[If] the pesach was offered in a state of contamination, zavim, zavos, menstruants, or women after childbirth may not eat of it; but if they did eat, they are exempt from [the penalty of] kares.  R' Eliezer exempts [them] even [from the kares due] for entering the Temple.

What are the differences between the pesach offered in Egypt and the pesach-offering of [succeeding] generations? —- The purchase of the Egyptian pesach was on the tenth [of Nissan], it required sprinkling [of its blood] with a bundle of hyssop upon the lintel and upon the two doorposts, and was eaten in haste, during one night; but the Pesach of [succeeding] generations is observed all seven days.