Infective larvae (third-stage larvae) of both Angiostrongylus cantonensis and A. costaricensis from their snail intermediate host were subjected to either X-ray or gamma-ray irradiation. The viability of the irradiated larvae was assayed by oral inoculation of the larvae into rodents (A. cantoflensis in mice and rats, A. costaricensis in mice only). From the results of worm recovery, the minimal dose of irradiation that inhibited the infectivity of the third-stage larvae of A. cantonensis and A. costaricensis was 2 and 4 kGy, respectively.

Strongylus (Dicerocola) tremletti sp.nov. is described from the black rhinoceros, Diceros bicornis L. from Kenya.

The affinities of S. (D.) tremletti sp.nov. with the other species of the genus Strongylus Müller, 1780 are discussed and the subgenus Dicerocola subgen.nov. is erected to contain it.

The species of Strongylus in Kenya are noted and original drawings of S. (D.) asini Boulenger, 1920 are included.

The parasite was found in the bile ducts of three sperm whales, which were caught in the 1957–58 whaling season.

As specimens were found independently in bile ducts of three whales this position in the host appears to be the natural habitat. All the worms were in pieces and incomplete. The pieces, in each case, totalled approximately 18 metres, 0·9 metres and 21 metres respectively. The holotype (length 18 metres) was probably complete except for a few terminal proglottids because it consisted of two very long pieces and one short piece which could be fitted together. The type material has been deposited in the British Museum (Natural History) Registered No. 1961·12·12·1 (Holotype) and 1961·12·12·1 (Para types).

A medium containing inorganic salts, vitamins and amino-acids is described for the in vitro cultivation of the amphistome, Orthocoelium scoliocoelium, from the rumen of buffalo. Based on the properties of rumen fluid, this medium promoted and sustained normal egg production, at 37°C temperature and pH 7·4 to 7·8 for 15 days. In contrast to other media used, no patho-physiological alterations except abnormal cytoplasmic lipid, were detected. Since the parasites produced normal eggs, it is concluded that this medium is suitable for short-term cultivation of the parasites.

The relationship between the cercarial allergen and two previously isolated egg allergens (J1, J2) of Schistosoma japonicum was examined especially in terms of the cross-reactivity between them. Semi-purified cercarial allergen (JAC) was obtained from the crude extract of S. japonicum cercariae by gel chromatography on Sephadex G-200. The apparent molecular weight of JAC was estimated approximately as 60–100 kDa. JAC could bind to Con A-Sepharose, indicating its glycoprotein nature. Three groups of BALB/c mice were immunized with JAC, J1 or J2 using A1(OH)3 as adjuvant, and the cross-reactivity of each antiserum was examined by PCA. Anti-JAC, anti-Jl or anti-J2 serum was highly specific to the corresponding antigen. When IgE-ELISA of S. japonicum patient sera was performed using JAC, J1 or J2 as an antigen, the correlation between anti-J1 and anti-J2 (r = 0.78) was high, whereas the correlation between anti-JAC and anti-J1 (r = 0.27) or between anti-JAC and anti-J2 (r = 0.12) was low. These results suggest that most IgE epitopes on cercarial allergen are independent from those on egg allergens in S. japonicum.

In an earlier paper Goodey (1940) gave a detailed description of the morphology of three species of Anguillulina viz.: A. multicincta (Cobb) Goodey, A. erythrinae (Zimmermann) Goodey and A. robusta (de Man) Goodey. All three species are associated with plant roots: A. multicincta is a parasite of banana roots, A. erythrinae is parasitic on the roots of certain common grasses and cereals such as Agrostis stolonifera, Lolium perenne and oats (the writer has also found it on hop roots), A. robusta though associated with grass roots has not, to the writer's knowledge, been found within plant tissues. In the case of all three species phasmids were easily recognized on the female tails and were described and figured but they were not seen on the male tails and it was assumed that they were probably absent.

A satisfactory antigen for use in serological studies of nematodiasis in sheep has been prepared from Bunostomum trigonocephalum.

The investigations are outlined and a method for its routine preparation from field material is described.

The worm burden in grazing ewes was studied. Analysis of the results showed that correcting worm egg counts (e.p.g. fresh faeces) for variations in faecal D.M. content and in total faeces output is not of any great benefit unless precise information is available.

Data are also presented which suggest that under normal circumstances variations in the sub-clinical worm burden of adult grazing ewes are not related to any variations in food intake.

In 1988, 1989 and 1990 second year grazing heifers, naturally infected with gastrointestinal nematodes, were separated into two groups, one of which was treated orally with albendazole. In 1988 and 1989 treatment was administered immediately after parturition (February), and in 1990 during the last term of pregnancy (December). Both treated and control animals were grazed on separate plots in a rotational system. Maximum faecal egg counts were observed amund parturition, except in 1990, when treatment was given at the end of gestation. The main genera identified were Cooperia, Trichostrongylus, Ostertagia and Oesophagostomum. The number of Ostertagia larvae in the treated groups increased from 1989 to 1990, while the others decreased. Pasture contamination with third stage larvae (L3) was lower on the piots grazed by treated heifers. Maximum numbers of L3 were found in autumn, at the end of winter, and at the beginning of spring. Mean serum pepsinogen concentrations were significantly higher in the untreated groups. This concurs with the pattern for L3 on pasture. The trial shows that if a single treatment against gastrointestinal nematodes is carried out, and the animals remain on contaminated pastures, the parasitic load tends to level out after 4–5 months under favourable climatic conditions. However, the percentages of nematode genera occurring in the new populations may differ from those in the original infection.

In two previous papers (Dissanaike et al., 1957a and 1957b) we described the technique of tagging Culex fatigans and Armigeres subalbatus (=obturbans) with P32 to obtain high beta activities. Filarial larvae were made to develop to the infective stage in these activated mosquitoes and were found to have beta activities high enough for detection individually.

Three new records are made, viz: Achillurbainia recondita Travassos, 1942; Metadelphis evandroi Travassos, 1944; Rhopalias coronatus (Rudolphi, 1819) Stiles and Hassall, 1898; all are recorded from the manicou, Didelphis marsupialis insularis (Allen) from Trinidad, British West Indies. Descriptions of all these species are given.

The aim of this study was to develop a simple method to purify Strongyloides eggs from rat faeces using a sucrose gradient centrifugal-flotation technique. This procedure is simple, rapid and possesses a high efficiency in recovering Strongyloides eggs without faecal detritus in less than one hour, thus eliminating the use of complex apparatus and different chemical substances. The possibility of working with pure and live Strongyloides eggs opens up a wide range of future studies on the biology of this parasite. This study constitutes the first report in the scientific literature on purifying Strongyloides eggs using a sucrose density gradient.

The objective of this study was to evaluate the predatory activity of the nematophagous fungus Duddingtonia flagrans on infective larvae of gastrointestinal nematodes from dairy heifers in different conditions (shaded and sunny) of a silvopastoral system (SPS) on an agroecological farm. Ten Jersey heifers were divided into two groups: treated (received pellets containing fungus); and control (received pellets without fungus). Twelve hours after fungus administration, faeces samples were collected for in vitro efficacy tests. The animals then remained for 8 h in the experimental pasture area. At the end of this period, 20 faecal pads (10 treated and 10 control) were selected. Pasture, faecal pad and soil collections occurred at intervals of seven days (d), totalling four assessments over 28 d. To evaluate the influence of the conditions shaded and sunny, we registered the condition of the location of each faecal pad per hour. After 12 h of gastrointestinal transit in dairy heifers, a reduction of 65% was obtained through the in vitro test. The treated group presented a lower number of infective larvae (L3) in the faecal pad and upper pasture. Differences in numbers of L3 were observed between the conditions (sunny and shaded) in the faecal pad of the control group; while in the treated group there were no differences between the conditions. The predatory activity of the fungus was efficient over time in the shaded and sunny conditions of an SPS, decreasing the parasite contamination during the pasture recovery time in a subtropical climate.

Populations of Pasteuria penetrans isolated from root-knot nematodes (Meloidogyne spp.) and cyst nematodes (Heterodera spp.) were tested for their ability to adhere to a limited selection of sheathed and exsheathed animal parasitic nematodes, free living nematodes, including Caenorhabditis elegans wild type and several srf mutants, and plant parasitic nematodes. The attachment of spores of Pasteuria was restricted and no spores were observed adhering to any of the animal parasitic nematodes either with or without their sheath or to any of the free living nematodes including C. elegans and the srf mutants. All spore attachment was restricted to plant parasitic nematodes; however, spores isolated from cyst nematodes showed the ability to adhere to other genera of plant parasitic nematodes which was not the case with spores isolated from root-knot nematodes. The results are discussed in relationship to cuticular heterogeneity.

An in vitro assay was used to examine the effect of Bothriocephalus acheilognathi Yamaguti, 1934 (Cestoda: Pseudophyllidea) on the polarization response of pronephric leucocytes of carp, Cyprinus carpio. Leucocytes, isolated from naive, naturally-infected fish and carp injected intraperitoneally with cestode extracts, were exposed to parasite extracts (protein concentrations 0–10.0 μg ml-1), for up to 24 h in the presence or absence of carp serum. In general, polarization responses of the pronephric leucocytes, primarily neutrophils and eosinophils, increased with incubation time although there was no significant difference in the response induced by the different protein concentrations. Differences in the polarization response were, however, observed in naive, naturally infected and injected fish and the cells responded differently in the presence and absence of carp serum. In the absence of carp serum the polarization response of pronephric leucocytes in vitro was significantly reduced with cells obtained from injected and naturally infected fish compared with those obtained from naive carp. This suppression of leucocyte migration was however reduced by the addition of carp serum to the in vitro system. The role of this interaction between the possible suppression of polarization induced by the parasite and stimulation by serum is discussed.

Epidemiological studies of Echinococcus multilocularis infections in definitive hosts require a reliable and economic diagnostic method. In this study, the current copro-DNA examination technique was modified by increasing the faecal amounts tested and adding a step to neutralize the faeces before DNA extraction. Reliability of the modified method was evaluated using rectal faecal samples from red foxes and comparing them with intestinal worms detected using the sedimentation and counting technique (SCT) following necropsy. The modified copro-DNA examination method demonstrated 93.9% sensitivity (138/147) on the SCT. Its detectability increased depending on the worm burden, and the sensitivity was 100% in cases harbouring over 1000 worms. From 111 SCT-negative cases, six (5.4%) were copro-DNA-positive, and all were confirmed as E. multilocularis via sequencing analysis. Five of the remaining 105 SCT-negative cases (4.8%) retained polymerase chain reaction (PCR) inhibitors in the extracted solution, suggesting that approximately 5% of the red fox faeces retained these inhibitors after treatment with the present copro-DNA extraction method. Although further evaluation is needed for faeces deposited in the wild, the present copro-DNA examination technique will help monitor the E. multilocularis prevalence in definitive hosts. When used for detailed evaluations of endemicity (e.g. changes in infection pressure or spread in non-endemic areas), the absence of PCR inhibitors should be confirmed, and multiple trials on faecal subsamples are recommended.

Stibocaptate (Astiban, Hoffman - La Roche) killed third stage larvae of Brugia pahangi in vitro at 50 p.p.m. but had no effect on microfilariae at 1 × 104 p.p.m. No larvae developed in infected mosquitoes fed 1% stibocaptate in 10% sucrose. It was neither micro-nor macrofilaricidal in neither jirds or cats but did affect embryogenesis.

Four strains of entomopathogenic nematodes were isolated with a live trap method in southern Poland. The isolates were identified as Steinernema silvaticum based on morphological, morphometric and molecular data. Infective juveniles of Polish S. silvaticum isolates differ in body length from S. weiseri (951 vs 740 μm, respectively), and in the hyaline tail portion from S. kraussei (48 vs 38%, respectively). First-generation males of S. silvaticum are longer than those of S. kraussei, S. weiseri and S. ichnusae (1829 vs 1400, 1180 and 1341 μm, respectively). Males of S. silvaticum and a sister species S. kraussei can be distinguished by the distance from the anterior end to the nerve ring (142 vs 105 μm), spicule (66 vs 49 μm) and gubernaculum length (45 vs 33 μm), and the presence of a mucron. The analysis of internal transcribed spacer (ITS), D2-D3 and cox1 sequences of the tested nematodes revealed differences of 3–5%, 3% and 12–13%, respectively, from S. kraussei strains. The phylogeny of both nuclear and mitochondrial genes indicated close relationships of the Polish S. silvaticum isolates with S. kraussei, S. oregonense and S. cholashanense. The reproductive isolation of the studied isolates was confirmed by hybridization tests with other European feltiae–kraussei group representatives. This study has supplemented the original description of S. silvaticum with morphological and morphometric characterization of the first-generation males and females. This is also the first molecular study of this species based on a multi-gene approach.