Why are gentiles not affected by these dangers?
We find that many of the recorded dangers in the Talmud which are followed only by Jews and not Gentiles do not seem to negatively affect the health of Gentiles. The reason for this is not because these recorded dangers are in truth not dangerous at all, but rather because the Jewish people have a different physique than Gentiles. Jews are more refined in nature due to the giving of the Torah and keeping of the Mitzvos and thus the body becomes a lot more sensitive to anything coarse and negative. Ever since we received the Torah on Mount Sinai, the impurity that was entered to the human body through the bite of the snake in the times of Adam has ceased, and made the Jewish body more refined. Therefore, the body of a Jew is more prone to subtle dangers than is the body of a Gentile. Furthermore, Gentiles eat non-kosher foods and insects and reptiles, which makes their body more coarse and less prone to the more subtle dangers. For this reason, one can explain also why we see secular jews who do not abide by the dangers recorded in the Talmud and are nonetheless not health compromised. [Perhaps this is similar to one who is wealthy and pampered and is repulsed by foods that normal people would eat without a problem in times of need.]
 See Ben Ish Chaiy Pinchas 2; Yabia Omer 1:8; Sefer Shemiras Haguf Vihanefesh [Lerner] Mavo Chapter 5
 See Shabbos 146a.
 Ben Ish Chaiy ibid
 Avoda Zara 31b; Ben Ish Chaiy Pinchas 2.
 Yabia Omer ibid