Groups of C57BL/6J mice, orally infected with 300 larvae each of Trichinella spiralis or T. pseudospiralis were injected with [3H]-alanine, tyrosine, tryptophan or glycine. The incorporation of isotope labelled amino acids into larval proteins was measured at 2, 6, and 12 months post-infection. It was shown that there is a significant increase in the in vivo uptake of isotope labelled amino acids with time by the larvae of T. spiralis and T. pseudospiralis. The level of uptake was highest for tyrosine followed by tryptophan, alanine and then glycine, for both species. The in vivo uptake of amino acids by T. pseudospiralis larvae was always higher than T. spiralis or the host at 6 and 12 months post-infection. At 2 months post-infection, T. spiralis uptake of these amino acids was higher, except for tyrosine. This may be related to the special needs of these larvae during the process of encystation. The higher metabolic requirements of T. pseudospiralis may be related to the higher energy needs of these non encapsulated, highly motile and mobile muscle larvae.

Entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) were isolated from Sri Lankan soils using the Galleria baiting technique. Samples collected from different agro-ecological regions and different habitat types revealed that the presence of nematodes was restricted to sandy coastal soils. Two heterorhabditid and three steinernematid RFLP types were discovered within 5–100 m of the sea. Members of both families were equally prevalent. However, no parasitized insects were found although insect species were encountered which are potentially natural hosts. These nematodes were present at high temperatures (some above 30°C) and neither the monsoon rain nor the drought had any effect on their prevalence.

The duration of primary infections with T. spiralis was dose-dependent with greater proportional loss of worms from heavily infected hamsters and longer persistence of worms in syngeneic DSN hamsters carrying initially low intensity infections. Intestinal worms were lost more rapidly from challenged immunized animals with over 80% loss of established worms by day 6 post infection, but survival of residual worms for a further 2 weeks. Hamsters carrying initially more than 140 intestinal worms began to lose weight during the second week indicating severe pathology at this stage of infection. Mucosal mast cell numbers increased from 50 cells/20 villus crypt units in uninfected animals to a peak in excess of 150 during week 4 pi, although intestinal mastocytosis persisted long after the loss of the majority of adult worms. Serum antibody responses to muscle stage larval antigen were detected in week 3 and increased subsequently. Both mastocytosis and antibody responses were more intense on secondary exposure to infection. Hamsters vaccinated with muscle stage larval antigen showed only a moderately accelerated loss of the intestinal phase but the fecundity of worms was severely suppressed. Overall it was concluded that the hamster host provided a model of trichinellosis that, in many respects was closer than mice and rats to the pattern of infection seen in economically and clinically important host species.

A total of 358 cattle was examined for schistosome infection in Zambian slaughterhouses. A total of 542 worms collected from 104 infected individuals was examined for glucose-6-phosphate dehydrogenase and phosphoglucomutase using isoelectric focusing. The overall prevalence of infection was 51%. Ninety three percent of the infected animals had less than 100 worm pairs in the mesenteric veins. Schistosoma mattheei was the predominant species (75%); S. leiperi (12%) and S. margrebowiei (2%) were also identified. The remaining 11% of the worms showed one of two distinct heterozygote patterns. Pattern A is identical to that of a laboratory-produced Fl S. mattheei × S. haematobium hybrid, but could also represent a S. mattheei × S. leiperi hybrid. Further studies are required to elucidate the origins of pattern B.

Six nocturnal microfilarial carriers (three with Wuchereria bancrofti and three with Brugia malayi) from mainland China were selected to determine the earliest appearance and peak count of microfilariae (mf) administration of DEC at noon. Before diethylcarbamazine (DEC) administration, blood samples of 60μl were obtained by finger-prick at 2 h intervals for 24 h. A blood sample was then taken just before each carrier intaking 100 mg, 150 mg or 200 mg of DEC orally at noon. After drug administration, blood samples were obtained at 45 and 60 sec and at 2, 3, 4, 5, 10, 15, 20, 25, 30, 40, 50, 60, 90 and 120 min. Samples were then taken at 2 h intervals for the next 2 h and at 6 h intervals for the next 7 days. Both W. bancrofti and B. malayi showed typical nocturnal periodicity. One mf was first detected in the peripheral blood 45 sec in a mf. carrier. The mf peak counts were found 1–40 min after DEC administration at noon. The nocturnal cycle was distributed during the first two days after DEC administration. It became regular with a much lower peak count by the third day after administration. The results of the present study indicate that the provocative effect of DEC on the mf is very fast; the first appearance in the peripheral blood vessels could be under 45 sec.

The enzyme-linked immunosorbent assay (ELISA) and immunoelectrophoresis (IEP) were used for the serodiagnosis of larval Anisakis simplex infections in man and immunized rabbits. Sephacryl S-300 gel filtration was used for separating crude antigen. Four fractions were obtained. Sera from patients with other helminth infections sometimes cross reacted with Anisakis larval antigens. With IEP, crude antigen is more sensitive than purified antigens. With ELISA, the third fraction is the most sensitive for detecting antibodies to Anisakis larvae in the sera of humans and immunized rabbits.

The viability rate of hydatid cysts was investigated in animals slaughtered in the abattoir of Thessaloniki, Macedonia, Greece. Two hundred sheep (100% infection rate), 106 cattle (56.6% infected), 203 pigs (9.3%) and 52 goats (15.4%) were examined. All fertile cysts contained viable protoscoleces. In sheep there was a mean of 1.1 (29.8% of total cysts) fertile cysts per animal containing 297.3 (81.3%) viable protoscoleces. The percentage of viable protoscoleces in the lungs was 82.3% and in the liver 71.2%. In cattle there was a mean of 0.1 (6.6% of total) fertile cysts per animal containing 46.4 (72.2%) viable protoscoleces. The percentage of viable protoscoleces in the lungs was 69.5 and in the liver 87. In swine there was a mean of 0.02 (9.5% of total) fertile cysts per animal containing 32.0 (76.8%) viable protoscoleces. The percentage of viable protoscoleces in the lungs was 97.1 and in the liver 68.9. In goats there was a mean of 0.1 (12.5% of total) fertile cysts per animal containing 12 (54.6%) viable protoscoleces. The percentage of viable protoscoleces in the lungs was 54.4% but no fertile cysts were found in the liver.

The distribution and host range of Sanguinicola armata, S. inermis and S. volgensis in British freshwater fish are described. S. inermis has been recorded in carp Cyprinus carpio, crucian carp Carassius carassius and tench Tinca tinca in southern, central and eastern England and in koi carp imported from Japan. S. armata has been detected in pike Esox lucius and tench and S. volgensis has been found in chub Leuciscus cephalus, dace Leuciscus leuciscus, perch Perca fluviatilis, roach Rutilus rutilus and pike in southern and eastern England. The first record of the co-occurrence of two species of Sanguinicola (S. inermis and S. volgensis) in a British inland water is reported. The importance of blood flukes and the role of anthropochore movement of fish hosts in dissemination of S. inermis are discussed.

The cephalic end of the type species of pharyngodonid genera Travnema and Cosmoxynemoides, T. travnema Pereira, 1938 and C. aguirrei Travassos, 1949, parasites of Brazilian freshwater fishes, was studied by scanning electron microscopy. The mouth aperture of Travnema was found to be circular, surrounded by four cephalic papillae and two lateral amphids and the cuticle of the cephalic end had a conspicuous dense sculpture. On the other hand, the mouth aperture of Cosmoxynemoides was triangular, surrounded by three lip-like elevations covering the whole surface of the relatively flat cephalic extremity, each with two inner lobes separated one from another by a short groove; the lip-like elevations bore four medium-sized, kidney-shaped cephalic papillae and two minute amphids (two papillae on the dorsal elevation and one papilla and one amphid on each of two ventrolateral elevations); the cuticle of the cephalic end was smooth. Both species were noted for the absence of oral lamellae and the presence of lateral alae. Both genera are listed in the family Pharyngodonidae but Travnema (and also Hakynema), due to its morphological peculiarities, is considered to represent a distinct subfamily Travnematinae within the Pharyngodonidae. The finding of both T. travnema and C. aguirrei in the characid fish Astyanax bimaculatus lacustris represents new host records.

The karyotypes of Vampirolepis nana, Hymenolepis diminuta and Vampirolepis erinacei (Cestoda: Cyclophyllidea) have been described. The number of chromosomes in the diploid cell of the studied taxa was 2n = 12. The absolute and the relative lengths of the chromosomes of V. nana and H. diminuta were measured. The chromosomes had similar metric values. In the karyotypes of V. nana and H. diminuta there were ten one-arm chromosomes and.one two-arm chromosome (the third in length in the karyotype of V. nana and the first in length in the karyotype of H. diminuta). The chromosomes in the karyotype of V. erinacei had one arm which was proved by the terminal localization of the constitutive heterochromatin. The examined species differed in the morphology of some chromosomes in the karyotypes.

Zygocotyle lunata adults grown in mice were treated in vitro with 3-H-adenosine to label sperm and then transplanted to the caecum of mice singly or with 6 to 8 unlabelled adults. After 6 to 10 days, worms were recovered, processed for autoradiography, and observed for radioactive sperm in their seminal receptacles. Adults would not incorporate radioactive thymidine into dividing cells. Tyrosine was utilized only by juvenile worms and then not enough to label germinal cells for mating studies. Four of 13 (31%) worms transplanted singly self-inseminated, whereas 9 of 10 (90%) labelled worms in multiple infections self-inseminated. When in groups, the labelled worms cross-inseminated with 14 of 43 (33%) unlabelled worms. This mating pattern was unrestricted in that both self- and cross-insemination took place in multiple infections, much like the mating pattern in another paramphistomatid, Megalodiscus temperatus, but unlike the restrictive pattern shown by three species of eyeflukes.

A survey was undertaken to study the epidemiology of Toxocara spp. in 350 dogs and 181 cats. A prevalence of 82.6% was recorded for Toxocara canis and 42% for T. cati. The distribution of parasite burdens in both dogs and cats was overdispersed. The highest parasite prevalence rates and burdens were found in hosts of 12 to 24 weeks of age. No Toxocara parasites were found in cats between 0 to 4 weeks old. There was no significant difference in parasite prevalence between male and female dogs or between male and female cats. The relationships between host age and sex with parasite prevalence, burden and length are discussed. Female T. canis worms with mature ova and those with immature ova differed significantly with regard to their length. The relationship between the length of mature T. canis female worms and the proportion of body length occupied by the uterus was highly significant.

The activities of some key enzymes of the glycolytic and pentose phosphate pathways were investigated histochemically in adult female Onchocerca fasciata (Nematoda: Filarioidea). The distribution patterns of phosphofructokinase (PFK), aldolase (ALD), glyceraldehyde 3-phosphate dehydrogenase (G3PDH) and glucose 6-phosphate dehydrogenase (G6PDH) in different tissues of the worm were determined by employing NitroBlue Tetrazolium (NBT). The glycolytic enzymes PFK, ALD, and G3PDH were distributed throughout the hypodermal tissue, somatic muscles and reproductive organs. These enzyme activities were predominantly expressed in the hypodermal and reproductive tissues, both of which appeared to be metabolically more active than adjacent tissues. The high activities of the enzymes studied in the hypodermal tissue when compared with the minimal or low activity in the intestinal epithelium support the assumption that the worm's intestine, in contrast to the body wall, plays no significant role in the nutrient acquisition process. The results emphasize that both the glycolytic and hexose monophosphate pathways of carbohydrate metabolism are active components in energy production and biosynthetic processes in the various tissues of the worm. The functional significance of these glucose-metabolizing enzymes has been discussed with regard to their location in the tissues concerned.

An experiment was carried out to investigate the anthelmintic activity of papaya latex (Carica papaya) against natural infection of Ascaris suum in pigs. Sixteen naturally infected pigs were, on the basis of faecal egg counts and body weight, allocated into four groups, each of four pigs. Three groups (groups B, C, and D) were given papaya latex per os at dose levels of 2, 4, and 8 g of papaya latex per kg body weight, respectively. The fourth group (group A) served as a non-treated control. Results of post mortem counts on day 7 post treatment revealed worm count reductions of 39.5, 80.1 and 100% in groups B, C, and D, respectively. Some of the pigs receiving the highest dose of the latex showed mild diarrhoea on the day following treatment. Otherwise, no clinical or pathological changes were observed in the treated animals. The possible future use of this traditional herbal medicine for livestock and humans is discussed.

Chamois (Rupicapra rupicapra tatrica) in the Low Tatra National Park are largely infected with the lungworms Mullerius capillaris and M. tenuispiculatus and sporadically with Dictyocaulus viviparus. The mean number of first stage larvae (Ll) per gram of faeces collected at chamois stands over the years 1981–1988 varied between 28.2 ( ± 11.9) and 61.6 ( ± 35.9). The degree of infection in chamois herds was significantly higher in the spring and autumn months, except for the spring of 1981, than in the summer season. The mean number of Ll per gram found in the dissected chamois (lung and intestinal content) varied between 64.53 ( ± 32.7) and 97.5 ( ± 36.4).

The ultrastructure of the reproductive system of adult male Trichinella spiralis has been examined, particularly to assist in recent advances such as the localization of target antigens of protective immunity and the mode of immune attack. The male reproductive system consists of a single tube with a hairpin-like bend, composed of a basal lamina, epithelial cells, rachis, circumferential and constrictor muscles, and germinal cells. The organs were surrounded by basal lamina and haemolymph. Germinal cells in different stages of maturation were found on the wall of the testis along its entire length. As the maturation of germinal cells proceeded, the cells moved towards the lumen of the testis. The germinal cells had a row of vesicles (cup-shaped structures) at the cell periphery. The mature sperm, lacking flagella and an acrosome, were stored in the seminal vesicle. The cytoplasm of the epithelial cells of the seminal vesicle and ejaculatory duct was filled with distended rough endoplasmic reticulum (rER) and exocrine granules which appeared homogenous and of medium electron density. The granules appeared to discharge to the lumen.

The migratory route of Toxocara canis in the mouse includes two phases: a hepato-pulmonary phase and a myotropic-neurotropic phase. A study was made of the migratory behaviour of larvae one year post-inoculation (p.i.) comparing the results to those obtained at the end of an initial experiment (day 63 p.i.). The larval distribution per organ was already definitive at 9 weeks p.i. The total parasitic load showed a reduction when the experiment was prolonged for one year.