The Veterinary Record, December 6, 2008 Fewer than 40 human infections with C hepatica have been reported (Sawamura and others 1999, Assis and others 2004), and a single human case has been reported from the UK (Slais 1974). Few cases are reported in non-human primates and, to the authors’ knowledge, none has been reported in the UK, or in these two species (Troisier and others 1928, Foaster and Johnson 1939, Fripp and Kaschula 1974, Graczyk and others 1999). Infection has been reported occasionally in animals in Britain; in wood mice (Apodemus sylvaticus), rats (Rattus spe- cies), a yearling foal and a 15-year-old West Highland white terrier cross dog (Lloyd and others 2002). Approximately half of the reported human cases were diagnosed antemortem by liver biopsy; the others were diag- nosed only postmortem (Junker-Voss and others 2000). It is possible that, due to the difficulty of antemortem diagnosis, the true prevalence of C hepatica infection in human beings has been underestimated. An immunofluorescent serological assay has been reported, but is not routinely available (Junker- Voss and others 2000). However, Assis and others (2004) used this technique to identify two out of 60 zoo workers from the Zoological Garden of Vienna with subclinical infections. The clinical signs described in cases of human infection include pyrexia, hepatomegaly, anaemia, respiratory signs, splenom- egaly, enlarged kidneys, weight loss, and leukocytosis with eosinophilia. Postmortem examination of mountain goril- las (Gorilla gorilla berengei) in the Parc National de Volcans, Rwanda, revealed C hepatica infection in 10 of 19 cases exam- ined (Graczyk and others 1999). The most likely source was judged to be rodents. Capillaria hepatica (syn Calodium hepaticum) in primates in a zoological collection in the UK R. Pizzi, J. C. Gordon, E. J. Flach, A. D. Routh, B. Clark, W. S. J. Boardman Capillaria hepatica (syn Calodium hepaticum), first described by Bancroft (1893) is a zoonotic liver nematode of mammals with a worldwide distribution. Its primary hosts are rodents, and there is a high prevalence of infection in the brown rat (Rattus norvegicus) (Lloyd and others 2002). The parasite has a direct life cycle. After the ingestion of embryonated eggs, larvae hatch in the caecum of the host and migrate via the portal venous system. After maturation in the hepatic paren- chyma, eggs are produced approximately 28 days after mat- ing. The adult life span has been reported to range from 18 days (Pavlov 1970) to 60 days (Wright 1961) in mice. Eggs in the hepatic parenchyma develop to the eight-cell stage but then develop further only once released by the death and decomposition of the host, or through excretion in the fae- ces of a carnivore feeding on the infected liver of the host. Eggs embryonate and become infective within five to eight weeks, and can remain viable for up to three years (Spratt and Singleton 2001). Ingestion of non-embryonated eggs does not lead to infection. This short communication described the identification of C hepatica infection in primates kept at two zoos in the UK. Postmortem examination of an adult female white- faced saki monkey (Pithecia pithecia) at the Zoological Society of London (ZSL) that died after collapsing suddenly at Whipsnade Zoo revealed a severe C hepatica hepatitis. Macroscopically, the liver was very firm, with an uneven, pit- ted surface. Examination of haematoxylin and eosin-stained sections of the liver demonstrated numerous large, coalesc- ing granulomas (Fig 1), containing large numbers of barrel- shaped, bipolar eggs with one circumference greater than the other, measuring approximately 60 μm in length, with a 3 to 4 μm thick, two-layered wall with a reticulated surface, consist- ent with C hepatica (Fig 2) (Wright 1961, Slais 1974, Graczyk and others 1999, Lloyd and others 2002). No parasitic ova had been demonstrated in faecal flotation tests, carried out regularly while the animal was alive. A retrospective examination of liver samples stored in 10 per cent neutral buffered formalin from 60 adult primates that died between 1994 and 2006 at the ZSL’s London and Whipsnade zoos was performed. Liver had been stored from most but not all primates that died during this period. Two further infections were detected: one in another white-faced saki monkey that had died suddenly, and the other in an adult Sulawesi crested macaque (Macaca nigra) that was euthanased after a chronic jaw disorder. Both ani- mals had been kept at London Zoo. Only 5 per cent (95 per cent confidence interval [CI] 2 to 14 per cent) of the primates examined postmortem had the characteristic eggs present in granulomatous foci, but 33 per cent (95 per cent CI 22 to 47 per cent) of the archived livers examined had granulomatous or fibrotic lesions but no eggs evident on sections. It is unclear whether any of these lesions may have also been due to C hepatica infection. The small tissue sam- ples, the focal nature of the lesions and the fact that not all the primates that died had tissue archived mean that the true prevalence may have been higher than that detected in this study. Veterinary Record (2008) 163, 690-691 R. Pizzi, BVSc, MSc, DZooMed, FRES, MACVSc, MRCVS, E. J. Flach, MA, VetMB, MSc, DZooMed, MRCVS, A. D. Routh, BVSc, CertZooMed, MRCVS, B. Clark, BTec, W. S. J. Boardman, BVetMed, MACVSc, MRCVS, Veterinary Department, Zoological Society of London, Regent’s Park, London NW1 4RY J. C. Gordon, BA, VetMB, MRCVS, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES Mr Pizzi’s present address is Zoological Medicine, 79A Garvock Hill, Dunfermline, Fife KY12 7UT Ms Gordon’s present address is PDSA PetAid Hospital, The Coco Markus Centre, High Road Vange, Basildon, Essex SS16 4TG Mr Boardman’s present address is Veterinary Conservation Programs, Animal Health Centre, Adelaide Zoo, Royal Zoological Society of South Australia, Frome Road, Adelaide, South Australia 5000, Australia FIG 1: Granulomatous hepatitis due to Capillaria hepatica in a white-faced saki monkey (Pithecia pithecia). Haematoxylin and eosin. x 40 FIG 2: Capillaria hepatica eggs in the liver of a white-faced saki monkey (Pithecia pithecia). The eggs have one circumference slightly larger than the other, and a thick, two-layered wall with a reticulated surface. Haematoxylin and eosin. x 400 Short Communications group.bmj.com on February 26, 2014 - Published by veterinaryrecord.bmj.com Downloaded from