Parvo in dogs: How to spot early signs (plus how your pup got sick in the first place.)

The spread of disease -- person to person, through a sneeze or a loud exclamation, or via an unwashed surface -- has been a hot topic of conversation in recent years. Plenty of people now know a great deal about how to slow the spread of illness. Do those same rules apply when it comes to the animal world?

Parvo, for example, is a common virus among dogs. How can canines stay protected? Get vaccinated and stay vigilant, just like us. Here's what you need to know about the disease that affects puppies of all kinds:

How is parvo spread in dogs?

Dogs contract the highly contagious virus through dog-to-dog interaction or contact with an infected surface, environment, or person, the American Veterinary Medical association reports.

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Despite there being an effective vaccine for the illness, parvo remains fairly common, Dr. Whitney Miller, Petco's chief veterinarian told USA TODAY. This is in part because it is able to withstand weather conditions and live in the environment for upwards of 6 months to a year, Dr. Miller reports.

What are parvo symptoms?

"Parvo is a viral disease that attacks a dog's immune and GI systems," Dr. Miller says, so the first sign a dog owner might see is their pet losing a healthy appetite.

This might eventually progress to "potentially bloody diarrhea and vomiting" she reports. This can dehydrate your dog, making it imperative to seek treatment sooner rather than later.

The American Kennel Club lists potential symptoms as:

• Bloody diarrhea

• Vomiting

• Fever

• Lethargy

• Loss of appetite

• Weight loss

• Weakness

• Dehydration

• Depression

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Is parvo contagious to other dogs?

Parvo is highly contagious, so if your dog has been in contact with a known infected pet or environment it is wise to seek treatment sooner rather than later.

There is an effective vaccine against the disease, and it is much more common for young dogs or unvaccinated canines to contract the disease. "The number one recommendation is to make sure that when your dog's a puppy that they start on their vaccination schedule," Miller says.

How likely is a puppy to get parvo?

This depends on a number of factors: how common parvo is in the environment where you live, how your puppy is, if they are vaccinated, and how social they are.

Since parvo can be spread through dog-to-dog contact, if your dog is highly social, often visiting dog parks or staying at a doggy day-care, they may be at a higher risk.

Dogs between 6 weeks old and 6 months are also at a higher risk, along with unvaccinated puppies, the American Kennel Club reports.

Certain dog breeds are also more susceptible to parvo AKC reports, including:

• Rottweilers Doberman Pinschers

• American Staffordshire Terriers

• English Springer Spaniels

• German Shepherd Dogs

• Labrador Retrievers

How many parvo shots does a dog need?

Three. The American Kennel Club reports that vaccination against parvo is a 3 shot series, and that owners should be particularly careful during the time in between shots so that their pup does not contract the illness.

Dogs should receive this shot series as puppies, when they are most vulnerable, ideally between starting at the age of 6 weeks.

How much does it cost to treat parvo?

There is no definitive cost that can be put on treating parvo.

Treatment depends on the severity of the illness, and in severe cases could involve a trip to emergency care which can be quite pricey. In less severe cases, the course of treatment is supportive care -- rehydration efforts and keeping your dog warm as they recover.

The total cost of such care depends on a variety of factors, including pet insurance and the seriousness of the condition.

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This article originally appeared on USA TODAY: How do dogs get parvo? Spot symptoms in puppies and grown dogs alike