Updated: Oct 30, 2020
This information is directly from VCA Hospital website
Do all kittens have worms?
Not all kittens have worms (intestinal parasites), but most of them do. The same milk that protects nursing kittens from disease and provides nutrition also carries intestinal worms, so drinking mother’s milk can transfer worms to young kittens shortly after birth. Infection can occur even earlier - before kittens are born - because some intestinal parasites are transmitted to kittens through the blood stream while they are still in the womb. Since kittens can become infected so early and since intestinal parasites can cause severe illness, treatment needs to begin when the kitten is only a couple of weeks old.
A microscopic examination of a stool sample will identify which worms the kitten is infected with so a specific treatment plan can be prescribed. Since many kittens are infected with the more common intestinal worms, your veterinarian may routinely administer a broad-spectrum dewormer that is safe and effective against several species of intestinal worms. This medication, which kills adult worms, is given every 2-3 weeks to target the most susceptible stage of the worm’s lifecycle. For other types of intestinal parasites, different medications and treatment intervals are required.