Intestinal infection with the protozoan Giardia lamblia. It is usually asymptomatic in human beings but may produce abdominal cramps, diarrhea, and nausea.

• 贾第虫病由原生动物引起的肠道感染（贾第虫）。人得了这种病经常是无症状的但可能产生腹部痉挛、腹泻和呕吐