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The short answers: Author decides. There are diseases that are highly specific, and there are others that are more promiscuous. Malaria is highly specific and will not exist without humans. Yellow fever lives in monkeys and humans. If the other world has monkeys, watch out! And so on down the scale to rabies that lives in most mammals. There are many ...


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It's very species dependent. In general, viruses have a hard time jumping the species barrier unless you live in areas where large numbers of people are in contact with large numbers of animals and their bodily products. That's why so many infectious diseases (swine flu, avian flu, SARS) come from Asia, where you have large numbers of people in contact with ...


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Yes, in fact we already sort of do this. During the Ebola outbreak, medical workers that survived had the antibodies in their blood separated from the red blood cells and injected into other people that way their own bodies could start building up an immunity to it and the immune system can start fighting the virus. Of course, this is a simplified version of ...


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