Fatal Hymenolepis nana-associated visceral larva migrans in captive juvenile white-tailed antsangies (Brachytarsomysalbicauda).

White-tailed antsangies (Brachytarsomys albicauda) are Madagascan rodents uncommonly kept in captivity. Hymenolepis nana is a cestode with an unusual life cycle, incorporating direct, indirect and autoinfective stages. This case series represents the first reported outbreak of H. nana cestodiasis in white-tailed antsangies, summarizing macroscopic and histological findings in four cases. On post-mortem examination (PME), numerous cysticerci were detected consistently throughout the intestinal serosa, liver, mesenteric lymphatic vasculature and mesenteric lymph nodes. Pancreatic cysticerci were observed in one case. Adult tapeworms, larvae and eggs were found only in the small intestine, and faecal egg shedding was a feature. Histopathological examination identified adult, larval and encysted cestodes within the respective gross lesions, with pulmonary, pancreatic and splenic involvement detected in a single case. The cestodes sampled on PME were identified by polymerase chain reaction and DNA sequencing, with H. nana confirmed in all cases. Visceral larva migrans was consistent throughout all specimens, in contrast with the natural infections of standard rodent hosts, and may be considered a likely pathological feature of H. nana infection in white-tailed antsangies.

Case series: Lymphoid neoplasia in three elasmobranch species.

Elasmobranchs (sharks and rays) are charismatic cartilaginous fish, popular in public aquaria. Almost 200 shark and ray species are listed as threatened by the International Union for Conservation of Nature (IUCN), demonstrating the importance of captive breeding and research programmes. Limited studies investigate diseases of elasmobranchs in captive and free-living environments, and among available literature neoplasia is rarely reported, with even fewer cases of lymphoid neoplasia documented. This article outlines the first reports of lymphoid neoplasia in three elasmobranch species in which haematopoietic neoplasms have not been reported to date. It summarizes signalment, history and histopathologic findings in an undulate ray, Raja undulata (Lacepede), a common smooth-hound, Mustelus mustelus (Linnaeus) and a bat ray, Myliobatis californica (Gill). Lesions were confirmed in a wide range of tissues and evidence of lymphoid leukaemia was seen in two cases. This small-scale review demonstrates that lymphoid neoplasia should be considered as a differential diagnosis in elasmobranchs presenting with lethargy and anorexia and highlights the challenges of immunohistochemical work up.