cancer screening techniques?

In 2002 a former product designer from Belgium called Bart Weetjens began wondering about African giant pouched rats and TB. As a boy Weetjens had kept pet rats. After graduating and starting work as a product designer, Weetjens found himself preoccupied with the problem of landmines.In 1997 he secured a grant. There were setbacks. At first, the rats didn’t breed well in captivity, and it took a while to work out how to train them. But the landmine programme, which operates from Sokoine University of Agriculture campus in Morogoro, is a success. The rats are too light to set off mines. They can scurry across and search 200 square metres of ground in 20 minutes.

The walls of Dr Claire Guest’s office re covered with pictures of dogs. Behind her head is a portrait of a dog called Daisy. IN 2009, when she was researching whether a group of dogs could reliably sniff breast cancer inhuman samples, the dog started “acting weird”. “She kept jumping at me. She bashed at me a few times. I felt where she’d bashed me” – Guest touches her chest – “ad I thought: there’s a bit of a lump there…” She discovered she had a deep-rooted malignant tumour.

Guest was chief executive of Medical Detection Dogs, a charity that she set up with support from Church, co-author of the second Lancet letter. It has 2 aims. Just before her diagnosis, Guest was teaching dogs to sniff, say, a low blood-sugar level in someone with diabetes. “But then Daisy did shat she did, ad I thought: this is something we just have to get to the bottom of.” Guest’s team is now working on major studies on breast cancer and prostate cancer.

Dr Georgies Mgode, head of Apopo’s TB programme in Tanzania, explains that, unlike with the cancer sniffing dogs, it is known what he rats are detecting. They respond to a combination of 6 volatile organic compounds. If the rats can detect TB at an earlier stage than ay other method, this could be a huge benefit. As for the rats, no matter what happens – “already they are saving a lot of people.”

This article comes from Mosaicscience.com, republished in i under a Creative Commons licence.

 

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