By: Trupanion Staff / Updated Aug 31, 2021

The whipworm parasite (or Trichuris trichiura) can affect both cats and dogs. Whipworms are so named because of their characteristic whip-like shape. Like many worm parasites, the whipworm attaches to an animal’s intestines and feeds on the victim’s blood and nutrition. They can be passed to other animals through feces. Should your pet become infected with whipworm, they may show signs of digestive or intestinal problems, extreme or bloody diarrhea, and weight loss.

Quick facts about whipworms

• As with many parasitic worms, puppies are particularly vulnerable to infection, and should be de-wormed early in life to remove any infection.
• There are many different types of whipworms that infect dogs, cats, humans and other animals. However, infection in dogs is by far the most common.
• Whipworms float! If you suspect your dog may be infected, your vet may carry out a flotation test on a stool sample to see if the parasites rise to the surface.

What do whipworms look like?

Adult whipworms are a very long thread-like parasite with one enlarged end, which is where the name comes from.

How do whipworms infect pets?

Whipworms are most commonly passed to a puppy from its mother, prior to birth. While puppies are by far the most at risk, older dogs and cats can also become infected in adult life.

Infection in adult dogs can occur in several ways:

• Contact with, or ingestion of, the feces of an infected animal
• Consumption of an infected animal (e.g. eating of wildlife such as mice or squirrels)
• Ingestion of infected water or soil in an outdoor environment

Infection timeline

1. Pet inhales or consumes live whipworms or whipworm eggs, from food, milk, vegetation or soil.

2. If eggs were consumed, they hatch during the pet’s digestion process, releasing the larvae.

3. If the animal is a suitable host, the larvae migrate to the intestines.

Symptoms of whipworm infestation

An early sign of whipworm infection may be a loss of appetite or disinterest in food, caused by discomfort in the digestive system. If your dog or cat refuses to eat or shows reduced interest in their meals, this could signify a parasitic infection.

In later stages, symptoms such as inflammation of the bowel area or bloody diarrhea may occur, in which case you should seek advice from a vet urgently. A loss of interest in physical activity should also be a cause for concern. As the parasites feed, they will cause blood loss and anemia, making your pet tired and lethargic.

Are whipworms dangerous?

Like most parasitic infections, the main concern of whipworms being present in your pet is the potential for blood loss. Prolonged infection can lead to a blood deficiency, and possibly anemia, which can be very serious. Bloody diarrhea may also occur.

Aside from the direct complications of blood loss, infected pets are also at risk of nutritional deficiencies. A drop in the body’s levels of iron and protein can lead to stunted growth, reduced or slowed mental development, and even a condition called ascites. Ascites, caused by a severe lack of protein, can result in a dangerous or even life-threatening fluid build-up in the abdomen.

At later stages of infection, a whipworm infection can cause sudden and unexpected death, which is why whipworm prevention in pets is so important. It is therefore vital to seek veterinary advice if you spot any symptoms of infection.

How to treat whipworms

Standard de-worming treatments available from your vet are usually sufficient to rid an infected pet of whipworm. Whipworm prevention can help avoid this.

If your dog or cat is infected, speak to your vet as soon as possible. Depending on the progress of the infection and the detrimental effects on your pet’s nutrition intake, they may also require supplements for deficiencies of vital nutrients such as iron or protein.