英语语法分析

Pellagra is a disease that results from niacin deficiency.

糙皮病是一种由烟酸缺乏引起的疾病。

Pellagra was virtually unknown at that time in the Americas, however, even among people who subsisted primarily on maize.

然而，糙皮病在当时的美洲几乎还不为人所知，甚至在主要以玉米为生的人之间也是如此。

Another form of erythema is pellagra.

糙皮病则是另一种形式的红斑。