The adult lion has practically no natural enemies because of its size and strength. Lions can become victims of other lions, dying in fights. The percentage of deaths of lions from such cases is quite large. When there are skirmishes of members of different prides or in the case of males of the same pride, lions inflict serious injuries on each other quite often.
Lions, as well as individuals that suffer from illness, injury, or lost their strength due to hunger during a drought, may become victims of leopards, hyenas, or be killed by buffaloes or elephants. There are also cases when lions died during hunting.
Despite the fact that the lion is the king of animals, he suffers quite enough from parasites. Parts of the body of lions with thin skin affect different types of ticks. And if the lion can not get there with his teeth or paw – then the insects give the animal huge trouble. Among the lions is widespread infection with helminths, in particular tapeworms of the genus Taenia, which enter the intestine. Infection usually occurs through meat eaten by antelopes.
While in captivity, lions can be prone to the virus of dogs cannabis (infected from dogs), feline infectious peritonitis and feline immunodeficiency virus. The outbreak of the disease in 1994 in the Serengeti Reserve led to the disease of several individuals with manifestations of neurologic symptoms, such as convulsions. During this outbreak several lions were victims of encephalitis and pneumonia. The virus of immunodeficiency of cats, which has a similarity with HIV, is mainly sick with lions from Namibia and Asia.