Pathogen: Listeria monocytogenes is a gram-positive cocci with no capsule and spores. There are 7 serotypes, 1 1 subtype. It can survive in soil, feces and silage for a long time, and has certain resistance to heat, but it is not strong to general disinfection. Sick animals and infected animals are the main sources of infection, which spread through digestive tract, respiratory tract, conjunctiva and broken skin. The disease is sporadic and occasionally prevalent, with low incidence and high mortality. Malnutrition, sudden weather change, parasite or salmonella infection are often inducing factors.
Symptoms: Sheep suddenly become manic, turn around with their heads against the wall, groan, have difficulty chewing, and have shortness of breath. Generally, they die in 1~3 days, and pregnant sheep often miscarry. Meningeal brain tissue is hyperemia and edema, needle-shaped gray-white lesions can be seen on the meninges, and cerebrospinal fluid of encephalitis is turbid. Hepatomegaly, splenomegaly, renal pelvis and endocardium bleeding.
Diagnosis: The sick animals have special nervous system symptoms, and the increase of mononuclear cells in blood test can be suspected as the disease. Microscopic examination of blood, liver, kidney, cerebrospinal fluid, etc. If gram-positive bacilli are arranged or juxtaposed in a "V" shape, a preliminary diagnosis can be made. Diagnosis requires isolation and identification of bacteria.
Prevention and treatment: People are easy to be infected with Listeria, and the prevention and treatment of this disease is of public health significance. The epidemic situation can be controlled by not introducing animals into wards, expelling rodents and ectoparasites, and moving uninfected animals into clean houses.