我国不同地区的杜氏利什曼原虫对亚历山大白蛉感染性的观察

OBSERVATION ON THE INFECTIVITY OF LEISHMANIA DONOVANI FROM DIFFERENT AREAS TO PHLEBOTOMUS ALEKANDRIFROM XINJIANG

用白蛉人工感染利什曼原虫的方法,观察从新疆荒漠、甘肃山区及河南平原三地自人体成蛉体分离出来的杜氏利什曼原虫对新疆亚历山大白蛉的感染性。以白蛉的感染率、感染程度以及原虫在白蛉消化道内的进展等项指标,来衡量原虫对白蛉的适应性。结果发现,新疆荒漠的原虫对亚历山大白蛉有高度的感染性,甘肃的原虫居次,河南的原虫对白蛉的感染性很差。结合以往用单克隆抗体检测法和K-DNA杂交法对我国一些地区杜氏利什曼原虫的研究,以及我国荒漠、山区和平原地区的黑热病具有不同的流行病学特征等的结果分析,认为我国的杜氏利什曼原虫很可能存在不同的地域株。

Hamsters or cotton rats-were infected with 3 stocks of L. donovani, one of which had been isolated from an infected Ph. major wui in Xinjiang desert area and 2 from kala azar patients in a mountain area of Gansu and in a plain area of Henan respectively. The purpose of the study was to compare the infectivity of the parasites from different geographic areas through artificial infection of Ph. alexandri. Sandflies were dissected in 4, 6, 8 and 10 days after feeding on the infected animals to observe the growth and development of promastigotes of different isolates in their alimentary tracts. Evaluation was made on 3 aspects, i. e. infection rates, infectiosity and migration of promastigotes in sandflies. It was demonstrated that Xinjiang isolate of L. donovani appeared to be particulary adapted to Ph. alexandri followed by Gansu isolate, the Henan isolate did not show good adaptation to this sandfly, because the number of promastigotes declined and the infection rate dropped after the digestion of the blood meal in the stomach of the sandflies. It seems that the phenomenon was related to the biological characteristics of L. donovani isolates. These results coincided with those of McAb dot ELISA(Qu,1987) and K-DNA dot hybridridization (Lu & Hu 1988) for identification of L. donovani from different areas in China, and were also in parallel to the diverse epidemiological characteristics of different kala azar endemic areas (Guan, 1976) .It is reasonable to infer that there may exist different geographical strains of L. donovani in China.