Whipworm is an intestinal parasite that can affect dogs across the world, including in the UK. Whipworms live in a dog’s large intestine. The canine whipworm (Trichuris vulpis) is becoming more common worldwide and, if numbers build up, it can cause a range of health problems. 

What do whipworms look like? 

Whipworms are small worms that can grow to around seven centimetres long. They have a thin, whip-like front end and a thicker rear end. They attach to the wall of the large intestine and feed on blood, and heavy infections can lead to chronic health problems in dogs. 

Adult whipworms produce distinctive, lemon-shaped eggs, which may be seen during microscopic examination of faeces from an infected dog. 

What is the lifecycle of the whipworm? 

Whipworms have a direct life cycle. Eggs are passed in the faeces and, under suitable conditions, can become infective in the environment after about two to four weeks. Dogs ingest the eggs, for example while grooming or eating material from the ground. The larvae then hatch, burrow into the lower small intestine and pass through four growth stages before maturing and moving to the large intestine, where the cycle begins again. 

Larvae take around 12 weeks to mature and begin producing eggs, which are then shed back into the environment. These eggs can survive potentially for years in the environment. Whipworms are more common in older dogs than puppies, but dogs of any age can be infected. 

How are whipworms transmitted? 

Dogs become infected by swallowing whipworm eggs that have been passed in the faeces of infected dogs. Once in the environment, the eggs can contaminate soil and grass, where dogs may accidentally ingest them while out walking, playing or grooming. 

What are the signs of whipworm in my dog? 

Whipworms embed their front end into the wall of the large intestine, where they feed on blood and tissue fluid and cause irritation and damage. Mild infections often cause no signs, but heavier infections can inflame the large intestine and may lead to symptoms such as: 

  • Weight loss 
  • Diarrhoea 
  • Mucus or blood in the faeces  
  • Anaemia, such as pale gums or weakness, in chronic or heavy infections 
  • Lethargy 

Symptoms may appear before whipworm eggs are detected in faeces. Older dogs are reportedly more likely than younger dogs to carry a significant whipworm burden. 

Are whipworms zoonotic? 

Canine whipworm has occasionally been reported in humans, but this appears to be extremely rare and is not considered a significant human health risk. 

Although animal whipworms are not usually a major risk to people, humans have their own whipworm species, Trichuris trichiura. If you are concerned about possible exposure, contact your local healthcare provider for advice. 

How can whipworms be diagnosed? 

Whipworm eggs can be identified in a stool sample under a microscope. However, unlike roundworms and hookworms, female whipworms shed eggs intermittently, so they may not always be found on a single faecal test. The eggs are lemon-shaped, with a thick, smooth shell and a clear plug at each end. 

Repeat testing may be needed. If whipworm infection is suspected, treatment may be recommended even if eggs are not found.  

How can I prevent and treat whipworms in my dog? 

Regular worming with an appropriate product can help prevent and treat whipworm. One NFA-VPS product used for whipworm treatment is Drontal for Dogs, a broad-spectrum dewormer effective against major roundworms, including whipworms, and tapeworms. Because whipworm eggs can survive in the environment for many years, routine worming is important for many dogs. 

Other wormers may also be suitable, so discuss the best option with your SQP or veterinary surgeon. Dogs are commonly wormed monthly until six months of age and then every three months for life, but the most appropriate schedule for your dog should be agreed with your vet or SQP. 

Other preventions include: 

  • Clean up after your dog quickly. This will help prevent further spread of whipworms. 
  • If you think your dog may have whipworm, contact your vet promptly. They can examine your dog, prescribe a suitable worming treatment if needed, and provide supportive care in more serious cases. Your vet can also help you create an ongoing parasite prevention plan to keep your dog protected. 
  • Owners should wash their hands regularly to help reduce the risk of parasite-related illness – or just spreading the eggs between dogs. 

Dog owners should know the signs of whipworm, how to reduce the risk of infection and when to seek treatment. If you have concerns about whipworm, other parasitic worms or worming products, speak to a qualified RAMA or veterinary surgeon.