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. 

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 13^th), 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.

Salmon Poisoning Disease

By Beth Guerra, DVM

Salmon poisoning disease (SPD) has been identified in the Pacific NW down through northern California. Because of the name, most people think of it as some sort of food poisoning obtained by eating bad salmon. The organism responsible for SPD is actually a small microscopic (rickettsial) organism located within the immature form of a fluke that colonizes the flesh of salmon. If raw fish are ingested by dogs, the fluke will mature within the intestine and release the rickettsial organism that causes disease.

Symptoms usually occur within five to seven days of ingestion of infected fish and may include fever up to 104F, vomiting, diarrhea, loss of appetite and weakness. The body’s lymph nodes are usually enlarged and can be palpated on exam. Diagnosis is often made by identifying the fluke eggs on a fecal exam, but a CBC/chemistry, abdominal x-rays or ultrasound should be performed to rule out any concurrent diseases.

Patients are generally hospitalized for aggressive supportive care due to rapid onset of symptoms. Diarrhea and vomiting can be severe or become bloody, so fluid support is required. Medications include a tetracycline antibiotic to eradicate the rickettsial organism as well as a general deworming medication to treat for the flukes. If SPD is caught early and treated appropriately, the prognosis is good and patients usually recovery fully. 

Are these foods REALLY toxic?

By Beth Davidow, DVM DACVECC

There are a number of foods that are now known to be toxic to pets. I tend to wonder each time I hear of a new toxicity, “is that really true?” I often think, “Well, I’ve seen lots of dogs who eat that who haven’t had a problem.” The growing list of toxic foods for pets now includes chocolate, onions, grapes, raisins, and chewing gum containing xylitol (many of the sugar free gums). Although I read these new reports critically, working in emergency, I have now seen all these toxicities first-hand.

Chocolate toxicity has been known to many of us for years. Theobromide, a methylxanthine, is the main toxic component, and causes extremely fast heart rates, tremors, and can lead to seizures. The darker the chocolate, the more theobromide is contained in each ounce and the less the pet has to eat of it to cause problems. White chocolate is actually not toxic at any amount. A 60-pound lab would need to eat 20 ounces of milk chocolate to have moderate to severe signs but only three ounces of dark bakers chocolate. Depending on when the chocolate was ingested, we might recommend inducing vomiting or having us administer activated charcoal. (Activated charcoal binds toxins that are in the stomach or intestinal tract so they can’t be absorbed into the blood stream.) We’ve seen many dogs that presented with agitation and severely elevated heart rates. Most have done well but some needed 24-48 hours in the hospital on IV fluids and medication to decrease the dangerously high heart rates.

Onion toxicity is one I hadn’t seen until a few years ago. Onions and other members of the Allium family (shallots, garlic, and green onions) contain a compound that can weaken red blood cells. The red blood cells break down causing anemia (lack of red blood cells) and hemoglobin (the protein inside red blood cells) to spill into the urine. Dog’s red blood cells have less antioxidants than people’s making their cells more prone to damage. Cats are even more susceptible to red blood cell damage. Ingestion of 5g/kg of onion in cats or 15-30 g/kg in dogs can lead to clinically important hemolysis. Damage consistently happens in dogs who ingest more than 0.5% of their body weight in onions at one time. A few years ago, an English setter was referred to us for inappropriate urination and red colored urine. It turns out he had eaten three cups of onions the day before – 1.5% of his body weight! The red color was hemoglobin in his urine. He became very anemic four days after he ate the onions and needed a transfusion. To complicate matters in his case, he also had a bacterial urinary infection. The combination of the hemoglobin going through his kidneys and the infection, despite antibiotics and IV fluids, led to acute kidney shut down. After 10 days of hospitalization, antibiotics, and IV fluids, he is doing well at home.

Grape and raisin toxicity was first reported by the National Animal Poison Center in 2001. At that time, they knew of 10 reported cases of acute kidney failure with ingestion of quantities varying from 0.2 oz/lb to 4.4 oz/lb. A retrospective study was published in 2005 in the Journal of Veterinary Internal Medicine involving 43 cases. Of the 43 cases, 20 died or were euthanized due to a poor prognosis. Unfortunately, it is still not known why some dogs, but not all dogs, develop acute kidney failure from ingestion of these foods. Pesticides, fungus and heavy metal contamination have been ruled out as causes and it appears that the toxic principle is in the flesh and not in the seed. Last year, we treated a dog who developed acute kidney shutdown after eating grapes off a vine at a friend’s house. The dog survived and is now doing well but was hospitalized for almost two weeks and required subcutaneous fluids for many weeks afterward. We do recommend inducing vomiting, activated charcoal and IV fluid diuresis with any grape ingestion over 0.7 oz/kg or raisin ingestions over 0.1oz/kg. Induction of vomiting is recommended up to eight hours after ingestion in these cases as in many of the cases reported to National Animal Poison Center, raisins were still found in the vomit at this point.

Xylitol is a sugar substitute that is good for people on a low carbohydrate diet, those with diabetes or those watching calories. It is found in sugar free gum, some toothpastes (it can prevent oral bacteria from producing acids that damage tooth surfaces), and can be bought as a powder for cooking. Although the lethal dose is >130 g/day in people and greater than 20g/kg in mice, the metabolism is different in dogs. It appears that doses greater than 0.1g/kg can lead to hypoglycemia 30 minutes to 12 hours after ingestion. This is because in dogs, but not in people, xylitol causes a dose-related rapid, severe insulin release. In addition, acute liver failure and bleeding problems has been reported in eight dogs after eating xylitol containing products. Most of the dogs presented with vomiting and lethargy nine to 72 hours after xylitol exposure. The reason for the liver failure is currently unknown. National Animal Poison Center does recommend vomiting induction, IV fluids, and careful monitoring of blood glucose and liver enzymes.

The NAPCC is a fantastic resource and we recommend that their phone number be easily accessible in your household. The Washington Poison Center now also has a veterinary toxicologist on staff and is also very helpful especially in cases of household chemicals or product exposure. In addition, our emergency doctors are very knowledgeable about toxicities and are always happy to answer questions at any time of day or night. (NAPCC, 888-426-4435 and Washington Poison Center, 800-222-1222)

Could Pollen Kill My Cat?

By Beth Davidow, DVM DACVECC 

Last week, we received a phone call from an owner who saw her cat walking around with pollen on its face. She had just received a bouquet of lilies, had put them up high, but then saw her cat in that area. A quick internet search revealed that lilies were toxic and she wanted to know what to do.

We informed her to come in right away. Although sometimes the internet has stories that scare you unnecessarily, the danger of lilies to cats is not scary or loud enough. In a recent study of 48 households with cats exposed to lilies, only 27% of owners knew that lilies were toxic. In those cases, the owners thought the lilies were out of the way enough but the cats reached them anyway.

Asiatic lilies, the big beautiful ones that are especially common around Easter, are incredibly toxic to cats. The lilies that are toxic are from the Lilium or Hemerocallus species. Common names include Stargazer, Easter, Tiger lily, and day lilies. We don’t know what the toxic compound is but we do know that it concentrates in the pollen and that only a small amount is enough to cause acute kidney shutdown. Lily of the valley is not a true lily and therefore does not cause acute renal failure. It has cardiac glycosides (similar to digitalis) that can cause other symptoms. Peace and calla lilies contain calcium oxalate crystals and usually cause immediate oral and GI irritation and vomiting but do not cause kidney failure.

As with many toxicities, signs don’t happen instantly. With lilies, some vomiting may be seen within a few hours. Cats then often seen to be OK or a little lethargic but then become very sick again in 24-72 hours. Elevations in renal values can be detected on blood work as early as 12 hours after ingestion. If treatment is delayed for 24-48 hours, the insult to the kidneys may be irreversible.

If you suspect your cat has chewed on a lily, it is best to err on the side of caution and seek treatment. Your veterinarian may induce vomiting (if the cat has not already vomited parts of the plant) and follow up with a slurry of activated charcoal to bind up any remaining toxins in the GI tract. Intravenous fluids are recommended for at least 48 hours.  Baseline blood work is obtained and renal values are monitored every 24 hours.  If caught early and treated aggressively, the prognosis is good and no lasting damage occurs.  In the study mentioned above looking at cats exposed to lilies, 90% did well with appropriate treatment but 10% did have renal damage. 

In our recent phone call, we recommended aggressive treatment, the cat was hospitalized on IV fluids for 48 hours, and did fine with no long term problems.

So this spring, tell your friends, tell your colleagues that yes, some pollen could kill your cat.

For more information on toxic plants, see http://www.aspca.org/.

References:

Slater MR, Gwaltney-Brant S.  Exposure Circumstances and Outcomes of 48 Households with 57 Cats Exposed to Toxic Lily Species.  JAAHA 2011; 47: 386.