What are the epidemic characteristics of bovine mucosal disease?

Bovine mucosal disease is also called bovine viral diarrhea ~ mucosal disease, referred to as bovine viral diarrhea. The general manifestations are fever, runny nose, cough, watery diarrhea, emaciation, leukopenia, mucosal erosion of digestive tract and obvious damage to lymphoid tissue. It is an important infectious disease of cattle.

The pathogen is goat virus belonging to powdery membrane virus, which is related to classical swine fever virus and can have specific precipitation reaction with each other in agar diffusion test. It is reported that pigs can be immunized against classical swine fever by inoculating attenuated strains of the virus.

Cattle of different breeds, sexes and ages can be susceptible, but calves aged from 6 to 8 months have the most serious symptoms. The blood, secretions and excretions of cattle suffering from acute diseases contain viruses. The disease can be transmitted through digestive tract, respiratory tract and reproductive route. After pregnant cows are infected, the virus can be transmitted to the fetus through the placenta, causing miscarriage and stillbirth. The disease can break out in new endemic areas, mainly in calves.

Sick cows can generally be divided into acute and chronic in clinic.

Symptoms of upper respiratory tract infection occur at acute onset, with fever of 40 ~ 42℃, runny nose, cough, salivation, tears, shortness of breath and leukopenia. Then, the oral mucosa is inflamed, and tiny erosions or ulcers are scattered on the lips, gums, cheeks of maxilla, tongue and inside of nasal endoscope, resulting in thin feces, such as watery diarrhea mixed with bloody gas. Cows stop lactation and pregnant cows miscarry.

Cows with chronic diseases often have long-term or intermittent diarrhea, runny nose, dry scab on nasal endoscope, repeated necrosis and ulcer of oral mucosa, excessive tears or viscous and transparent diarrhea, and sick cows have chronic hoofitis. Sick cows often die or are eliminated because of poor development. At present, there is no effective treatment for this disease.