OME PARASITES are caused human-animal diseases, the pathogens carring from the animals to the people through the direct and indirect trance. The uncontrolled use of vaccinations and medications, as well as climate change and genetic engineering, have all contributed to the rise of novel diseases passed from animals to people. Leishmania is a parasitic organism that is transmitted by vectors and is capable of surviving exclusively within host cells. Belonging to the Trypanosomatidae family, this organism is accountable for causing many ailments, such as mucocutaneous, cutaneous, and visceral diseases, in both Old and the New World. Leishmaniasis is a disease caused by subspecies that have different clinical manifestations, leading to experts' confusion Parasites cause inflammation, secrete poisonous compounds into tissues. Understanding the pathophysiology of parasites transmitted from animals to people aids in the development of efficient ways for eliminating these parasitic illnesses as well as the development of effective vaccinations for other bacterial infections.