Bovine parainfluenza-3: symptoms, treatment and prevention

When transporting cattle, buying calves or moving them to other farms, a highly contagious disease - parainfluenza-3 of calves and cattle (Paragrippus bovum) - may occur. This disease is otherwise called "transport fever", in English - parainfluenza-3. The disease is manifested by high fever, catarrhal phenomena of the nose and throat, lesions of the bronchi and lungs. With a hyperacute course, a lethal outcome is possible.

Historical background

Symptoms of the disease in cattle were first reported and described in the United States by Scott and Farley (1932).). Initially, there was an erroneous opinion about the causative agent of the disease - bacteria of the genus Pasteurell. In 1959, it was found that the causative agent is a virus characterized by an antigenic structure similar to the human parainfluenza-3 virus (PG-3). In the USSR, the disease was first registered in 1969

At present, the disease has not been overcome in the global industrial animal husbandry, a set of quarantine measures and mandatory vaccination of animals against bovine PG-3 has been developed in all countries.

Causes of pathology

The etiology of the disease is associated with the introduction into the epithelium of the respiratory tract of cattle, especially calves, a virus belonging to the paramyxovirus family. Its size is 150-250 nanometers, RNA is present in the structure. The danger of defeat lies in the fact that the virus has the properties of gluing, decomposition and sedimentation of blood erythrocytes (hemagglutination, hemolysis and hemadsorption). As a result of the penetration of the virus into the body, two types of antigens appear in the blood of animals: S and V.

The virus is spread by air currents from the respiration of animals, nasal fluids and expiration from the reproductive organs of cows.

During crowded transportation of livestock or keeping in rooms with high air humidity from the carrier, the virus penetrates the respiratory epithelium of he althy animals and begins to multiply actively, causing symptoms of the disease.

Symptoms of parainfluenza-3

In adult animals, the disease is mild. In calves, variants of the course of the disease are possible:

• spicy (including extra-spicy);
• subacute;
• chronic.

Depending on the variant and severity of the course of parainfluenza-3, it can occur in the form of rhinitis, bronchitis, bronchopneumonia. Each type of the course of the disease is characterized by a complex of features.

Spicy

This type is divided into two stages - super-acute and acute. In the first variant of the course, if calves fall ill before 6 months, then coma and death are possible within the first 24 hours from the onset of the disease. In an acute course, in the first 2-3 days, an increase in body temperature to 41-42 degrees is observed, a dry cough, nasal and eye discharges increase. The animal refuses to eat, breathing becomes rapid and shallow (up to 84 breaths per minute), the heart rate increases to 120 beats per minute. Later salivation and diarrhea join. The animal quickly loses weight, inhibition of nervous and cardiac activity is possible. Wool looks dull, disheveled.

Subacute

Subacute course of bovine PG-3 disease is characterized by the same symptoms as acute, but the body temperature does not rise to such high values, and the condition of the animal is not very depressed. Full recovery occurs in 7-10 days.

Chronic

This variant of the course of the disease develops as an unfavorable complication and is expressed as chronic bronchopneumonia. Animals become significantly emaciated, cough and rhinitis become protracted and difficult to treat. In the lungs of animals, wheezing and crepitus can be heard. Cattle with this stage of the disease are usually slaughtered because the animals are very weak, and sick pregnant cows infect calves in utero. The question of the suitability of carcasses for sale is decided upon analysis for pathological changes.

Treatment methods

Treatment is effective in a complex of activities carried out in the acute and subacute stages. It includes general measures, administration of hyperimmune serum and antibiotic therapy.

Common wrestling meta

Of great importance in the recovery of animals is the organization of normal conditions and the regime of keeping - complete feed, frequent ventilation and disinfection of premises, replacement of bedding, stay of cows and calves in the open air, compliance with spatial requirements when keeping young cattle. When examining an animal, a veterinarian may prescribe general strengthening and symptomatic therapy, which includes:

• antiviral drug "Mixoferon";
• "Trivitamin" - to activate metabolic processes - intramuscularly, 5 ml of the drug per day;
• bronchodilators and expectorants - Theobromine, Theophylline, ammonium chloride, potassium iodide;
• in case of depression of nervous and cardiac activity in cattle - solutions of caffeine, camphor, glucose;
• diuretics.

Sick animals are isolated in separate sections or boxes, after which the premises are completely disinfected, and contact animals are vaccinated. Farm quarantine is imposed for 14 days from the date of the last case of the disease.

Hyperimmune Serum

Assigned as early as possible when a disease is detected. The serum contains antibodies to the PG-3 virus, while they have not yet been developed in the own body of sick calves

In addition to hyperimmune serum, for the treatment of parainfluenza-3, serum of convalescent calves with a high level of antibodies is used, immunoglobulins are effective.

Antibiotics

Antibiotics are prescribed to prevent bacterial infection and pneumonia in animals.Modern antibacterial drugs belong to the groups of cephalosporins, macrolides. Susceptibility testing of microflora can also show the effectiveness of sulfa drugs. In a more severe course of the disease, combined antibiotics are prescribed - Oleandovetin, Tetraolean.

Immunity

After birth, up to 2-4 months, calves can retain immunity obtained with cow's milk. However, it does not guarantee protection against animal disease during transit or temporary crowding.

For reliable protection of young cattle from PG-3, a dry cultural vaccine "Paravak" has been developed. In disadvantaged farms, it is more effective to use a complex vaccine against parainfluenza-3 and infectious bovine rhinotracheitis - "Bivak". Calves from 20 days of age are subject to immunization. Vaccines are administered in two doses: the first time - in the nasal passages, the second, after 2 weeks - subcutaneously.Immunity is formed 2 weeks after the second injection and lasts 6 months.

Prevention measures

Prevention of parainfluenza-3 dictates to farms a special regime for keeping and receiving animals:

• if cattle are purchased from abroad, they are kept in quarantine for at least 30 days;
• young animals are purchased only from reliable suppliers;
• livestock management is carried out according to the flow scheme - the entire barn is filled, then immediately released, followed by a complete disinfection of the premises;
• strict adherence to cleaning and ventilation of premises with animals;
• The veterinary control service should inspect animals several times a day.

Responsibility for the spread of the disease lies with the heads of livestock enterprises. This should be remembered by every leader, only under their strict control and with immediate action it is possible to achieve a he althy livestock.

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