Massive, disseminated and lethal cysticercosis caused by Taenia crassiceps (Cestoda) in captive western grey bamboo lemur (Hapalemur occidentalis Rumpler) in Zoo in the Czech Republic.

Taenia crassiceps (Zeder, 1800), a zoonotic cestode with a wide geographical distribution, utilises canids as definitive hosts and small rodents as intermediate hosts. However, accidental infections in non-human primates, particularly in captive lemurs, have been increasingly documented. In this case report, we describe the first documented case of cysticercosis caused by the larval stage of T. crassiceps (metacestode; also known as Cysticercus longicollis Rudolphi, 1819) in a captive western grey bamboo lemur (Hapalemur occidentalis Rumpler). The affected female lemur showed progressive abdominal distension over a period of two months, which initially indicated pregnancy. At necropsy, multiple thin-walled metacestodes were discovered throughout the abdominal and thoracic cavities, including a large polycystic mass involving the liver and peritoneum. Histopathological analysis revealed larval cestodes with armed (hook-bearing) scoleces embedded in vascularised stromal tissue, accompanied by marked eosinophilic and macrophage infiltration and focal necrosis, particularly in the lungs. Morphological and molecular identification based on COI gene sequencing confirmed the presence of T. crassiceps. Despite extensive parasitological investigations, no definitive host excreting T. crassiceps eggs was found in the zoological facility where the lemur was kept. These results emphasise the possibility of indirect environmental transmission and highlight the susceptibility of lemurs as atypical intermediate hosts. This case confirms previous reports of lethal cysticercosis in lemurs, which is often characterised by rapid systemic spread of metacestodes. Our findings also emphasise the need for increased awareness and preventive measures to reduce the risk of parasite infections in vulnerable captive primates.