Eosinophilic meningitis risk associated with raw Ampullarium canaliculatus snails consumption

In Taiwan, Angiostrongylus cantonensis infection has been reported in foreign laborers who had consumed raw Ampullarium canaliculatus snails. This study analyzed three foreign laborers who had contracted enzyme-linked immunosorbent assay-confirmed A cantonensis infection while working in Taiwan. All three workers had consumed either roasted snails or raw snails flavored with seasoning while drinking wine. This study investigated possible risk factors for A cantonensis, including naturally occurring A cantonensis in A canaliculatus snails, viability of third-stage A cantonensis larvae in raw seasoned snails and in roasted snails, infectivity of larvae, and effects of alcohol while consuming snails. Positive infection rates in snails from five different irrigation canals in south Taiwan ranged from 12.3% to 29.4% and the average number of motile larvae per infected snail ranged from 36 to 65. The number of motile and coiled larvae in snail meat after 120 minutes seasoning was 93 (27.7%) and 233 (69.3%), respectively. After 20 minutes of roasting, most larvae in the snail meat were dead. The infectivities of motile and coiled larvae from snail meat after 60 minutes seasoning were 53.2% and 33.2%, respectively, and those from snail meat after 5 minutes roasting were 33.2% and 7.0%, respectively. Eating Taiwan A canaliculatus snails raw is extremely risky given their high infection rates and infection intensities. Even after 120 minutes seasoning or after 20 minutes roasting, snail meat should be considered unsafe for human consumption. Finally, experimental rodent studies indicated that consuming alcohol while ingesting larvae does not significantly reduced infectivity.

摘要生吃福壽螺肉會感染廣東住血線蟲，經訪視血清抗體陽性的外勞，瞭解他們都是喝酒時吃烤螺肉或吃浸在辣椒醬、醋及魚醬等量混合的調味料的生螺肉，因此本研究分析田野福壽螺感染率及帶蟲數，在浸調味料的生螺肉或螺烤後的螺肉內第三期幼蟲的活性和感染力，以及酒精對蟲體感染的影響，來探討感染廣東住血線蟲的危險因子。結果在台灣南部5條灌溉渠道的福壽螺感染率介於12.3%至29.4%，每個螺帶蟲數介於36至65，螺肉切成0.5公分厚浸於調味料120分鐘分別有27.7%及69.3%第三期幼蟲呈活動及捲曲狀，螺烤20分鐘後尚有少部份蟲體成捲曲狀，螺肉浸調味料60分鐘後活動及捲曲蟲體的感染力分別為53.2%及26.1%，而螺烤5分鐘蟲體的感染力分別為33.2%及7.0%，因為福壽螺在台灣高感染率及高帶蟲數，因此吃浸調味料120分鐘及烤20分鐘的福壽螺肉均不安全，而且在鼷鼠的感染實驗顯示酒精並不會降低感染風險。