Complex sentence: Some golden jackals can carry diseases and parasites harmful to human health, including rabies and Donovan's "Leishmania" which, although harmless to jackals, can cause leishmaniasis in people.
Split into simpler sentences: Some golden jackals carry diseases and parasites harmful to human health. These include rabies, and Donovan's "Leishmania" that is harmless to jackals but may cause leishmaniasis in people.