内蒙古羊种布鲁氏菌传播模式调查研究

目的调查内蒙古羊种布鲁氏菌的传播模式和流行规律。方法采用AMOS-PCR对60株布鲁氏菌的种型进行鉴定,用Hunter-Gaston Diversity Index(HGDI)评价菌株的遗传多态性特征,采用MLVA-16分型方法对菌株进行基因分型,确定菌株的亲缘关系。结果 60株试验菌全部为羊种布鲁氏菌。MLVA-16对菌株具有极高的分辨力,多态性指数为0.981;Panel 1,Panel 2A和Panel 2B的多态性指数分别为0.264,0.345和0.980;Panel 2B中Bru16位点的多态性指数最高,多态性指数为0.835。60株羊种布鲁氏菌聚为5大类37个基因型,其中15个共享基因型包括38株羊种布鲁氏菌,聚类率为63.3%(38/60),提示病例多为有流行病学关联的暴发流行;另外22株菌表现为独特基因型表明菌株无明显的流行病学相关性。共享基因型GT5包括2株分别分离自羊和骆驼的菌株且有相同的MLVA-16基因型,提示布鲁氏菌在羊和骆驼中循环传播;3个共享基因型(GT11、GT17和GT23)分别包含来自人和羊的菌株并呈现完全相同的MLVA-16基因型,表明羊是人间布病的传染源。GT35由3株分离自羊脾的菌株构成且共享相同的基因型,提示布病在羊中呈暴发流行。类群E由12个来自不同宿主(羊,牛,野生骆驼和人)的菌株构成,共享相同或相似的MLVA-16基因型,揭示了内蒙古羊种布鲁氏菌潜在的传播模式。结论疫羊是主要传染源,野生动物(骆驼)是贮藏宿主。羊种布鲁氏菌在羊牛(骆驼)和骆驼(羊牛)中相互循环传播,最后传染给人是内蒙古羊种布鲁氏菌的潜在传播模式。

Transmission pattern investigation of Brucella melitensis from Inner Mongolia,China

Aim of this study is revealed transmission pattern and epidemic feature of Brucella melitensis from Inner Mongolia, China. A total of 60 strains of Brucella were investigated and type of these Brucella strains were identified by AMOS-PCR. HIGD was used to assessed genetic diversity characteristics of strains in this study, MLVA was applied for gene-typing and determined genetic relationship between strains. AMOS-PCR confirmed that all of the testing strains belongs to B.melitensis, result showing that MLVA-16 exhibited the higher discriminating and diversity index was 0.981, diversity index of Panel 1, Panel 2A and Panel 2B were 0.264, 0.345 and 0.980, respectively, and bru16 in Panel 2B present the highest polymorphis in this assay, and diversity index was 0.835. A total of 60 strains were divided into 5 subgroups and comprised of 37 gene-types, which of 15 were shared gene-types in 38 strains including, with a clustering rates of 63.6% (38/60), these data showed that brucellosis exhibited multi-point outbreak in this region. Other 22 strains present unique gene-types that indicated these brucellosis was sporadic or without epidemiological link cases. GT5 gene-types were comprised of two strains obtained from sheep and camel, respectively, and had identical MLVA -16 gene-types that revealed B. melitensis were cycle transmission between sheep and camels. Three genetypes (GT11, GT17 and GT23) showing the same genetypes shared feature which strains were obtained from human and sheep exhibited the identical MLVA-16 gentypes, this data suggested that infected sheep was source of infection for human brucellosis.Three strains of GT35 were obtained from sheep spleen and shared identical MLVA -16 genetypes, hinted that sheep brucellosis exhibited outbreak. Twelve strains of E subgroup were isolated from different host (including in sheep, cattle, wild camel and human) and shared the identical or similarly MLVA-16 genetypes, this information maybe revealed a potential transmission pattern of B.melitensis from Inner Mongolia. In conclusion, infected sheep is source of infection for human brucellosis, camel or other wild animals maybe play as a role of reservoirs. B.melitensis are circulated transmission between sheep (cattle) and camels (other wild animals), later transmitted to humans is a potential transmission pattern of B.melitensis in examined area.