Verminous meningoencephalomyelitis in a red kangaroo associated with Angiostrongylus cantonensis infection

Angiostrongylus cantonensis is a zoonotic parasitic helminth that normally resides in the pulmonary arteries and the right ventricle of rats ( Rattus sp.), the definitive host, where it causes little disease. Humans, dogs, opossums, and various zoo animals are “accidental” hosts. Here we report verminous meningoencephalomyelitis caused by A. cantonensis in a 9-mo-old male red kangaroo ( Macropus rufus). The kangaroo was first presented lethargic, recumbent, and hypothermic, with severe muscle wasting. Within 3 wk, he progressed to non-ambulatory paraparesis and died. Gross examination revealed multifocal areas of dark-brown discoloration, malacia, and cavitation in the brain and the spinal cord. Histologically, there were several sections of nematodes surrounded by extensive areas of rarefaction, hemorrhage, spongiosis, neuronal necrosis, and gliosis. Based on size, morphology, and organ location, the nematodes were identified as subadult males and females. Interestingly, an eosinophilic response was largely absent, and the inflammatory response was minimal. A. cantonensis infection had not been reported previously in a red kangaroo in Louisiana or Mississippi, to our knowledge. Our case reaffirms the widespread presence of the helminth in the southeastern United States and indicates that A. cantonensis should be considered as a differential in macropods with neurologic clinical signs in regions where A. cantonensis is now endemic.

Osphranter rufus (Diprotodontia: Macropodidae)

Osphranter rufus (Desmarest, 1822) is a macropod commonly called the red kangaroo and is the largest extant marsupial. Sexually dimorphic in size and coat color, this large macropod is one of four species in the genus Osphranter. In general, males are larger than females, and are reddish-brown in color, whereas females are bluish-gray. O. rufus is endemic to Australia, where it inhabits both arid and semiarid areas with wide habitat preferences that include open plains, open desert, grassland, woodland, or shrubland habitats. Although it is regularly harvested for its meat and hide, O. rufus is an abundant species that is not of special conservation concern and it is listed as “Least Concern” by the International Union for Conservation of Nature and Natural Resources.