Cholecystitis in otters (Lutra lutra) and mink (Mustela vison) caused by the fluke Pseudamphistomum truncatum.

Between 1988 and 2004, postmortem examinations were carried out on 445 otters found dead, mostly as a result of road traffic accidents, in southern and south-west England. Thickened, shrunken gall bladders were observed in 10 cases, the first in 2000 and the others between February 2002 and August 2004. A digenean fluke, Pseudamphistomum truncatum, was found in the gall bladders of three cases and also in three of seven American mink examined. Nine of the 10 otters and all the mink came from a localised area of Somerset, indicating that the fluke has become established in the local fish population. P. truncatum has not been recorded previously in Britain, and the results suggest that it has been introduced recently, possibly in imported fish.

Observations on a lesser-known monogenean, Udonella myliobati, from a copepod parasite, Lepeophtheirus natalensis, parasitizing the spotted ragged-tooth shark, Carcharias taurus, from South African waters.

The phylogeny of the genus Udonella has been disputed for quite some time, but recent phylogenetic analysis of molecular data confirms that the genus is a monopisthocotylean monogenean. Specimens of Udonella myliobati parasitizing the copepod Lepeophtheirus natalensis, an ectoparasite of the spotted ragged-tooth shark, (Carcharias taurus), were collected and studied. A total of 771 monogenean specimens were recovered from 54 infected copepods examined, with a mean intensity of 14,3 worms per copepod. Most of the monogeneans were found attached to the dorsal surface of the lateral and frontal marginal membranes of the copepod carapace. Eggs, with filaments and adhesive discs, were found ventrally on the host, mainly attached to the maxillae and maxillipeds, in clusters of 12-14. Observations on the morphology, distribution and behaviour of this monogenean are presented with the aid of light and scanning electron microscopy.

The African monogenean gyrodactylid genus Macrogyrodactylus Malmberg, 1957, and the reporting of three species of the genus of Clarias gariepinus in South Africa.

Three different species of the genus Macrogyrodactylus Malmberg, 1957, collected from the gills and skin of Clarias gariepinus (Burchell, 1822) from the Middle Letaba Dam and Mokgoma-Matlala Dam in South Africa were examined and identified. This is the first record of a species of the genus in South Africa. The three species are M. congolensis (Prudhoe, 1957)--found on the skin, M. clarii Gussev, 1961 and M. karibae Douellou & Chishawa, 1995--found on the gills. The last species is elevated to the status of a species having been described previously as a subspecies of M. congolensis. The present study presents and discusses the value of some of the taxonomic characters which can be used to differentiate the species of the genus. The shape and size of the sclerites of the haptor are found to be the most reliable characters. Only four species of the genus, namely M. polypteri and the three above-named species are regarded to be valid. Three species, namely M. latesi Paperna, 1969, M. anabantii Paperna, 1973 and M. ctenopomii Paperna, 1973 are regarded as species inquirenda. Generic diagnoses, measurements and illustrations of the sclerites of the four valid species are presented and a key for their differentiation is provided. The development of the gyrodactylid population on C. gariepinus during the filling of the Middle Letaba Dam in South Africa is discussed.

Paraorientatractis semiannulata n. g., n. sp. (Cosmocercoidea: Atractidae) from the large intestine of the side-necked turtle, Podocnemis unifilis Troschel, 1848 (Testudines: Pelomedusidae) in Brazil

Specimens collected from the large intestine of the side-necked turtle Podocnemis unifilis Troschel, 1848, in the region of Cumina and Trombetas rivers near Para, Brazil are assigned to a new genus and Paraorientatracti semiannulata. The new genus is separated from the nearest genus Orientatractis by the funnel-shaped mouth opening, the presence of 4 distinct lips, 4 papillae in the internal cycle, one on each lip margin, 2 lateral amphids with large amphidial pores and absence of submedian papillae. It is also separated from Orientatractis and Proatractis by the presence of striated lateral alae which curve dorsally extending from mid oesophagus to mid tail, the difference in size of the vulvar opening and the presence of large transverse ridges or semiannules on the dorsal surface. The new species can be separated from the species of the genera Orientatractis and Proatractis by the characters that distinguish the genera and the arrangement of the caudal papillae on the male. A host/parasite list for Podocnemis spp. is included.

Paraorientatractis semiannulata n. g., n. sp. (Cosmocercoidea: Atractidae) from the large intestine of the side-necked turtle, Podocnemis unifilis Troschel, 1848 (Testudines: Pelomedusidae) in Brazil.

Specimens collected from the large intestine of the side-necked turtle Podocnemis unifilis Troschel, 1848 in the region of Cuminá and Trombetas rivers near Pará, Brazil are assigned to a new genus and new species of the nematode superfamily Cosmocercoidea and family Atractidae and named Paraorientatractis semiannulata. The new genus is separated from the nearest genus Orientatractis by the funnel-shaped mouth opening, the presence of 4 distinct lips, 4 papillae in the internal cycle, one on each lip margin, 2 lateral amphids with large amphidial pores and absence of submedian papillae. It is also separated from Orientatractis and Proatractis by the presence of striated lateral alae which curve dorsally extending from mid oesophagus to mid tail, the difference in size of the vulvar opening and the presence of large transverse ridges or semiannules on the dorsal surface. The new species can be separated from the species of the genera Orientatractis and Proatractis by the characters that distinguish the genera and the arrangement of the caudal papillae on the male. A host/parasite list for Podocnemis spp. is included.

Cooperioides antidorca from intestinal nodules in Gazella thomsoni and G. granti in Kenya.

Examination of nodules from the intestine of Gazella thomsoni and G. granti in Kenya revealed the presence of the trichostrongylid nematode Cooperioides antidorca. Nodules from the two hosts were histologically similar and took the form of chronic inflammatory lesions extending through the wall of the gut from the submucosa into the muscular layers. There was some necrosis around the parasite located in the centre of the nodule, a varying population of inflammatory cells and a varying degree of fibrous tissue encapsulation. One nodule possessed an aperture into the lumen of the gut and there was also evidence of serosal proliferation, probably due to the parasitic lesion penetrating the deeper layers of the wall. The morphology of Cooperioides antidorca recovered from the nodules was examined by scanning electron microscopy and is briefly described.

A key for the identification of genera of the nematode family Trichostrongylidae Leiper, 1912.

The nematode family Trichostrongylidae is divided into six subfamilies Trichostrongylinae, Libyostrongylinae, Haemonchinae, Cooperiinae, Ostertagiinae and Graphidiinae which are briefly reviewed. The key is based mainly on specimens examined by the authors and includes one genus in the Trichostrongylinae, three genera in the Libyostrongylinae, six in the Haemonchinae, seven in the Cooperiinae, 17 in the Ostertagiinae and two in the Graphidiinae. Pseudostertagia, Pararhabdonema, Parostertagia, Obeliscoides and Travassosius are briefly described, figured and considered as genera of uncertain affinities. Nine genera, namely, Moguranema, Neocooperia, Bergheia, Mazamastrongylus, Paramecistocirrus, Ostertagiana, Ostertamia, Graphidiella and Trichostrongyella, specimens of which have not been available to the authors for examination, are listed giving details of host, habitat and geographical location, together with a summary of the diagnostic characters as described by the original authors.

A survey of thelazia worms in the eyelids of British cattle.

Thelazia skrjabini and T gulosa were found in the eyes of 237 of 566 bovine heads (41.9 per cent) examined in a Surrey abattoir during 1976. The prevalence of infection increased during late June, July and August, when a new generation of worms emerged in eyes. The burden in eyes ranged from one to 170 worms, with a mean count of 10.44 +/- 3.23. Worms were found behind and in third eyelids and in the lacrimal ducts of lower eyelids, which makes their detection very difficult by clinical examination. They were significantly more common in cattle 21 to 38 months old than in those less than 21 months old. Lesions occurred in 14 of 327 (4.3 per cent) infected eyes. No worms were seen in eye washings from cattle in nine herds experiencing outbreaks of keratoconjunctivitis.

Gazellostrongylus lerouxi Yeh, 1956 from antelopes in East Africa and its relation to the genus Paracooperia Travassos, 1935.

A detailed redescription of Gazellostrongylus lerouxi and Paracooperia serrata was given from specimens collected from antelopes in Kenya. It was felt that there was no justification for the synonymy of the genus Gazellostrongylus with Paracooperia. Gazellostrongylus was placed in the tribe Ostertagiea.