Paratuberculosis of cattle: causes and symptoms, prevention

Paratuberculosis in cattle is one of the most insidious and dangerous diseases. It not only brings economic losses. Other domesticated herbivorous artiodactyls are also susceptible to the disease. But the main problem is that paratuberculosis may also infect humans.

What is paratuberculosis

Other names: Yone’s disease and paratuberculous enteritis. This chronic bacterial disease is characterized by intermittent diarrhea, productive enteritis, gradual malnutrition and subsequent death of the animals. The causative agent of the disease is the bacterium Mycobacterium avium subspecies paratuberculosis.

Susceptible to bacteria:

• cattle;
• sheep;
• buffalo;
• camels;
• goats;
• deer;
• or

The rating of animal species is built on the decrease in the level of susceptibility to bacteria.

Causative agents of paratuberculosis in cattle under a microscope

The bacterium Mycobacterium avium is common in almost all countries with intensive livestock production. Microorganisms are well preserved in soil and manure – up to 10-12 months. In stagnant water bodies and feed, bacteria remain viable for 8-10 months.

Mycobacterium avium is also very resistant to disinfectants. The best preparations for disinfection in case of a paratuberculosis outbreak:

• formaldehyde;
• xylonaphtha;
• freshly slaked lime;
• cresol;
• caustic soda.

All drugs are poisonous to humans.

Most animals either do not get sick, or cattle become a latent carrier of paratuberculosis. The mortality rate for Mycobacterium avium infection is only 1%. But this 1% includes the entire population of cattle, which has obvious clinical signs. Otherwise, the disease is dangerous because it reduces the productivity of animals.

In humans, similar signs are observed, but the possibility of infection with bovine paratuberculosis is still in question. This problem has not yet been fully explored. Perhaps another disease causes similar symptoms.

A person infected with paratuberculosis in the last stage of the disease

Sources and routes of infection

The source of infection is a sick animal. Private owners need to be especially careful, as the bacterium is easily transmitted from one artiodactyl species to another. The source of infection is the feces of a sick animal. Paratuberculosis in cattle develops slowly, and an outwardly healthy animal can actually already be a carrier of the infection.

Most often, infection occurs during the first year of life. The calf ingests the bacteria in its mother’s milk or dung particles if the cattle are kept in unsanitary conditions. Cleanliness in foreign cowsheds is not from a high culture. Just dried manure on the thighs of a cow is a breeding ground for pathogenic bacteria. It is also possible intrauterine infection.

A clear illustration of the ways the infection spreads: the faeces of a sick animal fall into the water and hay

Cattle are most susceptible to paratuberculosis in the first year of life. But the signs of the disease appear only after 2 or more years after infection. If a cow becomes infected with paratuberculosis at an older age, she will definitely not show clinical signs until 2 years after infection. The same applies to a calf that has received a small dose of paratuberculosis pathogens.

Provoking factors:

• decreased immunity due to inadequate feeding;
• helminths;
• hypothermia;
• overheating.

All this can be attributed to improper conditions of detention.

In the second stage of the disease, diarrhea is liquid, and the animal has significantly lost weight.

Symptoms of paratuberculosis in cattle

The main signs of Mycobacterium avium infection in cattle are diarrhea and malnutrition. Moreover, usually the clinical manifestation of symptoms occurs at the age of 2 to 6 years, although cattle become infected even in the first year of life, and even in the womb.

At the first stage, the signs of paratuberculosis are mild. They can be expressed in weight loss, reduced productivity and a slight ruffle of the coat. The cow defecates more often than normal, but the manure is quite thick, without epithelial residues, blood or mucus. Periodically, the work of the digestive tract returns to normal.

A few weeks after the onset of diarrhea in cattle, the soft tissues of the lower jaw swell. This symptom is known as “bottle jaw” or “intermaxillary edema. Edema is caused by the removal of protein from the blood stream as a result of disruption of the gastrointestinal tract.

Swelling of soft tissues under the lower jaw and on the breast with bovine paratuberculosis

With the further progress of the disease, cows lose more and more weight. Death occurs as a result of dehydration and severe cachexia.

Symptoms of dehydration

Dehydration is the loss of water by the soft tissues of the body as a result of metabolic disorders. In paratuberculosis, dehydration occurs as a result of diarrhea. If more than 25% of water is lost by soft tissues, the animal dies.

Dehydration is accompanied by:

• thirst;
• oppression;
• decrease in the amount of urine;
• convulsions;
• with a pinch test, the skin fold does not straighten out for a long time;
• wool is dry, disheveled;
• nasolabial speculum dry.

Dehydration in paratuberculosis of cattle occurs already at the last stage of the disease.

Cachexia

Outwardly, it does not differ from dehydration, but with cachexia, the animal does not lose water. With this phenomenon, cattle lose weight. There is muscle atrophy and weakness. But the pinch test does not show dehydration. However, in paratuberculosis, cachexia and dehydration are combined.

Appearance of cattle with paratuberculosis at the second stage of the development of the disease

Diagnosis of the disease

Symptoms of paratuberculosis coincide with signs of other diseases and even non-contagious diarrhea caused by improper diet. Paratuberculosis must be differentiated from:

• strongyloidosis;
• coccidiosis;
• tuberculosis;
• alimentary diarrhea.

The diagnosis is established taking into account epizootological data in the region.

Diagnosis is carried out by 2 methods:

• serological;
• allergic.

With serological serum, serum is made from the blood of suspicious individuals, after which they are analyzed using RSK. The percentage of detection of sick animals is 85%.

With the allergic method, there are two ways to check: altuberculin for birds and paratuberculin. In the first case, 80% of sick individuals show a positive reaction, in the second – 94%.

Allergic diagnostics is carried out using an intradermal test. The reaction is checked after the first injection after 48 hours. With a positive reaction at the injection site, edema appears without strict boundaries and configuration, approximately 4×11 cm in size or more. Local temperature at the site of the tumor is elevated. The edema is testy at the edges, hard in the center. The injection site is painful.

If suspicious individuals gave a dubious reaction, the test is done again. The result is checked a day after the injection.

Not only lymph nodes and parts of the intestines from slaughtered and dead animals are sent to the laboratory. Also, feces with scraps of mucous and lumps of mucus are sent there for bacteriological examination.

Treatment of paratuberculosis in cattle

There is no treatment. Even the impact of the vaccine remains in question. All animals diagnosed with paratuberculosis are slaughtered. These requirements apply even to calves born from sick cows.

Prevention

Since healthy cattle become infected with paratuberculosis from sick individuals, measures are taken to prevent unnecessary contact and increase the individual resistance of the cattle organism to the pathogen of paratuberculosis.

They observe zoohygiene: animals of different species susceptible to the disease are kept in separate buildings. Distances between farms should be at least 100 m. Cattle and small cattle are not released for joint grazing.

Regularly conduct a study on paratuberculosis. Cattle with a positive allergic reaction to the CSC sample are sent for slaughter. Calves under the age of 10-18 months, who reacted twice to tuberculin, are also determined there.

For a person, the main preventive measure is the use of only pasteurized milk. Farm workers should keep their clothes clean and disinfect them in time.

They also carry out systematic disinfection of the cowshed (whitewashing of the walls) and treatment of inventory and equipment with disinfectant solutions.

Conclusion

Since paratuberculosis in cattle and other artiodactyls is incurable, sick animals should not be hidden from veterinary services. One sick animal can infect all other livestock in the area. In the event of an outbreak of an epizootic, veterinary services will destroy all susceptible animals in the region. This will cost more than slaughtering one diseased individual.