Lymnaea truncatula, 4 mm in height, were subjected to infection by a single miracidium of Fasciola gigantica, then raised at 23°C until day 60 of the experiment. Histological study of these snails demonstrated a mean redial burden of 34 parasites at day 60, of which one third were degenerating forms. The mean number of living independent rediae did not exceed 5 for the first and second generations. Conversely, in subsequent generations there were as many as 18 rediae per snail at day 60. The first living redia of the first generation in particular gave rise to daughter rediae. Mature rediae appeared at day 35 and especially concerned the first and second generations at day 60. The authors conclude that development of the first and second redial generations occurs during the same period, and that the forms of the first cohort of the second generation are produced from the first redia of the first generation which originated from the sporocyst.

The morphology of the tegument in the redia of Paramphistomum epiclitum (Digenea: Paramphistomidae) resembles that shown by most larval and adult digeneans; an outer surface syncytium is in continuity with the cytoplasm of in-sunken, nucleated cytons. Although tegumental cytons usually contain a single nucleus, some display up to six nuclei. The tegumental syncytium lining the pharynx of P. epiclitum rediae lack underlying cytons. The apical membrane of the tegument is elaborated by folds and microvilli, which presumably facilitate uptake of nutrients and/or exchange of ions involved in osmoregulation. A single type of secretory body, resulting from the fusion of smaller vesicles produced at Golgi complexes in the cytons, occurs throughout the tegument. Uniciliate sensory receptors occur in the surface syncytium particularly around the oral opening.

Haematuria and proteinuria as detected by chemical reagent strips correlated moderately (r=0·7) with prevalence and intensity of infection with Schistosoma haematobium in an area of Anambra State, Nigeria. Differences attributable to age and sex were also reflected in a similar pattern, all peaks occurring in the 5–14 year age group. The differences observed with varying levels of intensity and haematuria at both 10 and 50 erythrocytes/μl (p<0·001) and proteinuria at 0·3 g/dl (p<0·01) were statistically significant. At a proteinuria level of 1 g/dl, the observed differences were however not statistically significant (p>0·5). The percentage of specimens from children (1–14 years) positive for S. haematobium eggs and with at least traces of haematuria and proteinuria (63·4% and 95%, respectively) was higher than in adults (33·3% and 80·2%, respectively). All individuals with more than 50 eggs/10 ml of urine were correctly identified using both indices either separately or in combination. For egg counts of less than 50 egg/10 ml of urine, false diagnosis occurred in only 5% of all specimens examined. The sensitivity and specificity of haematuria and proteinuria at trace quantities was very high, hut haematuria had a higher predictive value for a positive test (PvPt) and was considered the overall better indicator. A combination of both indices did not significantly increase the PvPt. When trace haematuria and moderate proteinuria were combined, both the sensitivity, specificity and PvPt were all above 90%, giving the best overall values in all the combinations made.

The abundance of six species of trematodes: Aphanurus stossichi, Bacciger israelensis, Diphterostomum israelense, Plagioporus idoneus, Lepocreadium album and L. pegorchis, parasitic in the digestive tract of marine teleostei (Sparidae) collected near Jounieh (east Mediterranean), was analysed as a function of the host-size. In two parasite/host systems, infections were observed from the lowest size classes of the sample, with a clear tendency to an increase of abundance in older fish. In four others, parasites appear only above a rather high threshold class, young individuals never being infected. In the last three parasite/host systems, host invasion may occur early or late, but infection decreases above a well defined size class, old fishes rarely or never being infected. A given trematode species. when parasitizing several host species, shows similar abundance/host size relationships, e.g. P. idoneus in Diplodus vulgaris and Oblada melanura. When more than one species of trematode infects a single host species, curves can be markedly distinct; for instance, L. pegorchis was collected from Pagellus erythrinus below 15 cm. whereas D. israelense parasitized the same fish approximately above the same size. There is no evidence that such a replacement of one trematode by another in the course of host growth is a result of interspecific competition.

Nondenatured and denatured total RNA from the tapeworm Diphyllobothrium dendriticum (Cestoda) was analysed by agarose gel electrophoresis. It was found that the large subunit ribosomal RNA (lrRNA) is 28.0S and the small subunit ribosomal RNA (srRNA) is 19.5S. Following denaturation the 28.0S rRNA was disrupted into a 19.5S subfragment and a 20.7S subfragment due to the presence of a centrally located hidden break. By hybridization of Northern blot membranes with oligonucleotide probes specific for the 5′- and 3′-ends of the lrRNA respectively, we have shown that the 19.5S sub-fragment is from the 5′-end (the α-subfragment) and the 20.7S subfragment from the 3′-end (the β-subfragment) of the 28.0S rRNA of D. dendriticum.

Two 22-day-old Landrace-Small Ear Miniature (L–SEM) pigs, five 45 to 66-day-old Small Ear Miniature (SEM) pigs, and one 16-day-old Holstein calf were each fed 1000, 3000 or 10000 Taenia saginata (Poland strain) eggs respectively and killed 34–77 days after inoculation. Four of the five SEM pigs and the Holstein calf were susceptible to this parasite. However, two L–SEM pigs and one SEM pig remained negative. The cysticerci recovery rates for the SEM pig and Holstein calf were 36% and 3%. respectively. All cysticerci from the SEM pigs were found in the livers, more in the parenchyma (89%) than on the surface (11%). Only eleven cysticerci in two SEM pigs were mature and the remainder were either immature, degenerated or calcified. The cysticerci in the calf were distributed throughout the body: leg muscles (248), heart (27), tongue (17), intercostal muscles (14), diaphragm (5), kidney (I) and liver (1). Most (299) of the cysticerci were mature, one was immature and 13 were degenerated or calcified. The length, width, diameter of the protoscolex and sucker of the cysticerci from the calf were larger than those from the SEM pigs. However, the diameter of the rostellum of the latter was slightly larger than the former. Hooklets were not found on any mature cysticercus recovered. The results of the present study provide evidence that the SEM pig can he used as an experimental intermediate host for T. saginata.

The localization and distribution of cholinergic, serotoninergic (5-HT, serotonin) and peptidergic components of the nervous system of adult Cephalochlamys namaquensis (Cestoda: Pseudophyllidea) have been determined using enzyme histochemical and immunocytochemical techniques interfaced with light and confocal scanning laser microscopy. All three classes of neuroactive substance showed a similar pattern of staining, occurring extensively throughout the central and peripheral nervous systems of the parasite. There were some minor regional differences in staining, suggesting specific roles for certain classes of neurone, and nerve cell bodies were most evident following immunostaining for serotonin. The general overlap in the distribution of staining may be indicative of some co-localization of neurotransmitter and/or neuromodulatory substances.

First-stage larvae of pure strains of M. capillaris and N. linearis (Nematoda: Protostrongylidae) from goats were used to assess the influence of rapid desiccation on survival. M. capillaris survived desiccation of faeces better than N. linearis. The latter species was particularly susceptible to duration of storage after desiccation (0 to 10 days). Surviving larvae of desiccated batches of M. capillaris were less able to infect the land-snail Candidula intersecta. Resistance of first-stage larvae to desiccation is a key factor in infectivity and may partly account for the geographical distribution of the two species of protostrongylids.

An enzyme-linked immunosorbent assay (ELISA) using antigenic β-galactosidase-Dirofilaria immitis recombinant fusion protein (FP) obtained by the recombinant DNA technique provided a useful diagnostic tool for human dirofilariasis. D. immitis-infected human sera reacted strongly with FP that was immobilized with anti-β-galactosidase monoclonal antibody on microplates. However, the FP did not react with sera from patients with other filariasis. In detection of anti-D. immitis IgG antibody. ELISA using FP was highly sensitive and specific compared to that using crude somatic antigen.

The feasibility of infecting laboratory rabbits experimentally with the ovine nematode Nematodirus spathiger was examined. Eight-week-old rabbits were dosed either with 5000 or with 17 000 third-stage larvae and killed on days 10, 21 or 42 post-infection. With the lower dose, 20 to 40% of the inoculum were recovered at necropsy. Similar values were recovered at necropsy. Similar values were observed with the 17 000 dose on days 10 and 21 post-infection, but on day 42 the worm population was residual (0·6%). With both dose levels, during the course of infection, the worm populations were mainly composed of fourth-stage larvae and worm egg excretion was low. N. spathiger mainly inhabited the proximal jejunum. The results were compared with N. spathiger infection in sheep to assess the usefulness of the rabbit as an experimental model for Nematodirus infection.

Comparison of antibody response and antigen recognition was made by ELISA and western-blot analysis in pig experimental infections by T-l and T-3 Spanish Trichinella isolates. Two groups of Iberian pigs were experimentally infected with 150 larvae/kg body weight of GM-1 and C-76 Spanish Trichinella isolates as representatives of T-1 and T-3 gene pools respectively. Antibody levels and antigen recognition were measured on days –14, 0, 6, 16, 20, 27, 34, 49, 63 and 82 after infection by ELISA and western-blotting assays. Antibody response against C-76 infection was significantly delayed and lower than against GM-1. The two Trichinella isolates were indistinguishable, however, by western blotting analysis, although recognition of larval antigens was quantitatively higher than adult ones. Interestingly, the principle larval antigenic components recognized by pigs were those recognized by the monoclonal antisera NIM-M1. Finally, there were no serological patterns indicative of the stage of infection (“antibody windows”) discriminating, for example between early versus late infections.

A simple aceto-carmine procedure was developed to relax, fix, stain, and clear excystcd metacercariae of Echinostoma caproni and E. trivolvis. This procedure allowed for morphologic details on whole metacercariae comparable to those seen with more elaborate staining procedures. Differences in dimensions and staining intensities between the two species of metacercariae are described.

Acanthocephalan ova, indistinguishable from the ovoid eggs of Moniliformis moniliformis, were detected in the stools of a 45-year-old man at the University of Jos Health Clinic. Nigeria. The patient complained of general body weakness, occasional giddiness and intermittent burning sensations around the umbilicus. Successful treatment with niclosamide and the possible source of infection are communicated.