Wednesday, December 5, 2012

Parvovirus – An update

By Beth Davidow, DVM DACVECC
ACCES Medical Director

A week ago, we alerted referring veterinarians in the area to an uptick in the number of parvovirus cases we were seeing at ACCES’ two referral hospitals (Seattle and Renton). Word quickly spread to the greater community setting off an unexpected scare.

Parvovirus is a virus that causes vomiting and severe diarrhea. In addition, it can suppress the immune system and put animals at risk for secondary infections. It mainly affects puppies and can cause death if not treated appropriately. With treatment, which includes intravenous fluids, anti-nausea medication, antibiotics and plasma in severe cases, survival is 90%. Adults dogs can get the infection as well but often are less sick or may shed virus and not have clinical signs.

The virus is shed in stool and can live in the environment for weeks to months. It is extremely hardy and not killed by standard disinfectants – bleach is most effective. The virus can be passed from an animal shedding the virus, picked up on clothes, shoes, and other objects, and then carried to another animal.

Parvovirus is not a new infection. It is a virus we have known about for a long time and one of the first diseases for which we developed a vaccine for dogs. The vaccine is extremely effective when administered properly. Puppies need to receive vaccines every three to four weeks from eight weeks of age until they are over 16 weeks of age, again at one year and then every three years thereafter.

The difficulty with this disease is that puppies often get sick in the window after they have had one vaccine but not the full series. If puppies are in environments where the virus has been shed by asymptomatic carriers, they can pick up the virus. Health for the dog population relies on compliance by everyone – a concept known as “herd immunity”.

This year we have seen an uptick in the number of parvo cases. We see an average of 16 cases a year and have diagnosed 28 this year, eight in the last three weeks. The virus does ebb and flow so this may just be a high year. Cases have been from a number of locations and have been mostly young, incompletely vaccinated dogs. However, it is also possible that the move away from vaccines has led to less herd immunity and more shedding of virus. Speaking to other hospitals in the area, some are also seeing more cases but other clinics north of us are not.

Our recommendations are:
1)     VACCINATE – make sure your puppy gets the full SERIES of vaccines up to at least 16 weeks of year. Make sure the vaccine is boostered one year later and then every three years after that.
2)     Do not take incompletely vaccinated puppies to dog parks or other high traffic areas. Dog parks are great places to socialize but only after the full series of puppy shots have been given.
3)     If you have a dog with vomiting and diarrhea, have them seen promptly. Early diagnosis and proper treatment does lead to a good long term outcome.

If your dog is fully vaccinated, there is no reason to avoid the dog parks – let your dogs play if we have a sunny day. 

Friday, November 9, 2012

Parvovirus; Think Outside the Box

By Dr. Beth Guerra

Quite a few years ago, I evaluated a one year old schnauzer for an acute onset of vomiting and diarrhea. He had no known medical problems and had not eaten anything unusual that could have caused his symptoms. The owner allowed me to do a complete workup, including x-rays and bloodwork. There were very few abnormalities except for a very low white blood cell count, which can indicate overwhelming infection or inadequate bone marrow response to infection. I was wracking my brains for a cause that would also explain his symptoms, when I noted in the chart that the owner had acquired him as a very young puppy and that he was not yet neutered.  When I asked why she had not neutered him, she said he had never visited a veterinarian. That set off a bell in my head, and I questioned her about vaccine status. She reported he had never had any vaccines or boosters and that the breeder did not mention that he was given any before she acquired him. I immediately set up a parvo test, and it was a strong positive.

Veterinarians tend to think of parvovirus as a disease of very young puppies, usually under 16 weeks of age. The general public knows of parvo as “the puppy killer” because it is highly contagious and often affects young dogs that are not fully developed and therefore have an immature immune system. What I had failed to think of in this case was that even though this dog was a year old, he had never been vaccinated and therefore was still at risk for contracting the virus. We just had another case present this week with a severe parvo infection who is 4 years old, but again, had not been fully vaccinated.  In our current case, he had a single puppy shot and not the full series needed to produce immunity.

Parvovirus is ubiquitous in the environment and very difficult to kill with normal disinfectants; prolonged contact with a bleach solution is required. It is highly contagious and can remain in the environment for many months. Transmission between animals is via oral exposure to feces containing the virus, however, objects such as bedding and toys can also transmit the virus. Infection can be widespread in environments such as pet stores or breeding facilities due to close contact between animals. Incubation within the body can be up to two weeks and the virus can continue to be shed in the feces after infection has resolved.

The virus targets specialized crypts in the intestinal lining where new cells are rapidly produced. These cells die off and the intestinal lining becomes more permeable, allowing for loss of vital blood proteins and electrolytes and also letting harmful bacteria into the bloodstream from the intestinal tract. 

Symptoms include vomiting, diarrhea (often bloody), inappetance, and abdominal pain. Septic shock or disseminated intravascular coagulation (widespread hemorrhage) can occur in severe cases. The virus can also destroy developing white blood cells. The drop in crucial white cells increases the risk of secondary bacterial infections.

Diagnosis is based on presenting symptoms, vaccine history, and test results, which can include a positive parvo test (fecal test that can be done in house), decreased white blood cell count, or low blood albumin. Some puppies also have intestinal parasites that are found on fecal exam. Therapy is supportive while the virus runs its course. Intravenous fluids, anti-emetics, and broad spectrum antibiotics are utilized to minimize secondary effects of the virus. Some animals receive transfusions of whole blood or plasma. Parvovirus can be rapidly fatal if left untreated and these cases usually require several days of hospitalization on the road to recovery. Puppies that develop severe sepsis or secondary infections, such as pneumonia, may succumb to the disease. However, studies have shown that chance of survival with aggressive treatment is over 90%.

Once infection has cleared, the puppy may have lifelong immunity, however, vaccines are the best prevention. Puppies usually receive a series of “combo” vaccines, which include distemper, parvovirus, adenovirus, and parainfluenza. Vaccines begin around 8 weeks of age and boosters are administered every few weeks until they are 16 weeks of age. Whether you obtain a puppy from a breeder, pet store, or friend, it is important to question them about the vaccination status up to that point. Infection with parvovirus can occur at any time between boosters, so it is important to have your puppy evaluated by a veterinarian and comply with the  FULL vaccine schedule.

Wednesday, October 24, 2012

Antifreeze Toxicity

By Dr. Beth Guerra

Ethylene glycol, the main ingredient in antifreeze, has long been known to be toxic to household pets. Exposure is usually from puddles under a leaking car or a container in the garage that has been spilled or chewed up by a pet. The minimum lethal dose is only around 2.5 tablespoons for a 20 lb dog or just one teaspoon in a seven-pound cat. The toxic component is not the ethylene glycol itself, but rather the metabolites that form when it is broken down by the liver.

There are three recognized stages to antifreeze poisoning:

Stage 1 (within 30min to 12 hours after ingestion) The pet usually experiences nausea, vomiting, lethargy, or neurological signs and can appear ‘drunk’. Increased thirst and urination may also occur.

Stage 2 (12 to 24 hours after ingestion) An increased respiratory and heart rate may be noted.

Stage 3 (24 to 72 hours after ingestion in dogs, 12 to 24 hours in cats) One of the byproducts of metabolism combines with calcium in the body to form calcium oxalate crystals that damage the kidneys. These crystals can be detected in the urine and can help confirm the diagnosis. A severe metabolic acidosis occurs as well. Oliguric kidney failure develops, characterized by a lack of urine production, can develop at this time. Additional symptoms may include nausea, vomiting, and severe depression.

There are several tests that can be used in dogs to test for ingestion of antifreeze. Some test for ethylene glycol itself, others for the metabolic byproducts. We do have screening tests at ACCES but usually submit the sample to a human hospital for confirmation.

If ingestion was suspected but not witnessed, it is always beneficial to run a test. Treatment varies based on time of ingestion and symptoms at presentation. If ingestion was within 30 minutes and there are no clinical symptoms, decontamination can be attempted with induction of vomiting. In the case of a positive results and symptoms, immediate care should be instituted to avoid impending renal failure. Therapy includes aggressive fluid therapy as well as IV infusions of 4-MP. If 4-MP is not available, intravenous ethanol also works to prevent metabolism of the ethylene glycol to its toxic compounds but causes more side effects. Daily monitoring of blood pH, fluid input, and urination is essential. Symptoms such as vomiting, seizures, or respiratory distress should also be anticipated and treated. Therapy is continued until the test is no longer positive; in some cases this may be several days to weeks. In dogs, the prognosis is favorable if treatment is within 12 to 16 hours and the kidney values are not elevated. In cats, treatment should be within three hours. Once there are signs of kidney failure and crystals, prognosis is grave. The mortality rate in dogs is reported to be 59-70% and is thought to be even higher in cats.

If you have witnessed your pet drink antifreeze, or think exposure has occurred, contact National Animal Poison Control Center; (888) 426-4435 or your veterinarian immediately.

Friday, October 12, 2012

Full Moon and the ER

By Dr. Beth Guerra 

There are nights in the ER where I take a moment to reflect upon the phase of the moon. This usually occurs when I have every exam room full of potential patients and multiple critical animals being carried into the ICU on stretchers hemorrhaging, seizuring, or gasping for breath. Every emergency doctor, human or veterinary, cannot shake the conviction that a full moon coincides with a full, and often crazy, emergency room.

I have several friends that are human ER physicians, and we all swear by this phenomenon. Reflecting back on my years in the ER, I can recall with difficulty the full moon shifts where I wasn’t up to my elbows in critical patients, no matter what clinic I was working at during that time. I even psych myself out driving to work when I happen to glance up and notice the moon is waxing full.

Multiple studies have been done about this correlation, in both human and veterinary medicine, and the bottom line is, there is no correlation. Separate statistical analyses have failed to show any link between a full moon and the caseload in the ER clinic.

One study from the Indian Journal of Medical Science (2004) failed to show any positive relation between full moon days and variables such as number of trauma patients, assaults, or attempted suicides. Another retrospective study in Resuscitation (2003) analyzed ER caseloads for six years and did not find a correlation between the number of ER visits, the phases of the moon, or the signs of the zodiac. A similar study in Journal of Veterinary Emergency and Critical Care (2007) found no correlation between case load and the phase of the moon (or Friday the 13th), but did note that weekends and holidays were consistently the busiest days of the year.

A literature search revealed that this phenomenon has been studied extensively since the late 1960s and has even delved into variables like number of births, dog bites, drug overdoses, suicide attempts, surgical complications, and cardiac arrest. In each instance, no relationship has been established that can be linked to a full moon.

Even with all this evidence to the contrary, I still approach my full moon shifts with a certain amount of trepidation. I make sure to get as much sleep as possible and eat before I get to work; as every emergency shift worker knows, you may not get another chance. I take a deep breath as I walk in the door and remind myself that it’s just another day, and that no matter how out of control things get, I can’t blame it on the moon.

Tuesday, September 4, 2012

SEPTEMBER- Healthy Aging Month

By Jennifer Waldrop, DVM DACVECC

What does “healthy aging” mean for your pet? Is it the same as for you? Basically, the answer is yes, with one glaring difference. Your pet cannot be trusted to tell you when something is starting to go wrong. Subtle warning signs of a problem may resemble age-related changes. For example, increased sleeping might be a headache or blurred vision. Difficulty rising could be arthritis, but could also be weakness related to low blood pressure, altered electrolytes, bone pain, or dizziness. We humans also tend to rationalize and “anthropomorphize” our pet’s issues, which can sadly delay diagnosis of many treatable diseases. Then it seems surprising when our pets are really sick and we hear of the degree or chronicity of the problem.

Given the rapidity of animal aging and their short life span, the only way to reliably monitor aging is by frequent visits to the veterinarian with an examination and geriatric lab work including a Complete Blood Count, Chemistry Panel and a Urinalysis. Chronic kidney disease is one of top three diseases of geriatric pets and kidney failure is only reliably diagnosed by checking a urine sample for concentrating ability (urine specific gravity.)  Ideally, this should be every six months for a dog over nine to 10 years (over seven years for Giant Breeds like Great Danes) and every year for cats over 10 years of age. For exotic pets, these recommendations will vary depending on the size and type of pet. This can become expensive and makes a good argument for pet insurance to cover some of the ongoing costs. When choosing a pet insurance, take care to check for geriatric exclusion clauses given that many pet insurance companies are also aware that aging pets require more care.

What else can we do to fend off some of the preventable changes of aging? Just as in humans, a healthy diet and exercise are crucial. Most commercial and many alternative diets are complete, but when in doubt, your veterinarian or a veterinary nutritionist will be able to consult on the appropriateness of the diet. Most “senior” diets do not have significant changes in ingredients or electrolytes that make them better than regular diets. Supplements like fish oil may have a place in treatment of canine osteoarthritis, but their role in prevention of other diseases such as heart disease or dementia is unknown. I still recommend them if there is no fish in the pet’s diet. There are instances when fish oil supplements are discouraged, specifically in some human cancers during chemotherapy.

Exercise of the body and mind are both important to provide your aging pet. Exercising with your dog has been found to improve health for the human in multiple research studies, and the reverse is likely true as well. The cardiovascular and muscular strength that moderate exercise provides is important to keep both healthy, but also serves as a reserve when you are sick. This reserve strength will improve recovery after accidents, surgery or other health issues. Outdoor exercise is also a mental boost for our dogs with input into all their senses. Time spent with their owner is also important for mental health, so part of a moderate exercise program should include an interactive component.

Exercising a cat or exotic pet can be a little more difficult, to say the least, but is extremely important given the high rate of obesity in our pets. Cats may enjoy chasing a toy on a wand or chase toys or balled up socks, but sadly some cats are not interested in chasing. For these cats, a companion cat or dog may provide some impetus for moving around even if it’s just to get away from the other animal. (Conflict can provide good stimulation ;) A younger cat could keep the older cat more active both physically and cognitively. The same is likely true for birds and small mammals.

At home, grooming and petting your cat or dog provides both with the benefits of companionship. Having friends and relationships is as important for our pets as for us. Studies in humans have shown increased longevity and mental health for those people who actively continue human interaction and relationships. Sometimes a pet and their human can become isolated from the rest of the world and this is not healthy for either individual. One of the least judgmental places for dog owners is the dog park where dogs of all sizes, temperaments and interests congregate with their humans of the same variability. For indoor-only cats, frequent household visitors and companionship with other housecats should provide good stimulation.

The best part of living with a pet is having a good friend who lives every day to its fullest. We can follow their example while we age as well and continue to fully enjoy each moment.

Men do not quit playing because they grow old; they grow old because they quit playing.
~Oliver Wendell Holmes