Parvovirus, commonly known as parvo, is a highly contagious virus that can infect dogs and cause severe gastrointestinal illness. Parvo is spread through contact with infected feces and can live in environments for months or even years. While parvo mainly affects dogs, some may wonder if humans can contract the virus as well. The short answer is no – parvovirus cannot be transmitted from dogs to humans. However, there are some important things to understand about parvo and humans.
What is Canine Parvovirus?
Canine parvovirus (CPV) is a specific strain of parvovirus that infects dogs. There are two main variants, CPV-2a and CPV-2b, with 2a being the most common currently. CPV-2a and 2b emerged in the late 1970s and quickly spread around the world. Parvo is extremely resilient and can persist in environments for a long time, contributing to its rapid spread.
In dogs, parvo typically causes severe gastrointestinal illness with symptoms like vomiting, diarrhea, loss of appetite, and fever. The virus attacks rapidly dividing cells in the intestines, depleting the lining of the GI tract. This allows toxins and bacteria to enter the bloodstream, causing sepsis, shock, and even death. Puppies and unvaccinated dogs are most at risk.
Can Humans Contract Canine Parvovirus?
No, humans cannot be infected with CPV-2a/2b strains that affect dogs and cause canine parvovirus. This is because parvoviruses are species-specific – they have evolved to only infect and replicate within cells of a single species.
CPV-2a/2b cannot bind to human cell receptors and enter human cells. When a parvovirus attempts to enter a cell from another species, it is unable to replicate and cause infection. So while humans may be exposed to particles of CPV through contact with infected dogs or environments, the virus cannot establish an active infection.
Human Parvovirus B19
There are parvoviruses that can infect humans, such as human parvovirus B19. However, the human parvovirus is genetically and antigenically distinct from CPV strains that affect dogs.
Human parvovirus B19 typically causes a mild childhood illness called fifth disease. It can also cause more serious symptoms in adults like joint pain and swelling. Pregnant women are at risk for complications like miscarriage if infected.
But human parvovirus B19 does not cause any illness in dogs, and CPV-2a/2b does not infect humans. The two viruses are separate strains with different evolutionary origins and host ranges.
Protecting Humans from Parvo Exposure
While humans cannot get dog parvo, it is still smart to avoid exposure to infected dogs or contaminated environments. Good hygiene practices like hand washing can prevent human exposure to CPV particles. Thoroughly disinfecting areas used by sick dogs is also important.
Some common sense tips include:
- Wash hands after contact with dogs, especially if they have diarrhea
- Change clothes and shoes after visiting areas dogs frequent to avoid tracking virus particles into the home
- Clean up dog accidents thoroughly with bleach-based disinfectant
- Quarantine dogs diagnosed with parvo to prevent viral shedding
- Avoid dog parks, shelters, and areas dogs congregate when parvo is active in the community
Following vets’ isolation and containment protocols for infected dogs can help protect you from exposure. Routine vaccination also helps prevent parvo spread between dogs.
Risks for Immunocompromised Humans
There is no evidence that immunocompromised humans are at risk for contracting CPV. Some speculate their weakened immune systems could make them susceptible. However, there are no documented cases of this occurring.
Studies exposing immunocompromised subjects (like HIV/AIDS patients) to CPV have failed to establish active infection. The cellular barriers that prevent cross-species transmission appear intact even in immunocompromised humans.
That said, severely immunocompromised individuals may want to exercise extra care around parvo exposure as a precaution, especially very young children. Consult a doctor if concerned.
Can Humans Spread Parvo?
Humans can indirectly transmit parvo through their clothing, shoes, hands, and other environmental contamination. Since parvo can persist in the environment, humans can pick it up and spread it to uninfected areas and dogs.
For example, a human can walk through an area contaminated with infected feces and track viral particles into a vet’s office on their shoes. Or they might pet an infected puppy and transfer virus to their hands, then touch a healthy dog later.
Humans should use good hygiene to avoid inadvertently spreading parvo. Methods like changing clothes/shoes, washing hands, and disinfecting potentially contaminated items help disrupt viral transmission.
Myths About Humans and Parvo
There are some common myths about humans and parvo. These false ideas often stem from misunderstandings about viruses.
Myth: Humans can get symptoms like vomiting and diarrhea from parvo
This is false – human cells cannot be infected by CPV, so it cannot replicate and cause illness in people.
Myth: Parvo can be spread through the air
Parvo is not airborne. It requires direct contact with infected feces or fluids. CPV cannot survive in the ultraviolet radiation, open air, and lack of moisture found outside a living host.
Myth: Parvo lingers at low levels in humans without symptoms
There is no evidence CPV can establish indeterminate or “latent” infections in humans without causing clinical disease. The virus simply cannot infect human cells.
Dispelling these fiction beliefs is important to understand the (lack of) risk parvo poses to human health. While parvo can be devastating to unvaccinated puppies, it does not infect or cause illness in people.
Key Points Summary
- Parvovirus strains like CPV-2a/2b only infect dogs – they cannot be transmitted to or infect humans
- Humans have their own parvovirus, B19, that does not cross over to infect canines
- Good hygiene helps prevent human exposure/transmission of CPV particles in the environment
- Immunocompromised humans appear at no added risk for CPV infection
- Humans can inadvertently spread CPV through contact, clothing, shoes, etc.
- Myths persist about humans contracting CPV – but the virus cannot infect human cells
Conclusion
In summary, while parvovirus is highly contagious between dogs, humans cannot catch canine parvovirus strains like CPV-2a/2b. The viruses are genetically distinct and species-specific – CPV cannot bind to or enter human cells to cause infection. Proper hygiene and containment protocols can reduce human exposure and inadvertent environmental spread. While parvo postures no direct human health risk, vigilance and prevention are still important, especially around at-risk animals. With sound information, humans can protect themselves and their dogs from the spread of this severe canine illness.