Infectious mosquitoes carry virus particles in their salivary glands and infect susceptible bird species during blood-meal feeding. Competent bird reservoirs will sustain an infectious viremia (virus circulating in the bloodstream) for 1 to 4 days after exposure, after which these hosts develop life-long immunity. A sufficient number of vectors must feed on an infectious host to ensure that some survive long enough to feed again on a susceptible reservoir host.
People, horses, and most other mammals are not known to develop infectious-level viremias very often, and thus are probably “dead-end” or incidental-hosts.
Dogs and Cats
West Nile virus does not appear to cause extensive illness in dogs or cats. There is a single published report of WN virus isolated from a dog in southern Africa (Botswana) in 1982. West Nile virus was isolated from a single dead cat in 1999. A serosurvey in New York City of dogs in the 1999 epidemic area indicated that dogs are frequently infected. Nonetheless, disease from WN virus infection in dogs has yet to be documented.
There is no documented evidence of person-to-person or animal-to-person transmission of WN virus. Because WN virus is transmitted by infectious mosquitoes, dogs or cats could be exposed to the virus in the same way humans become infected. Veterinarians should take normal infection control precautions when caring for an animal suspected to have this or any viral infection. It is possible that dogs and cats could become infected by eating dead infected animals such as birds, but this is undocumented.
There is no reason to destroy an animal just because it has been infected with WN virus. Full recovery from the infection is likely. Treatment would be supportive and consistent with standard veterinary practices for animals infected with a viral agent.
Cases of WN virus disease in horses have been documented, either by virus isolation or by detection of WN virus-neutralizing antibodies in 1999, 2000, and 2001. Approximately 40% of equine WN virus cases results in the death of the horse. Horses most likely become infected with WN virus in the same way humans become infected, by the bite of infectious mosquitoes.
In locations where WN virus is circulating, horses should be protected from mosquito bites as much as possible. Horses vaccinated against eastern equine encephalitis (EEE), western equine encephalitis (WEE), and Venezuelan equine encephalitis (VEE) are NOT protected against WN virus infection. A West Nile virus vaccine for horses was recently licensed, but its effectiveness is unknown. Horses infected by WN virus develop a brief low-level viremia that is rarely, if ever, infectious to mosquitoes. There is no reason to destroy a horse just because it has been infected with WN virus. Data suggest that most horses recover from the infection. Treatment would be supportive and consistent with standard veterinary practices for animals infected with a viral agent.
Through December 2001, CDC has also received a small number of reports of WN virus infection in bats, a chipmunk, a skunk, a squirrel, and a domestic rabbit.
Zoonotic diseases, or zoonoses, are those diseases which can be passed from animals to people. Some of these diseases can involve our pets. And, in some cases, the disease can also be passed from people to animals as well.
These are some of the most commonly encountered zoonotic diseases. This list is not exhaustive but includes the diseases that are the most dangerous and/or the most commonly diagnosed.
Rabies: Rabies is a disease that is transmissible to dogs, cats, humans and a wide variety of other animals. Pets are often exposed through contact with wildlife, particularly skunks and raccoons. Rabies is a deadly disease and most communities have laws that regulate the vaccination of pets for rabies in order to protect the general public.
Intestinal Parasites: There are several types of intestinal parasites that are common in dogs and cats. Some of these parasites, such as roundworms, hookworms and others, can also be passed to people.
Leptospirosis: Leptospirosis is a disease that is caused by a bacteria. It is passed through contact with body fluids, particularly urine. In some areas, it is frequently seen in dogs though in other areas it is far less common. It can be passed to people from infected pets through contact with their urine. It can also be passed to people through contact with urine from other infected animals, such as rodents.
Cat Scratch Disease: Cat scratch disease is also sometimes called cat scratch fever. It is caused by a bacteria, known as Bartonella henselae that is carried by fleas. Though passed to people through wounds caused by cat scratches, it is actually contamination of the wound with flea feces which may be found on the cat’s nails that causes the disease. A flea infestation is necessary in order for this disease to be passed to a person.
Ringworm: Ringworm is a fungal skin infection that is easily passed from pets to people and from people to pets. It is not, as the name seems to infer, caused by a worm. Ringworm is particularly common in puppies and kittens that are housed in less than ideal circumstances.
Salmonella, E. coli and Campylobacter: Salmonella, E. coli and Campylobacter are bacteria that can cause infection of the intestinal tract of dogs, cats and other pets. The disease can also be passed to people through contact with infected feces. It can be a concern with feeding raw food diets but many commercial food recalls are a result of contamination with Salmonella or E. coli as well.
Lyme Disease and Other Tick-Borne Diseases: Lyme disease is one of many diseases that can be carried be ticks, along with ehrlichiosis, anaplasmosis, Rocky Mountain Spotted Fever and more. Many of these diseases are zoonotic and can be passed to people, dogs and other pets. In most cases, disease is not passed directly from a pet to a person. However, pets can bring ticks into the home or yard that can transmit a zoonotic disease.
These are some of the zoonoses that are most commonly seen and diagnosed. There are many other zoonotic diseases in addition to these however.
Canine gastropexy is a surgical procedure performed on large breed dogs to prevent “gastric dilatation”, commonly known as torsion bloat. Torsion bloat is a life-threatening condition in which the stomach flips over and expands, trapping air and gases in the stomach. Because circulation to the stomach and spleen are cut off the dog goes into shock and dies.
In gastropexy, the stomach is tacked to the right side of the abdominal wall, so it cannot shift or twist. The procedure can be conducted laparoscopically as well.
Gastropexy is an effective preventive against death from torsion bloat in large dogs. In studies of dogs treated for bloat, of those with gastropexy, only 4.3% had a re-occurrence of bloat, compared to 54.5% of those dogs that did not have a gastropexy.
Human medicine has long recognized the health and cost benefits to early detection of disease. The good news is that pets are now living longer. The largest contributing factors to this longevity is advancement in veterinary medicine and increased owner compliance to veterinary recommendations. As is commonly known, pets age faster than we do, consequently health problems develop rapidly, especially in older animals. Fortunately, with through physical exams and modern diagnostic testing, we can detect the onset of disease and conditions early, when treatment and prevention are most effective.
Senior wellness programs provide an assessment of your pets overall health. Your veterinarian can give timely recommendations from issues ranging from arthritis, to dental disease to serious medical conditions. Remember, for optimal care your pet should at least be examined every six months, which is similar to a time span of 2 to 3 years in people.
Review the following early detection questionnaire to see if your pet has any “red flag” symptoms.
· Bad Breath or drooling
· Change in activity level
· Change in appetite or weight
· Change in attitude or responsiveness
· Change in sleeping patterns
· Change in Urination (amount of frequency)
· Change in water consumption
· Confusion or disorientation
· Constipation, diarrhea, or vomiting
· Heavy or rapid breathing at rest
· Lethargy or depression
· Lumps or bumps on or under skin
· Noticeable decrease in vision (bumping into furniture)
· Stiffness ( trouble jumping, climbing stairs, or walking)
There are five types of basic tests your veterinarian will use to evaluate wellness.
1. Complete Blood Count (CBC) – The CBC tests for anemia, infection, inflammation and overall healthiness of the blood cells.
2. Chemistry Test- The chemistry panel surveys many of the organ systems of the body to make sure they are working normally.
3. Thyroid Function Tests-These test are useful in diagnosing hypothyroidism (too little thyroid hormone) which is common in dogs and to a less degree horses, and hyperthyroidism (too much thyroid hormone) which is common in older cats.
4. Urinalysis- While some serum chemistries help evaluate kidney function, much more information is obtained when a urinalysis is done at the sametime. The urine sample is tested for several chemical components (glucose, protein, blood and more) , as well as any cells (wbc,rbc,epithelial etc) , and crystals.
5. Parasite Exam
A. Fecal- Hookworms,whipworms,round worms, coccida, giardia and other intestinal parasites can be detected with a stool sample.
B. Blood Serum is tested for presence of heartworms, and whole blood can be tested for parasite such as babesia, hemobartonella, and cytauxzoon.
Recognizing, diagnosing and treating early will improve quality of life and minimize financial cost.
John Bitter DVM
Argyle Veterinary Hospital
Dogs may play a larger role in health than realized. (Viktor Korotayev/Reuters)
Dogs have long had special standing in the medical world. Trained to see for the blind, hear for the deaf and move for the immobilized, dogs have become indispensable companions for people with disabilities.
But dogs appear to be far more than four-legged health care workers. Over the years, data on the larger role dogs play in health has trickled out from various corners of the world. One Japanese study found pet owners made 30 percent fewer visits to doctors. A Melbourne study of 6,000 people showed that owners of dogs and other pets had lower cholesterol, blood pressure and heart attack risk compared with people who didn’t have pets. Obviously, the better health of pet owners could be explained by a variety of factors, but many experts believe companion animals improve health at least in part by lowering stress.
Dogs, in particular, also have been shown to do remarkable things to improve the health of their owners. There are stories of dogs warning their owners of imminent health threats. In 2003, University of Florida researchers published a report in the journal Seizure noting that some dogs seem to have an innate ability to detect impending seizures. A 2000 report in the British Medical Journal examined case studies of dogs alerting people with diabetes of a coming hypoglycemic episode.
More recently, some studies have suggested dogs can be cancer detectors. In 2006, the medical journal Integrative Cancer Therapies reported how ordinary house dogs could identify breast and lung cancer patients by smelling their breath. A University of Maine study is testing whether dogs can sniff out ovarian cancer.
The role dogs play in medicine is celebrated in a new book, “Paws & Effect: The Healing Power of Dogs’’ (Alyson Books, 2007), which chronicles the numerous ways dogs contribute to our health. Author Sharon Sakson is a journalist and television producer, dog breeder and American Kennel Club dog-show judge. She admits to being biased about her subject matter, and she tends to write about the mundane details of dogs and their owners. Much of the evidence surrounding dogs and health is anecdotal, although Ms. Sakson includes many references to published research. The stories of service dogs are particularly impressive, as is the nascent research into dogs’ ability to detect cancer.
Ms. Sakson said she first began thinking about the link between dogs and health while reporting an earlier book on men and dogs. A few men she interviewed who had AIDS credited their dogs with playing a role in their improved health.
While Ms. Sakson says more studies are needed to show exactly what role dogs play in health, any dog owner already knows the benefits of their relationship with their pet.
“I went into it because I loved my dogs — they can do so much for our society,’’ said Ms. Sakson. “There’s no question they give us emotional support.’’
First case of VSV in Colorado; Delta County horse tests positive
LAKEWOOD, Colo. – Colorado has become the fifth state in the country to
have a confirmed case of vesicular stomatitis virus (VSV). A six-year-old
horse in Delta County tested positive for the disease, and the premise has
been placed under quarantine.
“VSV is not a human health issue, but it can have severe economic impact on
livestock owners, especially in the dairy industry,” said Wayne Cunningham,
state veterinarian at the Colorado Department of Agriculture. “The disease
usually doesn’t result in an animal’s death, but the main reason we watch
it closely is due to fact that the symptoms closely resemble foot-and-mouth
disease, which is much more economically devastating.”
In 2004, 148 horses, 119 cattle, four sheep and goats, and two alpacas were
infected with the disease, involving a total of 107 premises across the
Vesicular stomatitis is a viral disease that is usually not fatal but
causes painful lesions around an infected animal’s mouth, nostrils, teats
and hooves, symptoms similar to foot-and-mouth disease. Only laboratory
tests can differentiate the diseases. All disease samples from Colorado
were sent to the National Veterinary Services Laboratory in Ames, Iowa, for
VSV primarily affects cattle, horses, and swine. These blisters enlarge and
break, leaving raw tissue that is so painful infected animals generally
refuse to eat or drink and show signs of lameness. Severe weight loss
Since the disease is believed to be spread by insects, preventative
measures include keeping susceptible animals in dry corrals and stables,
using insecticides and insect repellents daily, providing good nutrition
and practicing best management techniques.
Prior to 2004, the last case of VSV in Colorado was diagnosed in 1998.
Although vulnerable, humans are rarely infected with the disease and
usually display flu-like symptoms. In addition to livestock, other
susceptible animals include llamas, goats and wild animals such as deer,
bobcats and raccoons.
As of July 12, the current number of premises quarantined because of VS:
Arizona 13; New Mexico 6;
Utah 4; and Colorado 1.
You can stay up to date on the case counts and states affected by going to
the Texas Animal Health Commission web site at : www.tahc.state.su and selecting the link to “USDA Vesicular Stomatitis Information Page.”