草原革蜱生理龄期的观察

草原革蜱Dcrmacentor nuttalli分布于我国新疆、内蒙等地.苏联、蒙古亦有发现,国内外均巳证实是蜱媒斑点热的传播媒介.采用目测、解剖、切片三种方法,进行了生理龄期观察,目测法是观测蜱的腹部厚度变化,以体侧缘为纵轴线比较腹面与此线构成的距离,分成4个生理龄期;解剖法的主要指征是蜱中肠支囊体积和形态变化,马氏管内鸟嘌呤含量和支气管束等形态的变化;切片法的主要指征是中肠上皮细胞形态变化和细胞内血红蛋白颗粒和血红素的变化.三种方法比较,结果基本一致,误差在10％左右.草原革蜱在新疆阿勒泰地区自3月下旬至5月上旬绝大部分为Ⅱ、Ⅲ期的强壮蜱,此时正值当地牧放季节,处于活动高峰的媒介蜱,具有重要的流行病学意义.

OBSERVATION ON PHYSIOLOGICAL AGE OF DERMACENTOR NUTTALLI IN ALTAI DISTRICT

For the determination of the physiological ages of the tick Dermacentor nuttalli in Altaj Dis-trict of Xiniiang Uygur Autonumous Region, thrce methods were used: ob.servation of cxtornal fi-gures with nakcd eye, anatomical nethod and histological merhod The more laborous histologi-cal method may be used as the criterion for comparison. The results of these three methods were found to be basically similar and the crror usually appeared around 10%. The swell or depres-sion of the ventral surface of the abdomen from a side view can be used as the criterion for na-ked eye observation. It is simple and convenient, The constriction of midgut caeca, the filling of guanine spherules in malpighian tubule and the development of loose conncctive tissues and tra-cheal trunks are used as the criteria for anatomical examination. The histological change of the midgut epithelium serve?as the criterion of histological method. By using these methods it was found that a young population in the grasslands of Altai District was present from the late de-cade of March to that of April when 47% of the population was in the second category of physiological age (in the third and fourth stages) and 11% in the third category (in the 5th stage). The tick population in these physiological ages was in a more vigorous state and had greater po-tential to attack their hosts.