Asian Elephants Infected with Human Disease?
Asian elephants, as it turns out, can contract the human disease tuberculosis. But because these are animals, and not humans, they are often difficult to treat, and scientists behind a new study are trying to change that.
Surprisingly, more than 50 elephants in captivity in the United States have been diagnosed with tuberculosis (TB) since 1994, the research team reports. The evidence suggests that humans can transmit the disease, caused by the organism Mycobacterium tuberculosis, and vice versa.
When infected, elephants may appear healthy or only show general symptoms, such as weight loss, which can be associated with any number of ailments. Diagnosing and treating these massive mammals can prove a challenge because little is known about their immune system and how it responds to infection.
Most cases are only caught as a result of routine testing which involve checking the blood for antibodies against TB, or collecting samples from an elephant's trunk and culturing the bacteria it harbors, but these approaches can be imprecise or take too long to yield results.
"We are always trying to improve and seek out new diagnostics that will allow for earlier, more accurate detection of this infection," Jennifer Landolfi, veterinary pathologist and lead researcher, said in a statement. "We also need to find ways to monitor the treatment response."
Among humans, less than 10 percent exposed to the bacterium actually develop the disease, most likely because of an inadequate immune response.
"Our hypothesis is that something similar is happening in the Asian elephants," Landolfi said.
To test the theory, researchers decided to look at messenger RNA (mRNA) - involved in the immune response - instead of cytokine molecules, as is typical, since they are difficult to detect.
After looking at 8 TB-positive and 8 TB-negative Asian elephants and isolating their white blood cells, scientists found that both groups indeed did have differing immune responses to the disease.
"The cytokines were at higher levels in the positive animals," Landolfi explained. "That suggested that those animals had more of an immune reaction when they were exposed [to proteins associated with TB] than the animals that were negative."
This method, provided more detailed research is done, offers a quicker, more effective way of finding this human disease in all elephants, not just Asian elephants.
"That is something that we want to move towards with elephants," Landolfi concluded.
The findings were published in the journal Tuberculosis.