Animal waste can contain numerous microorganisms that are pathogenic to humans. These include bacteria such as Escherichia coli, Salmonella, and Campylobacter, viruses like Norovirus and Hepatitis E, and parasites such as Cryptosporidium and Giardia. These pathogens can cause a range of illnesses, from mild gastrointestinal distress to severe conditions like hemolytic uremic syndrome.