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 email@example.com.
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
New study: How stable is the West Antarctic Ice Sheet?
09.02.2016 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
Online shopping might not be as green as we thought
08.02.2016 | University of Delaware
Today, plants and microorganisms are heavily used for the production of medicinal products. The production of biopharmaceuticals in plants, also referred to as “Molecular Pharming”, represents a continuously growing field of plant biotechnology. Preferred host organisms include yeast and crop plants, such as maize and potato – plants with high demands. With the help of a special algal strain, the research team of Prof. Ralph Bock at the Max Planck Institute of Molecular Plant Physiology in Potsdam strives to develop a more efficient and resource-saving system for the production of medicines and vaccines. They tested its practicality by synthesizing a component of a potential AIDS vaccine.
The use of plants and microorganisms to produce pharmaceuticals is nothing new. In 1982, bacteria were genetically modified to produce human insulin, a drug...
Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock which attains an accuracy which had only been predicted theoretically so far. Their optical ytterbium clock achieved a relative systematic measurement uncertainty of 3 E-18. The results have been published in the current issue of the scientific journal "Physical Review Letters".
Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock...
The University of Würzburg has two new space projects in the pipeline which are concerned with the observation of planets and autonomous fault correction aboard satellites. The German Federal Ministry of Economic Affairs and Energy funds the projects with around 1.6 million euros.
Detecting tornadoes that sweep across Mars. Discovering meteors that fall to Earth. Investigating strange lightning that flashes from Earth's atmosphere into...
Physicists from Saarland University and the ESPCI in Paris have shown how liquids on solid surfaces can be made to slide over the surface a bit like a bobsleigh on ice. The key is to apply a coating at the boundary between the liquid and the surface that induces the liquid to slip. This results in an increase in the average flow velocity of the liquid and its throughput. This was demonstrated by studying the behaviour of droplets on surfaces with different coatings as they evolved into the equilibrium state. The results could prove useful in optimizing industrial processes, such as the extrusion of plastics.
The study has been published in the respected academic journal PNAS (Proceedings of the National Academy of Sciences of the United States of America).
Exceeding critical temperature limits in the Southern Ocean may cause the collapse of ice sheets and a sharp rise in sea levels
A future warming of the Southern Ocean caused by rising greenhouse gas concentrations in the atmosphere may severely disrupt the stability of the West...
12.02.2016 | Event News
09.02.2016 | Event News
02.02.2016 | Event News
12.02.2016 | Physics and Astronomy
12.02.2016 | Life Sciences
12.02.2016 | Medical Engineering