AGREE 100%
I believe there is a link between zinc deficiency and more severe cases of Wubonic Plague...1. Zinc deficiency decreases as we age
2. Those with: cancer, diabetes, alcohol issues are more likely to have zinc deficiency
3. Those on an ACE inhibitor (often heart patients) are more likely to be zinc deficient.
4. And people withe type A blood are more likely to be zinc and magnesium deficient than other blood types.