Mycobacterium tuberculosis, the organism that causes tuberculosis in humans, also afflicts Asian (and occasionally other) elephants.
Diagnosing and treating elephants with TB is a challenge, however, as little is known about how their immune systems respond to the infection. A new study begins to address this knowledge gap, and offers new tools for detecting and monitoring TB in captive elephants.
The study, reported in the journal Tuberculosis, is the work of researchers at the University of Illinois Zoological Pathology Program (ZPP), a division of the veterinary diagnostic lab at the College of Veterinary Medicine in Urbana-Champaign. ZPP is based in Chicago, serving zoos and wildlife in the region and beyond.
More than 50 elephants in captivity in the U.S. have been diagnosed with tuberculosis since 1994, the research team reports. The evidence suggests that humans can transmit the disease to elephants and that elephants also may serve as a source of exposure for humans.
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 who led the new research. Most cases are found as a result of routine tests 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 are problematic, Landolfi said. Culturing mycobacteria takes time and is imprecise, while antibody responses may take weeks to develop and only indicate exposure, not necessarily infection or disease.
"We are always trying to improve and seek out new diagnostics that will allow for earlier, more accurate detection of this infection," she said. "We also need to find ways to monitor the treatment response."
In humans, exposure to tuberculosis rarely results in full-fledged disease. Most people's immune systems eradicate the bacterium or at least keep the disease at bay, Landolfi said.
"Less than 10 percent of the people who are exposed actually develop the disease," she said. In those cases, an inadequate immune response is almost always to blame. "Our hypothesis is that something similar is happening in the Asian elephants."
To test this, Landolfi and her colleagues looked at protein mediators that are part of an elephant's immune system. These small signaling molecules, called cytokines (SIGH-toe-kines), spur a cascade of cellular reactions that help the body fight infection. But detecting cytokines in elephants is difficult because antibodies that target elephant cytokines are not available.
"Instead of trying to detect the cytokines using antibodies, we said, 'why don't we take a step back and detect the nucleotides that code for those proteins?'" Landolfi said. "We're talking about messenger RNA (mRNA), which is used by the cell to synthesize these proteins."
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 analyzed 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."
If confirmed in future studies, the findings suggest a faster and more reliable way to diagnose TB in captive elephants, Landolfi said. The same kinds of tests are already used in humans.
"That is something that we want to move towards with elephants," she said. "Most of the elephants don't show us a lot of signs of disease, and even when they do appear to be sick, it's very non-specific."
This makes it difficult to diagnose them and to determine if treatment is working, she said. Having a new way to monitor the elephants' immune response would improve both tasks, she said.
Editor's notes: To reach Jennifer Landolfi, call 708-216-1185; email firstname.lastname@example.org.
The paper, "Differences in immune cell function between tuberculosis positive and negative Asian elephants," is available online or from the U. of I. News Bureau.
Diana Yates | University of Illinois
Diagnoses: When Are Several Opinions Better Than One?
19.07.2016 | Max-Planck-Institut für Bildungsforschung
High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences