The results to date show that 14 cynomolgus macaques exposed orally or intracerebrally to CWD remain healthy and symptom free after more than six years of observation, though the direct relevance to people is not definitive and remains under study.
Cynomolgus macaques often are used as research models of human disease because they are very close genetically to humans and are susceptible to several forms of human brain-damaging disease. Thus, it was decided to see whether exposure to CWD could induce disease in the macaques. The study appears online in the journal Emerging Infectious Diseases.
CWD is a type of brain-damaging disease known as a transmissible spongiform encephalopathy (TSE) or prion disease. CWD primarily affects deer, elk, and moose. Other TSE diseases include mad cow disease, or bovine spongiform encephalopathy (BSE) in cattle, scrapie in sheep, and sporadic Creutzfeldt-Jakob disease (CJD) in humans. Humans are not susceptible to sheep scrapie, but BSE appears to have infected about 200 people, primarily in Europe in the 1990s. Those findings provided the rationale for the present CWD-macaque study, which began in 2003.
"We plan to continue this study for at least several more years because, although the risk to macaques so far appears to be low, we know that these diseases can take more than 10 years to develop," says Bruce Chesebro, M.D., chief of the Laboratory of Persistent Viral Diseases at Rocky Mountain Laboratories (RML) in Hamilton, Mont. RML is part of the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH). The RML group is leading the study with collaborators from the Colorado Division of Wildlife; State University of New York Downstate Medical Center; New York State Institute for Basic Research in Developmental Disabilities; American Red Cross; and the University of Wyoming.
The findings by the RML group support published field studies done by others in regions of Colorado and Wyoming where CWD is endemic. Between 1979 and 2001, there were no significant increases in human TSE diseases despite the likelihood that hunters in those areas were exposed to CWD through contact with infected animal tissue and contaminated hunting tools such as knives and saws. Extensive laboratory data also supports a human species barrier against CWD.
Notably, the RML study also included identical testing in squirrel monkeys, which are genetically less similar to humans than macaques. Of 15 squirrel monkeys exposed orally to CWD, two displayed disease symptoms 69 months after infection. Of 13 squirrel monkeys exposed intracerebrally to CWD, 11 displayed symptoms between 33 and 53 months after infection. In symptomatic animals, the presence of the CWD agent was confirmed in brain, spleen and lymph nodes.
The results in squirrel monkeys were not surprising because a study elsewhere in two squirrel monkeys yielded similar results. The study by the RML group was different, however, in that it tested oral exposure to CWD and also studied eight CWD samples from different areas of the country. The results in squirrel monkeys confirmed that disease progression in that species appears consistent with disease progression in deer and elk, where severe weight loss is nearly always present.
"The fact that the squirrel monkeys, like the deer and elk, suffered severe weight loss suggests that chronic wasting disease might affect a common region of the brain in different species," notes Dr. Chesebro.
NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.
The National Institutes of Health (NIH)—The Nation's Medical Research Agency—includes 27 Institutes and Centers and is a component of the U. S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.
Reference: Race B et al. Susceptibilities of nonhuman primates to chronic wasting disease. Emerging Infectious Diseases. DOI: 10.3201/eid1509.090253.
Ken Pekoc | EurekAlert!
Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University
New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy