A Sudanese isolate of Schistosoma bovis from experimentally infected sheep was found to be highly pathogenic to albino mice. Eggs were first found in the livers 42 days after exposure. The distribution of eggs in the liver and small and large intestines changed little during the course of infection. Results arc compared with others using an Iranian isolate of S. bovis, which causes only a mild infection, and S. mattheci.

Metazoan parasite communities of Crassostrea gigas and Ostrea edulis from Great Britain, Crassostrea virginica from Mexico, and Saccostrea commercialis from Australia are described and summarized in terms of species composition, species richness, total number of individuals and dominance. Metazoan parasite communities in all host species were composed of turbellarians and the metacercarial stage of digeneans, with the exception of S. commercialis where only metacercariae were found. Arthropods, including one copepod and one mite species, were present only in British oyster species. All metazoan parasite communities of oysters had few species and low density of individuals. Richest communities were found in C. virginica at both component and infracommunity level. The least diverse component community occurred in S. commercialis. Infracommunities in O. edulis and S. commercialis never exceeded one species per host. The host response against parasites is suggested as the principal factor responsible for depauperate parasite communities of oysters. Environmental factors characteristic of tropical latitudes are likely to have enhanced both the number of species and the densities of parasites per host in the infracommunities of C. virginica.

Excretory and secretory (ES) products collected from adult worms of Strongyloides ratti stimulated interleukin-3 (IL-3) production with mesenteric lymph node cells from infected C57BL/6 mice, hut not with normal mesenteric lymph node cells. The IL-3 stimulating components were not major IgG binding antigens. Activity of the IL-3 stimulating components was stable by treatment with protease, although reduced by heating in boiling water.

Previously, an in vitro effect was observed on the complement system not only of the excretory-secretory products but also of somatic antigens from L3 Anisakis simplex larvae. In the present work the effect of anti-A. simplex specific antibodies on C3 and C4 levels in human sera was investigated. Up to 309 samples of sera were tested to determine levels of C3 and C4 and anti-A. simplex antibodies, including immunoglobulins IgG, IgM, IgA and IgE. Significant differences were observed between levels of C3 and C4 and all immunoglobulins except for IgE. In the case of immunoglobulins, the probability that an anti-A. simplex positive subject has a C3 deficiency was 3.8 times higher than a subject without specific antibodies. In conclusion, an association between elevated levels of anti-A. simplex antibodies and C3 and C4 deficiency was demonstrated.

(1) Cercaria splendens Szdiat was found in a specimen of Planorbis vortex, caught in a ditch near Utrecht, the Netherlands.

(2) Its morphology and behaviour are briefly described and compared with the data given by previous authors.

(3) A feeding experiment with the stickleback, Gasterosteus pungitus, is described. The preliminary conclusion is drawn that Gasterosteus is not the final host but probably acts as a transport host for this species.

Fresh eggs obtained from female Nematospiroides dubius were cultured at temperatures ranging from 5°C to 33°C. Hatching occurred between 5°C and 30°C; third stage larvae were obtained between 5°C and 25°C. The minimum time required from hatching to development to the third stage was 3.6 days (at 20°C) and the maximum was seven days (at 5°C). Larvae cultured at higher temperatures were smaller than those cultured at lower ones.

Histochemical tests indicate the presence of tanning precursors namely protein, phenols and phenolase in the vitelline glands of the temnocephalid Paracaridinicola platei. This suggests the occurrence of a tanned egg shell in this organism, a feature it shares with many other parasitic and free living platyhelminths. The large eggs are laid singly and are attached to the gill lamellae of the host.

Schistosoma haematobium and S. mansoni are two medically important schistosomes, commonly occurring sympatrically in Africa and so potentially able to infect the same human host. Experiments were designed to study the mating behaviour of these two species in mixed infections in hamsters. Analysis of the data obtained showed that both heterospecific and homospecific pairs readily form. No significant difference was seen between the two species in their ability in forming pairs, however, S. mansoni showed a greater homospecific mate preference. Analysis of the data using the Mantel-Haenszel test suggests that mating competition does occur between S. haematobium and S. mansoni, the former being the more dominant species. Both species appeared to be able to change mate, with S. haematobium showing a greater ability in taking S. mansoni females away from S. mansoni males when introduced into a pre-established S. mansoni infection highlighting the competitiveness of S. haematobium. The significance of the results is discussed in relation to the epidemiological consequences occurring in Senegal, and other areas where both species are sympatric.

The distribution of cobalt in parasitic helminths belonging to the trematodes, cestodes or nematodes was determined by the use of an atomic absorption spectrophotometer. The results of these analyses have demonstrated that growing trematodes (smaller forms) with active oogenesis and spermatogenesis contained more cobalt than older forms (large or very old adults) with empty uteri and large lobulated testes. In cestodes, the neck region of cysticerci and immature proglottids of adults showed more cobalt than the cyst portion of cysticerci and hydatid or mature and gravid proglottids of worms. Similarly, the youngest endogenous daughter cysts of Echinococcus granulosus showed more cobalt in their walls than those of larger forms. The element was found more concentrated in nematode eggs than in adult females, irrespective of species of host.

Chromosomal complements of an oocyte and a fertilized ovum from the ootype of Isoparorchis hypselobagri Billet, 1898 have been studied. Twenty diploid and 10 haploid chromosomes have been observed. In the karyotype the presence of five submetacentric, four acentric and a pair of sex chromosomes provide a significant cytotaxonomic information.

As far as the authors are aware, no standard technique has been described for the enumeration of infective trichostrongylid larvae recovered from faecal cultures. In experiments involving artificial infestations it is usually necessary to divide a concentrated suspension of larvae into a number of doses. In measuring the doses a dilution method may be used in which all the larvae in one or more aliquots taken from the diluted suspension are distributed on to a convenient number of slides and counted under the microscope. Alternatively, aliquots may be placed on the counting slide devised by Scott (1927). Such procedures are, however, time consuming and are fatiguing to the operator, where a large number of enumerations has to be made. They have the further disadvantage that the arbitrary dilution factor employed may result in too great a dispersion or conversely too great a concentration, either of which is undesirable from the point of view of accuracy and ease of counting.

Two new species of helminths, Fastigiuris prudhoei from Ochotona rufescens Gray, 1842, and Trichuris mofidii from Rhombomys opimus Lichtenstein, 1823, have been identified and described from mammals collected in Iran.

By kind permission of the Trustees of the British Museum (Natural History) the writer has had the opportunity of studying some tapeworms collected from a Greenland Salmon (Salvelinus alpinus subsp. ?) from Ottostrand, East Greenland, in August 1948 by Hjalmar Fleischer of Oslo. The material was found in the “gut” and contained about thirty specimens of an adult Diphyllobothrium, which appears to be new, along with specimens of Diplocotyle olrikii Krabbe, 1874 and Eubothrium crassum (Schrank, 1790).

Potato tubers infected with Heterodera marioni having been received at this Institute, it was decided to attempt to infect a small field plot with this eelworm for experimental purposes. The tubers were planted in the plot but the infection never became established. This was thought to be due to the heavy nature of the soil, since H. marioni has been recorded as a field parasite in Britain (Triffitt, 1931), and it is therefore unlikely that climatic conditions were the cause of its failure to become established in this instance. In order to verify this, and to find out how long this parasite can survive in soil in the absence of a host, the following experiment was carried out.

Buckley and Fairley (1950) working in England found segments of a species of Bertiella passed by an eight year old girl who had lived in Kenya for 14 months during 1946–47. Since only the terminal segments were available for study, a specific identification could not be made, though the authors thought that it was probably Bertiella studeri (Blanchard, 1891). Nelson (1963) has found that baboons in Kenya are commonly infected with species of Bertiella.

Spiny mice, Acomys cahirinus dimidiatus, inhabiting the wadis close to St Katherine in the mountains of the Sinai peninsula, were trapped and their helminth parasites were studied. Sixty one mice provided faeces for analysis and 27 were killed and autopsied. Six species of helminths were recorded (the spirurid nematodes, Protospirura muricola (74.1%) and Mastophorus muris (11.1%), the oxyuroid nematodes, Dentostomella kuntzi (59.3%), Aspiculuris africana (3.7%), and Syphacia minuta (3.7%) and the hymenolepidid cestode Rodentolepis negevi (18.5%)). The spirurids were the dominant species present, accounting for up to 0.87% of total host body weight. Analysis of worm weights and lengths suggested that transmission had been taking place in the months preceding our study. No sex difference in the prevalence or abundance of spirurids was detected. Significant differences were identified in the abundance of total nematode burdens and the mean helminth species richness between the three wadis which provided multiple captures of mice. There was also a marked effect of host age on both parameters. A highly significant positive correlation between spirurid egg counts and total worm biomass indicated that non-invasive techniques based on egg counts could be used to quantify worm burdens and when this technique was applied to a larger sample size (n = 61), a significant difference between sites but no host sex or age effects were detected for spirurid faecal egg counts. The data suggest that there are differences between helminth component communities infecting spiny mice in different neighbouring wadis, a hypothesis which will be explored further through our continuing studies in the Sinai.

1. Presence of Molineus patens in England is recorded for the first time.

2. A more complete description is given of the morphology of M. patens including details of the spicules of the male and of some interesting papillae in the female tail.

3. The species of the genus Molineus are reviewed and compared and the suggestion is made that M. americanus is a synonym of M. patens.

Twelve amino acids were detected in six davaincid ecstodes, Davainea hewetensis Dhawan & Capoor (1972) collected from one Gallus gallus domesticus L. at Allahabad, India. Chemotaxonomic studies within the family Davaineidac have shown the presence of cystine and hydroxyproline only in D. hewetensis, although phenylalanine and proline occur in all species examined previously.

The large number of species of the genus Opisthorchis Blanchard, 1895 that have been reported from different regions of the world as parasites of dog, cat, man and lower groups of fish-eating vertebrates, have generally been identified on such adult morphological characters as the size or shape of the gonads, the position and shape of the excretory bladder and the character of the vitellaria, whether in acini or in linear distribution. The validity of the allied genera, Amphimerus Barker, 1911; Paropisthorchis Stephens, 1912 and Clonorchis Looss, 1907, proposed for some of these opisthorchids, had been questioned, among others, by Tubangui (1921), Morgan (1927), Baylis (1929), Faust (1930, 1949), Bhalerao (1935), Erhardt (1935), Wallace and Penner (1939), Price (1940), Dawes (1940), Bisseru (1957) and Watson (1960).