The Roundworm (Toxocara) is the common intestinal worm of dogs. It looks like spaghetti, thin, round, and up to eight inches in length. In adult dogs, roundworms in the intestine absorb nutrients from the surrounding fluid; then they mate and lay microscopic eggs. Once the eggs pass out of the dog in his stool, they hatch into larvae ready to infest another dog. The next dog becomes infested by eating the stool or grass contaminated with larvae.

The time from egg-laying to larvae depends on the temperature. If it is hot, eggs can hatch in less than a day. If it is cold, they can stay dormant for a month.

These worms can actually tell the difference between a puppy and an adult dog, and change their travel routes accordingly.

A larva eaten by a puppy less than 3 months old does not develop into an adult worm right away, it first has to go on a walkabout. The larva burrows through the pup’s intestinal wall, tunnels through the liver, passes through the diaphragm, and finds its way into an airway in the lung. Once there, it is coughed up and swallowed, returning it to the intestine where it can mature and produce eggs.

If enough worms migrate at one time, puppies can become quite ill. When infestations are severe, puppies may vomit up a pile of writhing worms or pass them in their stools.

In adult dogs, Toxocara larvae follow a very different path. They burrow through the intestinal wall as in puppies, but they end their journey in muscle tissue where they enclose themselves in cysts. These lay dormant forever, with one important exception: If a larva is lucky enough to encyst in a breeding female dog, it gets a reprieve.

The hormonal changes of pregnancy trigger the larva to emerge. It then goes to one of two places, either into the uterus and directly into a puppy, or into the mammary glands where it ends up in the dam’s milk. These two mechanisms explain how puppies may be infested at a very young age, or even be born with roundworms.

You will need a rectal thermometer to take your dog's or cat's temperature. You do not need a special 'dog' or 'cat' thermometer – you can use one designed for human use.

Shake down the thermometer until the reading is 96°F or less. Lubricate the thermometer with some vaseline or lubricating jelly.

Grasp your pet's tail at the base and raise it. Hold it firmly so your pet will not sit down. Reassure and talk quietly to your pet during the whole procedure. This will help keep your pet calm, relaxed, and holding still.

Taking a dog's temperature Gently insert the bulb portion of the thermometer into your pet's anus. It works best if you use a twisting motion. Insert the thermometer about 1 inch in cats and small dogs, and up to three inches for giant breed dogs.

Leave the thermometer in place for 1-2 minutes. Then remove it and wipe it with gauze or a cotton ball. Read the temperature at the end of the column of mercury. Clean the thermometer with rubbing alcohol and store it safely.

Temperature - 100.5 to 102.5 This is the normal reading for your pet.

By Wendy C. Brooks, DVM, DipABVP

Parvoviruses are a large group; almost every mammal species (including humans) seems to have its own parvovirus. Fortunately, each virus is pretty specific about what animals it can infect (i.e. the pig parvovirus will not infect people, the canine parvovirus will not infect cats, etc.) The canine parvovirus will affect most members of the dog family (wolves, coyotes, foxes etc.)

Parvoviruses are smaller than most viruses and consist of a protein coat (a capsid) and a single strand of DNA inside. It is hard to believe that such a simply constructed organism could be so deadly; however, this virus has proved especially effective at infecting rapidly dividing host cells such as intestinal cells, bone marrow cells, cells of the lymph system, and fetal cells. Parvoviruses are not enveloped in fat the way many other viruses are. This makes parvoviruses especially hardy in the environment and difficult to disinfect away.

While the parvoviruses of other species have been well known for decades, the canine parvovirus is a relative newcomer. The original canine parvovirus, discovered in 1967 and called CPV-1 did not represent much of a medical threat except to newborn puppies but by 1978, a new variant, CPV-2 appeared in the U.S. This newer version seems to represent a mutation from the feline parvovirus (which is more commonly known as the feline distemper virus). Because this virus was (and is) shed in gigantic numbers by infected animals, and because this virus is especially hardy in the environment, worldwide distribution of the virus rapidly occurred. At this time, the virus is considered to be ubiquitous, meaning that it is present in EVERY ENVIRONMENT unless regular disinfection is applied.

Attempting to shield a puppy from exposure is completely futile.

In 1978, no dog had any sort of immunity against this virus. There was no resistance and the epidemic that resulted was disastrous. To make matters worse, a second mutation creating CPV-2a had occurred by 1979, and it seemed to be even more aggressive. Vaccine was at a premium and many veterinarians had to make do with feline distemper vaccine as it was the closest related vaccine available while the manufacturers struggled to supply the nation with true parvo vaccines.

Over thirty years have passed since then. The most common form of the virus is called CPV-2b. Virtually all dogs can be considered to have been exposed to it at least to some extent, which means that most adult dogs, even those inadequately vaccinated, can be considered to have at least some immunity. It is also worth mentioning the new particularly virulent strain of parvovirus: CPV-2c, which is rapidly becoming the second most common form of canine parvovirus. CPV-2c was discovered in the year 2000 and is able to infect cats. Cats vaccinated against feline distemper can be considered protected. Currently available vaccines cover all variants of canine parvo including CPV-2c as do all the commercially available diagnostic test kits.

For more specific information about Canine Parvovirus-2c, see the American Veterinary Medical Association's FAQ.

Parvoviral infection has become a disease almost exclusively of puppies and adolescent dogs.

Parvoviral infection must be considered as a possible diagnosis in any young dog with vomiting and/or diarrhea. With proper hospitalization, survival rates approach 80%.