SYSTEMIC HISTIOCYTIC SARCOMA IN A COMMON HIPPOPOTAMUS (HIPPOPOTAMUS AMPHIBIUS).

A 37-yr-old captive common hippopotamus (Hippopotamus amphibius) developed lethargy and decline in mobility that progressed to death, despite supportive therapy. Histopathologic examination revealed severe, diffuse, intravascular and interstitial infiltration of neoplastic histiocytes in the spleen, liver, lymph nodes, lungs, large intestine, kidneys, and thyroid gland. Neoplastic cells were pleomorphic with marked anisocytosis and anisokaryosis, scattered multinucleated giant cells, numerous bizarre mitotic figures, and marked erythrophagocytosis. Immunohistochemistry demonstrated that neoplastic cells were positive for ionized calcium-binding adapter molecule 1 (a histiocytic marker) and negative for CD3 (a T-cell marker) and myeloperoxidase, confirming the diagnosis of systemic histiocytic sarcoma.

Naturally acquired visceral leishmaniasis in non-human primates in Brazil.

Visceral leishmaniasis (VL) is a chronic and often fatal protozoal disease that is endemic in Belo Horizonte (State of Minas Gerais, Brazil). Leishmania sp. is an intracellular obligatory parasite of macrophages that can naturally infect several mammalian species. Non-human primates (NHP) have been used as experimental models for infection with Leishmania of the donovani complex. The present report describes a case of visceral leishmaniasis in a black-fronted titi. Among 41 primates kept in captivity in a zoo in Belo Horizonte (State of Minas Gerais, Brazil), one animal, a black-fronted titi (Callicebus nigrifrons), was positive for Leishmania chagasi infection by PCR and immunohistochemistry, and developed a fatal disease with clinical signs and lesions compatible with VL. Other 17 NHP, including six black-fronted titis (C. nigrifrons), one howler monkey (Alouatta guariba), three golden-bellied capuchins (Cebus xanthosternos), one golden-headed lion tamarin (Leontopithecus crysomelas), one black-headed owl monkey (Aotus nigriceps), two Rio Tapajós sakis (Pithecia irrorata) and three emperor tamarins (Saguinus imperator) had blood samples that tested positive for amplification of Leishmania kDNA by PCR, although these NPH had no clinical signs of the disease.