Can People Get Parvo From Pets?
There are a number of diseases that are classified as zoonotic, a term that refers to a diseases' capability to easily slip between species, infecting different species of animals, and even humans. Such has been the case with the most recent H1N1 virus, also commonly known as the swine flu, which has crossed from the porcine population to humans. It is now known to be capable of crossing over from humans to domestic pets as well.
There is also the type that will inhabit a host, remaining benign until it comes into contact with its target host, where it then becomes a full blown disease. An excellent example of this is is the Baylisascaris procyonis, or Raccoon disease, a roundworm infection that is carried harmlessly by a host raccoon, but which is deadly when acquired by a human host.
There are other types of diseases that belong to the same genus, or family of organisms, but which differ in degree enough so that they cannot be passed from one species to another. Such is the case with the viral Parvoviridae family. There are some dozens of species of parvovirus within the familial classification, but they are all limited to their taxonomic units. That is, mouse parvovirus is limited to mice, hamsters and other rodents of its order, porcine parvovirus is limited to pigs, chicken parvovirus is limited to chickens, etc. In the same regard, dogs and cats are affected by species specific parvovirus' -- canine parvovirus and feline panleukopenia, respectively. In the canine family, the parvovirus crosses over different genus' within the family group, so that a fox can infect a wolf, or a hyena can infect a dog, and so on, but it is otherwise limited to the canine family.* The same holds true for cats.
Likewise, the species of parvovirus that infects humans is limited to the human species. Viral human parvovirus is a common childhood ailment that is passed strictly by other humans.
In a healthy immune system, the human parvovirus is relatively mild and brief. It is only contagious before the show of symptoms, so it cannot be entirely prevented from spreading within any given population. Its known paths of communications are like the common cold: hand-to-hand contact, sharing of utensils and drinks, exchange of mucus and saliva, etc.
Mild but uncomfortable symptoms of human parvovirus include a bright red rash on the face and body, low fever, and a general malaise, lasting about a week. Healthy adults who have not previously been through the childhood infection will often develop swelling and aches in the joint, similar to an arthritis, and the bright red rash. For adults, the symptoms may carry on for months before subsiding.
This virus is also referred to by two other names: as the B19 virus because it was initially discovered in a laboratory vial of serum labeled '19' in the B panel (year 1974); and as 'fifth disease' because as it came to be known as a typical childhood condition it was linked with the four previously known childhood rash causing diseases: measles, scarlet fever, rubella, and Duke's disease.
The main concerns with the B19 virus are for people with previous conditions, such as leukemia, anemia, sickle cell anemia, HIV, and generally weakened or compromised immune systems. As well, pregnant women are at increased risk of miscarriage, but the risk is still relatively low.
While immunizations have been developed to protect smaller animals from their own distinct parvovirus', a human immunization has not. This virus is infamously regarded for its particular resistance to preventative medicine, but on the upshot, once one has been infected with the B19 virus the body is immune from reinfection for the lifetime.
Where the different parvovirus' dovetail is in the method for prevention from spread. Whereas animals cannot be held accountable for the spread of human B19 parvovirus, humans are known as a main culprit in the spread of canine and feline parvovirus', as they (humans) may move from animal to animal without cleaning their hands or tools adequately. This may occur in veterinary clinics, kennels, shelters, or even from a behavior as innocent as petting a friendly animal and then going home to pet one's own cat or dog.
Clean hands, tools and surfaces are the key to prevention, in both animal and human parvovirus infections. The same can be said to be true of many viruses that depend on direct contact for dispersion.
In summary, although you cannot catch a parvovirus infection from an animal, nor they from you, you do play a lead role in the prevention of its spread in both humans and animals.
Image: trumanlo / via Flickr
* There is some evidence that the canine parvovirus can cross over to cats, but the incidence has this far been rare and is not generally assumed to be a normal occurrence. Conventional precautions (e.g., sanitized conditions) should be taken.