Their findings, published today in the journal Emerging Infectious Diseases, could lead to a better understanding of how viruses can cause cancer in animals and humans.
Necropsies conducted since March 2010 by scientists at the UC Davis School of Veterinary Medicine and UC Davis-led California Animal Health and Food Safety Laboratory found brain tumors in 10 raccoons, nine of which were from Northern California, the article reports. The 10th was sent to UC Davis by researchers at Oregon State University in Corvallis, Ore.
The common factor, found in all of the tumors, was a newly described virus, dubbed raccoon polyomavirus. Researchers suspect this virus contributes to tumor formation.
Polyomaviruses, which are prevalent but rarely cause cancer, do not typically cross from one species to another, so the outbreak is not expected to spread to people or other animals.
Two more raccoons with the tumor and the virus have been found in Yolo and Marin counties since September 2012, when the article was submitted to the journal for publication.
"Raccoons hardly ever get tumors," said study author Patricia Pesavento, a pathologist with the UC Davis School of Veterinary Medicine. "That's why we take notice when we get three tumors, much less 12."
Polyomaviruses are known to cause cancer under laboratory conditions. Less is known about their ability to cause cancer under natural conditions among people, because cancer often takes decades to develop.
Raccoons, with their short lifespans of two to three years, can provide a model for studying how these viruses spread outside the laboratory, how they cause cancer, and how easily they can jump from species to species.
Of the 12 raccoons affected, 10 were collected from Marin County. Pesavento said this does not mean the virus is limited to that county, or even to Northern California. Marin County is home to WildCare, an animal rescue and rehabilitation center that routinely submits animal remains for diagnostic testing, which might result in a sampling bias.
Other California raccoons were submitted by Lindsay Wildlife Museum in Contra Costa County and Sonoma Wildlife Rescue. Pesavento said her lab is collecting specimens and data from other sources across the country, looking for the virus and for raccoon exposure to it.
Pesavento said more research is needed to understand whether an environmental toxin, genetics or other explanation is contributing to the cancer. The study said that raccoons are exposed daily to human waste, garbage, environmental toxins and environmental pathogens as they travel along sewer and water lines.
"This is just the beginning of a story," said Pesavento, adding that high rates of cancer among wildlife are found in animals that live in close proximity to humans. "Wildlife live in our fields, our trash cans, our sewer lines, and that's where we dump things. Humans need to be guardians of the wildlife-human interface, and raccoons are important sentinel animals. They really are exquisitely exposed to our waste. We may be contributing to their susceptibility in ways we haven't discovered."
Infectious pathogens, such as viruses, are associated with 15-20 percent of all human cancers worldwide, according to the American Cancer Society. For example, human papillomavirus can lead to cervical cancer. Feline leukemia virus, for which UC Davis developed a vaccine, can cause cancer in cats. UC Davis also continues to study Marek's disease, a deadly virus in chickens that is providing insight into human cancer.
"This work to investigate natural associations of cancer verifies the importance of our One Health approach to addressing complex biomedical problems, such as viral causes of cancer," said Michael Lairmore, dean of the School of Veterinary Medicine, of which the UC Davis One Health Institute is a part. "Understanding how infectious agents may contribute to cancer in animals has provided fundamental new knowledge on the cause of cancer in people."
The study was funded through The Bernice Barbour Foundation, the UC Davis Center for Companion Animal Health, and Meadowview Foundation.The study's authors include lead author Florante Dela Cruz, Federico Giannitti and Leslie Woods from UC Davis; Eric Delwart from University of California, San Francisco, and Blood Systems Research Institute in San Francisco; Linlin Li from Blood Systems Research Institute; and Luis Del Valle from Louisiana State University in New Orleans.
About UC Davis
For more than 100 years, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has more than 33,000 students, more than 2,500 faculty and more than 21,000 staff, an annual research budget of nearly $750 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science. It also houses six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.
Kat Kerlin | EurekAlert!
Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care
Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses