Many puppy owners are aware of the dangers of parvo and they may be familiar with the grave impact this disease has on a puppy's digestive system, but not many are aware of cardiac parvo in puppies and the effect this form of parvo can have on the puppy's heart. Fortunately, this type of parvo nowadays is no longer as popular as it was decades ago and remains almost unheard of today. Hopefully, this form of parvo will remain rare and we will never have a resurgence considering its disturbing and deadly effects on dogs.
The Cardiac Form
Parvo in puppies is known for being a highly contagious condition that is transmitted from one puppy to another through a virus. It commonly affects the puppy's digestive tract causing the abrupt onset of acute gastrointestinal illness. Puppies start vomiting and having blood diarrhea and often die from the serious consequences of dehydration.
Cardiac parvo is a rare variant of this disease and it mostly affects very young puppies. When parvo affects the heart, it causes inflammation of the middle layer of the heart wall (myocardium), a condition known as myocarditis. According to Cornell University College of Veterinary Medicine, this type of parvo first emerged back in 1976 and affected many dogs in Europe. By 1978, the virus spread globally, affecting dogs worldwide and causing myocarditis along with gastroenteritis in many puppies between 3 and 10 weeks of age.
According to a study, in 1979 canine parvovirus (CPV) myocarditis was diagnosed in 11 puppies between the ages of 31/2 to 8 weeks of age and most of them died suddenly even prior to showing symptoms.
"There is some reference in the literature to Parvo Induced Myocarditis, but that is an infection of the heart that a puppy would get if they got parvo in the first 4 weeks of life. Most veterinary cardiologists would tell you that they have never seen parvo be the cause of a heart problem -- it's really a "historical" entity and not seen in recent years."~Dr. Lisa
Symptoms of Parvovirus Myocarditis
While in the regular form of parvo the disease is transmitted by exposure to the feces and vomit of infected dogs along with objects contaminated with the virus, heart parvo is transmitted from an infected mother dog to her puppies from the uterus prior to or shortly after birth. When the virus is passed to the pups, it attacks the puppies' myocardium, causing inflammation and serious damage to the heart.
This condition has a very fast onset, often causing difficulty breathing and shortly death as the puppies' hearts undergo congestive heart failure and deadly pulmonary edema (excess fluid in the lungs). The affected puppy may be acting normal, and then, stops nursing, gasps for air and its mucous membranes become pale and bluish and the puppy dies suddenly or briefly, anywhere from minutes to hours or sometimes day after having difficulty breathing.
Treatment for Cardiac Parvo
Sadly, cardiac parvo is a condition that is very difficult to treat and there is often a grim prognosis for the affected puppies. There are reports though of puppies surviving when treated promptly with steroids so to reduce the inflammation of the heart. Puppies that survive though may be predisposed to having difficulties due to their damaged hearts and may only live a few extra months.
Any puppies who die for an unknown reason should undergo a necropsy so to determine the cause of death. Death from cardiac parvo shows a dilated heart and a pale myocardium which can be recognized by the vet.
An Ounce of Prevention
An ounce of prevention when it comes to cardiac parvo is worth a pound of cure considering how deadly this condition can be. It's important to ensure thorough cleanliness around the litter of pups using a disinfectant that is capable of killing the parvo virus. Puppies should be raised in isolation away from other dogs in the home. Hand washing, changing shoes and wearing a protective gown are good preventive measures to limit virus exposure.
Although there is no vaccine that is 100 percent effective, breeders should vaccinate their breeding stock to minimize the chances for disease. Puppies should be vaccinated as soon as possible, starting at six to eight weeks of age, suggests veterinarian Dr. Scott Nimmo. It is likely thanks to widespread immunity and vaccination that this form of parvo has remained rare, and hopefully things will remain this way!