first intermediate host

基本解释

Objective Investigation of the species ofParagonimus, its first and second intermediate host (snail and crab) and the infection rate ofParagonimus in Songxi county, Fujian province.
目的调查福建省松溪县肺吸虫虫种，第一、二中间宿主及其感染率。
Two species of snails, namely, Tricula fujiansis and Semisulcospira libertina were found, but only the former was the first intermediate host. The infection rate of snails was 0.7%(4/569).
全县发现福建拟钉螺和放逸短沟蜷两种螺蛳，只有前者为斯氏狸殖吸虫和泡囊狸殖吸虫的第一中间宿主，其感染率为0 7% （4/ 5 6 9）。