2024年湖南省部分地区鸡球虫病流行病学调查OA

In order to investigate the prevalence,species distribution and composition of chicken Coccidia in Hunan Province,and to identify corresponding factors,a total of 245 fresh fecal samples were collected from 28 farms in 8 regions including Loudi,Xiangtan,Zhuzhou,Shaoyang,Yongzhou,Hengyang,Huaihua and Chenzhou,to count oocysts per gram(OPG)using the McMaster method,and to identify the species of Coccidia using multiplex PCR,followed by analysis on the differences in positivity rates by region,farming mode,purpose,day old and medication status.The results showed that the overall positivity rate was 59.18％(145/245),mild infection(OPG＜1 × 104)was predominant(72.41％).The positivity rate of samples was obviously different(P＜0.05)depending on various regions,and highest in Chenzhou(100％)and Shaoyang(100％);the differences were of statistical significance(P＜0.05)by farming mode,day old and medication status,specifically,the positivity rate was higher in medicated flocks(65.00％)than that of those non-medicated(33.33％);and higher in cage-free chickens than that of those caged.The positivity rate of broilers aged 15-60 days(70.00％)and＞60 days(58.33％)was higher than those＜15 days(33.33％);and that of layers aged 15-120 days(100％)was higher than those＞120 days(44.44％).No significant difference(P＞0.05)was observed between broilers(59.46％)and layers(58.33％).7 species of Eimeria were detected,with a mixed infection rate of 96.55％.Eimeria necatrix(E.necatrix),Eimeria praecox(E.praecox)and Eimeria acervulina(E.acervulina)were identified as the dominant species.Based on analysis of associated risk factors,infections with species such as E.necatrix and E.acervulina were positively correlated with infection intensity.Cage-free was identified as a high risk for severe mixed infection,while day old was uncorrelated to infection intensity or the level of mixed infection.In conclusion,infection with chicken Coccidia was widely distributed in these regions,dominated by mild infection,and characterized by complex species,sever mixed infection,obvious regional differences and high-risk populations of cage-free and growing flocks.It was recommended to improve the effectiveness of coccidiosis control by implementing specific measures targeting high-risk regions and populations,taking into account the characteristics of farming modes and day old.