吉林省长白山区斑点热立克次体自然疫源地调查

A new type of spotted fever group Rickttsiaes detected in the area of Changbai mountain,Jilin province

目的 了解吉林省长白山区蜱传斑点热的自然疫源地情况。方法 利用立氏立克次体[相对分子质量 (Mr) 190× 10 3 ]外膜蛋白A(R .rOmpA)基因序列设计引物 ,对 6 83只蜱类标本进行聚合酶链反应 (PCR)检测 ,并随机抽取一株森林革蜱阳性扩增产物进行克隆与序列测定。结果 从森林革蜱和嗜群血蜱标本中检测出了斑点热立克次体DNA片段 ,阳性率分别为 5 3.81%和 7.4 1% ;所测序列与前苏联的DnS 14株的同源性为 10 0 .0 0 % ,与DnS 2 8和RpA 4的同源性均为99.0 0 % ;而与国内所检测的BJ 90、HLJ 0 5 4的同源性分别为 88.0 0 %和 86 .0 0 %。结论 长白山区存在斑点热的自然疫源地 ,存在与DnS 14株型别一致的斑点热立克次体 ,在中国系首次发现。

Objective In order to find out the current situation of tick-borne spotted fever in the area of Changbai mountain, Jilin province. Methods In this study, a polymerase chain reaction(PCR) method was developed with primers R.rOmpA 190.70p and R.rOmpA 190.701n designed on the basis of rOmpA gene, which is specific for examining spotted fever group Rickttsiaes (SFGR). Six hundred nighty-three ticks were tested and a positive PCR product amplified from D.silvarum specimen (named JL-02) was cloned and sequenced. Results The SFGR DNA was detected from D.silvarum, Haemaphysalis concinna with the positive rates were 53.81 % and 7.41 % respectively. Its nucleotide sequence of 587 bp rOmpA and derived amino-acids showed 100.00 % similarity with nucleotide sequence of DnS 14 and 99.00 % with DnS 28 from the Former Soviet Union according to the result of BLUST and CLUSTAL, which was differential from the DNA sequences of strains previously detected in China. Conclusion The natural focus of tick-borne spotted fever did exist in the area of Changbai mountain. The DNA sequence of SFGR was similar to that of DnS 14, which was first reported in China.