roughly 16% of Zimbabweans are Ndebele; the huge majority are Shona. A genocidal war against the Ndebele was carried out on Mugabe's orders in the 1980's, and there has been some recurrence of oppression.
Because HIV, and poverty caused by Mugabe's politics & corruption
HIV is widely under-reported in #Zimbabwe, & it doesn't get much international aid for fighting HIV - because Mugabe & his cronies kept stealing all aid money.
That's a big if. A lot of youths were recruited into the kleptocracy enforcement groups.