How to prevent and treat orf in sheep? A full analysis of prevention and treatment methods

Orf in sheep, also known as contagious ecthyma of sheep, is a contact infectious disease of sheep and goats caused by a virus, characterized by the formation of papules, vesicles, pustules and wart-like scabs on the lips, tongue, nose, udder and other parts. The antigenicity of viruses isolated from different regions is not entirely consistent. Let us take a look at the prevention and treatment methods for orf in sheep below!

Clinical symptoms of orf in sheep

1. Sick sheep: Sick sheep have decreased appetite, poor spirits, increased oral temperature, and red and swollen gums. Scattered small red spots appear around the eyes, at the corners of the mouth, on the upper lip and on the nose pad. The red spots gradually become papules and small nodules, then become vesicles and pustules, and after rupturing form yellow or brown wart-like hard scabs. After 1 to 2 weeks, in milder cases the scabs on the affected parts dry and fall off, leaving red spots. In severe cases, ulcers of varying sizes appear on the gums, tongue surface and buccal mucosa, then form papules, vesicles, pustules and scabby crusts, which merge with each other to form large areas of scabby crust. The scabby crust continuously thickens, and granulation tissue proliferation accompanies it beneath the scabby crust. The entire lip of the sick sheep becomes swollen and everted, presenting a mulberry-like bulge, seriously affecting feeding.

2. Dead sheep: Dead goats are extremely emaciated, with black scabs on the lips, and the scabs extend to the face. There are vesicles, ulcers and erosions in the oral cavity, and hemorrhagic spots under the facial skin. There are scabs and ulcers at the corners of the mouth, lips, tongue surface and other parts. The tracheal rings show hemorrhage and congestion, the lungs are congested and swollen with a darkened color, the myocardium and epicardium show punctate hemorrhage, the small intestinal wall becomes thin with mild hemorrhage, and no characteristic changes are seen in other parts.

Preventive measures for orf in sheep

1. In areas where this disease is prevalent, an attenuated vaccine strain identical to the locally prevalent strain can be used for immunization. The Gansu Institute of Animal Husbandry and Veterinary Medicine of China, through continuous passage in calf testicular cells, developed an attenuated strain into a freeze-dried live vaccine, suitable for scratch inoculation of the lower lip mucosa of sheep and goats of various ages, with an inoculation dose of 0.2 milliliters per animal. It can also be inoculated by scratching the skin on the inner thigh. The immunity period is 3 months. When used on a large scale in the field, the protection rate reaches more than 80%.

2. In areas where this disease is prevalent, naturally diseased sheep scabs can also be collected, ground, and made into a 1% virus suspension with 50% glycerol-saline buffer, then inoculated by scratching the hairless area at the tail base of healthy sheep. After about 7 days, inflammation or pustular lesions occur at the inoculation site, followed by scabbing, and after several weeks the scabs fall off. This method of immunization can produce lasting immunity. Inoculation of ewes should be completed 3 to 4 weeks before parturition. This method carries the risk of spreading the virus, so it is limited to use in epidemic areas.

Treatment methods for orf in sheep

1. Melt 1 kilogram of marmot oil and mix evenly with 300 grams of trichlorfon, then apply to the affected area. Recovery can occur after 1 day. This method has been used to treat more than 12,000 sheep, all of which were cured.

2. Ribavirin (ribavirin injection) 100 mg/mL and dexamethasone injection 5 mg/mL, mixed at 2:1 for intramuscular injection, 3 mL for adult sheep, halved for lambs or 2 mL, with local application of iodine glycerin or gentian violet. Generally, after 2 to 3 days of medication, the effect is relatively good and the cure rate is high. Severe cases should also be combined with penicillin and streptomycin twice daily.

3. Use sterilized surgical scissors and forceps to remove the scabs and pustule skin of affected sheep, disinfect the wound surface with strong disinfectant solution, then mix Bingpeng San powder (borneol 50 grams, borax 500 grams, glauber's salt 500 grams, cinnabar 30 grams, ground into powder and mixed evenly) with water into a paste, apply to the affected area, apply once every other day, for 2 to 3 consecutive applications, treating for 7 to 10 days, until the scabs or crusts at the affected area fall off. A total of 20 cases were treated, all cured.

4. The wound surface may be treated with the following drugs: 2% gentian violet or 3% iodine tincture glycerin (iodine 3 grams, potassium iodide 5 grams, 75% alcohol 10 mL dissolved, then add glycerin 10 mL) or iodine-pine tar-stone mixture (iodine tincture 1 part, pine tar 1 part, paraffin oil 1 part), twice daily for 3 consecutive days.

5. After removing the scabby crust, first wash the wound surface with 0.1% potassium permanganate water, then use a mixture of 3% iodine tincture, pine tar oil and paraffin oil (1:2:2), mix evenly before use, or iodine glycerin (7% iodine tincture 70 mL plus anhydrous glycerin 30 mL), all once daily for 7 consecutive days, then after 3 days proceed to the next course of treatment.

6. Application of traditional Chinese medicine to ulcer surfaces

① A mixture of bletilla powder, vegetable oil and borneol (10:5:1), mixed evenly.

② Equal parts of rendongbai, artificial cow bezoar, indigo naturalis, borneol, gypsum and catechu, ground together into powder.

③ Indigo naturalis 9 grams, phellodendron 9 grams, coptis 6 grams, platycodon 6 grams, catechu 6 grams, mint 3 grams, ground into powder.

④ Koujiling: more than ten herbs including indigo naturalis, phellodendron, violet, dried alum and baijiaojian are ground into fine powder and mixed with water into a paste.

⑤ Catechu 15 grams, dried salt 12 grams, rendongbai 9 grams, coptis 9 grams, feifan 9 grams, indigo naturalis 6 grams, ground together into fine powder and applied or sprayed into the oral cavity. The above drugs are applied 1 to 2 times daily. Use cotton dipped in 50 g/L copper sulfate aqueous solution to wipe off the hard scabs, then apply iodine glycerin (50 g/L iodine tincture 100 mL, glycerin 100 mL) to the affected area.