Sarcoptic mange in pigs is common in winter, pig farmers should take preventive measures

Sarcoptic mange in pigs, also called scabies, commonly known as mange, is caused by Sarcoptes scabiei mites parasitizing in the pig's skin, causing skin lesions such as red spots, pustules, crusts and fissures. It is characterized by intense itching, restlessness, reduced appetite, slow growth and decreased feed conversion, and is one of the diseases that seriously harm @#@227@#@ production. It is widespread in some farms and difficult to cure. The severity of its clinical symptoms is related to the pig's resistance. When climatic conditions are suitable and feeding management is good, the pig's resistance is strong and there are generally no obvious symptoms. In the high-temperature summer season, frequently washing the pig pens and pig bodies helps to alleviate the symptoms of sarcoptic mange; when the weather is cold, the pig's physical reserves are heavily consumed, and feeding management is poor, the pig's resistance declines and the clinical symptoms worsen.

Life cycle and epidemiological characteristics of Sarcoptes scabiei

The entire development process of mites of the family Sarcoptidae takes place on the animal body, including four stages: egg, larva, nymph and adult, among which the male mite has 1 nymphal stage and the female mite has 2 nymphal stages; the entire development process of Sarcoptes scabiei is 8 days to 22 days, with an average of 15 days. The survival period of Sarcoptes scabiei outside the host varies significantly with changes in various factors such as temperature, humidity and intensity of sunlight exposure. At 18°C to 20°C and an air humidity of 65%, it dies after 2 days to 3 days; while at 7°C to 8°C, it dies only after 15 days to 18 days.

Causes of the disease

Sarcoptic mange occurs mainly in winter and in late autumn and early spring, because in these seasons sunlight exposure is insufficient and livestock hair is long and dense. Especially under conditions of damp sheds, poor animal body hygiene and relatively high skin surface humidity, it is most suitable for the development and reproduction of mites. From late autumn to early spring each year, northern China mostly uses plastic sheeting covering for insulation when raising pigs. This method has poor ventilation and insufficient light, leading to another major disease in winter pig production besides respiratory diseases --- sarcoptic mange in pigs.

Clinical symptoms

Pigs are only infested by Sarcoptes scabiei, and piglets are more commonly affected. At the beginning of the disease it starts from the eyes, cheeks and base of the ears, then spreads to the back and the inner side of the hind legs; affected pigs often rub the affected areas against walls, pig pens, troughs and other places, and in severe cases this causes bleeding, connective tissue proliferation and skin thickening, with localized hair loss. Due to itching, the affected pigs' normal feeding and resting are affected, and their digestive and absorptive functions are reduced; in cold seasons, because of hair loss and exposed skin, body heat is lost in large amounts, and accumulated body fat is heavily consumed, leading to emaciation; sometimes when secondary infection is severe, it causes death.

In summary, intense itching, hair loss, crusting, skin wrinkles or fissures, and high contagiousness are the characteristics of this disease.

Diagnosis

For sarcoptic mange with obvious symptoms, diagnosis can be confirmed based on the season of onset, intense itching and skin lesions in the affected areas; when symptoms are not obvious, it is necessary to take crusts from the junction between healthy and diseased areas and examine them for the presence of mites to confirm the diagnosis.

Clinically, attention should be paid to distinguishing it from eczema, allergic dermatitis, and infestation by lice and biting lice.

Prevention and treatment

① In terms of feeding management, improvements should be made starting from several aspects: hygiene, lighting, ventilation, dryness, density, disinfection and enhanced nutrition.

② For severely infected pig herds (farms), commercial coccidia vaccines and certain nematode vaccines can be selected for vaccine immunization, together with regular deworming work (especially in winter). At intervals of 2 months to 3 months, mix two tablets of Chudazhuang tablets per 35 kg of body weight into the feed once for prevention.

③ Diseased animals should be isolated promptly and treated with chemical drugs. Ivermectin injection by subcutaneous injection at 0.2 mg to 0.3 mg per kg of body weight, with a repeat injection after 10 days to 14 days; or oral administration of Chudazhuang tablets, two tablets per 35 kg of body weight, repeated once after an interval of 7 days to 10 days (because most acaricides at that time can only kill the mites but not the eggs, treatment must be carried out 2 times to 3 times, with an interval of 7 days to 10 days, to kill the newly hatched larvae).