Эпидемии СПИДа  --> Эпидемия СПИДа.

In Russian plural version of word "'эпидемия" used only in case you describe several diseases.

Зачем в России эпидемии СПИДа:   -->Почему 

If you need to ask "for what?" ""--> Зачем 

If you need to ask "what the reason?" "what was the cause?" --> Почему

I find this difference hard to explain =)

роли образования, -> роль

образованиe - has no plural. 

недостаток правительства - I'm sorry, but I don't get what do you mean. There are several different variations how to say something. Try to rephrase. 

и стигмы -> this is seldom used word, a few people would get what you say. Better to rephrase and use "дискриминация", or even "предвзятое отношение"

I really hope You find it helpful =)