On another occasion, they said to Rav Yehuda: There is pestilence among the pigs. Rav Yehuda decreed a fast. The Gemara asks: Let us say that Rav Yehuda maintains that a plague affecting one species will come to affect all species, and that is why he decreed a fast. The Gemara answers: No, there is no cause for concern in other cases. However, pigs are different, as their intestines are similar to those of humans.