Several species of endoparasitic nematodes have been recovered from the intestines of crested serpent eagles, including "Madelinema angelae". Avian pox virus infections which cause warts on the face have been observed in a wild bird living in Taiwan. A number of ectoparasitic bird lice have been described from the species including "Kurodaia cheelae". In Penang, it was found that cinereous tits ("Parus cinereus ambiguus") tended to nest close to nesting crested serpent eagles, presumably due to safety from predators like crows that may be driven off by the eagles. They have also been found to visit the nests of the eagles to collect fur from the remains of dead mammal prey.