Worms in cats can cause poor growth, a pot-bellied appearance or vomiting in affected kittens and cats. Some infections cause no obvious signs. You might also notice seed-like tapeworm segments near your cat's tail or in their poo. These observations need veterinary interpretation: they cannot tell you which parasite is present or which medicine to use. If your cat has black, tarry poo or is losing weight with diarrhoea, contact the vet for assessment. Severe hookworm infection can be fatal. [1, 2, 3, 4]
The wider cat deworming guide explains how testing fits into prevention.
Roundworm-related signs
One feline roundworm, Toxocara cati, can cause poor growth and a pot-bellied appearance in kittens. Mature roundworms may also appear in an infected cat's vomit. The word “adult” in a description of an adult worm refers to the worm's stage of life; it does not mean that only an adult cat can have it. [1]
A rounded belly alone is not a diagnosis. The useful observation for the vet is the change you've seen: whether your kitten seems to be growing poorly, whether vomiting occurred, and whether you actually saw something in the vomit. Keep those details separate from your guess about the cause. You don't need to name the worm before asking for help.
If weight measurements are already recorded, bring them to the conversation. Saying that a kitten “looks smaller” and showing a series of recorded weights are different kinds of information. Share what you have, without filling in dates or measurements you cannot remember. The vet can decide what the observations mean in the context of that cat's care.
Hookworm-related illness
Feline hookworms can cause illness that needs veterinary assessment. Ancylostoma tubaeforme can cause anaemia, diarrhoea and weight loss in kittens; heavy infections can be fatal. Severe blood loss associated with hookworms can also make a cat's poo look black and tarry. [2, 3]
Contact the vet about these signs. Don't wait to find a visible worm before describing the illness, and don't use a picture comparison to decide how long your cat can wait.
When calling, describe the colour and texture you actually saw and mention any observed weight change. If you are unsure whether “tarry” describes the stool, say so. A plain account of what happened gives the vet something to assess.
Visible segments
Tapeworm segments can sometimes be seen near a cat's tail or in their poo. General feline tapeworm descriptions compare fresh segments with rice grains and dry ones with sesame seeds. Dipylidium, the flea tapeworm, has visible segments described as cucumber-seed-like. These descriptions help explain an observation, but appearance alone cannot establish a diagnosis. [3, 4]
If that sounds like what you've seen, the separate guide to flea tapeworm signs and care explains the narrower Dipylidium question. Keep the location of the observation in your account: something beside the tail and something seen in the litter tray are details worth distinguishing.
A negative faecal flotation sample can miss Dipylidium infection. That limitation belongs to the particular parasite and testing method; it should not be stretched into “all worm tests are unreliable”. Ask the vet how the test result fits with the material you noticed. [4, 5]
When there are no obvious signs
Cats of any age can have ascarid infections without showing signs of disease. Looking well therefore does not establish that a cat is free of those worms. Waiting for vomiting or poor growth would leave this part of the picture unanswered. [1]
The cited veterinary guidance recommends at least four faecal examinations during a cat's first year and at least two per year in adults, adjusted for health and lifestyle. These are testing recommendations for discussion with your vet. They are separate from the dates on which medication is prescribed. [1, 6]
When a care note says “due next month”, ask which event it refers to. A stool examination and a medicine dose need their own descriptions in the record, even if your vet happens to arrange them for the same visit.
What to tell the vet
Start with the observation that prompted the call. Then give the known age, relevant treatment history and any current instructions. If another family member arranged the last visit, use the original note rather than reconstructing the prescription from a message that only says “deworming done”.
For example, you can leave unknown fields blank while recording the date you noticed the change and the question you want answered. Avoid adding a diagnosis to the record before the vet has assessed it.
Nuzzy's PetLife supports weight logs and vet-visit history. PetID links medical documents to your pet's digital identity. Keep the vet's instructions with the relevant visit, and follow the directions provided for any prescribed medicine. [3]
Questions about worm symptoms
What are the symptoms of worms in cats?
Possible signs include poor kitten growth, a pot-bellied appearance and mature roundworms in vomit. Some ascarid infections have no obvious signs. Hookworms can cause anaemia, diarrhoea and weight loss; black, tarry poo can occur with severe blood loss. These signs need veterinary assessment, and severe hookworm infection can be fatal. [1, 2, 3]
What can worms in a cat's poo indicate?
Visible seed-like material may be tapeworm segments, but appearance needs veterinary interpretation. Tell the vet what you saw and where you saw it. A negative faecal flotation sample can miss Dipylidium infection, so ask how the result relates to your observation. [3, 4, 5]
Sources
- CAPC: Ascarid guidance, feline sections
- CAPC: Hookworm guidance, feline disease section
- Cornell Feline Health Center: Gastrointestinal parasites of cats
- CAPC: Dipylidium caninum guidance
- Little et al. (2015), Journal of the American Animal Hospital Association: High Prevalence of Covert Infection With Gastrointestinal Helminths in Cats
- CAPC: General guidelines
