Giardie u psů a koček: příznaky, léčba a prevence

What Giardia is

Giardia is a single-celled organism called a protozoan, far too small to see in the stool. It attaches to the lining of the small intestine and makes it harder for the gut to absorb food and water. Infected animals pass tiny cysts in their stool, and these cysts spread the infection.

Jak se šíří

An animal gets Giardia by swallowing cysts from the stool of another infected animal. A dog may drink from a puddle, pond or stream, lick grass where another dog has been, or eat stool, which many puppies do. A cat can pick up cysts on its paws or fur in a shared litter box and swallow them while grooming. Food and water bowls, toys and bedding can carry cysts too.

The cysts can infect another animal as soon as they are passed, and only a few are needed. In cool, damp places they can survive for weeks or even months.

Cysts usually appear in the stool within about two weeks of infection. An infected animal can shed them for weeks or months, whether or not it looks sick, and keep reinfecting itself and the animals it lives with.

Risk to other pets and people

Giardia spreads easily between animals of the same species. If one dog in the home has it, the other dogs are at risk, and the same is true for cats. Your vet may suggest testing the other animals. Dogs and cats usually carry different types of Giardia, so spread between a dog and a cat seems uncommon.

The risk to people is low. The types that infect dogs and cats are usually different from the ones that make people sick, and public health experts say you are unlikely to catch Giardia from your pet. The risk is still not zero, so careful hygiene makes sense, especially in homes with young children or anyone with a weakened immune system. Anyone in the home who also has diarrhea may want to see their own doctor.

Příznaky, kterých si všímat

Many infected animals, especially adult dogs, show no signs at all. When signs do appear, they mostly involve the gut.

• Soft, pale or greasy stool, often with mucus and a strong, unpleasant smell
• Diarrhea that comes and goes over days or weeks
• More gas than usual, or signs of belly pain
• Weight loss
• Less energy than usual, or a poor appetite
• Vomiting, though this is less common

Blood in the stool is not typical of Giardia. If you see it, something else may be going on, either instead of Giardia or alongside it.

Kdy jde o akutní stav

Giardia on its own is rarely life-threatening in a healthy adult animal. The main danger is dehydration from ongoing diarrhea, which can develop quickly in small puppies and kittens, older animals and animals with other illnesses. Contact your vet the same day, or an emergency clinic, if you notice any of these signs.

• Blood in the stool, or black, tar-like stool
• Repeated vomiting, or your pet cannot keep water down
• Weakness, collapse or unusual quietness
• Dry or sticky gums or sunken eyes
• A puppy or kitten with diarrhea that stops eating or drinking
• A swollen or painful belly

In a young puppy that is not fully vaccinated, vomiting and bloody diarrhea can also be signs of parvovirus, a serious viral disease that needs urgent care. For milder diarrhea that lasts more than a day or two, or keeps coming back, a regular appointment with a fresh stool sample is a good idea.

Jak veterináři nemoc diagnostikují a léčí

Diagnosis starts with a stool sample. Your vet may look for cysts under the microscope, use a test that detects Giardia proteins, or send the sample to a laboratory. Cysts are passed on and off, so one negative result does not always rule Giardia out. Vets often ask for samples from several days or use more than one test.

A positive test does not always mean treatment is needed. Veterinary guidelines generally recommend treating animals that have diarrhea or other signs. For animals without signs, the vet weighs the situation, such as whether the pet lives with many animals, young children or people with weak immune systems.

Treatment usually means a course of medicine against the parasite, given by mouth for several days. Sometimes the vet combines two medicines or repeats the course, and may suggest an easily digested diet for a while. It helps to give the full course, even if the stool looks normal sooner.

Bathing is often part of the plan. Cysts stick to the fur around the tail and back legs, and an animal can swallow them again while grooming. Many vets recommend a bath at the end of treatment, and sometimes at the start as well. For a cat, the vet may suggest washing only the area around the tail. Ask your vet which shampoo to use.

Your vet may ask for a follow-up stool test. Some tests stay positive for a while even when treatment has worked, so the vet reads the result together with how your pet is doing. Giardia often comes back because the animal picks it up again from its surroundings, so cleaning at home matters as much as the medicine.

Cleaning and prevention at home

There is no recommended vaccine for Giardia. International vaccination guidelines advise against the Giardia vaccines that exist, and most countries no longer sell them. Prevention comes down to hygiene, clean water and stool checks as advised by your vet.

During treatment and for some weeks afterwards, a few habits help stop reinfection. Pick up stool at least once a day and put it in the household waste. Wash food and water bowls daily with very hot water. Wash bedding and soft toys on a hot cycle. Clean litter boxes often and let them dry completely before refilling. Clean hard floors and crates with a steam cleaner or a disinfectant your vet suggests. Cysts survive best where it is damp, so drying is part of the cleaning.

Grass and soil are hard to clean, so quick pickup and sun drying help most outdoors. Try not to let your pet drink from puddles, ponds or streams, and carry fresh water on walks. Wash your hands after picking up stool, cleaning litter, giving medicine or bathing your pet.

Why it matters for rescued and adopted animals

Across Europe, surveys find Giardia in only a few percent of pet dogs and cats overall. Rates vary by region and are much higher in animals under one year old and in places where many animals live together, such as shelters.

A study published in 2015 tested about 1,600 dogs from several Southeast European countries, including Bulgaria, North Macedonia and Serbia. It found Giardia in about one dog in three, and in more than half of the dogs living in shelters. All the samples that were typed further carried dog types, and none carried the types usually linked to illness in people.

Street animals share space and water with many others. Rescue, travel and a new home are stressful, and stress can bring out signs in an animal that was carrying Giardia quietly. Soft stool in the first weeks has many possible causes, including a change of food, and Giardia is one of them.

At Paw Squadron, the first stops after every rescue are the vet and a bath. Each animal gets a checkup, deworming and treatment against fleas and other parasites, and every animal is vaccinated and microchipped before adoption. Giardia can still appear later. Cysts are shed on and off and are easy to miss, a routine deworming dose may not clear Giardia, and an animal can pick up a new infection at any time.

If you have just adopted, it is a good idea to see your own vet soon after arrival and bring a fresh stool sample, especially if you have other pets. European parasite guidelines recommend testing new puppies and kittens that join a home with other animals. If you can, keep the newcomer's bowls, bedding and litter box separate for the first weeks.

Giardia is common and usually treatable, and most pets recover well with the right treatment and good hygiene at home. For questions about the care our animals receive before adoption, see our FAQ or visit the Adoptions page.