Syphilis

aids did not happen because of bestiality. it was supposedly caused by a different flavour of sin, that is greed. ape hunting for various reasons such as meat and selling gorilla heads as fancy ornamets for rich people's houses led to blood-borne spread of siv (simian hiv) which was back then a zoonosis. it happily mutated, probably as a giant fuck you to humanity for not leaving out monkey ancestory in peace. the ironic bit however is that there's horribly a lot of damage done by hiv precisely in africa, amongst the poor people who were likely the least responsible for the ape-made-ornaments fashion that plagued rich white people of the time.
as i am not allowed to include a link i suggest you google origin of aids pandemic for refs. there's scholarly articles all over the place.

Our guest is correct, in a vaguely guest sort of way.
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The history of SIV to HIV is super fascinating and way better then some guy boning a chimp. Various viruses crossed over from smaller monkeys up into chimps and finally into humans because we were all hunting and eating the next smaller money. It came from eating monkey meat, and I'm guessing the same happened with the llamas?
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Here's an interesting short article about SIV->HIV: https://www.avert.org/professionals/history-hiv-aids/origin

I'm betrayed, I've always been told and believed that a scientist working with AIDS monkeys made a mistake with his scalpel and cut his finger through his glove at the same time as he cut the monkey.

That's just the slightly less wack version of "aids was invented by cia scientists to get rid of [insert victim group here]"
This is an interesting article on the origin of syphilis: https://news.nationalgeographic.com/2018/06/syphilis-genomes-dna-mexico-skeletons-science/