Eosinophilic meningoencephalitis associated with rat lungworm () migration in two nine-banded armadillos () and an opossum () in the southeastern United States.

, the rat lungworm, was the cause of neural larval migrans in two nine-banded armadillos () and one Virginia opossum () from the southeastern United States. Histologic findings in all three cases included eosinophilic meningoencephalitis with variable numbers of nematode larvae in the meninges or the neuroparenchyma. In two of the three cases, nematodes were extracted from brain tissue via a "squash prep" method. Identification of the nematodes was confirmed by amplification and sequence analysis of the partial cytochrome oxidase subunit I gene from all three cases. Sequences (704bp) from the two cases from Louisiana were identical and 99.7% similar to nematodes detected in the armadillo from Florida. As is now considered endemic in the southern United States, it should be considered as an important differential for any wild or domestic animal or human patient with neurological signs and eosinophilic meningitis. Many wildlife species frequently consume snails and slugs and could serve as sentinels for the detection of this parasite in regions where the presence of this parasite has not been confirmed. To the authors' knowledge, this is the first report of neural larval migrans due to in an armadillo and provides additional documentation that this nematode can cause disease in wildlife species in the southeastern United States.