(Press-News.org) Rare brain tumors emerging among raccoons in Northern California and Oregon may be linked to a previously unidentified virus discovered by a team of researchers, led by scientists from the University of California, Davis. 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 the UC Davis School of Veterinary Medicine
Leading Veterinary Medicine, Addressing Societal Needs: The School of Veterinary Medicine serves the people of California by providing educational, research, clinical service, and public service programs of the highest quality to advance the health and care of animals, the environment, and the public, and to contribute to the economy. For more information, visit www.vetmed.ucdavis.edu.
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.
Emerging virus in raccoons may provide cancer clues
2012-12-12
ELSE PRESS RELEASES FROM THIS DATE:
Researchers find algal ancestor is key to how deadly pathogens proliferate
2012-12-12
Long ago, when life on our planet was in its infancy, a group of small single-celled algae floating in the vast prehistoric ocean swam freely by beating whip-like tails, called flagella. It's a relatively unremarkable tale, except that now, over 800 million years later, these organisms have evolved into parasites that threaten human health, and their algal past in the ocean may be the key to stopping them.
The organisms are called Apicomplexa, but are better known as the parasites that cause malaria and toxoplasmosis—serious diseases that infect millions of people every ...
New method quantifies uncertainty in estimates of child mortality rates
2012-12-12
Measures of uncertainty should be taken into account when estimating progress towards Millennium Development Goal 4 (to reduce the mortality rate of children under 5 years by two thirds from the 1990 level by 2015) in order to give more accurate assessments of countries' progress, according to a study published in this week's PLOS Medicine.
Leontine Alkema and Jin Rou New from the National University of Singapore used a statistical method called bootstrapping to calculate uncertainty intervals for the estimates of mortality rates in children aged under 5 years and the ...
Prevalence of visual impairment in US increases
2012-12-12
CHICAGO – The prevalence of nonrefractive visual impairment (not due to need for glasses) in the U.S. has increased significantly in recent years, which may be partly related to a higher prevalence of diabetes, an associated risk factor, according to a study in the December 12 issue of JAMA.
"It is estimated that more than 14 million individuals in the United States aged 12 years and older are visually impaired ( END ...
Taxes on sugary drinks and high fat foods could improve health
2012-12-12
Taxes on soft drinks and foods high in saturated fats and subsidies for fruit and vegetables could lead to beneficial dietary changes and potentially improve health, according to a study by experts from New Zealand published in this week's PLOS Medicine.
Helen Eyles and colleagues from the University of Auckland and the University of Otago (Wellington) reached these conclusions by reviewing all relevant modelling studies that investigated the association between food pricing strategies, food consumption and chronic diseases (often referred to as non-communicable diseases, ...
Combination therapy may help decrease sleep apnea symptoms at higher altitudes
2012-12-12
CHICAGO – For individuals with obstructive sleep apnea traveling to higher altitudes (which may exacerbate symptoms), use of a combination therapy resulted in improvement in symptoms including reduced insomnia and better control of sleep apnea, according to a preliminary study published in the December 12 issue of JAMA.
As travel to the mountains for professional and recreational activities is increasingly popular, involving millions of persons worldwide, the estimated number of patients with obstructive sleep apnea (OSA) among mountain tourists is also high, and may ...
Long-term public health support needed to tackle infectious disease outbreaks
2012-12-12
Outbreaks of infectious diseases, such as swine flu (H1N1) threaten global health and should be considered by funding agencies and humanitarian organizations as development issues rather than emergency situations, requiring long-term support and investment, according to US experts writing in this week's PLOS Medicine.
The authors from several US institutions, led by Tiffany Bogich from Princeton University, reached these conclusions by reviewing nearly 400 serious international public health events. They found that the disruption to, or lack of, public health infrastructure ...
Industry sponsorship leads to bias in reported findings of clinical trials
2012-12-12
Studies reporting the results of industry sponsored clinical trials present a more favourable picture of the effects of drugs and medical devices than those reporting on non-industry sponsored trials, according to a new Cochrane systematic review. The researchers call for a rethink of the way that industry bias is handled in medical guidelines and reviews.
The outcomes of clinical trials influence the recommendations that doctors make about drugs and other medical interventions. Therefore, it is important that trials are designed, carried out and reported on without bias ...
Just a spoonful: Sweet taste comforts babies during injections
2012-12-12
The sweet taste of sugar may provide some comfort for babies during immunisations, according to a new Cochrane systematic review. Researchers found babies did not cry for as long if they were given drops of sugar solution before injections.
Between birth and 18 months, babies may have as many as 15 injections. It is not certain whether babies feel pain in the same way as older children and adults, or whether they are simply unable to express it. Recent evidence has proven they do feel pain and efforts have been made to reduce pain caused by injections through the use ...
Psychological therapies improve life for children with post-traumatic stress disorder
2012-12-12
Children suffering post-traumatic stress disorder (PTSD) as a result of traumatic events, including child abuse, may benefit from psychological therapies, according to a review published in The Cochrane Library. In the first systematic review of PTSD in young people, researchers found that children and teenagers diagnosed with PTSD showed signs of improvement up to three months following treatment and called for more studies to assess long-term benefits.
People who develop PTSD have usually experienced extreme traumatic events, such as abuse, war or natural disasters. ...
Resurrection of extinct enzymes reveals evolutionary strategy for the invention of new functions
2012-12-12
How does evolution innovate? We exist because our ancestors have had the ability to adapt successfully to changes in their environment; however, merely examining present-day organisms can limit our understanding of the actual evolutionary processes because the crucial events have been masked by the passage of aeons – what we need is a time machine. Scientists from VIB, KU Leuven, University of Ghent and Harvard have done the next-best thing; by reconstructing DNA and proteins from prehistoric yeast cells, they were able to directly examine the evolutionary forces that have ...