Abstract

Prosthodendrium naviculum (Trematoda) is a common parasite of bats in North America, which has occasionally also been reported in raccoons and mink.¹ Lecithodendriid trematodes are multiple life stage parasites which use snails as the first intermediate host and aquatic arthropods (insects and crayfish) as the infective intermediate host. Meerkats at the Toledo Zoo have traditionally been offered crayfish (Cambarus diogenes) as seasonally available enrichment. In June 2012, three of four slender-tailed meerkats (Suricata suricatta) developed acute lethargy, cardiac and respiratory distress, and then died either shortly after empirical treatment was initiated or before any treatment could be initiated. Histology revealed that all three animals had lymphoplasmacytic inflammation in the lamina propria of the small intestine and colon and two animals had large numbers of trematodes in the small intestinal lumen. Death was attributed to systemic lymphoplasmacytic inflammation, most notably in the heart, kidneys, liver, lungs, and skeletal muscle. Two animals had reactive lymphoid hyperplasia and medullary histiocytosis in the lymph nodes, and one had splenic microgranulomas. Histologic examination of the feeder crayfish identified large numbers of metacercariae in the muscles. PCR testing of frozen tissue from all three meerkats identified the organism Neorickettsia risticii, the causative agent of Potomac horse fever. Sequencing for the rickettsia in the flukes and crayfish is ongoing, as is sequence identification of the flukes in the crayfish and meerkats. This disease, which has proven fatal in equids, has not been previously reported in meerkats and identifies an unexpected risk of live enrichment feeding.

Literature Cited

1.  Williams, R. R. Metacercariae of Prosthodendrium naviculum Macy, 1936 (Trematoda: Lecithodendriidae) from the crayfish Orconectes rusticus (Girard). Proc PA Acad Sci. 1967;41:38–41.