Worms in Dogs
Roundworms, tapeworms, hookworms, whipworms and lungworms are among the internal parasites that can affect dogs.
Some infections cause only mild or initially unnoticed symptoms, while others can result in serious illness. Hookworms and lungworm can be particularly dangerous, and puppies may become unwell quickly if they carry a substantial worm burden.
Possible Signs of Worms
Symptoms can include:
- Diarrhoea, which may contain blood
- Vomiting
- Weight loss or failure to gain weight
- A change in appetite
- A swollen or pot-bellied appearance, particularly in puppies
- A rough or dry coat
- Scooting or irritation around the anus
- Visible worms or segments around the anus or in faeces
- Lethargy or an overall poor appearance
- Constipation or straining
- Coughing or breathing difficulties
- Pale gums, weakness or collapse in severe cases
Some infected dogs show no obvious symptoms but may still shed worm eggs or larvae into the environment.
Roundworms
Roundworms are particularly common in puppies because infection can pass from the bitch before birth or through her milk. Affected puppies may have swollen abdomens, poor growth, diarrhoea, vomiting or a dull coat.
Roundworm eggs can survive in the environment for a considerable time. Some roundworm species can also infect people, which makes prompt collection and safe disposal of dog faeces important.
Tapeworms
Tapeworms consist of a chain of segments. Small segments resembling grains of rice may sometimes be seen around the dog’s anus, in bedding or in faeces.
The common flea tapeworm is transmitted when a dog swallows an infected flea during grooming. Effective flea control is therefore an important part of preventing repeated infection.
Hookworms and Whipworms
Hookworms attach to the lining of the intestine and feed on blood. Heavy infections can cause anaemia, bloody diarrhoea, weakness and poor growth, particularly in young puppies.
Whipworms live in the large intestine and may cause diarrhoea, weight loss and irritation of the bowel. Diagnosis may require faecal testing because eggs are not necessarily shed continuously.
Worming Puppies
Puppies require more frequent worming than most healthy adult dogs because they can acquire roundworms from their mother.
Recommended puppy-worming schedules vary according to the product used, the puppy’s circumstances and the advice of the breeder or veterinary surgeon.
One commonly published schedule is:
- Begin treatment when the puppy is two weeks old
- Repeat treatment every two weeks until two weeks after weaning
- Continue at suitable intervals during the puppy’s early months
Some breeders use a slightly different programme, such as worming puppies at approximately three, five and seven weeks before they leave for their new homes.
The appropriate schedule depends upon the product, its licensed age range and the risks affecting the litter. Only use a wormer suitable for the puppy’s exact age and weight.
The breeder should provide the new owner with a written record showing the product used and the date of each treatment.
Worming Adult Dogs
There is no single worming schedule that suits every adult dog. Frequency should be based upon the individual dog’s lifestyle, health, environment and risk of exposure.
Some veterinary guidelines recommend frequent routine treatment for dogs considered to be at higher risk. However, many experienced breeders and owners do not worm adult dogs every month unless there is a particular reason to do so.
Some owners use regular laboratory worm-count tests and treat only when evidence of infection is found. Others follow a less frequent routine schedule.
My personal approach: I worm my own adult dogs every six months unless there is a particular reason to test or treat them sooner.
A dog may require more frequent testing, treatment or preventative cover if it:
- Scavenges or regularly eats faeces
- Hunts or eats rodents and other prey
- Has a recurring flea problem
- Eats slugs, snails, frogs or grass
- Lives with young children or vulnerable adults
- Travels abroad
- Lives in or visits an area where lungworm is reported
Owners should consider their individual dog rather than automatically following a fixed monthly programme.
Worm Counts
A faecal worm-count test can be a useful part of a responsible parasite-control plan. A sample is sent to a laboratory and examined for evidence of intestinal worm eggs.
This allows owners to monitor their dogs and consider treatment when evidence of infection is found, rather than automatically administering a wormer at very frequent intervals.
However, a negative result does not guarantee that a dog is free from every type of worm. Worms may not be producing eggs at the time of the test, and some eggs or segments are shed intermittently.
Tapeworm may therefore be missed, and a standard intestinal worm count does not necessarily test for lungworm. Owners should check exactly which parasites are covered by the laboratory test they choose.
Lungworm
Not every ordinary intestinal worming product protects against lungworm.
Dogs can become infected with the potentially serious lungworm Angiostrongylus vasorum through contact with or ingestion of infected slugs and snails.
Small slugs and snails may also be accidentally swallowed from grass, toys, outdoor water bowls or other objects.
Possible symptoms include:
- Coughing or breathing difficulties
- Tiring more easily
- Unexplained bruising or bleeding
- Bleeding from the nose
- Blood in urine or faeces
- Pale gums
- Loss of appetite or weight
- Weakness, collapse or neurological signs
Lungworm can be fatal. Seek prompt veterinary attention if your dog develops unexplained breathing problems or abnormal bleeding.
A product that treats ordinary roundworms or tapeworms may not prevent or treat lungworm. Ask your veterinary practice to confirm exactly which parasites a product covers.
Choosing a Worming Product
Different products contain different active ingredients and do not all protect against the same parasites. The correct choice depends upon the dog’s age, weight, health, lifestyle and travel history.
Do not combine parasite treatments unless a veterinary professional has confirmed that they can be used together. Weigh your dog accurately and use the correct product strength.
Ask for veterinary advice before treating a pregnant or nursing bitch, a very young puppy, an unwell dog or a dog with a history of medication sensitivity.
Reducing the Risk
- Collect and dispose of dog faeces promptly
- Maintain effective flea control
- Wash food and water bowls regularly
- Do not leave toys and bowls outside overnight
- Discourage scavenging and the eating of faeces
- Wash hands after handling faeces and before eating
- Teach children to wash their hands after playing outside
- Ask about additional parasite precautions before travelling abroad
Further Information
This information is not intended to replace veterinary care. Worming and testing decisions should take account of the individual dog’s circumstances. Always use parasite products according to their instructions.