Faecal test first. Not a calendar.

The claim that deworming turns 8 years into 14

Published ages have moved. Older US referral series sit near 8.5 years. In a large English primary-care series the median is 12.0 years, and the upper quarter of those deaths reaches 14.2. In a US clinic population the median survival is 14.13 years, while the median age at death in the same paper is 11.57. Those are different statistics. None of the papers shows that a dewormer, by itself, produced the shift.

Breed and body size outweigh any single worming habit. The age band is published. “The wormer doubled the life” is not.

BThe shift in reported central estimates.DIf the sentence means “the wormer did it”.

The age table and the sources

Sweden first

For a dog or cat that lives in Sweden and does not travel to a place where heartworm is transmitted: ask for a faecal test (träckprov) and treat what is actually found. Do not copy a US monthly heartworm calendar.

• Dog

  Puppies are the exception that matters early, not six extra years at the end of life.

• Cat

  Kittens are not puppies. Indoor adults are not outdoor hunters.

• Horse

  Foal ascarids and adult strongyles are not the same job.

Heartworm, only as a contrast

Adult Dirofilaria immitis live in the pulmonary arteries and can kill. Where the worm is transmitted, the American Heartworm Society canine guideline (revised 2024) and CAPC (updated 14 January 2026) say: yearly testing, and prevention prescribed by a vet year-round. That is not the default for a dog that stays in Sweden, and it is not a longevity tablet.

What these pages will not tell you to do

• No dose, in milligrams, for any species.
• Do not give a dog a horse wormer. Horse ivermectin can kill some herding breeds that carry the MDR1 / ABCB1 variant.
• Do not put a dog permethrin spot-on on a cat.
• Pumpkin seed, herbs and diatomaceous earth are not equivalent worm control.
• “Some studies show 80 percent of colic cases relate to parasites” is still on a University of Minnesota Extension page. It is not current colic epidemiology. Grade D.

Ask your vet.