"In those cases, an inadequate immune response is almost always to blame."
New York, July 16 - Tuberculosis (TB) not only attacks humans but elephants too and scientists have now developed new tools to detect and monitor TB in elephants, including Asian breed.
When infected, elephants may appear healthy or only show general symptoms, such as weight loss that could be associated with a variety of maladies, said Jennifer Landolfi, a veterinary pathologist with University of Illinois' zoological pathology programme (ZPP).
In the study, Landolfi and her colleagues looked at protein mediators that are part of an elephant's immune system.
These small signaling molecules, called cytokines, spur a cascade of cellular reactions that help the body fight infection.
After developing the tools to detect cytokine mRNA in elephants, the researchers collected blood from 8 TB-positive and 8 TB-negative Asian elephants and isolated the white blood cells.
They exposed the cells to proteins associated with TB and then analysed the cell culture for expression of certain cytokines.
Their analysis showed that TB-positive and TB-negative elephants differed in their immune responses after exposure to TB bacterial proteins.
The cytokines were at higher levels in the positive animals, Landolfi said.
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.
The findings suggest a faster and more reliable way to diagnose TB in captive elephants, Landolfi concluded.
In humans, most people's immune systems eradicate the bacterium or at least keep the disease at bay.
Less than 10 percent of the people who are exposed actually develop the disease.
In those cases, an inadequate immune response is almost always to blame.
Our hypothesis is that something similar is happening in the Asian elephants, she concluded.