摘要
陇南、川北是我国目前黑热病高发区,病人与病犬颇为常见。中华白蛉是本区常见的、分布广泛的优势种,也是本区山野唯一昼夜吸取人、畜血的蛉种。中华白蛉随海拔高度递增蛉体大小差异显著,大个体多见于海拔2000米或以上,小个体则常见于海拔1600米以下。 给311只中华白蛉饲吸感染杜氏利什曼原虫的背纹仑鼠,结果有229只白蛉感染了前鞭毛体,感染率为69.2％。前鞭毛体不仅见于白蛉中胃内,也见于食道、咽喉和啄部等。前鞭毛体见于白蛉食道的有104只(54.4％),见于咽喉和啄部的分别为40只(17.5％)和5只(2.2％)。 在海拔2000米以上山野剖检吸血雌性中华白蛉440只,其中有1只(0.23％)发现自然感染前鞭毛体,其病原鉴定为杜氏利什曼原虫。在海拔1600米以下剖检吸血雌性中华白蛉1293只,发现3只(0.23％)白蛉有自然前鞭毛体感染,其中一只阳性白蛉经斑点ELISA检侧确定为杜氏利什曼原虫。自然感染前鞭毛体在白蛉体内的分布与人工感染所见结果相似。 流行病学调查表明本区黑热病患者和病犬主要见于海拔1600米以下地带,在海拔2000米以上山野系无人居住,既无病人又无病犬,显然白蛉自然感染前鞭毛体来自野生动物,这一山野为黑热病自然疫源地。 根据流行病学和生态学资料论证结果,作者认为大个体中华白蛉主要在海拔2000米以上野?
Southern Gansu and northern Sichuan are the high endemic areas of kala-azar, where human case and dog visceral leishmaniasis is not uncommon.Phlebotomus chi-nensis is the only sandfly species which takes mammalian and human blood day or night.It is the most commor sandfly with a large number ard wide distribution.
Altitude distribution of sandfly P,chinensis in the mountainous regions was observed.Two sized sandflies P.chinensis are distributed,the large size exists above 2000 m and the small one below 1600 m sea level.
Artificial infection of P.chinensis by biting the kala-azar infected Cri- cetulus barabensis showed that 229 of 331 sandflies (69.2%) became infected. The promastigotes not only devloped in the midgut, but also invaded esophagus, pharynx and proboscis. In 104 (45.4%%) of the sandflies, promastigotes were found in the esophagus;40(17.5%) in the pharynx and 5 (2.2%) in the proboscis.
A total of 440 female sandflies P.chinensis were collected in the wild mountainous regions 2000 m above sea level, in which, one (0.23%) was found naturally infected and the promastigotes were identified as Leishmania donovani. Of the 1293 females collected in the wild mountainous regions below 1600 m sea level, 3 (0.23%) were found naturally infected and the promastigotes in one of them were also identified as L.donovani by Dot ELISA.The distribution of promastigotes in the naturally infected sandfly was similar to that by artificial infection.
Epidemiological survey reveals that most of the kala-azar patients and visceral leishmaniasis dogs are in the area below 1600 m sea level and the area above 2000 m sea level is not inhabited where neither man nor dog existed, therefore, the natural infection of sandflies evidently comes from wild animals and there is located a natural nidus of kala-azar.
According to the ecological and epidemiological data obtained in the present study, we deem it adequate to conclude that the large size P.chinensis is a favourable vector in the mountainous regions above 2000 m transmitting visceral leishmaniasis in wild animals and there is a natural enzootic focus. In the mountainous regions below 1600 m sea level the small size P .chinensis is a very good vector in the transmission of human and dog visceral leishmaniasis.
Kala-azar management in these mountainous regions is analyzed and discussed
出处
《地方病通报》
1989年第4期15-21,共7页
Endemic Diseases Bulletin
基金
国家自然科学基金
关键词
中华白蛉
黑热病
垂直分布
感染
Phlebomus chinensis—distribution, logitudinal—infection,artificial, natural—promastigote—Leishmania donovani—animal, wild—natural focus
