It's crazy how similar your writing style is to mine! With that, I'm a bit biased, but I think it's a good essay. You hit all the points I would have, especially explaining how you became interested in public health. the one thing I would be concerned with is why do you want to concentrate in epi, but your interests seem to lean towards social and behavioral health. Epi methods are essential tools in all of public health, but I would write just a bit more about that to show that you have an idea of how you may use epi in your particular areas of research interest.
Also, others have warned in the past not to post you entire statement for everyone to see because there may be some individuals who will steal it and you may become embroiled in a plagiarism thing (unlikely, but possible), so I would be careful about doing this again.