From land mines to cancer, animals' incredible sense of smell is saving lives

In Tanzania, they use giant pouched rats to smell for TB and landmines. In Britain, they're researching why dogs are able to sniff out some sorts of cancer. Emma Young reports on how mammals' olfactory gifts are being harnessed

Emma Young 

Thursday 18 February 2016

In a small, hot room within a compound in Tanzania's southern highlands are three white-clad technicians, a glass-and-metal chamber and a rat named Charles. After being gently dropped into the chamber, Charles aims his snout at the first of a series of 10 sliding metal plates in the base. A technician swiftly opens it, revealing a small hole. Charles sniffs… and moves on. The hole is closed, and the next one opened. This time, he sniffs hard, scratching at the metal. The technician calls out: "Two!" Over by the window, a colleague holding a chart inserts a tick. It's highly possible that Charles has just saved someone's life.

Charles is an African giant pouched rat, a species endemic to sub-Saharan Africa. 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 (TB).

TB is a disease that can destroy the lungs. About nine million new cases are diagnosed worldwide every year, one-quarter of them in Africa. Antibiotics can cure TB, but it's fatal if untreated, and many patients are never diagnosed. This is partly because the 125-year-old microscope-based test used across Tanzania (and in many other cash-strapped countries) picks up only about 60 per cent of cases, a figure that drops as low as 20 per cent for people also infected with HIV.

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