The rate of uptake of H3 tyrosine by unisexual females in vitro was accelerated by 22% when male worm extract was added to the culture medium. Pairing of unisexual females with mature male worms in vitro resulted in a similar acceleration of H3 tyrosine uptake. As tyrosine is avidly taken up by the vitelline gland for the formation of egg shell protein the change in the rate of H3 tyrosine uptake can be employed as a sensitive quantitative criterion for assessing its development following stimulation.

Trematodes of the family I Ictcrophyidac in man and carnivores were studied in Khuzcstan, south-west Iran.Hight hundred and eleven stool samples from a population of 3400 in 13 villages in a swampy area located incentral Khuzcstan were examined by the formalin-ether concentration technique. The following helminths were found: Ascaris lumbricoides 7%, Trichostronayius spp. 53%, hookworms 4%, Trichuris trichiura 5%, Hywenolepis nana 12% and hetcrophyid spp. 8%. Post-mortem examination of carnivores revealed that 14·2% of jackals, 33·3% of foxes and 2·5% of dogs were infected with hctcrophyids, namely Metagonimus yokogawai, Heterophyes heterophyes and H. katsuradai. The freshwater snails Melanoides and Melanopsis spp. and brackish water fishes ltarhus spp. and Mugil spp. were thought to be the intermediate hosts of these flukes in this area. This is the first report of hctcrophyid infection in man and carnivores in Iran.

Plots of pastureland with well grown herbage provided a more favourable environment for the survival and development of the free-living stages of Oesophagostomum dentatum in faeces during warm dry weather than did plots with short herbage. This was because well grown herbage gave better protection against the unfavourable effects of dryness than did short herbage. There was no significant difference between the plots during cool wet weather.

Sera from 36 slaughtered camels with proven hydatid disease, from 46 camels found to be free of hydatidosis at post-mortem meat inspection, and from 26 animals with confirmed caprine heartwater, bovine trypanosomiasis and cysticercosis were examined. The indirect haemagglutination was found to be the most sensitive but least specific of the three tests. Ouchterlony's double diffusion (DD) test was specific and fairly sensitive. Although the countercurrent immunoelectrophoresis was as specific as DD, it was the least sensitive of the three serological tests.

All three serological tests were always positive in camels with hydatid cyst infection affecting both the liver and the lung. A combination of indirect haemagglutination and Ouchterlony's double diffusion tests could be useful for diagnosing hydatidosis in camels and probably other animals.

The effect of oxyclozanide, hexachlorophene, nitroxynil, rafoxanide and diamphenethide on malate dehydrogenase activity of homogenates of Fasciola gigantica, Fasciolopsis buski and Paramphistomum explanatum was investigated. The ratio of oxaloacetate reduction to malate oxidation in homogenates of Fasciola gigantica, Fasciolopsis buski and P. explanatum was 4·5:1, 3·6:1 and 5·2:1 respectively. Oxyclozanide and rafoxanide at 10−3 M inhibited enzyme activity by 100% in homogenates from all three species while hexachlorophene at 10−3M also caused 100% inhibition in homogenates from Fasciola gigantica and P. explanatum but only 65% of malate oxidation in Fasciolopsis buski homogenates. Nitroxynil at 10−3M produced 60% inhibition in F. buski homogenates yet had little effect at this concentration on preparations from the other species. Little inhibition was seen with diamphenethide, even at high concentrations. Rapid death of Fasicola gigantica and P. explanatum resulted in vitro when 10−3M oxyclozanide, hexachlorophene, nitroxynil or rafoxanide, were added to the incubation medium. Fasciolopsis buski was killed by 10−3M oxyclozanide but at this concentration the remaining compounds only caused reduced activity. Assay of malate dehydrogenase following drug treatment in vitro failed to show any appreciable reduction in enzyme activity in Fasciola gigantica and P. explanatum but oxyclozanide and hexachlorophene produced inhibition in Fasciolopsis buski. The mode of action of these compounds is discussed.

A substantial level of resistance to a lictcrologous challenge with Fasciola hepatica was demonstrated insheep harbouring primary non-patent (two- to three-week-old) and newly patent (seven- to cight-wcck-old)Schistosoma hovis infections, the liver-fluke burdens being reduced by 70% and 93%, respectively, ( p< 0·01) inthese groups compared with that of the challenge control group.

Experiments were carried out to investigate if sera of animal species other than dog are chemotactically active for infective larvae of Ancyclostoma caninum. Those sera were also found to contain such a factor(s), although the larvae were attracted significantly better by dog serum. How this chemotaxis might be applied to the in vivo situation, when infective A. caninum larvae penetrate the skin of dogs, is discussed.

Paradistomoidella cerberi n.g, n.sp. and Paracanthostomum cerberi from Cerberus rhynchops, Xenopharynx pyriformis and Allopharynx mehrai from Ptyas korros, Neopronocephalus orientalis from Geoemyda spinosa, and Duthiersia expansa from Varanus salvator are all reported from the area of Kuala Lumpur, Malaysia. Paradistomoidella cerberi most closely resembles members of Paradistomum and of Paradistomoides but is characterized by relatively short caeca, a cirrus sac containing a bipartite rather than sinuous internal seminal vesicle, and unevenly-sized suckers. Kuala Lumpur is a new locality for Paracanthostomum cerberi, X. pyriformis, A. melvrai, and D. expansa. Ptyas korros is a new host for X. pyriformis and G. spinosa is a new host for N. orientalis.

The chemotherapeutic responses of three test nematodes, Nippostrongylus brasilietxsis, Nematospiroidesdubius and Ancylostoma ceylanicum to standard antihookworm drugs were assessed in order to select asuitable host-parasite system for the primary screening of potential antihookworm compounds. N. dubiusbehaved inconsistently and, with some infections, required more drug to achieve 100% clearance. Nippostrongylus brasiliensis was found to be sensitive to thiabendazole, tetramisole and levamisole but the broad spectrum anthclmintic mebendazole was ineffective. A. ceylanicum was very sensitive to mebendazole, sensitive to tetramisole and levamisole and refractory to thiabendazole. In vitro, none of the compounds had any lethal effect against any of the nematodes, except mebendazole against A. ceylanicum.

A. ceylanicum does occur in man and its chemotherapeutic reactions are similar to those of target hookworm infections of economic importance. As such, although not equally sensitive to standard anthelmintics, it is recommended for routine primary screening.

The metacestodes of Taenia crassiceps removed from a stock infection of Sprague Dawley rats were injected into seven inbred and one outbred strain of rats. The results showed that over-all female rats are more susceptible to the infection than male rats. Only one strain of rat, the Lewis male rats, was found to be resistant to the infection. There was no significant difference in the volume of metacestodes recovered from the male and female rats. The sizes of the metacestodes, after two passages through the rats, were compared to those of the original mouse strain and it was found that metacestodes from two strains of rats were significantly smaller. The antigenic expression of the metacestodes from the different strains of rats was compared and some variation in the antigenicity was observed.

The major organs, other than lymphatics, of jirds (Meriones unguiculatus) with prepatent and chronic patent infections of Brugia pahangi were studied by standard histological, electron microscopical and fluorescent antibody techniques. Changes observed and not previously described in detail or in large numbers of animals are reported. Multifocal non-suppurative interstitial nephritis was observed in 4% of animals with patent infections of 163 days duration and in 69% of animals with patent infections of 274 days duration. Glomerular changes were not observed in kidneys of any animals infected with B. pahangi. The occurrence of large granulomata composed of lymphocytes, macrophages, eosinophils and giant cells in the liver and smaller granulomata in the spleen correlated with patency of infections but microfilariae or worm antigens were not observed in these areas. Amyloid deposits were demonstrated in the spleens of 4% of animals with patent infections of 163 days duration and in 38% of animals with patent infections of 274 days duration but were not seen in uninfected animals of the same age or animals receiving only challenge inoculations of 28 days duration.

Two types of neurosecretory cells (NSC), large a cells and small β cells were detected on the basis of their size and characteristics as shown by aldehyde fuchsin and chrome haematoxylin-phloxin staining. A histochemical survey of the neurosecretory material indicates that it is a glycoprotein. Phosphatases and esterases present in NSC probably help in the transfer of metabolites and their hydrolysis and in the control of secretory material produced in a NSC, while SDH provides the necessary energy for the synthetic activity of the latter. The role of neurosecretion in governing the reproduction of this parasite is discussed.

A. A comparative study of a simplified radioimmunoassay (RIA) technique with the indirect haemagglutination (IHA) test in the diagnosis of 72 patients with hydatid disease indicated the greater sensitivity of the former. Both methods had an equal specificity in 60 control patients. RIA will serve as a useful addition to tests already available in hydatid serology.

B. A comparison of the (RIA) technique with the fluorescent antibody test (FAT) in the diagnosis of 33 patients with early, active trichinosis and 30 healthy controls indicated an equal sensitivity and specificity of both methods. The adoption of RIA as an easier method is recommended.

This study of a simplified radioimmunoassay technique for the diagnosis of hydatid disease and trichinosis in man is presented in two sections.

The reliability of Stoll's dilution egg count technique, Beaver's direct smear technique and Katz's modified thick smear technique were evaluated on patients with ascariasis. Studies revealed that the modified thick smear technique appears to be more reliable and accurate. The use of these three techniques revealed a significant correlation between the number of eggs per gram (e.p.g.) and worm load. Following the introduction of a standardized factor in a study of 30 patients with worm infections, a highly significant correlation was obtained between the e.p.g. and the worm load for all three techniques. The use of a Standardized Factor is recommended for better prediction of the worm burden. The results of this study reveal that a female Ascaris lumbricoides lays an average of 218,094 (range 82,251–365,200) eggs daily. The ratio of male to female A. lumbricoides was 1:1·4

The utility of human filarial serum immunoglobulin (FSI) in detecting circulating antigen in filarial sera was studied by counter Immunoelectrophoresis (CIEP) and the indirect haemagglutination test (IHAT). CIEP was found to be better than IHAT. 23 out of 30 sera from persons with microfilaraemia and one of 30 clinical cases of filariasis, but none of the normal sera or sera from those with helminths other than filariae, showed the presence of circulating filarial antigen in CIEP. FSI was fractionated by DEAE- Sephadex A-50 column chromatography and the antibody active in CIEP was found to be IgG in nature.

The critical-point-dried specimens of Gastrothylax crumenifer (Creplin, 1847) Poirier, 1883 and Paramphistomum epiclitum Fischoeder, 1904, both recovered from the rumen of sheep, were studied by scanning electron microscopy at magnifications ranging from 10 to 10,000 x to reveal the structural differences of the tegument between the two species.

In G. crumenifer, both dorsal and ventral surfaces have tubercle-like tegumental elevations, devoid of spines. A row of prominent, regularly arranged, button-like protuberances encircle the rim of mouth. It is suggested that these are sensory in nature. The lining of the buccal tube also bears papillae, some of which appear balloon-like. The tegument near the outer acetabular rim is thrown into prominent ridges bearing groups of six to eight small papilla-like elevations. Towards the interior of the acetabular cavity this pattern merges into one with stout, finger-like projections with groups of papillae at their blunt tips. From their structure, these projections appear to aid strong anchorage to the host's surface and the papillae to be secretory.

P. epiclitum has a similar tuberculated pattern on the dorsal and ventral surfaces. In the oral region, the tegument has some irregular, patch-like elevated areas. The acetabular surface is thrown into a pattern of deep folds and craters.

Histochemical techniques were used to study the chemical composition of Mehlis’ gland secretion in Ceylonocotyle scoliocoelium. The results suggest the secretion to be lipoproteinous in nature, containing several hydrolytic and oxidative enzymes. In tests for nine hydrolytic enzymes only seven were detected in relation to gland cells, ihe two enzymes not showing any reactivity being glucose-6-phosphatase and 5-Nucleotidase. Alkaline phosphatase and ATPase have been associated with the permeability and transport of precursors of synthetic material from the surrounding parenchyma and with eliminating the waste products from the gland: ACPase in (i) generating a favourable milieu in the gland for the synthesis of secretory material and (ii) in regulating secretion and its over production; TPPase in elaborating the secretion, esterases in the metabolism of the gland. Intense SDH and MAO activities were related to high synthetic activity of the gland cells. Phenol oxidase—a key enzyme involved in tanning was absent.

Mice infected for one to eight weeks with Trichinella spiralis cleared either 51Cr-labelled sheep red blood cells (SRBC) or I-polyvinyl pyrrolidone (PVP) given intravenously. PVP was cleared more rapidly from the blood of mice infected for one week than from uninfected mice with older infections which behaved in a similar manner to the controls. SRBC were consistently cleared faster from the blood of mice infected for one week than from normal mice. If the infections were older than this a more rapid clearance was also demonstrated as long as the infections were reasonably heavy.