Parvo enteritis, Part 1

I have the dubious experience of being in practice prior to the latest round of canine parvo outbreak.  The first outbreak occurred in 1978 or so and it was referred to as the St Louis Collie disease.  The first case to get national rumor status was traced back to a dog show in that region.  It was a terrible disorder.  Dogs would come in with temperatures above 104, panting and emitting foul smelling feces.  All members of the veterinary community can detect parvo with their olfactory system.   Veterinarians are and adventure some lot and this became known as "Parvo diarrhea".   A specific odor / smell that is almost pathognomonic for parvo.  If I mention the smell of burning leaves, most adults of my generation can relate instantly to a mental / sniffing synapse that brings the smell back into active memory.   This pungent odor clings to what seems every available mucous membrane cell in your nasal cavity. 

Historically Canine Parvo Virus -1 (CPV-1) discovered in 1967 was nonvirulent except to newborn puppies.  Things changed drastically in 1978 when there was a mutation from feline panleukopenia virus.  This cat parvovirus is 98% the same as CPV.  Somehow, there was a tweak in the virus genetic code.  This code became instantly deadly to a population of dogs with no resistance to this assault on the immune system.  Treating these cases was extremely frustrating.   Eventually veterinarians came up with treatment protocols that give 90 % plus survival rates.  It involves intensive care for 7-14 days.  The fee total would be astronomical also.  We were desperate for a cure.   Cat distemper (panleukopenia) and mink enteritis vaccines were the only choice to use to try to stimulate the immune system to fight off parvo.  Looking back it is my personal opinion that they did not work very well.  They were all that was available at the time
In the thirty-one years since there have been multiple vaccines developed giving an excellent protection level if the manufactures vaccination protocol is followed.  Some breeds are outside the norm for the last "permanent" adult shot.  Rottweilers and Doberman pinchers are two that come to mind.

What is "Parvo"?
The parvoviruses are a large group.  Almost every mammal species (including humans) has its own parvovirus.  Each virus is usually extremely specific about which animal it can infect.  At present porcine (pig) parvovirus will not infect people.   Canine parvovirus will affect most members of the dog family such as wolves, coyotes, foxes, etc. 
Parvoviruses are a small virus.  It consists of a protein coat (capsid) and a single strand of DNA interior.  It is hard to believe a simply constructed organism could be so deadly.   This virus is especially effective at targeting and infecting rapidly dividing host cells.  The body's rapid turn over cells, include intestinal cells, bone marrow cells, cells of the lymph system, and fetal cells.  Parvovirus lacks a protective envelope of fat the way many other viruses are.  They are lean mean killing machines.  Parvoviruses are especially hardy in the environment and difficult to disinfect away.  The virus sheds in gigantic numbers by infected animals. 
At present, the most common form of the virus is CPV-2b.  Virtually all dogs have or will be exposed to canine parvovirus.   Most adult dogs, even those inadequately vaccinated (least efficient vaccines, never finished a recommended  vaccination protocol, or only got first dose when exposed to parvovirus) are considered to have some immunity.  This may help to "temper" the seriousness of the illness.
 There is a new particularly virulent strain of parvovirus, CPV-2c.  This is becoming the second most common form of canine parvovirus.  This variant discovered in the year 2000 and is able to infect cats.  Cats vaccinated against feline distemper have protection against CPV-2c.  Ironic is not, a full circle from cats back to infecting cats.   Current vaccines cover all current variants of canine parvovirus including CPV-2c.  Commercially available diagnostic test kits detect the virus and current street variants in feces or vomitus.
Parvoviral infection is now a disease almost exclusively of puppies and adolescent dogs.  Parvoviral is a rule out diagnosis in any young dog with vomiting and/or diarrhea.  With proper hospitalization, survival rates approach 90%.  There are misunderstandings about parvo, how parvo is spread, and how to prevent infections of parvo enteritis. 
Canine parvovirus does not have a protective layer of fat as canine distemper virus does.  It is especially hardy in the environment.  It is carried on shoes or clothing to new areas.  It survives freezing temperatures in the ground during winter.  Many household disinfectants are not capable of killing it indoors.   Bleach kills canine parvovirus.  Bleach also kills grass and will decolorize carpet and other interior cloth material.
This is a tough virus to destroy.  People want to know how to disinfect an area that contained an infected dog.  How long must one wait before safely introducing a new dog to a contaminated area.   Stay tuned for part two, next week.
Follow up on Monroe County Fair.  Our granddaughter, Paige, entered more projects than her Papa can remember.   I tried to console her after the Princess contest.  I told her I was never selected Fair Princess.   The next day she had her smile back.  This nine-year old had her "Pickled Watermelon Rinds" selected for exhibition at this year's Michigan State Fair. 
I see a proud Papa making a trip to Detroit and the "Big Fairgrounds" in my future.
For more information about a specific case, consult your veterinarian.