Roundworms have evolved in such a manner that they can thrive in almost any environment. They can be found in freshwater, sea water and even terrestrial environments. There are nearly 20,000 species of roundworms, out of which 15,000 are parasitic. They are also the most prevalent of the worms compared to all other types of worms in dogs.
Many dogs are born with roundworms. These are generally passed to them by their mothers through the uterus or through the mammary glands. A mother can transmit larvae that are lying dormant in her tissues or organs to the fetuses she is carrying. She can also transmit the larvae while nursing since the larvae can enter the mammary glands and be ingested by the puppies.
There are, however, other ways in which roundworms can enter the body of a dog. The most common among them is by ingestion. Dogs can consume roundworm eggs or larvae-infected feces since many dogs do have a tendency towards coprophagy (eating feces). They can also ingest larvae by eating other infected animals like rodents.
Roundworms have a complicated system of migration in the body. The migration process depends upon the age of the dog. In adult dogs, roundworm eggs hatch inside the body and the larvae migrates to the respiratory system or other parts of the body. They can remain dormant inside an organ and can resurface years later.
In younger dogs, the larvae generally migrate to the respiratory system. These are then coughed up as vomit. In most cases, the dogs eat the vomit and the larvae enter the stomach. Upon maturing in the intestines, the adult worms produce eggs that are excreted in the stool, and the cycle continues.
All parasites feed off the host. Unlike dog tapeworms that absorb food through their skin, roundworms have separate orifices for ingestion and excretion. Roundworms intake whatever they can from what the dog eats, depriving the host dog of the nourishment that is necessary for its growth and health.
Diagnosing the prevalence of roundworms is relatively easy. A close examination of the stools shall reveal if your dog in infected with roundworm since the whole worm can be seen in the stool. The round spaghetti-like shape is also easy to decipher. It is possible that you observe symptoms of worms in dogs even when there is no physical evidence of the presence of roundworms in the stools. In such cases, a microscopic evaluation of the dog’s stool becomes essential to determine if roundworm eggs are present. Many times you may actually see some common feline parasites in dog stools. This can happen if your dog has ingested infected cat feces.