First report of fatal Physaloptera sibirica infection in Eulemur macaco macaco in a Italian zoological park

Background. Adults of the nematode genus Physaloptera Rudolphi, 1819 occur in a wide range of insectivorous or omnivorous mammals and birds throughout the world (Soulsby, 1982; Norman and Beveridge, 1999; Anderson, 2000). At least four species of Physalopera were found in oesophagus, stomach and small intestine of the primate species in Asia, South-East Europe, Africa and South America (Hayama and Nigi, 1963; Yamashita, 1963; Soulsby, 1982). Life-cycle involves insects as intermediate hosts and reptiles as paratenic hosts (Anderson, 2000). Black lemurs are limited to Madagascar and, in captivity, they are popular in zoos worldwide, as in the Garda Zoological Park (Verona) where is present the largest lemur captivity population of Italy. The presence of Physaloptera sp. has been already diagnosed in captivity lemurs (Junge, 1997), even if in literature there is no evidence to support which species and the pathogenic role of the parasite in this species. The present study describes a fatal Physaloptera sibirica infection in Eulemur macaco macaco hosted at Parco Natura Viva-Garda Zoological Park of Bussolengo (VR, Italy). Methods. All specimens of Physaloptera were collected during the necroscopy of a dead animal (10 years old female, having 3150g weight) and they were fixed in 4% buffered formaldehyde solution and cleared in Hoyer’s solution (Sloss et al., 2004) or in glycerin. Adult parasites were identified in according to the morphological descriptions of Nevue-Lemaire (1936) and Quentin and Biocca (1976). Results. Initially during an explorative laparotomy and then necroscopy (the lesion seriousness determined the euthanasia of the animal), in the stomach lumen several adult parasites were found firmly attached to the gastric mucosa. The adult nematodes measuring 1.6-3.5cm in length and the morphological details indicate that they belong to genus Physaloptera (order Spirurida, family Physalopteridae). The nematode have a cuticular collarette around the head, mouth present two pseudolabia provided with a characteristic dental and papillae pattern. The male tail bears wide lateral alae: three precloacal sessile papillae are arranged in a triangular row and four sessile papillae are arranged around the cloaca (postcloacal papillae); there are four pairs of pedunculated papillae in cloacal region; the first pair of sessile postroventral papillae are half-way through the cloaca and the queue and one pairs of phasmids are situated at the middle between the second and third pairs of sessile posteroventral papillae. Spicules are unequal in length: 643µm for the left and 500µm for right. Conclusions. P. tumefasciens, P. dilatata, P. caucasica and P. poicilometra have been recorded in simian primates (Yamaguti, 1961). However we can exclude a primate species by mean of Beaver et al. (1984) and Nevue-Lemaire (1936). In fact, on the basis of our morphological survey of the specimen, that correspond to the description of Quentin and Biocca (1976), the species seem to be Physaloptera sibirica. This infection report appears relevant because, for the first time, it describes a severe anatomopathological findings (suppurative metastatic inflammation as a consequence of gastric perforation) ascribable to Physaloptera sibirica in black lemur with fatal outcome. Furthermore, our anatomopathological and parasitological findings suggest that in captivity (in the Park other lemurs were infected) it is necessary to carry out an intensive sanitary control with a regular faecal examinations despite the partial efficacy of this method due to intermittent eggs output of this parasite.