湖南省1990-1999年钉螺面积变化情况分析

目的对湖南省1990-1999年10年间的钉螺面积变化趋势进行分析.方法收集1990-1999年湖南省血吸虫病各疫区上报有关钉螺面积的报表资料,作统计分析.结果10年间除1992、1993和1994年3年未发现新的流行区外,其余每年均有新流行区被发现,其中新发现流行村以1996和1998年较多,分别为30个和52个,新发现的流行乡以1998年最多,为11个;10年间全省查出的有螺面积从1990年至1994年呈下降趋势,以后呈增长势头,以1996、1998年增幅较多,1996年比1995年增长了2.54%;1998年比1997年增长1.56%;10年中灭螺面积除1992年有上升之外,总的呈下降趋势,至1999年灭螺面积为1700万m2,比1990年下降了54.20%;垸外灭净钉螺面积除1991年超过垸内之外,其余各年均低于垸内,从1996年起垸外灭净钉螺面积为0.垸内灭净钉螺面积在10年中以1998年最多,为246.2万m2.结论我省钉螺面积近年来有增长的趋势,并且有向城市逼近的特点,引起钉螺面积增长的重要原因之一可能是特大的洪灾造成部分堤垸溃决和渍水,引起钉螺不同程度的扩散所致.垸内灭螺能对控制垸内钉螺面积的增长起到一定的作用.

Analysis on Change in Snail Habitat Areas in Hunan Province from 1990-1999

Objective To analyse the change tendency of snail habitat areas in Hunan Province from 1990 to 1999. Methods Data on snail habitat areas submitted from all endemic areas were collected and analysed. Results New endemic areas were found every year except 1992, 1993 and 1994. For instance, 30 and 52 new endemic villages were found in 1996 and 1998 respectively and 11 new endemic townships were found in 1998 which showed a marked increase over other years. The snail habitat areas decreased from 1990 to 1994 but increased from 1995 to 1999. The snail areas increased 2.54% in 1996 and 1.56% in 1998 as compared with last year 1996 and 1997. The areas carried out snail control measures revealed decreasing tendency except 1992. The snail control area was 17 million m 2 in 1999 which reduced 54.2% as compared to 1990. After snail control measures, the snail free areas inside embankment were larger than that outside embankment every year except 1991. Since 1996, no snail free area has been found in outside embankment. The largest snail free area inside embankment reached 2.462 million m 2 in 1998. Conclusions The snail habitat areas showed not only increasing tendency but pressing on towards the city areas in Hunan Province during the studied period from 1990 to 1999. The main reason might be flood disaster,but changeable water level, large snail habitat areas, expansive snail control measures, unsatisfactory snail control effect were also the objective causes. Activities such as snail surveillance in outside and inside embankment, comprehensive snail control measures in inside embankment, snail control and cercaria killing measures in higher risk areas of outside embankment should be strengthened.