Last week I met Captain South, so called because his new owner found him roaming the streets one early morning somewhere in the south of Malta.
The larvae infest puppies through the mother’s milk. It’s almost like something out of the movie Alien
Although seriously filthy when found, Captain South could not have been alone for too long since he was well nourished and exhibited no footpad abrasions – the telltale sign of being on the road for a long time.
Captain South is a liver-coloured, male, short-haired pointer-cross puppy of about two months. Like many puppies of his age, he was suffering from an infestation of roundworms.
Roundworms are the most common intestinal worms that infest dogs, particularly puppies, and the most important roundworm to be found in dogs is the Toxocara canis. This worm is smooth and round (hence the name), and the adult can grow to a length of 15 to 18 cms.
Like all internal worms, it is whitish in colour and resembles fine noodles. This genus of roundworm is highly successful because it has a very cunning lifecycle while living inside the dog, and is also very resilient outside, that is, when it has not yet infested a dog.
When a female adult roundworm is inhabiting the intestine of a dog, it is capable of laying up to 200,000 eggs in just one day. These eggs are microscopic, and therefore not visible to the naked eye. They are dispersed in the environment through the dog’s faeces, and are capable of surviving external elements.
The eggs attach to any passing dog by means of a sticky substance that coats them, and inside the egg sacs, the fully-formed roundworm larvae lie in wait.
As their new canine host grooms itself, it ingests the larvae, which then enter the blood system to migrate to the liver. They continue upstream using the blood circulation system to get to the lungs. They then break free into the air sacs there and work their way up the airways through the bronchi and trachea to be finally swallowed through the digestive system, where they are now ready to develop into adult roundworms in their preferred location – at the beginning of the small intestine. The cunning aspect of this roundworm happens in older dogs that have developed a certain resistance to it. In these dogs, the tiny larvae embed themselves in the body, usually in muscle tissue, and lie there as dormant cysts.
In female dogs, the larvae suddenly awaken during pregnancy, re-enter the circulatory system and either enter the unborn puppies, or travel to the mammary glands to infest the newborn puppies through the mother’s milk. It’s almost like something out of the movie Alien.
The quantity of roundworms can be huge and possibly life-threatening in smaller puppies. When this happens, the puppies will generally look very lacklustre and pot-bellied, their stools are mostly on the loose side and if vomiting occurs, worms can come up. The best thing you can take to your vet for identification purposes is a sample of the stools in a glass jar with some water added to prevent the sample from drying out.
If eggs are ingested by humans, Toxocara canis larvae do not develop into the adult form but are more likely to form the relatively harmless microscopic cysts embedded in the muscle tissue.
However, on rare occasions, these cysts can occur in eye or brain tissue with serious consequences. It is therefore important that you do your utmost to reduce the incidence of roundworm in your dog – both for the sake of your canine friend, as well as for your own.
The best way to reduce the number of worms in the community and in dogs is to deworm your dog on a regular basis with effective products prescribed by your veterinarian. Puppies should be dewormed at a very early age with repeated treatment.
Captain South’s owner phoned me two days after I gave him his worming pills to tell me his dog had expelled a large number of worms in his stools. I explained that Captain Sputh had these worms before the pills were given and they were only visible now in the stools because the pills were working.
Effectively, the worms were being paralysed and no longer had the energy to swim upstream to the intestine – with the result that the adult worms were being excreted along with Captain South’s stools.
thisweekwiththevet@gmail.com
Dr Martin Debattista is a veterinary surgeon.