by Christopher Forsythe, DVM

Hello, readers. Welcome to Health Matters. My name is Dr. Christopher Forsythe. I am a small-animal veterinarian practicing in Sonoma. Each month I will contribute a pet veterinary care topic with the hope of tweaking your interest, making you smile, and educating you about your pets.

It is the scariest word you can say around a veterinary hospital because it is so infectious and deadly. It is the worst diagnosis a veterinarian can confirm for a breeder regarding a sick puppy. It can kill an entire litter in just a day. It is almost impossible to rid it from the environment; it can practically withstand an ice age! Unless you remove all the affected soil, saturate everything with bleach, or blow torch the area, it can thrive for years. A sick puppy will poop out bloody-tinged diarrhea that reeks of death, and will make you swear off old Aunt Mary Lou’s turkey gravy for years to come. To what am I alluding?

I refer to parvovirus, the worst and one of the deadliest diseases that puppies can get. In this January issue, as we bring in the new year, I hope to inform you about this important, nasty, and ubiquitous virus so you can avoid the heartbreak of parvo affecting your puppy, your home, and your heart.

Parvo: it dates back to bell bottoms

Parvovirus infection is an acute systemic illness that is characterized by severe bloody enteritis. It is often fatal in puppies, who may collapse in a “shock-like” state and die suddenly without gastrointestinal signs, after only a brief period of malaise. In 1976 a one-year parvovirus pandemic broke out resulting in many deaths. The disease then became endemic. So while John Travolta was shimmying on the dance floor to the music of the Bee Gees, veterinarians all around the world were being baffled by puppies suddenly becoming sick and dying of a bloody enteritis. Antibodies to the virus have changed since parvo emerged back then, and the original virus is now virtually extinct in domestic dog populations.

The viruses currently circulating in dogs, designated CPV-2a and 2b have been genetically stable since 1984. These contemporary strains are more virulent than the original isolates, and death rates are even higher now than back in the late 70s and early 80s when the virus first “hit the scene.”

The poop on parvo, please!

Parvo is most commonly seen in breeding kennels, animal shelters, pet stores, or wherever pups are born. It is found in puppies and dogs of any age, but most severe illness occurs in those 6-16 weeks of age. We see it most commonly in Rottweilers, Dobermans, Springer Spaniels, and Pit Bulls, but it can affect any breed of dog, from the micro Chihuahua to the Irish Wolfhound.

Puppies are vulnerable to the deadly effects of parvo when just few weeks old. This is the time when their precious antibodies derived from their mother’s milk are beginning to wear off, and they have not yet received their series of vaccines to build up life-saving immunity they need to combat the disease. This period between 6-16 weeks, known as the “dip in maternal antibody protection,” can vary from pup to pup depending on several variables: the amount of colostrum each puppy gets from nursing during the first crucial days after birth, individual appetite, genetics, and others. Excellent hygiene with puppies is very important; frequent hand-washing and sanitizing surfaces with bleach, the best known parvicidal agent, will greatly eliminate the risk of parvo causing health problems in your home.

The microscopic viral particles are transmitted from the fecal/oral route to infect a pet. Crowding and poor sanitation increase the risk of infection, especially in kennels or animal shelters. This means people can track these germs into your house on the soles of their shoes, and your puppy can become exposed by walking through the particles and/or licking the pathogens off the floor. Once these microorganisms are swallowed and incubate for 3-5 days, the virus infects crypt cells of the small intestines, leading to clinical disease 90 percent of the time. What about symptoms? They are not particularly pleasant for dog or man.

There is sudden onset of bloody diarrhea, anorexia, and repeated episodes of vomiting. In breeding kennels, several littermate pups may become ill simultaneously or within a short period of time of each other. Occasionally, one or two puppies in a litter may have minimal or no signs, followed by the death of littermates who presumably encountered greater amounts of virus. Other times a client might call and report that puppies in her litter don’t seem to be feeling well and “aren’t right.” The next morning, the entire litter is dead.

You win some, you lose some

They say veterinarians have to be hearty, and this isn’t an easy job. Well, this is never more valid than when it comes to parvo. Case in point, a recent litter of yellow “labradorable” puppies brought in after their owner reported foul smelling diarrhea and “squirty blood” coming out of them. “Hey doctor,” she said over the phone, “they just won’t nurse, either, they just cry and cry.” Naturally, my heart sank, suspecting parvo. When the blond little blobs of fur got dropped off and brought into the isolation ward of my hospital, I was even more worried. The five puppies were six weeks old, cute as buttons, but practically lifeless. Their physical exams revealed low temperatures, pale mucous membranes, and distended, fluid-filled bowel loops. They looked sleepy, lethargic, and dull, like the Pillsbury dough boys who’d gone on a drinking binge.

When my nostrils took in the almost unmistakable fetid smell of “parvo poop,” I knew we needed to do a stool swab for a definitive diagnosis. Parvo is easily tested for by your veterinarian by an in-house Elisa test which is very accurate, cost effective and takes only ten minutes. Unfortunately, some sick pets who have acute disease will have negative tests if they have not yet begun shedding the virus in their feces. These pets should be treated based on a veterinarian’s suspicions, the pet’s clinical signs, and the fact that parvo can become so lethal so quickly. Once confirmed, the entire hospital needs to be cleaned with bleach, one of the only cleaning agents that kills this virus.

Fluids anyone?

The members of my new “puppy patrol” each received IV catheters, fluids, and aggressive antibiotic therapy to combat severe dehydration, shock and sepsis. Time is of the essence, and antibiotics are essential to prevent secondary infection from killing the puppy. The goal is to restore and maintain the intestinal tract, fluids, and electrolytes and resolve shock, sepsis and “endotoxins,” or the germs that penetrate the pup’s blood stream and lead to death.

In other words, all we veterinarians can really do is keep the puppies alive and hydrated and minimize infections while the intestines slowly rid themselves of the vicious viral killer particles. The questions then are whether the infection has become too vast, and replicated and done too much damage for the puppy to survive? Has the pathogen eaten away at the mucosal layer of the intestines and caused too many ulcers along the pet’s delicate intestines for our aggressive, supportive therapy to allow the puppy’s fragile, juvenile body to heal itself?

One day after treatment in our hospital with IV fluids, IV antibiotics, anti-vomiting medication, deworming for intestinal parasites, and all the specialized nursing care we had to offer, three of the puppies were tromping around in their cages like little soldiers ready for battle. They were crying out, hungry, and happy. They had each “turned the corner” and were going to survive. One of the puppies, the chubbiest little boy, and pick of the litter, was still dull and vomiting. He would need several more treatments and much TLC before he was ready to go home. And their little sister, the precious little girl, the blondest pup of all, with the little pink collar, had sadly passed away in the night, another victim of the worst disease I deal with. As I scooped up her little lifeless body, I lamented this painful loss, and silently cursed this dreadful virus. But then, looking at those other little faces in the cages, the ones who made it, I realized it was really time to just say a little prayer of thanks that they survived.