Dear Pet Doctor:
My Puppy vomited some big disgusting worms! Help!
Dear Reader: Round worms, probably Toxocaracanis, are among the
more disgusting surprises that a puppy can bring to the house. They’re also disturbing, as roundworms are transmittable to children and people with immune deficiencies. Roundworms are a type of parasite called a nematode. As adults, these parasites live in a dog’s gastrointestinal tract. Adult roundworms can make
a puppy sick, causing it to be malnourished and become pot-bellied with a dull, rough coat. An infected puppy may have seizures from low blood sugar because the roundworms make it unable to properly absorb food. The adult worms often are vomited or passed whole in the stool. Their eggs are passed in the feces and are hardy - they can live in soil for months or years. A canine becomes infected by eating these eggs.
Roundworms also can pass from a mother to her puppies through the placenta or even in her milk. Once a dog is about 3 months old, its no longer easily infected by round worms as its immune system is becoming too strong. To avoid the immune system, the roundworm larvae find a convenient bit of muscle or organ tissue to hide in, effectively shutting down their metabolism and “going to sleep” rather than risking attack by growing into adults. This is a dead end stage unless these larvae are in a female dog that gets pregnant.
About the 42nd day of pregnancy, a female dog has a shift in her hormones and her immune system isn’t as good at policing against roundworms. At this stage, the larvae reactivate and cross the placenta to infect her babies. Some even go to the mammary gland and get passed on to puppies through nursing. Because of this trick, the puppies have roundworms. There’s no practical way around it.
Roundworm larvae can also infect humans. A puppy can pass infected eggs by the time it reaches 3 weeks old. Because the eggs can survive the environment so long, a child can become infected playing in the dirt where dogs have gone to the bathroom. When a roundworm has gotten into a human, it is called “larval migrans,” and can cause serious illness. If the larvae migrate into the eye, they can cause blindness.
There is a simple way to prevent roundworms from getting into humans. All puppies and their moms should be treated for worms by the time the puppies are 2 weeks of age, with repeat treatments every two weeks until they are at least 8 weeks old.