Specimens Hepatojarakus malayae Yeh, 1955 and H. bandicoti Sood & Parshad, 1973 arc illustrated and their measurements tabulated. H. bandicoti is considered a synonym of H. malayae.

During a survey in 1980–81, 125 of 478 (26·2%) camels in Saudi Arabia were found infected with onchoccrciasis. The prevalence rates in local and imported camels were 93/272 (34·2%) and 32/206 (15·5%), respectively. The disease was characterized by hard nodules in the connective tissue around the nuchal ligaments and in the subcutis. The nodules consisted of cavities containing live, degenerate or dead Onchocercafasciata, inflammatory cells, fibrosis and calcification. The microfilariac were concentrated in the skin over the head and neck regions and often caused mild non-suppurativc dermatitis.

The effects of insulin on worm (Hymenolepls diminuta) migration was studied. Insulin injection (20 U/kg, s.c.) significantly increased gastric acid output but did not affect the serotonin content of blood, intestinal lumen or worms. The drug produced, dose-dcpcndcntly, postcriad migration of the worms in rats without pylorusligation but ligation of the pylorus prevented this migration. It is concluded that the hypcrsccrction of gastric acid induced by insulin is responsible for the postcriad migration of H. diminuta in rats.

Third-stage larvae of Trichostrongylus tenuis, the caccal threadworm of red grouse, show strong positive phototactic behaviour which is reinforced by negative geotactic behaviour. The surfaces of various grouse food plants were examined and those of young Calluna vulgaris (common heather) were suitable for ncmatodc migration. Transmission is probably achieved by third-stage larvae of 71 tenuis migrating up young heather plants, rather than by direct ingestion with grit from the ground.

Mice infected with Nematospiroides dubius show non-specific immunodeprcssion (NSID) of immune responses to concurrently administered antigens. This project investigated the factors influencing the response of oxazolone (T-dcpcndcnt antigen) and LPS (T-indcpcndent antigen) in infected mice. Depressed responses to both antigens were observed in mice infected with N. dubius, although the pattern of immunodeprcssion was influenced by both the level and the relative timing of infection and antigen presentation. Consistent NSID was only achieved when the mice were given the higher levels of infection and there was some evidence that NSID was more severe when infection preceded the administration of antigen by 14 days.In general, although NSID was significant, the degree of immunodepression was not considerable. It was concluded that the underlying mechanism of NSID was likely to be different from that enabling the parasite to survive in the intestine of the chronically infected host, and that altered physiology and host's modulation of the immune responses in heavily infected animals may have given rise to a general weakening of the immune system. It was suggested that future work should investigate NSID and parasitespecific immunodeprcssion locally in the intestine where parasite survival is likely to be determined by events at the nnicosal surface.

The host-parasite interaction at the site of attachment of the adult hookworm, Ancylostoma ceylanicum, to the small bowel mucosa of the dog has been examined by transmission electron microscopy. The lamina propria around the heads of the worms showed intense infiltration with neutrophilic and cosinophilic leucocytes, and plasma cells were also prominent. Erythrocytcs were cxtravasatcd within the lamina propria while the portions of mucosa engulfed into the buccal cavities of the worms were nccrotic and included aggregates of collagen fibres. Within the lumina of the worms were erythrocytcs in varying stages of lysis together with other nccrotic debris.The mucous membrane adjacent to the heads of the worms was ulcerated while more distant cntcrocytcs were small, distorted and displayed various degrees of microvillar loss. Many mucosal blood vessels had platelet aggregates within their iumina but no fibrin deposition was observed. Vessels were often seen in the bases of the ulcers and were prone to rupture. Erythrocytcs and leucocytes were seen in the dog intestinal lumen in close proximity to the bodies of the worms.

Counter current Immunoelectrophoresis was used to detect porcine cysticcrcosis and water soluble extracts of scolex and of scolex with cyst wall were used as antigens. Serum samples from 40 pigs infected with Cysticercus cellulosae, five infected with C. tenuicollis and five with hydatid cysts, and 15 healthy pigs were tested. A sharp and thick concave precipitin band was observed at the point of interaction of antigen and antibody within 90min in 39 sera from infected pigs (97–5%). The precipitin reaction was better in barbitone buffer of pH 8–6 with the well distance at 6 mm. No false or cross reaction were found and the test was rapid and sensitive.

Twelve amino acids were detected in six davaincid ecstodes, Davainea hewetensis Dhawan & Capoor (1972) collected from one Gallus gallus domesticus L. at Allahabad, India. Chemotaxonomic studies within the family Davaineidac have shown the presence of cystine and hydroxyproline only in D. hewetensis, although phenylalanine and proline occur in all species examined previously.

Three adult male greyhounds have been repeatedly infected with Toxocara canis by oral administration of 100 to 200 infective ova. Each infection has become patent as shown by the presence of eggs in faeces. Anthelmintic treatment between 7 and 14 weeks after infection yielded an average of 25% of the inoculum as adult worms. These dogs have continued to be fully susceptible to infection despite repeated exposure to this parasite, and despite the presence of scrum antibody to both parasite surface and secreted antigens. These findings imply that adult dogs may not always be immune to toxocaral infection and may therefore contribute significantly to the problem of environmental contamination with T. canis ova.

Inorganic elements as micronutricnts play a vital role in metabolism and in immune mechanisms (Ballerker & Prasad, 1983) and a significant role in the physiology of parasites. Their importance is shown by the harmful effects of mineral deficiencies in the host diet, particularly on gastro-intcstinal parasites (Von Brand, 1966). The presence of aluminium, cadmium, iron, manganese, nickel, sodium and tin has been shown in the corpuscles of Echinococcus granulosus which causes hydatid disease in man (Agosin, 1968). In this preliminary report, the quantities of trace elements in hydatid fluid from sheep and man are reported to show their possible importance as nutrients or as cofactors in the metabolism of the parasite.

Third-stage larvae (L3) of Anisakis simplex of a known minimum age of 60 to 61 weeks, the oldest of which may have spent at least three years in herring, were artificially excapsulated in saline and appeared healthy. A small proportion succccded in penetrating the gut wall of rats. The length distribution of L3 of minimum age 18 to 23 weeks did not differ significantly from that of larvae of minimum age 60 to 61 weeks.