A curious little girl in Springfield, Mo., got an unpleasant surprise when she walked up to a car in a parking lot to greet an animal sitting inside it. The animal, a type of monkey known as a macaque, bit her on the forehead.
The parents of 8-year-old Tayce Nickel told the local TV station KY3 that she just wanted to see the car's unusual passenger.
"As we got out, Tayce, being 8 years old, wanted to see the monkey, so she got out, looked up at the monkey, said, 'Hi,' and [the person in the car] gave the animal just enough slack to where it could jump out, grab her by her hair, and bite her on the forehead," said Mike Weeks, Tayce's father.
The monkey's owner, Vicki Pulley, said her husband was in the car with the monkey, named Charlie. When Tayce reached into the car, she said, Charlie felt threatened and scratched her. There was no bite, she insisted.
Tayce's parents called local animal control officials, who decided to not confiscate the monkey, but did take it to a veterinarian for testing. Tayce, in the meantime, is taking antiviral drugs and antibiotics as a precaution.
Infectious disease experts say monkeys can carry the Herpes B virus, which can be transmitted through saliva and can be potentially deadly.
"Herpes B can lead to encephalitis, a swelling of the brain. The virus is in the saliva and can get into the brain," said Dr. William Schaffner, professor and chairman of the Department of Preventive Medicine at Vanderbilt University School of Medicine in Nashville, Tenn. "Fortunately, it's pretty rare."
Monkeys aren't the only animals able to spread serious illnesses to humans. Experts consider the diseases spread by the animals on the following pages -- ranging from reviled rodents to cute and cuddly family pets -- among the most serious:
Although encounters with bats are rare, they can also lead to serious illness.
"Bats can transmit rabies to people," said Schaffner. "That's pretty high on the list of serious illnesses spread by contact with animals."
The rabies virus is more often spread through contact with other infected animals, such as coyotes, foxes, raccoons and, sometimes, dogs and cats.
Rabies affects the central nervous system and, as it progresses, can cause confusion, hallucinations, partial paralysis and difficulty swallowing. If untreated, it is typically fatal within days after these symptoms appear.
While wild rabbits may seem as sweet and snuggly as their domesticated cousins, they can spread tularemia, an illness that can lead to serious respiratory problems. Tularemia is also known as rabbit fever.
Symptoms include sudden fever, chills, joint pain and progressive weakness. Infected people can also develop pneumonia and chest pain as well as trouble breathing.
"Wild rabbits are more apt to be encountered by hunters," said Dr. Gordon Dickinson, professor of infectious diseases at the University of Miami's Miller School of Medicine and chief of infectious diseases at the Miami VA Medical Center.
"Hunters now wear gloves and are more cautious, and the cases of tularemia have diminished," said Schaffner.
Birds can transmit a number of diseases. Among them is the bird flu, an illness that gained international attention back in the 1990s.
Avian flu is caused by a virus, H5N1, that can be contracted through handling infected birds. Since 1997, more than 120 million birds worldwide have died from the flu or after being destroyed to prevent the disease's spread. H5N1 is highly lethal in humans.
According to the World Health Organization (WHO), more than 300 people have died worldwide from avian flu since 2003, none of them in the U.S. To date, no human or bird in the U.S. is known to have contracted bird flu.
Another disease spread by birds is parrot fever, or psittacosis. Parrot fever is spread by breathing in the aerosolized dried feces infected parrot-like birds or by handling the birds themselves.
The symptoms of parrot fever include fever, chills, headache and in some cases, pneumonia.
The U.S. Centers for Disease Control and Prevention estimates there are about 50 to 100 cases of parrot fever per year.
"Imported birds are screened and treated, which has helped reduce those illnesses," said Schaffner.
|Groundhogs and Other Wild Rodents|
Groundhogs, ground squirrels and other wild rodents may carry fleas infected with the bacterium that causes bubonic plague. If someone is bitten by an infected flea, they may develop plague.
Most cases of plague in the U.S. happen in only a few parts of the country: northern New Mexico, northern Arizona, southern Colorado, California, southern Oregon and western Nevada.
It's the same bubonic plague that decimated 14th century Europe, characterized by swollen glands called buboes. While the infamous "Black Death" killed hundreds of millions of people, today, there are about 1,000 to 3,000 cases worldwide every year and only about 10 to 15 cases in the U.S. There have been a number of reported deaths in the U.S., including a University of Chicago biology professor who died after being accidentally exposed to the plague bacterium in his lab back in 2009.
|Mice and Rats|
Historians widely believe that rats were the cause of the Black Death, and these furry urban scourges are also known to carry other harmful microorganisms.
Among them are rat-bite fever, a disease that can be caused by two different bacteria. Humans can contract rat-bite fever by either consuming contaminated food or water or through bites. Symptoms vary depending on the type of illness present.
"Rats carry more bacteria than mice, but mice can also transmit certain diseases," said Dickinson.
One of the most well-known is hantavirus. Hantavirus can lead to an illness that starts out mimicking the flu, but as it progresses, it can cause fluid to build up in the lungs and can be fatal.
Hantavirus is most common the the southwestern U.S. and is mainly carried by the deer mouse.
Rodents can also spread leptospirosis, a serious bacterial disease that can lead to kidney damage and meningitis. They can also transmit salmonella and giardia, which can cause gastrointestinal illness.
Reptiles are dangerous because they naturally carry salmonella on their skin.
"Much like we have staph on our skin, they have salmonella on theirs," said Emilio DeBess, Oregon state public health veterinarian.
Children are especially vulnerable to salmonella infection caused by reptiles.
"Animals are allowed to roam in the household or on the floor, and the organisms contaminate household surfaces and then children crawl on them and pick up the bacteria," DeBess explained.
Tiny turtles were once all the rage as pets, but back in1975 the U.S. enacted a ban on selling them in order to protect children from salmonella infection.
The CDC estimates that about 74,000 people contract salmonella-related illness from reptiles.
DeBess said cattle are associated with spreading three major illnesses: salmonella infection, E. coli infection and bovine encephalitis.
While the strain of E. coli known as O157:H7 is harmless to cattle, it can cause serious illness and even death in humans.
There have been a number of outbreaks linked to contaminated beef, including one in August 2011 in Michigan that claimed at least nine lives.
Bovine encephalitis, or Mad Cow Disease, causes a degenerative brain disease in cattle. It can be spread to humans if infected parts of the brain or spinal cord are consumed. It can lead to Creutzfeld-Jakob Disease, a degenerative and fatal brain disease in humans.
DeBess said it's difficult to determine how many cases of Creutzfeld-Jakob disease there are because it has a long incubation period.
Man's best friend could also be man's worst enemy when it comes to spreading diseases. In addition to sometimes spreading rabies, dogs can transmit parasites such as hookworms and roundworms.
They can also harbor other disease-causing organisms.
"Puppies are known to have campylobacter, salmonella and giardia," said DeBess.
Dog ticks can also carry the bacteria that causes Rocky Mountain Spotted Fever, which can be fatal if not treated.
Dog ticks, however, are not as notorious as deer ticks when it comes to spreading serious illnesses.
"Dog ticks don't transmit much to us," said Dickinson.
Deer ticks can carry Lyme disease, babesiosis and other diseases.
Despite their delicate purr and graceful gait, they wield a nasty bite.
"Fifty to 90 percent of cat bites get infected," said DeBess. "The mouth of a cat is pretty dirty."
Kittens can cause cat-scratch fever, which can cause fever and just a general sick feeling.
"On rare occasions, it can cause a bone infection or encephalitis," said Schaffner.
They can also spread rabies as well as tularemia and toxoplasmosis. The bacterium that causes tularemia and the parasite that causes toxoplasmosis are carried by other animals, but cats that are outdoors or otherwise come into contact with them can spread these diseases to humans.
People can contract toxoplasmosis by coming into contact with contaminated cat feces or consuming contaminated food or water.
"We always worry about it in pregnant women because it can also be spread from mother to fetus," said Dickinson.
Severe toxoplasmosis can cause damage to the brain, eyes or other organs.
Although cats, dogs and certain other animals are well-known disease spreaders, DeBess said these creatures are far from the only ones that are carriers.
"Potentially, all animals can spread diseases to humans," he said.