The Toxocara is most commonly found and is harmful to kittens. Also, people (especially children) can quickly become infected with the larvae of this worm when eggs are taken from the ground (for example, during gardening or playing in the sandbox). In humans, however, roundworms do not grow in the intestine, but the larvae ‘migrate’ through the body.
Adult cats are sometimes carriers of adult roundworms (about 5 to 10% of cats). In the tissues of the body of almost all cats, there are roundworm larvae in a kind of sleeping state. During gestation, the grubs wake up, and after birth, the kittens are then infected by drinking the mother’s milk. In the intestinal system of the kittens, the larvae grow directly into adult roundworms. As a result, from the age of six to seven weeks, a kitten can start excreting roundworm eggs in the stool, which also infects the environment. After a few weeks, these eggs are mature. When the kitten licks these contagious eggs (from its coat or in the whelping box), re-infection takes place.
By licking her kittens clean, the mother cat will get eggs or larvae, which are located in the stools of the kittens. The mother cat has to be dewormed after giving birth. Besides hygiene, deworming is extremely important. Worming a pregnant female cat, doesn’t make much sense. The larvae which are in the resting stage in the tissue are practically not reached by the worming medicine. They cause hardly any trouble for the host animal. Therefore, as a precaution, the female cat should be dewormed before mating to control any adult worms present in the intestine.
The most recommended worming schedule is at the age of 3, 6, and 9, 12 weeks, and 24 weeks and then every six months. In periods when the cat comes in the garden a lot or catches a lot of (hum)flies, it is recommended to deworm every 3 months.
All products to control roundworms, which are available from veterinarians or pet shops, are effective against worms. However, they are not all equally effective against the larvae that are growing into adult worms in the intestine. After deworming, new worms can also come in via the mother’s milk. Therefore, the treatment should always be repeated after one to two weeks, depending on the remedy. For kittens, it is better to choose a worming remedy that also kills the larvae (larvicide efficacy), and that can be accurately administered on body weight. Attention: not all worming products can be used on both the adult cat and kittens.