福建省2008-2017年人间布鲁氏菌病流行特征及分离株MLVA分型研究

目的探讨福建省人间布鲁氏菌病流行特征,并对其分离株进行分子分型,为制定预防控制策略提供依据。方法收集中国疾病预防控制信息系统中2008-2017年福建省布鲁氏菌病报告数据,进行流行特征分析;采用传统生物学鉴定和BCSP31-PCR、AMOS-PCR、MLVA-16进行布鲁氏菌分离株分子鉴定和分型,并进行聚类分析。结果福建省2008-2017年布鲁氏菌病发病呈逐年上升趋势,年均发病率0.11/10万;疫情波及福建省80%的县区,呈高度散发态势;发病高峰为4-8月;40～64岁发病数占62.7%,60～64岁组发病率最高(0.27/10万);男女比为2.50∶1,农牧民占50.7%。40株布鲁氏菌分离株分子检测结果与传统分型基本相符,为2个种(羊种和猪种)和2个生物型(羊3型和猪3型),其中羊种布鲁氏菌占绝大多数(87.5%);MLVA-16分型将其分为羊种和猪种2个种群,35株羊种菌分为28种基因型,5株猪种菌分为4种基因型,其中26种基因型为单分离株,6种基因型为共享基因型(共14株,35.0%)。同国内147株布鲁氏菌进行聚类分析显示,福建省菌株与广东和内蒙古地区存在4种共享基因型,均为羊种菌,其他部分菌株与外省菌株存在着较近的遗传距离,主要集中在panel 2B上,仅存在1～3个位点的差异。结论福建省布鲁氏菌病流行强度逐年增高,建议相关部门加强传染源的管控、对疫情高发地区的重点人群采取必要防控措施,控制其发生与流行。福建省布鲁氏菌MLVA-16分型显示高度基因多态性,提示MLVA-16可用于遗传多样性分析和分子流行病学溯源调查,可以提高布鲁氏菌病监测能力。

Epidemiological characteristic of human brucellosis and MLVA genotyping for Brucella isolates in Fujian,China,2008-2017

To explore the epidemiological characteristics of human brucellosis in Fujian Province and the typing of Brucella isolates, the data of brucellosis cases during 2008-2017 were extracted from China Information System for Disease Control and Prevention and analyzed; molecular biological methods(BCSP31-PCR,AMOS-PCR and MLVA-16)were used for Brucella typing. The results showed that during 2008-2017, the incidence of brucellosis in Fujian increased year by year with an annual incidence of 0.11/10⁵; a total of 416 cases were reported and distributed sporadically in 70 counties (80%) in the province; the peak of brucellosis occurred from April to August; 261 (62.7%) cases aged 40-64; the highest incidence rate was at age group 60-64 years old (0.27/10⁵); the incidence ratio of male to female was 2.50:1; farmers and herdsmen accounted for 211(50.7%) cases. With classical biotyping and molecular genotyping, two species (B. melitensis and B.suis) and two biovars (B. melitensis biovar 3, n=35; and B. suis biovar 3, n=5) were identified in the 40 Brucella isolates, and B. melitensis species (35, 87.5%) were dominant in Fujian Province. MLVA-16 revealed 28 genotypes in 35 B. melitensis isolates and 4 genotypes in 5 B. suis isolates respectively, including 26 unique and 6 shared genotypes (14 isolates, 35.0%). Comparison with 147 isolates from other provinces showed that 4 genotypes of B. melitensis in Fujian were shared with that in Inner Mongolia or Guangdong. And some isolates were genetically closed with isolates in other provinces, mainly concentrated in panel 2B, with differences only in 1-3 sites. Our study indicates that the epidemic intensity of human brucellosis in Fujian increased yearly. It is necessary to strengthen surveillances and take corresponding measures in high-risk population for brucellosis control and prevention. MLVA-16 revealed highly genetic polymorphism in Fujian Brucella isolates suqqests that this method is a useful tool for genetic diversity analysis and molecular epidemiology trace-back investigations in brucellosis surveillance.