肺检法和组织匀浆法检测福寿螺广州管圆线虫效果比较

目的 比较直接组织匀浆法和肺检法检测福寿螺广州管圆线虫检出率, 寻找简便快捷适合不同场境的检测方法。方法 在前辈报道已确认的疫区的水塘、沟渠、河流边等环境,捕捞收集福寿螺。每只螺逐只称重后,分别解剖成螺肺囊与肌肉两部分,先用肺检法镜检每只螺肺囊内是否有结节进行初筛,把结节用解剖针挑出单独压片用显微镜查找虫体,并在显微镜下鉴定虫种,然后再把肺囊和螺肉一起用组织匀浆法复检。结果 共检测330只福寿螺,组织匀浆法检出广州管圆线虫Ⅲ期幼虫的福寿螺63只,检出率为19.1%（63/330）,肺检法查见结节的福寿螺52只,检出率为15.8%（52/330）,其中肺检法查见结节并查到幼虫的福寿螺36只,其匀浆法也全部阳性,符合率100%（36/36）;肺检法查见结节但未查到幼虫的福寿螺16只,其中有6只匀浆法阳性,10只匀浆法阴性,错检率19.2%(10/52 );肺检法未查见结节福寿螺278只,但用匀浆法检查有21只检出广州管圆线虫Ⅲ期幼虫,漏检率7.6%（21/278）。匀浆法与肺检法（以查见结节判定阳性为标准）比较,两者之间差异无统计学意义（χ²=1.27,P= 0.26,P>0.05）。匀浆法与肺检法（以查到幼虫判定阳性为标准）比较,两者之间差异有统计学意义（χ²=8.66,P=0.003,P<0.01）。两种方法对不同体质量的福寿螺广州管圆线虫检出率比较,结果显示肺检法2种判定方法在检测大螺（≥25 g）时与匀浆法比较其检出率之间差异都没有统计学意义（χ²=0.08,P=0.777;χ²=2.58,P=0.108）,但在检测小螺（≤10 g）方面与匀浆法比较其检出率之间差异有统计学意义（χ²=5.63,P=0.02）。结论 肺检法的检测效果与组织匀浆法相比, 在检测大螺方面方法简单所需仪器设备更少,其检测速度更快, 适合广州管圆线虫的自然疫源地现场调查。而直接组织匀浆法灵敏度高,能直观地显示虫态与活度,虫体活力强,检出率高,更适合用在食品安全风险监测方面。

A comparative study of lung-microscopy and tissue homogenate in detecting Angiostrongylus cantonensis in the Pomacea canaliculata

Objective To compare the efficiency of lung-microscopy and tissue homogenate in the detection of Angiostrongylus cantonensis larvae from Pomacea canaliculate, with the amin of finding a simple and rapid method suitable for different scenarios. Methods Pomacea canaliculata was caught and collected from ponds, ditches, rivers and other environments in the confirmed epidemic areas reported by predecessors. After each snail was weighed one by one, and dissected into two parts: lung sac and muscle. Firstly, each snail lung sac was check for nodules with lung-microscopy, and the nodules were picked out with anatomical needle and press them separately. Then, the worm was found and identified for worm species under microscope, and the lung sac and snail meat then was rechecked with tissue homogenate. Results A total of 330 snails were detected, with 19.1% (63/330) snails with Angiostrongylus cantonensis stage Ⅲ larvae were detected by tissue homogenate and 15.8% (52/330) snails with nodules were detected by lung-microscopy. Among them, 36 snails with nodules and larvae were detected by the lung-microscopy, and all of them were positive by the tissue homogenate, with a coincidence rate of 100% (36/36); 16 snails with nodules but no larvae, among which 6 snails were positive and 10 snails were negative by the tissue homogenate, The false detection rate was 19.2% (10/52). 278 snails with no nodules, but 21 of them were detected by the tissue homogenate, the missing rate was 7.6% (21/278). There was no significant difference between tissue homogenate and lung-microscopy (taking the positive determination of nodules as the standard) (χ²=1.27, P=0.26, P>0.05). There was significant difference between tissue homogenate and lung-microscopy (taking the detection of larvae as the standard)(χ²=8.66, P = 0.003, P<0.01). There was no significant difference between the two methods and tissue homogenate in the detection rate of large snails ( ≥25 g, χ²=0.08,P=0.777; χ²=2.58, P=0.108), but there was significant difference between the two methods and tissue homogenate in the detection rate of small snail (≤10 g, χ²=5.63, P=0.02). Conclusions Compared with the tissue homogenate, lung-microscopy is simple in the detection of large snails, requires less instruments and equipment, and its detection speed is faster. It is suitable for the field investigation of the natural focus of Angiostrongylus cantonensis. The tissue homogenate has high sensitivity, can directly display the insect state and activity, has strong insect vitality and high detection rate, it's more suitable for food safety risk monitoring.