Entries in Rodents (3)


Rare Virus Kills Camper at Yosemite National Park

iStockphoto/Thinkstock(NEW YORK) -- A California man has died after contracting a rare virus in Yosemite National Park, according to officials from the California Department of Public Health.

The man, whose name has not been released, died in late July from hantavirus pulmonary syndrome, a flu-like disease spread to humans by exposure to rodent droppings and urine.  He had been camping in the California park's Curry Village Campground, where hantavirus has been detected in deer mice.

"Nearly 40 percent of people who develop this syndrome die from it," said ABC News' chief health and medical editor, Dr. Richard Besser.

Since hantavirus was first identified in 1993, fewer than 600 cases have been reported nationwide.Most people are exposed to the virus in their own homes, according to the National Institutes of Health.  But campers might have a heightened risk because of close contact with forest floors and musty cabins.

"You'd want to keep your campsite clean and food-free to keep mice away," Besser said.  "If you see mouse droppings in your cabin, that's probably not a good place to stay."

Like the flu virus, hantavirus can enter the body through the mouth and nose by breathing or ingesting in tiny particles of rodent feces, urine or saliva, according to the U.S. Centers for Disease Control and Prevention.  In rare cases, it has also been transmitted through rodent bites.

Hantavirus cannot pass from person to person through touching, kissing or blood transfusions, according to the CDC.

The man from Alameda County in the San Francisco Bay area is the first person to die from the disease contracted in the park, although two others were stricken in a more remote area in 2000 and 2010, officials said.

Hantavirus causes flu-like symptoms, starting with fever, body aches and fatigue, Besser said.  But in four to 10 days, "the severe symptoms kick in: shortness of breath and coughing as the lungs fill up with fluid," he said.

People with flu-like symptoms who might have been exposed to rodents or their nests should see their doctor immediately, according to the CDC.

"There is no specific treatment, cure or vaccine for hantavirus infection," the CDC warns on its website.  "However, we do know that if infected individuals are recognized early and receive medical care in an intensive care unit, they may do better."

Copyright 2012 ABC News Radio


Does Parasite Cause Rats to Love Cats?

Hemera Technologies/Thinkstock(STANFORD, Calif.) -- While the smell of cat urine is normally a turn-off for rats, a group of Stanford University researchers found a certain group of rats was actually attracted to that same odor.

Cat urine is naturally a warning to rats to stay away from an area where their natural predators may be lurking. But study rats infected by the parasite Toxoplasma gondii ("toxo" for short) didn't show that fear and, instead, parts of their brains associated with sexual arousal were activated.

"Normally, we would expect toxoplasma to knock out the normal fear function in the brain, but in these rats the parasite also tapped into the sexual arousal pathway, which is strange," said Robert Sapolsky, a professor of neuroscience at Stanford University and a co-author of the study.

The belief is that the mind-manipulating parasite acts that way in order to ensure its reproduction. Toxo can only reproduce in the guts of cats, so if an infected rat wanders into cat territory, then there's a possibility the cat will eat the rat and toxo can multiply.

"The parasite does actually alter the brain of its host," said Patrick House, a doctoral student who is also a co-author of the study. "The fact that a parasite can get into an organism, target its brain, stay there without killing the host and alter the circuitry of the brain -- we've seen this is insects and fungi, but it's the first time we've seen it in a mammalian host."

Toxoplasma affects a rat's amygdala, the part of the brain associated with fear and anxiety.

"It atrophies some of the neurons along the pathway associated with fear," said Sapolsky. "What we don't understand is how it affects the fear response and then accesses the sexual arousal circuitry."

Toxo does infect humans. Humans contract the parasite by consuming contaminated food or water or by coming into contact with cat feces.

"It doesn't make people sick at all. It just infects them and the body holds it off, and it becomes a latent infection," said Dr. William Schaffner, chair of the Department of Preventive Medicine at Vanderbilt University Medical Center.

But occasionally, Schaffner added, people who are immunocompromised can become ill. Pregnant women who are infected can also pass toxo along in the womb, which can cause serious complications, including still birth and neurological problems.

Previous research has linked to the parasite to schizophrenia and depression, but little is known about how it causes changes in human behavior. Some experts, including Schaffner, are skeptical that toxoplasmosis has a link to mental illness at all.

But while Sapolsky believes there could be an association between human behavior and infection with toxoplasma, that relationship needs additional study before making any firm conclusions.

His future research, he said, will once again focus on rats. He hopes to learn more about how this mysterious parasite affects rats and whether it plays tricks on the human mind, as well.

"One of the more interesting questions," he said, "is: How many cases are there of parasites manipulating human behavior?"

Copyright 2011 ABC News Radio


Woman’s Pet Rat Senses Debilitating Spasms

One of Dani Moore's former service rats. (Courtesy of Dani Moore)(HESPERIA, Calif.) -- Dani Moore of Hesperia, Calif., owes much of what she can do in her life to a rat.

The rat, named Hiyo Silver, has the unique ability to feel when the 56-year-old Moore's body is just starting to shake because of muscle spasms. Because she suffered injuries to her spinal nerves, she can't feel those spasms until they become extremely bad. By then, it's sometimes too late to avoid a serious injury.

"Since I have osteporosis, if the spasms get too bad, they can fracture vertebrae, which has happened to me before."

When Hiyo licks her neck or face, Moore knows it's time to take action either by stretching her muscles or taking medication to stop the spasms. She keeps Hiyo on a leash atop her shoulder wherever she goes because she never knows when she'll get spasms.

"Before I got my service rat, I would sometimes spend weeks in bed because the spasms would not let up. I was so much more limited to where I could go or what I could do," Moore said.

Despite the freedom she's able to enjoy now, she wasn't always able to take Hiyo or her other rats with her anywhere. The Americans With Disabilities Act only recognizes dogs and miniature horses as service animals, meaning that businesses are only required to allow these animals onto premises. But back in March, Moore's home city of Hesperia voted to allow all species of service animals into local businesses provided they behave appropriately.

Hiyo isn't the only animal believed to be able to sense a human's physical ailments. Studies have shown that dogs may be able to sense when their diabetic owners are having trouble with their blood sugar. Other research has shown that dogs can sniff out cancer.

Experts say what animals sense is most likely a smell or some type of body language that alerts them that something is amiss.

"It can be as minute as a slight change in respiration, or the person just moves at a different pace, or he has a different look, or a smell -- it can be any of those things," said Dr. Marty Becker, a veterinarian in Idaho and author of The Healing Power of Pets.

In Hiyo's case, that signal is shaking from the very beginning of a muscle spasm. Moore said she first started using a service rat when her daughter was training them to provide therapy, meaning they're trained to assist with healing and rehabilitation.

"She noticed that one of her therapy rats was extremely sensitive to my spasms, so she trained him to tell me when I was starting to have them," Moore said.

"I never thought a rat would be this helpful," said Moore. "But I certainly can't say I would trade them for anything nowadays."

Copyright 2011 ABC News Radio

ABC News Radio