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, Paramecistodrrus, 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.

2419 freshwater fishes from the Sudan were examined for helminth parasites and found to harbour one monogenean species, 15 species of adult digenetic trematodes, three species of larval trematodes, 16 species of adult cestodes, 13 species of adult nematodes, two species of larval nematodes and three species of acanthocephalans. Four species of adults and four species of larval worms are recorded for the first time in the Sudan and 30 new hosts are listed. The intensity of infestation of each species, the host‐specificity and the variations in the infestation of fishes are discussed. The helminth fauna of the Sudan is compared with that of other African countries.

Investigations on larval nematodes in herring revealed that Anisakis sp. larvae occurred in the body cavity of 34 % of 5646 juvenile and adult herring examined; and that the infection increased with increase in fish length (age) and varied with the locality, being greater in herring caught nearer to the British coasts. The effect of temperature and salt concentrations on the survival of the larvae and the public health hazards of the larvae were discussed.Fifteen per cent of 3320 juvenile herring examined were found infected with larvae of Contracaecum aduncum (Rudolphi, 1802) in the body cavity but this infection decreased with increase in fish length (age), probably due to the development of resistance with ageing. The infestation was compared with that of sprat.

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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.