Pathogen and Epidemiology of Infectious vesicular Disease in Pigs

The disease is an acute infectious disease caused by porcine vesicular virus. Usually only pigs can be infected naturally, cattle, sheep and other animals are not easy to be infected, so it can be distinguished from foot-and-mouth disease. The disease is characterized by blisters in the skin and oral mucosa of the hairless part of the pig body. There are blisters and rotten spots around the crown of the hoof, between the toes, the skin of the heel and around the nipple of the sow. The disease is widely distributed and spreads rapidly. The disease was first found in Italy in 1966. In the 1970s, after the epidemic in the United States, Austria, Hungary and other Eastern and Western European countries, it also occurred in Japan, and the disease also occurred in Hong Kong, China.

1. The pathogen is porcine vesicular disease virus of enterovirus, which has antigenic relationship with human enterovirus Coxsackie B. The virus is three-dimensional symmetrical, roughly spherical, without envelope, and the virus has a certain resistance to heat. Within 50 ℃ 30 minutes, it was still contagious, 56 ℃ 30 minutes, 85 ℃ 1 minute could inactivate the virus, perm the hair of sick pigs, soak in 65 ℃-67 ℃ water for 3-5 minutes, the skin was still contagious. The virus can survive in feces and bacon for a long time and is highly resistant to alkali and disinfectants. It can be inactivated in 33 ℃ 3% caustic soda for 24 hours, or 13 ℃-18 ℃ 2% formalin for 24 hours, 5% formalin 1.5 hours. The bleach solution containing 0.5% available chlorine can be inactivated in 20 minutes at 10 ℃-25 ℃, and 70% alcohol, 4% coal phenol soap and 10% quicklime milk can be inactivated.

two。 Epidemiology this disease can be infected to pigs of different breeds and ages. In natural epidemics, only pigs can be infected, cloven-hoofed animals such as cattle and sheep are not infected, the disease has no obvious seasonality, and it is easy to occur in pig farms with high concentration and high feeding density. and wet and dirty places on the ground, in general scattered feeding conditions, rarely cause infection. Humans have a certain degree of susceptibility. But it doesn't necessarily form blisters. The symptoms of the disease are similar to those caused by Coxsackie virus in human intestinal tract. The disease is mainly infected by wounds of digestive tract, respiratory tract, skin and mucosa. The diseased part of pig head and hoof is highly toxic and contagious, and the same group of pigs and their products are the main source of infection. The feces and urine of diseased pigs and the means of transport contaminated by virus, feed and water are all infectious vectors. The disease can occur all year round. The general morbidity can reach 70% Mel 80%, and the mortality rate is very low.