Groups of mice (NMRI) were infected with 0.6 and 25 metacercariae of the intestinal trematode Echinostoma caproni. An enzyme linked immunosorbent assay (ELISA) was developed for measuring the specific IgM, IgG and IgA antibody responses in serum, small intestinal tissue and small intestinal lumen of the mice, by using a crude adult E. caproni antigen. In infected mice, significant levels of IgM were measured in the sera from day 14 after infection and of IgG and IgA from day 28 after infection. Early in the infection, the mean level of serum IgM was higher in 6-worm infections than in 25-worm infections. Late in the infection, higher mean levels of IgA were reached in the serum of mice with high than in those with low dose infections. The onset of appearance of antibodies in the tissue of the small intestine reflected the picture seen in the serum. For IgM, and to a lesser degree for IgG, the highest mean antibody levels appeared in the posterior sections of the small intestinal wall, where also the parasites were located. The mean level of IgA, however, was uniform throughout the length of the small intestinal tissue. High levels of specific IgA were detected in the lumen of the small intestine on day 28 after infection, especially in the anterior sections, where only few parasites were located. No specific IgM or IgG could be detected in the intestinal lumen on this day. The results are related to the intestinal location and the pattern of expulsion of E. caproni in the mouse host.

Mouse (C3H) mucosal glycoconjugates were examined in normal small intestines and intestines infected with Echinostoma caproni, or E. trivolvis using six different fluorescein-conjugated lectins: Triticum, vulgaris agglutinin (WGA), Ulex europaeus agglutinin I (UEA-I), Ricinus communis agglutinin I (RCA-I). Glycine max soybean agglutinin (SBA), Dolichos biflorus agglutinin (DBA), and Arachis hypogaeu peanut agglutinin (PNA). The expression of lectin-binding sites and the intensity of the binding of lectins in the mouse small intestines were changed by infection with the echinostomes. Specific differences in the reaction to glycoproteins were clearly observed between the mouse intestines infected with E. caproni and those infected with E. trivolvis. In E. caproni infection, binding of most of the lectins to the villi was remarkably reduced in accord with the villous atrophy and loss of goblet cells. In contrast, in E. trivolvis infection, the binding of WGA, RCA-I and DBA was reduced in the microvillar surfaces, but binding of UEA-I and SBA were unchanged compared to the control intestines. The lectin binding to goblet cells in E. trivolvis-infected mice mostly increased. These observations may reflect the marked increase in goblet cells and the less severe damage in the villi of E. trivolvis infection compared to E. caproni infection. Most of the glycoconjugates were slightly reduced in the hyperplastic crypts except for N-acetyl glucosamine. It is possible that glucose metabolism in the host intestines infected with E. trivolvis was activated. resulting in an increase in the rate of mucin synthesis as well as qualitative changes in mucus, thereby mediating the expulsion of the worms.

Adult Corrigia vitta (Trematoda: Dicrocoelidea) inhabit the pancreatic duct of the fieldmouse, Apodemus sylvaticus, where, in numbers, they may occlude the duct lumen and prevent the flow of pancreatic secretions. Enzyme histochemical and immunocytochemical techniques, in conjunction with confocal scanning laser microscopy, have been used to examine the localization and distribution of cholinergic. serotoninergic (5-HT, serotonin) and peptidergic components of the nervous system of the adult worm. All three classes of neuronal mediator showed a common pattern of staining, occurring throughout the central and peripheral nervous systems. Of the four peptide immunoreactivities (IR) demonstrated (pancreatic polypeptide (PP), peptide YY (PYY), substance P (SP), FMRFamide), PP-IR was the most predominant, occurring not only within the central ganglia and longitudinal nerve cords, but also in subtegumental plexuses and in fibres associated with the egg-forming apparatus. PYY and FMRFamide IRs were evident throughout the central and peripheral nervous systems; FMRFamide immunostaining, in particular, highlighted innervation of the ootype and immunoreactive cell bodies around the Mehlis' gland. Both SP- and 5-HT-IRs were restricted to the cerebral ganglia, ventral nerve cords and associated cell bodies. The distribution pattems of these peptides and 5-HT within the nervous system of C. vitta suggest they are likely to function as neuronal mediators. PP, PYY and FMRFamide may also serve in regulating egg production.

A comparative studs of the spectral, electrophoretic and isoelectric properties of the haemoglobins of three trematodes. Paramphistomum epiclitum. Gigantocotyle explanatum and Gastrothylax erumenifer was carried out. A high absorption in the beta band region indicates that trematode haemoglobins have high oxygen affinities. Electrophoretic mobilities of all trematode and their host haemoglobins were different. The isoelectric points of trematode haemoglobins were found to focus in the acidic range except that of G. crumenifer haemoglobin I. which focused at an alkaline pH.

Pyridoxine (vitamin B6) deficiency was induced in cotton rats which were then infected with the filarial parasite Litomosoides carinii. Embryogenesis was assessed microscopically in worms taken from pyridoxine deficient cotton rats and from various categories of control animals. Embryogenesis was retarded in worms from pyridoxine deficient hosts and more abnormal embryos were present in such worms than in those from control animals.

This paper describes a study carried out in a rural area of Ghana on the drinking water sources and other determinants of dracunculiasis (guinea worm disease). The results confirm the association between water source choice and the prevalence of the disease. A logistic regression model was used to show the combined effect of several behavioural, biological, and environmental risk factors. The important behavioural factors were related to the head of household, fetching of water, travelling, and farming. Age was found to be an important biological risk factor for dracunculiasis, but the greatest relative risk applied to those who had suffered from guinea worm disease in the previous year. Although males were significantly more infected than females when analysing the raw data, sex did not prove to be a significant risk factor in this model. Village of residence was an important environmental risk factor for dracunculiasis. Factors related to socio-economic status were not associated with the risk of infection. The paper concludes by presenting the policy implications of the study findings.

The isoenzymatic pattern of glucose 6-phosphate dehydrogenase (abbreviation G6PD) from Ascaris suum has been studied by vertical polyacrylamide gel (PAGE) and horizontal starch gel electrophoresis. After polyacrylamide gel electrophoresis, two stained zones could be identified. One corresponded to tetrazolium oxidase activity; since this zone was stained even in the absence of glucose 6-phosphate (G6P), non-specific staining could be detected. In the other zone of activity, seven regularly-spaced bands were identified by staining in the presence of G6P and NADP as substrates. By using starch gel electrophoresis, different electrophoretic patterns for G6PD have been observed in the muscular sac, intestine and reproductive system from A. suum. The existence of three different alleles of G6PD in the same individual suggests the existence of at least two genes for this enzyme.

An optimum protocol for the cryopreservation of third-stage larvae (L3) of Angiostrongylus cantonensis was determined by: (i) use of different dimethyl sulphoxide (DMSO) concentrations; (ii) use of different FBS concentrations in RPMI-1640 medium; and (iii) variation in the thawing temperature. Studies showed that with Concentrations of DMSO at 4·8% and FBS at 40% and a thawing temperature of 43°C, L3 survival assessed by motility was highest at 56%. The infectivity of the cryopreserved L3 of A. cantonensis was 20% compared to controls obtained from slugs.

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.

The inhibition of acetylcholinesterase secretion by male and female Heligmosomoides polygyrus was tested on worms taken from experimentally infected mice and maintained for 3 days in vitro in levamisole. The dose inhibiting 50% of enzyme secretion (ID 50) of male worms was twice the ID 50 for female worms. A similar difference was observed in vivo between the dose of levamisole removing 50% (LD 50) of male and female worms from the mouse. Acetylcholinesterase secretion by worms and ID 50 were tested in vitro at 3-weekly intervals from 3 to 21 weeks post infection (WPI). Acetylcholinesterase secretion was always significantly higher for male than for female worms. A decrease of ID 50, correlated with the age of the worms was observed: from 1·5 to 0·5 μg/ml for males and from 0·7 to 0·1 μg/ml for females. These results were confirmed in vivo by a higher efficacy of the anthelminthic at 21 than at 4 WPI.

A total of 2.8% (5 of 176) sera from schoolchildren and university students were seropositive for hydatidosis (Echinococcus granulosus) by the ELISA IgEtest. The prevalence of seropositivity was 4·5% among females of all age groups (5–24 years) and among males of the age group 18–24 years. Males of the age group (5–17 years) were seronegative. The ratio of seropositivity between schoolboys and schoolgirl was 1:4. Sera collected from 1085 university students, aged 18–24 years, and from 1656 outpatients from northern and central Jordan, and the Jordan River valley, when tested by the IHA test, revealed the presence of antihydatid agglutinating antibodies in 5·16% (56 of 1085) and in 3·6% (60 of 1656) respectively, with a male to female infection ratio of 1:3 in the unviersity students and 1:1·1 in the outpatients. Intensity, prevalence and cyst fertility of E.granulosus increased increased in sheep with age. The results of this study indicate that hydatidosis is in an endemic steady state in Jordan with estimated economic losses if JD 3·0 (=US $ 4·4) per infected sheep.