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 survey of larval helminths in freshwater snails of Kinmen was conducted from 1986 to 1987. Parasitological examinations of a total of 726 live snails collected from 25 loci revealed that 20 of 80 Bithynia fuchsiana were infected with metacercariae of Echinostoma gotoi and 36 with metacercariae of other echinostomes. Among 57 Radix auricularia swinhoei snails, 27 were infected with echinostomes and with metacercariae of other flukes. Of 20 Cipangopaludina chinensis, 18 were found with larvae of echinostomes. Larval trematodes were also found in three of 37 Austropeplea ollula and two of 87 Gyraulus spirillus. Third-stage larvae of Parastrongylus cantonensis were found in Ampullarius canaliculatus (5/103), Sinotaia quadrata (20/141), Hippeutis umbilicalis cantori (1/70) and Gyraulus spirillus (2/87). Segmentina hemisphaerula were not infected. Cercariae of Centrocestus formosanus, Haplorchis pumilio and xiphidiocercaria were found in three, two and two specimens, respectively, of 37 Thiara tuberculata.

Acanthocheilonema viteae, Litomosoides carinii and Setaria cervi were found to actively synthesize proteins in vitro. Different centrifugation fractions and their TCA-precipitable fractions were assessed for the distribution of newly synthesized proteins. Penicillin and streptomycin inhibited the process in A. viteae. The synthesis in S. cervi was susceptible to puromycin, chloramphenicol, cycloheximide, neomycin and polymyxin B. The process in L. carinii was strongly blocked by puromycin while chloramphenicol had no significant effect.

Proteolytic enzymes present in extracts of third (L3) and fourth (L4) stage larvae and adults of the cattle nematode Ostertagia ostertagi were defined on the basis of pH optima and proteinase inhibitor sensitivity in spectrophotometric assays using azocasein and elastin-orcein as protein substrates. Evidence that different classes of proteinases are expressed in a stage specific manner was provided by the contrasting pH optima and inhibitor sensitivities shown by the enzymes in the different parasite stages. Stage specificity was confirmed by gelatin-substrate analysis. In addition, proteolytic activity was sought in the excretory/secretory products (ES) of the L4 following simple in vitro culture. Contrasting pH and inhibitor sensitivities as well as gelatin-substrate analysis showed that different proteinases were present in somatic L4 extracts and L4 ES products. The secreted proteinases may be useful targets for serodiagnosis or vaccination.

The Enzyme-linked immunosorbent assay (ELISA) was used to detect Ascaris suum antibodies in swine sera with adult body fluid (ABF) as an antigen. The assay was standardized with respect to the antigen concentration and serum and conjugate dilutions. Cross reaction was found between the antigen and the sera from the swine infected with Metastrongylus apri. The ELISA was more sensitive than the complement fixation test. Five protein peaks were obtained from ABF by gel filtration on Sephacryle S-300. Fraction I was the most specific. A 105 kDa protein in the fraction reacted with swine lgG in the serum of infected animals in Western blot analysis.

Male Hisex chicks were used in two experiments to investigate the interaction between Ascaridia galli infection and supplemental copper from basic and neutral salts. This was assessed by means of body weights, mortality, parasite burden and liver copper level. Cu2(OH)3Cl reduced the number of parasites but CuSO4.5H2O and CuCO3.Cu(OH)2.nH2O did not affect the parasite burden.

Sera of 908 blood donors, average age 35 years, living in towns and villages of the Slovak Republic were tested for Toxocara canis antibodies using an ELISA-IgG test. The seroprevalence in the healthy population was estimated at 13·65%. Antibodies were predominantly demonstrated in the sera from persons living in rural communities (17·09%) compared to the sera investigated from urban communities (11·82%). Women had a significantly higher seropositivity than men. The serological response in 2703 sera from patients suspected of toxocarosis was compared with their clinical manifestation, sex and age. Toxocara antibodies were found in 27·41% of suspected patients. Although the seroprevalence in adults was significantly higher among women than men, in children, boys had a higher seroprevalence than girls. The main clinical manifestations were leucocytosis and eosinophilia (46%), ocular disorders (36%), lung, liver and neurological disorders (26%). The most severe forms of this disease were observed in 2 to 5-year-old children with geophagy.

Specific immunoreactive components present in crude somatic extract and in excretory-secretory (ES) products of Gnathostoma spinigerum advanced third-stage larvae (L3) were identified by Western blotting and their diagnostic potential evaluated by indirect ELISA. Although both crude antigen preparations were highly complex, the ES antigen gave a more satisfactory diagnostic result. Most G. spinigerum specific components present in the somatic and ES preparations had molecular weights below 29 kD and were not glycosylated, judging from the concanavalin A staining pattern. Specific diagnostic antigens were prepared by subjecting the crude preparations to SDS-PAGE. Low molecular weight components were identified and electroeluted from the gel. Excess SDS was removed by the use of an ion retardation resin. The antigens obtained by this relatively simple procedure were found to be highly specific for G. spinigerum. Sensitivity, specificity, and positive and negative predictive values for the assay using the fractionated somatic antigen were 100%.

Total ecdysteroid-like immunoreactive material was assayed and quantified in adults of the parasitic nematode N. brasiliensis during the intestinal phase in the rat in order to detect possible physiological fluctuations in titre. Worms of the same sex isolated from one rat were pooled in order to quantify ecdysteroids using enzyme immunoassay (EIA). The concentration of ecdysteroids fluctuated during adult life according to the sex and the age of the parasite. Important differences of levels of ecdysteroid-like compounds between the two sexes of parasites were noted particularly at 128 and 168 h post-infection. The peak at 128 h, present in female, but not in male worms, corresponds to the time of egg-laying. Following HPLC-EIA analysis, the presence of ecdysone, 20-hydroxyecdysone and apolar ecdysteroid-like material was ascertained during this peak. The physiological role and the possible origin of ecdysteroids in this nematode are discussed.

The development of the tapeworm Proteocephalus torulosus (Batsch, 1786) (Cestoda: Proteocephalidae), a parasite of cyprinid fish, was studied in the intermediate host under experimental conditions. The eggs of P. torulosus were typified by a relatively small outer envelope (hyaline membrane) and a thick middle layer surrounding the oncosphere. Incubation of P. torulosus eggs at different temperatures revealed the ability of some oncospheres to survive and remain infective to the intermediate host for up to 5 weeks at 5–7°C, 12 days at 10–12°C, and 8 days at 20–22°C. Of 8 copepod species used in these experiments, complete development of larvae was observed only in Cyclops strenuus. Growth was completed in 9–12 days at 20–22°C and four weeks at 9–10°C. During development the cercomer was not observed. The infectivity of larvae from C. strenuus for the definitive hosts, cyprinid fish, was very low and only one chub of 26 fish used for feeding experiments (21 chub, Leuciscus cephalus, 3 bleak, Alburnoides bipunctatus, 1 rudd, Scardinius erythrophthalmus—all the family Cyprinidae, and 1 loach, Noemacheilus barbatulus—the family Cobitidae) became infected.

Dissolved carbon dioxide was deemed not to be an important factor in the activation of Taenia taeniaeformis oncospheres. Rabbit bile was found to provide the most appropriate whole bile for in vitro activation of oncospheres