New method developed for identifying tuberculosis in rhinos

Current testing for tuberculosis in rhinos is deemed to be unreliable, so researchers have developed a more accurate technique for detecting the disease.

Rhinos in a zoo. © Tina Caunt/EyeEm/Getty

Epidemics of diseases such as tuberculosis can have catastrophic effects on the populations of endangered species.

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Tuberculosis has only been detected in 22 rhinos during the past 53 years, but until recently, the methods for detecting the disease have been deemed unreliable and the disease can only be confirmed during autopsies.

Scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) and the Friedrich Loeffler Institute (Federal Research Institute for Animal Health) decided to tackle this issue and have developed a new method of identifying the disease, which involves collecting respiratory fluids from rhinos to examine the mycobacteria (a genus of bacteria).

“There are two groups of mycobacteria, differing in their hazardous nature,” says Professor Robert Hermes, an associate professor at Leibniz-IZW.

“On the one hand there are a few mycobacteria that can cause tuberculosis, and on the other, there are numerous, mostly harmless, mycobacteria not associated with any disease.”

The current methods of diagnosis often cause a false positive result, as they react with the harmless mycobacteria.

The new technique, which requires repeated lung lavage on the rhinos to collect the respiratory fluids, followed by analysing the genetics of the mycobacteria, was found to reduce the false diagnosis of tuberculosis.

The technique developed by Hermes and the team involves sedating a standing rhino, passing a bronchoscope through the mouth or nose into the lungs, and squirting some fluid into a small section, which is then collected for analysis. The entire procedure takes just 45 minutes.

The testing focussed on seven captive animals in European zoos, and the researchers suggest that it will improve decision-making on treatment, husbandry and euthanasia especially.

Tuberculosis is a zoonotic disease, which means it can be passed from animals to humans, and quick, reliable testing of the disease in rhinos will minimise the risk to zookeepers and handlers, as well as to other captive rhinos.

The researchers say that this technique may not be “practical on large scale under free range conditions, but might aid in determining the prevalence of live shedding animals [which could pass on the infection to other animals].”

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Read the full paper in PLOS One.