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parasitic disease Dog Transmissible to humans

Echinococcosis

Echinococcosis is caused by a tiny flatworm, Echinococcus granulosus, only a few millimeters long, which lives by the hundreds in the dog's intestine without making it sick. The danger is not for the dog: it is for humans and for ruminants....

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Definition Signs Causes Transmission Diagnosis Treatment Prevention Complications When to see a vet Zoonosis Prognosis FAQ Sources Affected species

What is it?

Echinococcosis is caused by a tiny flatworm, Echinococcus granulosus, only a few millimeters long, which lives by the hundreds in the dog's intestine without making it sick.

The danger is not for the dog: it is for humans and for ruminants. The eggs passed in the stool, once swallowed by a human, give rise to a cyst which slowly grows in the liver or lungs over years. This is the hydatid cyst.

The disease is a recognized public health issue in Tunisia and throughout the Maghreb, where sheep farming and family slaughter maintain the cycle between sheep and dogs.

Key point

Mild for dogs, potentially very serious for humans. A major zoonosis in Tunisia and the Maghreb, preventable through simple actions.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Related signs — each one links to its page:

Diarrhea Weight loss Visible worms in stools Hard or painful abdomen Reduction Gas and flatulence

In dogs, the infestation is almost always silent: the worm is too small to be seen and most often causes no signs.

Loose or irregular stools are possible in cases of very heavy infestation.

There are no “large worms” visible in the stool, unlike other tapeworms: this is what makes this parasitosis deceptive.

A perfectly fit dog can therefore carry and eliminate eggs. This is why prevention is never based on the observation of symptoms.

When to consult without delay

This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.

Causes and risk factors

The adult worm Echinococcus granulosus, hosted by the dog, which is the definitive host.

Dogs become infected by consuming raw offal, especially liver and lungs, of sheep, goat, cattle or camel containing cysts.

These offals most often come from family slaughter, slaughter outside a controlled circuit, or butchery waste left accessible.

Herding dogs, farm dogs and stray dogs living near sheep farms.

Sheep and goat breeding areas, particularly in rural areas.

Family slaughter or outside controlled slaughterhouses, particularly during holidays.

Slaughter waste accessible to dogs: discarded offal, unburied carcasses.

Absence of targeted deworming in exposed dogs.

In homes: young children in close contact with farm dogs, consumption of poorly washed raw vegetables.

Transmission

The cycle needs two hosts: a carnivore, the dog, and a herbivore, primarily the sheep.

The infested dog sheds microscopic eggs in its stools. These eggs stick to its fur, especially around the anus, and are dispersed in soil, grass, water and on vegetables.

Sheep become contaminated while grazing; cysts develop in his organs.

If its offal is given raw to a dog, the loop closes.

Humans become infected by swallowing eggs: by putting their hands in their mouth after stroking a herding dog, or by contaminated raw vegetables or water. It does not transmit the disease to anyone: it is a dead end for the parasite, but a dangerous dead end for it.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

In dogs, diagnosis is difficult: the worm is too small to be spotted with the naked eye and routine stool tests often lack sensitivity for this specific parasite.

Specific examinations exist and are reserved for investigations or risky situations; the veterinarian judges their interest.

In practice, in an exposed dog, we do not try to prove the infestation before acting: we implement prevention and targeted deworming.

Be careful when handling the stools of a dog at risk: gloves, hand washing, careful disposal.

Treatment

A dewormer specifically active on cestodes, prescribed by the veterinarian: not all dewormers are suitable and a commercial broad-spectrum product may be ineffective on this parasite.

In dogs at risk, this treatment is repeated at short intervals, defined by the veterinarian, to eliminate the worms before they produce eggs.

In the days following treatment, stools contain eggs and must be collected and disposed of with enhanced hygiene precautions.

No treatment has any effect on cysts already formed in a human or a sheep: only prevention protects.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

Never give raw offal to a dog, whatever the species and the occasion: this is the most effective measure, in itself.

Completely cook any offal intended for an animal; domestic freezing does not offer the same guarantee.

Regularly deworm herding and farm dogs with a product active on cestodes, at a frequent interval set by the veterinarian.

Dispose of slaughter waste correctly: do not leave it within reach of dogs, bury it deeply or have it handled by a suitable channel.

Have the carcasses checked at the slaughterhouse and do not bypass this step during family slaughters.

Wash your hands after touching a farm dog, before eating, and do the same with children.

Wash raw vegetables and fresh herbs carefully, drink quality-controlled water.

Avoid close contact with the muzzle and hindquarters of herding dogs.

Possible complications

In dogs, practically none: they tolerate the parasite very well, which explains why it goes unnoticed.

The complications concern humans: a hydatid cyst of the liver or lung which grows over years, compresses neighboring organs, and can rupture or become infected. The treatment is cumbersome, often surgical, and the follow-up is long.

In sheep, cysts lead to the seizure of organs at the slaughterhouse and a significant economic loss for the breeder.

When to see a veterinarian

Your dog lives on a farm, looks after a herd or has access to raw offal: speak to the veterinarian to organize suitable deworming, even if he is well.

You gave your dog raw liver or lungs after slaughter.

You adopt a dog from a breeding area with no history of deworming.

You discover that your dog ate a carcass or slaughterhouse waste.

On the human side, any persistent pain in the right side of the abdomen, an abdominal mass or a lasting cough in a person living in contact with herding dogs warrants medical consultation.

Transmission to humans

It is a serious zoonosis and one of the most important in the region: the dog carries the worm without being sick, the human suffers the consequences.

We become contaminated by swallowing microscopic eggs present on the dog's coat, on our hands, on poorly washed raw vegetables or in uncontrolled water. Contact with a herding dog is not dangerous in itself; it is the fact of then putting your hands to your mouth without having washed them that is.

In humans, the egg does not produce a worm but a cyst filled with fluid, which most often settles in the liver, sometimes in the lungs, and grows silently for years before manifesting itself.

It is not caught from person to person or by eating cooked mutton.

Actions that really protect, without changing anything in the affection shown to animals: do not give raw offal to dogs, regularly deworm herd dogs, wash your hands after any contact with a dog and before meals, wash raw vegetables, dispose of slaughter waste properly and respect the control of carcasses at slaughter.

These measures have proven their worth: where they are applied sustainably, the disease declines significantly in humans.

Prognosis

In dogs, the prognosis is excellent: the infestation does not make them sick and the appropriate treatment eliminates the worms.

The issue lies elsewhere: each untreated carrier dog continues to scatter eggs around it. This is why this sheet places more emphasis on prevention than on care.

Frequently asked questions

My dog seems in great shape, can he still be a carrier?

Yes, and that is the heart of the problem. The worm measures a few millimeters, causes no symptoms and is not seen in the stool. A perfectly healthy dog can shed eggs for months.

After slaughtering a sheep, can I give the liver and lungs to the dog?

No, never believed: this is precisely how dogs become infected. If you want to give it to him, these offal must be completely cooked. Organs with cysts should be disposed of out of reach of dogs.

Is it dangerous to pet a farm dog or let it approach children?

The contact itself is not the problem: the risk comes from the hands being brought to the mouth afterwards. Wash your hands, especially those of children, after touching a dog, and prevent them from licking their face. A dog that is dewormed regularly represents a very low risk.

Can you get hydatid cyst from eating mutton?

No. Sheep meat, cooked or not, does not transmit the disease to humans. Contamination occurs only through the ingestion of eggs eliminated by the dog.

Is a commercial dewormer enough for this parasite?

Not necessarily. You need a molecule active on flatworms, and the rhythm is as important as the product. In a herding dog, the veterinarian prescribes a targeted and close treatment.