Contagious ecthyma is a viral disease of sheep, in which ulcers, vesicles, papules and crusts form on the oral mucosa, skin of the lips, genitals and udder. Animals aged 1.5 to 3 months are most susceptible. The mortality rate of young animals is 90%, of adults – 5-10%. The virus can survive in scabs at room temperature for up to 15 years.
Causes of the disease
The causative agent of contagious ecthyma is an epitheliotropic virus belonging to the Poxviridae family. Under favorable conditions in the external environment, it persists for quite a long time - from 4 to 15 years.At high air humidity and under the influence of high temperatures, it is quickly disinfected.
The carriers of the disease are recovered or infected individuals. Their secretions enter the external environment, contaminating the litter, drinking bowls, feeders, and pastures. If there are papules and vesicles on the ewe's udder, the lambs will be infected.
Outbreaks of contagious ecthyma occur in young sheep when they are separated from their mother and moved to other pastures. The general maintenance of healthy and infected animals leads to the fact that after 2-3 weeks from the moment of infection, the parapox virus affects the entire herd.
Signs and symptoms
Depending on the dose of the virus that has entered the animal’s body and its immunity, the incubation period ranges from 4 to 8 days. In young sheep, abscesses and papules form:
- on the mucous membrane of the oral cavity;
- on bare scalp (nostrils, eyelids, cheeks);
- genitals.
First, red spots appear in the corners of the mouth and along the edges of the lips, within which nodules form, turning into pustules and vesicles. After a while they open, the integrity of the mucous membrane is damaged. In place of the ulcers, scabs and a dry crust of dark brown color form. Infected lambs develop a fever and have difficulty eating or drinking water. As a result of exhaustion, almost 90% of the young animals die.
If the virus affects the lamb's hooves, they become sensitive and the animal lame.The genital form of the disease is characterized by the formation of ulcers and crusts on the inner surface of the thighs, on the foreskin of the penis, and on the udder. The recovery period for individuals that have been re-infected is 40-50 days.
Diagnostic rules
Help to establish the fact of disease in sheep:
- Clinical and laboratory tests of smears. Samples of scabs or purulent discharge are sent for testing. If group or fractional colonies of dark red elongated bodies of the epitelotropic virus are found in them, the animal is infected.
- Biological samples. They are carried out on clinically healthy individuals by rubbing liquid from scabs into the inner thigh of their skin. If, after 3-5 days from the moment of infection, lambs exhibit classic symptoms, this is contagious ecthyma.
When making a diagnosis, it is necessary to exclude diseases such as mycotic dermatitis, necrobacteriosis, foot-and-mouth disease and smallpox.
How to treat contagious ecthyma of sheep
Having discovered signs of parapox virus infection in sheep, they begin to treat it:
- the virus has reached the oral mucosa. Therapy involves treating the affected area with a 1% solution of potassium permanganate, 5% copper sulfate, 3% carbolic acid emulsion, 3% hydrogen peroxide;
- if the skin is affected, use a 10% solution of copper sulfate, salicylic or dibiomycin ointment, and tincture of iodine.
If the sheep practically does not eat food (severe course of the disease), it is treated with the listed means or prescribed broad-spectrum antibiotics along with biomycin.
Disease prevention
Measures to prevent the spread of the disease:
- separation of infected individuals from the general herd;
- carrying out preventive measures in the external environment to destroy the infectious agent;
- When purchasing sheep from other farms, the animals are quarantined for up to 30 days. During this period, they are examined for signs of the disease every week;
- maintaining watering places, pastures and sheep farms in a condition that complies with sanitary and veterinary standards;
- timely vaccination of animals, after which the sheep become immune to the virus for 6-8 months;
- regular implementation of measures for disinfection of inventory, equipment, work shoes and clothing, buildings and surrounding areas.
It is not recommended to graze livestock on pastures where sick animals were kept for 2 years.
