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parasitic disease Cow Transmissible to humans

Calf cryptosporidiosis

Cryptosporidiosis is caused by a microscopic parasite, Cryptosporidium parvum, which attaches to the wall of the calf's small intestine and destroys the cells responsible for absorbing nutrients. It mainly affects the calf between the end o...

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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?

Cryptosporidiosis is caused by a microscopic parasite, Cryptosporidium parvum, which attaches to the wall of the calf's small intestine and destroys the cells responsible for absorbing nutrients.

It mainly affects the calf between the end of the first week and the third week of life, a little later than colibacillosis.

It is one of the most widespread causes of calf diarrhea in the world, and it is distinguished by two characteristics: no vaccine exists, and the parasite is transmitted to humans.

Key point

It is calf diarrhea that deceives the most: the animal continues to suck even though it is becoming dehydrated. Preserved appetite is never a reassuring sign in case of liquid stools.

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 Dehydration Reduction Loss of appetite Pain Fatigue Stunted growth Dull coat

Yellowish or greenish diarrhea, often pasty to liquid, sometimes containing mucus.

Diarrhea lasts several days and may recur in waves, which distinguishes it from sudden, short-term diarrhea.

Appetite preserved at the beginning: the calf is still suckling even though it is emptying itself, which often deceives the breeder.

Abdominal pain: the calf pushes, lies down groaning, keeps its back rounded.

Progressive dehydration with sunken eyes and persistent skin folds.

Dejection, then weight loss and dull hair.

Fever is usually absent or moderate.

Calves that recover often remain stunted for weeks.

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 parasite Cryptosporidium parvum, which multiplies in the small intestine and destroys the villi, these microscopic reliefs through which the calf absorbs water and nutrients.

Once the mucous membrane is damaged, the milk is no longer digested correctly: diarrhea persists even after the parasite has disappeared.

The infection is frequently associated with other agents – rotavirus, coronavirus, colibacillus – and the disease is then more serious.

Damp building and litter rarely replaced: the parasite survives there for a very long time.

High density of calves and grouped calving season.

Mixture of ages: adults contaminate newborns.

Lack of colostrum, which does not prevent infection but significantly aggravates the disease.

Common and poorly cleaned drinking and feeding equipment.

Reuse of the same box without complete cleaning between two calves.

Association with other agents of diarrhea, very common.

Transmission

The infected calf sheds enormous quantities of resistant forms of the parasite, the oocysts, in its stools.

These oocysts are immediately infective as soon as they are released: there is no maturation time, contamination from one calf to another is therefore very rapid.

They are extremely resistant in the outdoor environment, surviving for months in humid and cool environments, and resisting many common disinfectants as well as water chlorination.

Contamination occurs through the mouth: litter, udder, buckets, breeder's hands and boots, contaminated water.

Adults and cured calves can excrete without being sick and maintain contamination of the building.

Diagnosis and care

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

The veterinarian evaluates dehydration and looks for other causes of diarrhea, because associations are the rule.

The diagnosis is confirmed by a stool examination in the laboratory or by a rapid test carried out on site.

Identifying the parasite changes the course of action: it avoids unnecessary antibiotics, directs you towards a specific product and imposes particular hygiene measures, including for people.

The age of the calf at the time of the first signs is useful information: it helps to distinguish the different causes of diarrhea.

Treatment

Rehydration, started early, remains the action that saves the calf: death is due to the loss of water and salts, not to the parasite itself.

Antibiotics have no effect on this parasite. Giving it without reason delays useful treatment and encourages resistance.

There is a specific treatment, prescribed by the veterinarian, which reduces the severity and duration of the shedding. It is all the more useful the sooner it is implemented.

The milk diet is maintained according to the veterinarian's advice: the damaged mucous membrane digests poorly, but the calf needs energy.

Sick calves should be isolated, kept dry and warm, and cared for last in the work order.

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

Prevention

Reducing the quantity of parasites in the environment is the only truly effective lever, in the absence of a vaccine.

Drain, clean then let the boxes dry between two calves; drying and crawl space are as important as disinfectant.

Choose a disinfectant that is effective against oocysts: many common products are not. Ask the veterinarian for advice.

House calves separately for the first few weeks when possible, and never mix ages.

Avoid the litter being damp: this is the most determining environmental factor.

Give quality colostrum as early as possible: it does not prevent infection but significantly reduces the disease.

Clean buckets and teats after each use, deal with sick animals last, change gloves between animals.

Protect water points and food storage from contamination by droppings.

Possible complications

Severe dehydration, especially when other agents of diarrhea are combined.

Long-term growth retardation due to destruction of the intestinal mucosa: the calf digests poorly for several weeks.

Diarrhea which continues after the disappearance of the parasite, while the intestine rebuilds itself.

Increased fragility in the face of respiratory infections in the months that follow.

Long-lasting contamination of the building, with cases repeating from one calving season to the next.

When to see a veterinarian

A one to three week old calf has diarrhea that lasts more than a day.

He is still suckling but is emptying: don't trust his appetite, dehydration is progressing.

He pushes, moans or keeps his back rounded.

His eyes sink, the skin on his neck remains wrinkled when pinched.

Several calves from the same batch show the same diarrhea: have the causative agent identified.

A person on the farm, in particular a child, develops diarrhea after being in contact with the calves: consult a doctor and report this contact.

Transmission to humans

Cryptosporidium parvum is transmitted to humans and causes sometimes prolonged diarrhea, accompanied by abdominal pain.

Contamination occurs through hands brought to the mouth after contact with a sick calf, its bedding or its equipment. A very small amount of parasites is enough.

Wash your hands with soap and water after each contact and before eating or smoking. Hydro-alcoholic gels do not destroy this parasite: washing with soap is essential.

Wear gloves when caring for diarrheal calves, as well as boots and clothing intended for breeding, removed before entering the house.

Keep young children away from sick calves: they easily put their hands in their mouth and develop more pronounced shapes.

People with weakened immune systems should avoid contact with diarrheal calves; in them, the infection can be severe and long-lasting.

Any diarrhea occurring in a person on the farm must be reported to the doctor, specifying contact with calves.

Prognosis

Most calves recover if rehydrated in time.

Recovery is slower than for other diarrhea, and it may take weeks for growth to resume.

The prognosis is significantly worse when other agents are combined or the calf has received its colostrum poorly.

On a building scale, the parasite re-establishes itself easily: the results depend on the thoroughness of cleaning and drying between calves.

Frequently asked questions

Can I catch cryptosporidiosis from my calves?

Yes. It is one of the few calf diseases that actually transmits to humans, and only a very small amount of parasites are needed. Wash your hands with soap after each contact, wear gloves when caring for sick calves, and keep young children away.

Is hydroalcoholic gel enough after treating a calf?

No. This parasite is resistant to alcohol. Only careful hand washing with soap and water, while rubbing, can eliminate it.

Is there a vaccine?

No, there is no vaccine against calf cryptosporidiosis. Prevention is entirely based on hygiene, drying of premises, age separation and good colostrum intake.

Why does diarrhea continue after treatment?

Because the parasite has destroyed the surface of the intestine. Even once it is gone, it takes time for the lining to rebuild and the milk to be properly digested again.

Is the disinfectant I usually use effective?

Not necessarily: many common disinfectants do not act on the resistance forms of this parasite. Ask your veterinarian for a suitable product, and remember that cleaning and letting the box dry is already considerable progress.