The cuticle of filarial nematodes is a specialized extracellular matrix that covers the parasite and protects it from adverse conditions of the environment. As a surface structure it is in direct contact with the host defence mechanisms and therefore plays an important role in the molecular host-parasite relationship. Using polyclonal antisera raised against the insoluble components of the cuticle of the adult filarial parasite Brugia pahangi, we have isolated cDNA clones encoding collagen molecules of the cuticle. The protein domain structure of cDNA clone Bpcol-1 was compared with the known structures of cuticular collagens of the nematodes Brugia malayi, Caenorhabditis elegans, Ascaris suum and Haemonchus contortus, confirming interspecies similarities. Using affinity-purified anti-Bpcol-1 antibodies we identified Bpcol-1 antigenic determinants in different nematode extracts, and determined the localization of such epitopes within the cuticle of B. pahangi.

Previous studies of mating interactions between schistosome species from different evolutionary lineages in mice showed that mating is not random: heterospecific pairs form but, given the choice, the preference is for homospecific partners. Mating competition and change of mate were also demonstrated. Schistosoma mansoni is a medically important parasite of humans belonging to a different evolutionary group from S. margrebowiei, a parasite of bovines of veterinary importance. Experiments were designed to investigate the mating behaviour of these two species in mice. Analysis of the data showed a preponderance of intraspecific pairs over interspecific, demonstrating a specific mate preference system for both species. The existence of mating competition between these species was indicated. Males of both species were able to actively compete for paired females by pulling them away from their partners, thus effecting a change of mate. Overall, neither species appeared to be competitively dominant to the other, and the data suggest that where this is the case in sequential infections, the most successful species in terms of worm return and ability to form pairs will be the first species to infect the host.

1. T. axei eggs in sheep faeces hatch at a temperature of 38° C. and a relative atmospheric humidity of 29%, but all of the larvae are dead 96 hr. after the initiation of the exposure. Eggs kept in faeces at −7° C. are killed within 96 hr.

2. Eggs do not hatch while under water but remain viable for 20 days under 15 mm. of water at temperatures ranging from 11 to 28° C. Under natural conditions the longevity would in all probability be influenced by such factors as depth of water, amount of decomposing organic debris, etc., which determine the amount of available oxygen present.

3. Completely embryonated eggs in sheep faeces possess a high resistance to drying. It is apparent that ranges and pastures in California cannot be freed of eggs by keeping suitable hosts off them during a single dry season, because the eggs can survive desiccation for a period exceeding the dry season. It is possible, however, that if the eggs were directly exposed to the rays of the sun they might be killed.

4. The non-infective larvae of T. axei are very much less resistant to desiccation than are the eggs. The population of non-infective larvae would, however, under the more common natural conditions, normally attain the infective stage before succumbing to desiccation.

5. Infective larvae lived for more than 104 days at a temperature of 38° C. and a relative atmospheric humidity of 29%. At −7° C. they were alive at the end of 25 days but were dead on the thirty-ninth day. It is believed that under natural conditions such larvae would not be exterminated by high temperatures. At low temperatures the usual covering of snow might sufficiently protective to prevent death.

6. T. axei infective larvae survived 230 days' submergence in 5 mm. of water at room temperature in diffused daylight. Direct sunlight appears have some lethal effect. The amount of oxygen available in the water appears to determine to a considerable degree the longevity of the larvae. Under natural conditions infective larvae can survive even greatly prolonged flooding.

7. The survival of infective larvae to desiccation is dependent upon the actual degree of dryness attained. Larvae dried on glass slides at room temperature ranging from 17 to 27° C. with a relative atmospheric humidity of from 35 to 51% survived up to 16 days after the initiation of exposure.

8. Different investigators have obtained different results in studying the longevity of infective larvae in soil. The writers believe that the infective larvae do not spend much time on soil or migrate through it unless to escape some unfavourable environmental factor such as particularly high or low temperatures or desiccation, or unless they are accidentally washed into it during heavy rainfall.

9. No evidence of phototropic behaviour was observed. It is believed that vertical migration up vegetation is caused by a negatively geotropic reaction which may be conditioned or altered at times by stronger external stimuli resulting from extreme temperatures, bright sunlight, low atmospheric humidity, etc.

10. It is believed that the seasonal incidence of trichostrongylosis on irrigated ladino clover pastures in California is determined by acquired resistance, age resistance, or both.

11. A mixture of a 1% solution of 40% nicotine sulphate and 1% copper sulphate appears to be a more efficient anthelmintic against T. axei than a straight 1% copper sulphate solution. Changing from green feed to hay or rendering hay available along with green feed may possibly have a therapeutic effect. Spontaneous recovery, so far as clinical symptoms are concerned, from an acute trichostrongylosis, without the administration of a drug or changing the diet, seems to be common, if not the rule, in the majority of lambs in an infected band.

An analysis of natural infections of Toxocara mackerrasae in Rattus fuscipes trapped in rain forests in south-eastern Queensland is given and Hydromys chrysogaster is listed as a new host.

T. mackerrasae larvae in egg-infected mice are incapable of somatic migration but some complete development to the young adult stage can occur entirely within the alimentary tract. T. mackerrasae is capable, in low numbers, of developing to maturity in experimentally infected Rattus spp.

The work was financed by grants from the University of Queensland and the National Health and Medical Research Council of Australia. I wish to thank Professor J. F. A. Sprent for his criticisms and suggestions during the preparation of this text.

The effect of hexachlorophene, a fasciolicide, on some enzyme systems in the liver fluke was studied. The enzymes were adenosine triphosphatase, succinate oxidase and cholinesterase. Adenosine triphosphatase was activated, whereas succinate oxidase and cholinesterase were inhibited when homogenized flukes were incubated in some concentrations of hexachlorophene. Of the three enzyme systems studied in flukes killed by hexachlorophene, only the succinate system showed reduced activity, whereas the other two showed almost normal activities. The study indicates that biochemical changes are associated with the effect of hexachlorophene on the liver fluke.

Thanks are due to Dr C. Grant for critical examination of the language, to Miss Maarja Kippar for valuable help with the experiments and to Mrs Astrid Holmström for the typing of the manuscript.

This work was supported by grants A 1108/B 904 and A 1635/B 1299 from Jordbrukets Forskningsråd.

1. A ciliate occurring in the caecum of about 25 per cent, of the cattle that were examined at Jeanerette, Louisiana, is herein classified as Buxtonella sulcata Jameson (1926) and it is proposed that it be removed from the Class Aspirigera, Family Isotrichidae, and included in the Class Spirigera, Order Heterotrichida.

2. The ciliate is characterised by the position of the cytostome near the permanently open cytopyge and within the peristome which continues from the cytostome around the oral end of the body to the extreme aboral end which during locomotion is anterior.

3. The infections were detected in slaughtered animals by examining faecal material in Syracuse watch glasses under the binocular microscope, this method of faecal diagnosis having advantages over the smear method.

4. By the administration of Epsom salts the ciliates may be obtained from living cattle.

5. A pipette is described and figured for the isolation of Protozoa.

6. Death of Buxtonella sulcata in an unfavourable environment occurred by disruption of the endoplasm through the cytostome.

7. Buxtonella sulcata disappeared from faecal material at room temperature more quickly than balantidia from the pig, but withstood manipulation under the microscope better than the balantidia.

8. The passage of an individual between two obstructions suggested a means of intercellular tissue penetration by ciliates.

9. The oral plug and the centralised neuromotor system described and figured by McDonald in Balantidium coli could not be differentiated by the writer, but McDonald's other morphological observations on the above ciliates were confirmed.

Woodcock (1910) discovered a trypanosome naturally occurring in the blood of British sheep. This finding was confirmed by Behn (1911, 1912) in Germany. In both cases the authors did not give any description of the parasite, which was seen by them only in single cases, and they failed to cultivate the trypanosomes.

A new trematode, Burnellus trichofurcatus, is described from South Australia from the freshwater catfish, Tandanus tandanus. It appears to have affinities with Monodhelmis Dollfus, 1937 and Mehratrema Srivastava, 1939, but is probably most closely related to Tandanicola Johnston, 1927 (Fellodistomatidae: Tandanicolinae). It is assigned to the Fellodistomatidae Nicoll, 1909, as emended by Cable (1953). Cercaria trichofurcata Johnston & Angel, 1940 is shown to be the larval stage. The cyst stage is omitted from the life cycle, with infection of the catfish occurring directly, probably by mouth. Further comments on developmental stages are given. The sporocyst is not branched, as described by Johnston & Angel (1940). The miracidium of Tandanicola bancrofti is reported, and the life history of this species is discussed. The genus is named for Dr R. H. Burnell in recognition of his help, over a number of years, in collecting animals used in these life history studies.

I would also like to acknowledge information and help given me by Dr J. C. Pearson, of the University of Queensland, and information on fish given me by Mr C. J. M. Glover, of the South Australian Museum.

Echinococcus granulosus is an important zoonotic parasite that is distributed worldwide. The EG95 vaccine was developed to assist with control of E. granulosus transmission through the parasite's livestock intermediate hosts. The vaccine is based on a recombinant antigen encoded by a gene which is a member of a multi-gene family. With the recent availability of two E. granulosus draft genomes, we sought to map the eg95 gene family to the genomes. We were unable to map unequivocally any of the eg95 gene family members which had previously been characterized by cloning and sequencing both strands of genomic DNA fragments. Our inability to map EG95-related genes to the genomes has revealed limitations in the assembled sequence data when utilized for gene family analyses. This study contrasts with the expectations expressed in often high-profile publications describing draft genomes of parasitic organisms, highlighting deficiencies in currently available genomic resources for E. granulosus and provides a cautionary note for research which seeks to utilize these genome datasets.

The egg-shell of Hammerschmidtiella diesingi and Aspiculuris tetraptera reduces the rate of water loss from the egg when exposed to desiccation. Staining of the enclosed larva by acid fuchsin and the collapse of eggs exposed to desiccation indicate that the permeability barrier is heat labile. This suggests that the lipid layer is the main permeability barrie of the shell. The complex structure of the uterine layers has a similar morphology to the respiratory structures of the chorion of some insect eggs. Reflections from the shell, the rate of embryonic development under various conditions and the penetration of lead ions indicate that the shell does not trap a layer of air when immersed in water and the uterine layers cannot, therefore, function as a plastron network. Calculations indicate that if diffusion is limited to the pores in the external uterine layer, the area available for gaseous exchange is reduced by 85·5% in H. diesingi, 95·6% in A. tetraptera and 96·8% in Syphacia obvelata. It is suggested that the uterine layers of oxyurid egg-shells function in a similar fashion to the pores in bird egg-shells and the aeropyles in the chorion of insect egg-shells which do not possess plastron networks. These structures reduce water loss from the egg whilst ensuring an adequate supply of oxygen for embryonic development.

A preparation highly enriched in tegument membranes from adult worms has been used to probe rodent responses to schistosome surface antigens. All exposure regimes in mice stimulated levels of anti-tegument IgG, measurable by ELISA. Plateau levels of circulating antibody attained were similar after mixed-sex and male-only infections, and vaccination with tegument membranes. Female-only infections and exposure to irradiated cercariae stimulated lower levels of anti-tegument antibody. Responses in rats were similar, but occurred more rapidly, probably due to the large initial parasite exposure. Although both mice and rats could be stimulated to produce high levels of anti-tegument antibody by multiple vaccination, consistent protection against a challenge was not obtained. Paradoxically, rats and mice vaccinated with irradiated cercariae developed low levels of antibody to tegument membrane antigens but were highly resistant to challenge. It was concluded that, in the range of sera examined, antibody responses to schistosome tegument membranes did not correlate with the immune status of the host.

By means of light and electron microscopical techniques, the organization of the reproductive tract of female Moniliformis dubius is described. The tract consists of an efferent duct system associated with 2 ligament sacs present in the body cavity. The efferent duct system consists of uterine bell, uterus and vagina. The uterine bell contains a complex system of routes and is associated with the ligament sacs in a way that facilitates egg sorting. The dorsal and ventral ligament sacs exist with separate cavities at the posterior end, where they are attached to the efferent duct, but merge into a single sac at the anterior of the trunk.

This study identified helminth species of wild boar (Sus scrofa) originating from northeastern and northwestern regions of Tunisia using 297 lungs, 297 livers, 264 intestinal tracts, 120 samples of muscle tissue (tongue, masseter, diaphragm, inter-costal) and 232 faecal samples derived from a total of 591 animals. Host gender was registered for the lung and liver wild boar group, which included 163 males and 134 females. All animals, excluding those used to retrieve muscular samples, were classified into three age classes, <2 (n = 212), 2–3 (n = 208) and ⩾4 years old (n = 141). Helminth fauna of the examined wild boar included 14 parasite species: one trematode (adult, Brachylaemus suis), three cestodes (metacestodes of Echinococcus granulosus, Taenia hydatigena cysticercus, adult, Hymenolepis diminuta), nine nematodes (adults of Metastrongylus apri, Metastrongylus pudendotectus, Ascarops strongylina, Globocephalus urosubulatus, Physocephalus sexalatus, Gnathostoma hispidum, Gongylonema pulchrum and eggs of Strongyloides ransoni and Capillaria spp.) and one acanthocephalan (adult, Macracanthorhynchus hirudinaceus). Trichinella larvae were not recovered from any of the 30 wild boar examined. Results showed a 73.5% global prevalence of infection with visceral helminths, 67.3% of which were lung and hepatic infections and 80.3% of helminths were recovered from the gastrointestinal tract. The most prevalent parasite was M. hirudinaceus (61.7%) while the highest intensity of infection was observed for Metastrongylus spp. The most prevalent cestode was E. granulosus (18.9%). This is the first detailed study on helminth infections of wild boar from a North African country.

Cod (Gadus morhua), an important fish species in the Baltic Sea, is the paratenic host for many parasite species, including the zoonotic nematodes, Anisakis sp. and Contracaecum osculatum. We aimed to identify which invertebrate species (found in situ in the fish stomach) are responsible for infection of cod with zoonotic nematodes. We found that Crangon crangon and Gammarus sp., both invertebrate prey species of cod, were infected with Anisakis simplex and C. osculatum, respectively. These host–parasite systems are reported here for the first time, implicating C. crangon and Gammarus sp. as sources of infection of Baltic cod with zoonotic nematodes.

We have previously shown that the C-terminal region of the intermediate subunit of Entamoeba histolytica galactose- and N-acetyl-D-galactosamine-inhibitable lectin (C-Igl) is a useful antigen for serodiagnosis of amebiasis. An immunochromatographic kit was developed using fluorescent silica nanoparticles coated with C-Igl prepared in Escherichia coli. Samples for examination were added to the freeze-dried particles and then applied to the immunochromatographic device, in which a test line on the membrane was also coated with C-Igl. Fluorescent intensity was measured using a hand-held reader. In an evaluation of the kit using a human monoclonal antibody, the minimum amount of C-Igl specific antibody showing positive results was 100 pg. In the evaluation of serum samples with different antibody titers in indirect immunofluorescent antibody tests in the kit, 20 µL of serum was sufficient to obtain positive results at 30 min. Serum samples from symptomatic patients with amebic colitis and amebic liver abscess and those from asymptomatic E. histolytica-cyst carriers showed positive results in the kit. Based on evaluation using sera from healthy controls and patients with other infectious diseases, the sensitivity and specificity of the kit were 100 and 97.6%, respectively. Therefore, we conclude that the newly developed kit is useful for rapid serodiagnosis of amebiasis.

1. Studies have been made of carbohydrate metabolism in Fasciola gigantica during starvation and these are compared with data available about carbohydrate metabolism in F. hepatica.

2. In F. gigantica the glycogen content before starvation was 5·4% of f.w. or 25·35% of D.W. of tissue, and the glycogen content after starvation was 3·5% of F.W. or 16·29% of D.W. of tissue.

3. The medium in which F. gigantica was incubated was analysed for lactic acid as one of the end products of glycogen consumption. The lactic acid given out in a period of 2 hr. was 0·46% of F.W. or 2·18% of D.W. of tissue.

I wish to thank Professor K. Sahai for his generous help in the preparation of this manuscript.

We set out to study how anti-filarial IgG4 and IgE, which have been studied extensively in adult populations, are influenced by gender and by the degree of filarial endemicity during childhood. Development of specific IgG4 and IgE was examined in 502 children aged 3 months to 12 years, who were resident in 3 villages in South-Sulawesi with microfilaria prevalences of 6, 23 and 42%. Specific IgG4 and IgE could be detected as early as 18 months after birth, in low amounts, and increased to levels comparable to those produced by adults at the age of 3 years. A higher prevalence of anti-filarial IgG4 in boys, indicating higher filarial infection compared to girls, became apparent after the age of 7. The specific IgG4 response was strongly influenced by the degree of filarial endemicity and production of this antibody was considerably delayed in the low transmission village. With respect to IgE, it was noted that specific IgE was consistently higher in boys from infancy onwards indicating a predisposition for high IgE production in males. The influence of filarial endemicity was less profound on IgE than on IgG4. In conclusion, reactivity to filarial antigens begins early in life and is differentially influenced by gender and transmission intensity.

Many medically important diseases of man are caused by blood-sucking arthropods which serve as vectors for a wide range of viral, bacterial, protozoal and nematode infections (Table 1). Furthermore, serious economic losses are caused by the numerous arthropod parasites which infect domesticated animals (for examples, see Table 2). Among these the ixodid hard ticks are particularly important and it has been estimated that the global cost of hard tick infections is $7000 million per annum (F.A.O., 1984). Not surprisingly, there have been strenuous efforts to control infections caused by arthropods.

Myxidium oviforme is described from Irish salmon Salmo salar. Its close relationship with M. folium, M. moxostomatis and M. aplodinoti, and its possible economic importance are discussed.

Attempts to establish infections of M. oviforme in young, parasite-free salmon are described, and the reasons for their negative results discussed.

This work was carried out during the tenure of a Medical Research Council Scholarship for Training in Research Methods between October 1964 and September 1966, and forms part of a thesis submitted for the Ph.D. Degree of the University of London. Grateful acknowledgement is due to Dr J. G. Ross and Dr G. Lawson of the Veterinary Research Division of the Ministry of Agriculture for Northern Ireland for information on salmon infections in Ireland, to the Ministry of Agriculture and Fisheries for the provision of young salmon, and to Messrs Barnetts of Frying Pan Alley Ltd., London, for the provision of salmon livers.

Trypanosoma musculi are readily killed when phagocytosed by mononuclear phagocytes but the nature of the mediators of this cytotoxicity is unclear. Among the most potent mediators are oxygen-derived species. The generation of chemilumine-scence (CL) by peritoneal macrophages from 12 day T. musculi-infected mice, which phagocytose and kill parasites when opsonizing antibodies are present, was recorded in the presence of antibody-coated trypanosomes. Taurine, a specific quencher of hypochlorous acid (HOCl) inhibited CL production by peritoneal macrophages, showing that HOCl is produced during phagocytosis of T. musculi. In vitro, HOCl alone exerted a powerful trypanocidal activity which was inhibited in the presence of specific quenchers. The role of HOCl generated by phagocytes in trypanosome killing was studied using granulocytes which produce more oxygen-derived species than macrophages when stimulated. Phorbol myristate acetate-triggered granulocytes can destroy T. musculi and trypanosome killing is inhibited in the presence of taurine. These data demonstrate that HOC1 produced by phagocytes can effectively destroy T. musculi.