| Porcine contagious pleuropneumonia(PCP),a serious respiratory infectious disease caused by Actinobacillus pleuropneumoniae(APP),results in great economic losses in pig industry worldwide. Zhoukou area is an important base of the pig industry of Henan province.In order to ascertain pig contagious pleuropneumonia in Zhoukou area,and to develope effective and comprehensive prevention and control measures,the following two aspects of studies were performed.First,all municipal veterinary stations and pig fanning associations,and 38 different types of pig farms in Zhoukou area have been visited and investigated.844 serum samples were collected from 5 pig farms(not vaccineated),and the antibody against APP was detected.Second,20 sows and 110 piglets were selected for vaccination,drug prevention experiments.1.By investigating,the results showed that the incidence of pig respiratory diseases was about 23.71%from 2005 to 2007 in Zhoukou.In the 38 investigated pig farms(households),The porcine contagious pleuropneumonia mainly happened in the winter.The pigs with PCP varied from 0 to 64.45 %.Among the infected pigs,343 pigs(12.8%) were under three weeks,621 pigs(23.2%) were from 3 to 6 weeks,1385 pigs(51.7%) were from 6 to 15 weeks,and 329 pigs(12.3%) were older than 15 weeks.The ill pigs were mainly foreign breeders,and had great relations with the importation of pig breeders.In Zhoukou,The common used vaccines were trivalent killed vaccine and autogene vaccine.18.42%of pig farms(households) performed the vaccination against porcine contagious pleuropneumonia.85.71%of the vaccinated pigs were protected from PCP.By detecting the antibody against APP in 844 serum samples collected from 5 pig farms where APP vaccine was not used,The positive rate of antibody was28.2%.It showed that the rate infected contagious pleuropneumonia of pigs was very higher.However,the positive rates of small pig farms were significantly lower than that of large-scale pig farms.The possible reasons were that they had smaller circulation and less chance of contamination.The infected sows were the main sources of APP infection.2.The vaccination,drug prevention experiments showed that the piglets from the vaccinated sows were protected from PCP when they vaccinated at 50-day old,whereas 54.4%(43/79) of the control piglets suffered with PCP.In addition,the vaccinated sows showed no respiratory signs,and 10%of the control sows(not vaccinated) exhibited respiratory signs.The incidence rates in both sows and their piglets had significent differences between experimental group and control group(P＜0.01). During the period of experiments,The incidence and lethal rates were 12%(3/25) and 4%(1/25), respectively,after they were immuned trivalent killed vaccine of contagious pleuropneumonia at the age of 30-day,then immuned once after one month,but the incidence and lethal rates of the control group were 44%(11/25) and 12%(3/25) respectively.Both rates had significent differentces between the two groups(P＜0.01).After vaccinated at 30-day-old,The mean levels of IHA antibody in the pigs at 60-,80-,and 100-day old were 1:38.5,1:24.3 and 1:18.8 respectively,while the those of control group were 1:5.9,1:6.3 and 1:9.0 respectively.This indicated that the active vaccination had a very good effect on preventing the pigs from PCP.In addition,several antibiotics were used to prevent and control PCP.The results showed that compound florfenicol,florfenicol,lincomycin-spectinomycin prcnux and ceftiofur hydrochloride were more sensitive for APP,especially the compound florfenicol had better curing effects.It was feasible to preventaion and control PCP by strengthening quarantine work,using all-in and all-out system,closing all pig farms and keeping good separation between production and external environments,ensuring feed quality and enhancing pig health status,enforcing strictly the veterinary health,epidemic prevention and disinfection systems,and vaccination and proper drug prevention.
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