The total DNA of two morphologically similar cestode species of the genus Proteocephalus parasitizing coregonid and salmonid fish, P. exiguus La Rue, 1911 and P. neglectus La Rue, 1911, was compared. The methods of DNA analysis involved digestion of the total DNA with restriction endonucleases and Southern blotting hybridization with the ribosomal DNA probes pSM 889, pSM 389 and pSM 890. No inter-specific variation was found between the two proteocephalid species. Distinct differences in RFLP patterns were recorded between two geographically distinct population of P. neglectus after BspRI digestion; after EcoRI digestion and following hybridization with the 32P-labelled probe pSM 890 and after BamHI digestion and hybridization with the 32P-labelled probe pSM 889. The high degree of genetic similarity revealed in the two Proteocephalus spp. could be a further argument for the conspecifity of both taxa.

The effect of exogenous steroid hormones on the egg output of Heligmosomoides polygyrus (Nematoda: Trichostrongylidae) was examined in vitro. Using worms raised in female mice, it was found that estradiol, testosterone, and cortisone each significantly decreased egg output. Although similar trends were found using H. polygyrus raised in male mice, none of the decreases found was significant. No significant differences were found with ecdysone or progesterone treatments using worms from female or male mice. Treatment of worms with cortisone did not significantly affect retention of eggs within the uterus of H. polygyrus. Titration of the effect of cortisone on egg output indicated that levels of reduction were significant for concentrations of 5·6 × 10−6 M to 5·6 × 10−3 M in worms from female mice and for concentrations of 5·6 × 10−8, × 10−7, × 10−5 and × 10−3 in worms from male mice. Radioisotope labelling experiments showed incorporation of 3H-corticosterone in the nucleus of intestinal cells of H. polygyrus suggesting that its effect on egg production may be via a modulatory effect on the intestinal cells.

Rodentolepis (sensu lato) asymmetrica (Janicki, 1904) is redescribed on the basis of materials from Microtus agrestis, Microtus arvalis and Myodes glareolus from Eastern Europe (Belarus, Lithuania, Latvia, Estonia, Ukraine and the north-eastern part of Russia). A new genus, Kontrimavichusia n. g., is proposed for it based on morphological and molecular evidence. The unique morphological diagnostic characters of this currently monotypic genus include the presence of an armature on the suckers, ventral osmoregulatory canals connected with irregularly spaced transverse anastomoses, an internal seminal vesicle with circular musculature and uterus with numerous diverticula, situated dorsally to the genital ducts, extending bilaterally beyond the longitudinal osmoregulatory canals. In addition, the new genus differs from morphologically related genera of the Rodentolepis clade by the structure of its vagina. The copulatory part of the vagina in specimens of Kontrimavichusia n. g. is surrounded by circular musculature and covered externally by a dense layer of intensely-stained cells; the conductive part of the vagina is clearly distinguishable from the seminal receptacle. Molecular analysis of the partial 28S rRNA gene fully supports the erection of Kontrimavichusia n. g. as a distinct lineage.

Aphelenchus ritzemabosi is known as a serious parasite of greenhouse plants such as chrysanthemums and gloxinias but the number of records of its attacks on plants grown out of doors is increasing. Disease due to it has been observed in the open on chrysanthemums and dahlias in this country and in the present paper a new out-of-door host is added to the list of plants attacked by it.

Comparative ultrastructural studies have been made of newly excysted metacercariae and worms recovered from abnormal (rats) and normal definitive hosts (dogs). Worms from rats survived for prolonged periods without any growth or development in muscles of the host. They appeared to resemble metacercariae in general features, although ultrastructural observations revealed differences in the composition of tegumental granules and the development of the excretory bladder and caeca. Worms from dogs showed well-developed morphology in association with active energy metabolism and biosynthesis.

Owing to the comparatively little use made of the flesh of the goat in this country, the helminthic parasites of this host have been far less studied than those found in other domestic animals. In other countries, where the goat plays a far greater economic rôle, a large number of parasitic worms have been recorded.

This worm was very abundant in the rectum of a tortoise, Homopus femoralis, from the Bloemfontein area, Orange Free State, South Africa. It was found together with several other oxyurids the description of which will form the subject of a later paper. Although the Probstmayria far exceeded the other oxyurids in number, male specimens of this genus were extremely rare for only one male was found after a prolonged search during the course of which many hundreds of females were encountered. In order that no specimens should be lost the entire alimentary canal together with its contents was submerged in hot 70% alcohol after scraping the mucosa.

The activities of selected enzymes of carbohydrate metabolism were measured in tetrathyridia of Mesocestoides corti and in adult females and males of Heterakis spumosa. When the species were compared, only lactate dehydrogenase and phosphoenolphyruvate carboxykinase activities were considerably higher in M. corti. Activities of other enzymes were higher in H. spumosa, with malate dehydrogenase activity being considerable so. In H. spumosa, enzyme activity was higher, and succinate dehydrogenase markedly so in males, when compared with females. Tetrathyridia aged 170 and 210 days show relatively stable malate and lactate dehydrogenase activities, and mice of ICR and BALB/c strains are suitable for the maintenance of tetrathyridia.

Seven species of acanthocephalans were identified for the first time in teleost fish from the Bizerte lagoon, Tunisia, including Neoechinorhynchus (Hebesoma) agilis (Rudolphi, 1819) Van Cleave, 1916; N. (Neoechinorhynchus) rutili Müller, 1780 (Neoechinorhynchidae); Acanthocephaloide propinquus (Dujardin, 1845) Meyer, 1932; A. incrassatus (Molin, 1858) Meyer, 1932 (Arhythmacanthidae); Longicollum pagrosomi Yamaguti, 1935 (Pomphorhynchidae); Rhadinorhynchus cadenati (Golvan et Houin, 1964) Golvan, 1969 (Rhadinorhynchidae); and Telosentis exiguus (von Linstow, 1901) Van Cleave, 1923 (Illiosentidae). Acanthocephaloide propinquus, N. (N.) rutili, L. pagrosomi and R. cadenati were restricted to the rectum and the posterior intestine, whereas the other species (A. incrassatus, T. exiguus and N. (H.) agilis) colonized two or three parts of the intestine. The most diverse acanthocephalan fauna was recorded in Lithognathus mormyrus, with three species; two species were reported from Trachurus trachurus; and a single species was recorded in Liza aurata and in Atherina boyeri. Neoechinorhynchus (N.) rutili, L. pagrosomi and R. cadenati attained the lowest prevalences of less than 6% and were considered as to be rare species. Acanthocephaloide incrassatus, A. propinquus, T. exiguus and N. (H.) agilis were satellite species. The diversity of the acanthocephalan fauna in the fish from the Bizerte lagoon is compared with previous studies from other localities. The report of A. incrassatus, A. propinquus and N. (N.) rutili in L. mormyrus presents new host records in Mediterranean waters.

Infective larvae of Bunostomum trigonocephalum exposed to gamma-irradiation at 60 kr failed to develop in the lamb. At levels of 20 and 40 kr, the infectivity of the larvae was reduced and fewer worms developed with a predominating female population. The worms developing from the irradiated larvae were smaller and the sex organs were ill developed. The females developing from larave irradiated at 40kr were functionally sterile with atrophied uterus devoid of eggs.

Experimental completion of the life-cycle of Paragonimus westermani (Trematoda: Troglotrematidae) (diploid type) from egg to adult has been achieved in the laboratory for the first time. A dog was fed metacercariae of P. westermani from naturally infected freshwater crabs, Geothelphusa dehaani. The adult flukes were recovered and their eggs were incubated in water at 28°C, hatching after 20 days. Laboratory reared marsh snails, Semisulcospira libertina, were exposed to miracidia from embryonated eggs. One of 47 snails became infected with a large number of 2nd generation rediae containing fully mature cercariae 245 days after exposure. Paragonimus-free crabs (G. dehaani) were then infected with the intramolluscan larvae. Of the 40 crabs examined 34–70 days after infection, 17 were infected with a total of 84 metacercariae. A cat and 4 dogs were fed with 55 metacercariae obtained. Eighty to 100 days later, a total of 40 flukes was recovered; 39 flukes were adults with eggs in their Uteri.

A detailed redescription of Gazellostrongylus lerouxi and Paracooperia serrata was given from specimenscollected 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.

The reproductive activity of feral male mice on an island of the sub-Antarctic Kerguelen archipelago was influenced by biological factors depending on periods within the breeding season. After having controlled host reproductive activity indices for body size, i.e. age, and body condition effects, Syphacia obvelata prevalence did not vary with host reproductive status or age either during the beginning or the middle–end of the reproductive season. Considering the beginning of the breeding season, worm abundance was more pronounced in males the year following a strong winter crash of the population than in years when high over wintering survival occurred. During the middle–end of the breeding season, males with the highest reproductive status were more infected than males with a lower reproductive status in years when oldest individuals dominated the population. It is suggested that this situation was due to an endocrine related increased host susceptibility partly influenced by a change in the age structure of the population, and that an increase in worm transmission was not directly related to male activity concurrent with reproductive status, nor to population density.

The authors describe Trichosomoides nasalis n.sp., parasitic in the nasal cavities of Epimys norvegicus and propose to modify slightly the definition of the family Trichosomoididae Yorke and Maplestone, 1926, especially in relation to the definition of the habitat (considered till now to be exclusively in the urinary tract).

A total of 180 individuals of Scardinius erythrophthalmus from Srebarna Lake, north-east Bulgaria, were examined for helminth parasites during spring, summer and autumn of 2005–2006 (30 specimens per season). Helminth parasites were recorded in 166 individuals (92.2%). Ten helminth species were found: trematodes – metacercariae of Posthodiplostomum cuticola, Diplostomumchromatophorum and D. spathaceum; monogeneans – Dactylogyrus difformis, D. difformoides and Diplozoon scardinii; cestodes – metacestodes of Paradilepis scolecina; nematodes – larvae of Spiroxys contortus and Rhabdochona denudata and adults of Schulmanela petruschewskii. Significant seasonal differences in the mean abundance were recorded for D. difformis, D. difformoides and D. scardinii. Significant seasonal differences in prevalence were recorded for P. cuticola, D. difformis, D. difformoides and D. scardinii. Dominant species in the component communities were P. cuticola, D. difformis and D. difformoides. The species composition of the component community essentially differs from that in the adjacent Danube River; a possible reason is the specific hydrobiological situation of the lake, characterized by a low density of benthic molluscs and crustaceans.

The following note is based on a sample of Filariae collected by Dr. W. Stefanski (University of Warsaw) from the trachea of a Black Stork shot in the neighbourhood of Warsaw and generously placed by him at my disposal.

A comparative study on the pathogenicity of two strains of Schistosoma mansoni one from Bor District and the other from the Gezira in the Sudan, using Cercopithecus aethiops monkeys as experimental hosts. The results, which were based on the assessment of various clinical, parasitological and pathological parameters, indicated that Bor strain was responsible for a more severe type of disease than its Gezira counterpart. Monkeys infected with Bor parasite generally revealed higher worm and egg loads, more marked changes inHb content and body weight gain and more extensive lesions in the liver and two monkeys died.

In the Sudan, it has often been noted that the disease produced by Schistosoma mansoni, as observed among patients from Bor District in the Southern Region, is far more severe than that usually encountered in those from the Gezira in the northern part of the country. These two areas which are about 500 miles apart differ widely in their climate, indigenous population, and social and economic status. It has been suspected that differences in the pathogenicity of the local S. mansoni strains may be one of the important factors determining the clinical presentation of the disease. Accordingly, a comparison of these two strains was undertaken, using the green monkey, Cercopithecus aethiops, as an experimental model. These animals varied in their response to the schistosomal infection, irrespective of the strain used, but the group infected with the Bor strain generally suffered from a more severe illness than their counterparts infected with the Gezira form of the parasite. This was evidenced by the higher worm and egg loads, and consequently the more severe clinical and pathological effects shown by the former group.

A number of these specimens were available for study. They were collected from the stomach of Galago crassicaudatus agisymbanus (Coquerel) in Tanganyika Territory by Dr. W. H. R. Lumsden whom I wish to thank for the material.

These stout worms have a thick cuticle which is finely striated. The well-developed lateral lips are smooth, hemispherical, each possessing a large triangular external tooth and three smaller internal teeth. There are two prominent papillae towards the dorsal and ventral margins of each lip. The cervical cuticle forms a collar round the anterior end.

The aim of this study was to determine the role in contractions of postsynaptic nicotinic acetylcholine (nACh) and γ-aminobutyric acid (GABA) receptors, in the bag region of Ascaris suum muscle cells, as well as the role of synaptic receptors between interneurons and motor neurons in the dorsal and ventral nerve cord. We have measured the isometric contractions of isolated segments of A. suum, with or without the nerve cord (dorsal or ventral). Contractions were caused by increasing concentrations of ACh or by electrical field stimulation (EFS). Based on our results, the presence of the nerve cord is essential for the contractile effects of ACh. The EC50 value of ACh for innervated muscle strips was 10.88 μm. Unlike intact (innervated) preparations, there was no contraction of the muscle flaps when the nerve cord was mechanically removed. Furthermore, continuous EFS produced stable contractions of innervated muscle strips, but they are not sensitive to mecamylamine (100 μm). However, GABA (30 μm) significantly inhibited the EFS-induced contractions. EFS with the same characteristics did not cause muscle contractions of denervated muscle strips, but EFS with a wider pulse induced the increasing of tone and irregular contractions. These contractions were completely insensitive to the effect of GABA. The EC50 for ACh did not differ between the dorsal and ventral segments (9.83 μm and 9.45 μm), while GABA exhibited features of competitive and non-competitive antagonists, regardless of whether it acted on the dorsal or ventral segments of A. suum. It is obvious that drugs will be more effective if they act on both the synaptic and extrasynaptic nACh and GABA receptors.