Keawjam R S, Poonswad P, Upatham E S, Banpavichit S
Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand.
Southeast Asian J Trop Med Public Health. 1993 Mar;24(1):170-7.
Golden apple snails, Pomacea canaliculata, were collected once a month during a year to search for their natural parasites. The collections were made at two localities having different ecological environments. Of 576 collected snails from a canal, 176 individuals (30.6%) were infected by three groups of metacercariae. These parasites were amphistome, distome and echinostome metacercariae, which had prevalences of 23.5, 19.5 and 0.5%, respectively. The incidence of infection was highest (68.4% in October) when the snail population was composed of the old, juvenile and young Pomacea. Amphistome metacercariae were found most frequently and echinostome metacercariae the least frequently; both parasites were localized in the foot muscle of the snails and had a Shannon index of zero. The range of amphistomes was 1 to 115 with the mean +/- SD of 1 +/- 2 and 95% CL of 1, 2. Distome metacercariae were found primarily in the heart (range: 1-13), and also in the foot muscle (range: 1-5) and kidney (range: 1-14), with a Shannon index of 0.4. The means +/- SD (with 95% CL) were 3 +/- 4 (95% CL = 1, 5), 3 +/- 4 (95% CL = 2, 4) and 2 +/- 1 (95% CL = 1, 2) for the foot muscle, heart and kidney, respectively. The snails from a pond, another locality, had a low proportion of infected individuals. Of 605 snails, only 24 individuals (4.0%) were infected, with the prevalence of amphistomes, distomes and echinostomes being 0.8, 1.8 and 2.1%, respectively. The incidence of infection for each month was zero or less than 10%, except in May when it was 30.2%.
在一年的时间里，每月采集一次福寿螺（Pomacea canaliculata），以寻找其天然寄生虫。采集工作在两个生态环境不同的地点进行。在从一条运河采集的576只福寿螺中，176只个体（30.6%）被三组尾蚴感染。这些寄生虫为双口吸虫、片形吸虫和棘口吸虫尾蚴，其感染率分别为23.5%、19.5%和0.5%。当福寿螺种群由老年、幼年和青年福寿螺组成时，感染率最高（10月份为68.4%）。双口吸虫尾蚴发现频率最高，棘口吸虫尾蚴发现频率最低；这两种寄生虫都位于福寿螺的足部肌肉中，香农指数为零。双口吸虫的数量范围为1至115，平均值±标准差为1±2，95%置信区间为1、2。片形吸虫尾蚴主要见于心脏（数量范围：1 - 13），也见于足部肌肉（数量范围：1 - 5）和肾脏（数量范围：1 - 14），香农指数为0.4。足部肌肉、心脏和肾脏的平均值±标准差（含95%置信区间）分别为3±4（95%置信区间 = 1, 5）、3±4（95%置信区间 = 2, 4）和2±1（95%置信区间 = 1, 2）。来自另一个地点（一个池塘）中的福寿螺，感染个体的比例较低。在605只福寿螺中，只有24只个体（4.0%）被感染，双口吸虫、片形吸虫和棘口吸虫的感染率分别为0.8%、1.8%和2.1%。除5月份感染率为30.2%外，每个月的感染率均为零或低于10%。
