I believe it could be true. The human sense of smell is an interesting thing, the most primitive one we have, and the closest to the brain center of all the senses.
I have often told people that I can smell snow coming. I cannot describe the smell at all...but when I smell it, it instantly becomes a feeling too.
Kind of when I smell jet exhaust. Just brings me right back.
Anyway, I don’t doubt for a minute that woman could smell snakes.
I can smell rain. Actually I think just about everyone can. Probably not the rain itself but whatever it first mixes with when it first starts.
I have read that coral snakes are the most venomous of all North American snakes but they do not have fangs which makes delivery a little slower.