wider distribution possibly new host organism parasites jumping nonhuman human hosts known zoonoses disease invasion parasite invades new host species may become pathogenic new host ref name krauss ref several human activities led emergence zoonotic human pathogens including viruses bacteria protozoa rickettsia spread vector borne diseases ref name krauss see also globalization disease wildlife disease encroachment wildlife habitats construction new villages housing developments rural areas force animals live dense populations creating opportunities
Applied science Medicine and health Infectious disease