The dry weight, nitrogen content, and total carbohydrate content of Hymenolepis diminuta were studied after a period of 15 days growth in rats, maintained on different diets. The special diets were fed during the last 7 days of this period.

Using equal iso-molecular quantities, seven amino acids, representing the different classes of neutral amino acids, acidic amino acids and basic amino acids, have been screened for their effect on worm growth when added as free dietary supplement to the different diets. All of them, to a greater or lesser extent, had significant effects on worm growth.

The award of a research grant by the Standing Advisory Committee for Medical Research in the British Caribbean is gratefully acknowledged. I am also indebted to Professors J. C. Waterlow and C. von Holt for the loan of equipment in order to carry out the carbohydrate and nitrogen determinations, to Professor I. M. Good-body for his continued interest and support, and to the Rippel Foundation for research facilities.

1. Observations have been made on the life cycles of Cercaria paracauda, Iles, G. tetraglandis, Iles, and C. Apatemon gracilis minor, Yamaguti. The development of the tetracotyle metacercaria of C. tetraglandis has been followed and also that of the metacercaria and adult of A. g. minor. The pathology and distribution of the metacercariae of the last two species within the leech, Erpobdella testacea (Sav.) has been studied.

2. It was noted that development of the metacercariae within the same host and resulting from the same infection was not simultaneous and that it was improbable that a 100 % encystment of the metacercariae would occur. Temperature was found to have a marked effect on the length of time required for encystment.

3. Data are given on the infectivity and excystation of the metacercariae of A. g. minor and on the biology and morphology of the adult of this subspecies.

4. Stress is placed on the importance, in the systematics of the digenetic trematodes, of considering both the morphological and biological characters of the adult and those of the related larval stages.

An attempt was made to evaluate the immunoprophylactic efficacy of Brugia malayi transglutaminase (BmTGA) as a DNA vaccine, for human lymphatic filariasis. BmTGA was cloned and characterized in the DNA vaccine vector pVAX1. Further, the tissue distribution study of the DNA construct, pVAX-TGA was carried out in mice and the DNA vaccine was shown to be efficiently distributed to all the organs, was accessible to the immune system, and at the same time was metabolized quickly and did not pose problems of toxicity. Intramuscular immunization in mice showed significant antibody production and splenocyte proliferation upon antigenic stimulation. The immune responses were biased towards the Th1 arm, as evaluated in terms of isotype antibody distribution and cytokine profile. Thus, analysis of the humoral and cellular immune responses indicated that BmTGA is a potent immunogen. However, protection studies as determined by the micropore chamber method using live microfilarial larvae, showed that the DNA vaccine could confer only partial protection in the mouse model. We conclude that despite the induction of sufficient humoral and cellular immune responses, BmTGA as a DNA vaccine could not confer much protection against subsequent challenge and other aspects of the immune responses need to be further investigated.

Patterns of genetic variation among populations can reveal the evolutionary history of species. Pinworm parasites are highly host specific and form strong co-evolutionary associations with their primate hosts. Here, we describe the genetic variation observed in four Trypanoxyuris species infecting different howler and spider monkey subspecies in Central America to determine if historical dispersal processes and speciation in the host could explain the genetic patterns observed in the parasites. Mitochondrial (cox1) and ribosomal (28S) DNA were analysed to assess genetic divergence and phylogenetic history of these parasites. Sequences of the 28S gene were identical within pinworms species regardless of host subspecies. However, phylogenetic analyses, haplotype relationships and genetic divergence with cox1 showed differentiation between pinworm populations according to host subspecies in three of the four Trypanoxyuris species analysed. Haplotype separation between host subspecies was not observed in Trypanoxyuris minutus, nor in Trypanoxyuris atelis from Ateles geoffoyi vellerosus and Ateles geoffoyi yucatanensis. Levels of genetic diversity and divergence in these parasites relate with such estimates reported for their hosts. This study shows how genetic patterns uncovered in parasitic organisms can reflect the host phylogenetic and biogeographic histories.

Hookworms are some of the most widespread of the soil-transmitted helminths (STH) with an estimated 438.9 million people infected. Until relatively recently Ancylostoma ceylanicum was regarded as a rare cause of hookworm infection in humans, with little public health relevance. However, recent advances in molecular diagnostics have revealed a much higher prevalence of this zoonotic hookworm than previously thought, particularly in Asia. This study examined the prevalence of STH and A. ceylanicum in the municipalities of Palapag and Laoang in the Philippines utilizing real-time polymerase chain reaction (PCR) on stool samples previously collected as part of a cross-sectional survey of schistosomiasis japonica. Prevalence of hookworm in humans was high with 52.8% (n = 228/432) individuals positive for any hookworm, 34.5% (n = 149/432) infected with Necator americanus, and 29.6% (n = 128/432) with Ancylostoma spp; of these, 34 were PCR-positive for A. ceylanicum. Considering dogs, 12 (n = 33) were PCR-positive for A. ceylanicum. This is the first study to utilize molecular diagnostics to identify A. ceylanicum in the Philippines with both humans and dogs infected. Control and elimination of this zoonotic hookworm will require a multifaceted approach including chemotherapy of humans, identification of animal reservoirs, improvements in health infrastructure, and health education to help prevent infection.

A detailed morphological investigation of the anterior sensory organs, the nerve ring and a glomerulus-like structure in male Onchocerca volvulus was performed by means of electron microscopy. The 8 head papillae are arranged in the common 4 + 4 pattern of most filarial worms in circles around the mouth opening. The amphidial openings are found between the circles of inner and outer papillae on both sides of the mouth. Inside, several additional nerve axons are seen in the tissue of the anterior tip not related to one of the identified papillar structures. The inner and outer papillae exhibit a remarkably different fine structure, and are part of a complex system of at least 2 different receptor cell types at the anterior tip of the worm. The amphidial channel contains 8 modified cilia; accessory axons are associated with the cytoplasm of the sheath cell. The anterior nerve ring of male worms is located about 150 µm posterior from the outermost tip of the head region. It consists of several fibres coiled around the oesophagus. The comparison of the fine structure of the central nervous system did not show the expected morphological differences associated with the heterogeneous age distribution in the natural worm population. This was in contrast to previous findings with respect to tissues in different parts of the worm. The study also provides the first evidence that suggests the existence of an excretory organ in a filarial worm in the region of the anterior nerve ring. Paired glomerulus-like structures in the lateral chords and a canal formed by a projection of the basal zone of the cuticle were identified.

The present report is confined to the species found in Chinese amphibians by Faust in his field studies during the period from 1920 to 1925. Two new species of the genus Acanthocephalus are described in this paper and notes on their geographical distribution and host relationships are included along with observations on the occurrence of undetermined species of encysted larval Acanthocephala in amphibian hosts.

The development of in vitro culture systems that allow the maintenance, and support the development of Echinococcus, Giardia and Cryptosporidium in the laboratory have had a significant impact on their biology and taxonomy and the epidemiology of infections they cause. This short retrospective review demonstrates how radical shifts in our understanding have occurred as a result of being able to grow these organisms in culture, and how molecular tools have helped in the interpretation of such research that often reflects the observations of earlier workers.

Unlike most bird species, individual kingfisher species (Aves: Alcedinidae) are typically parasitized by only a single genus of louse (Alcedoffula, Alcedoecus, or Emersoniella). These louse genera are typically specific to a particular kingfisher subfamily. Specifically, Alcedoecus and Emersoniella parasitize Halcyoninae, whereas Alcedoffula parasitizes Alcedininae and Cerylinae. Although Emersoniella is geographically restricted to the Indo-Pacific region, Alcedoecus and Alcedoffula are geographically widespread. We used DNA sequences from two genes, the mitochondrial COI and nuclear EF-1α genes, to infer phylogenies for the two geographically widespread genera of kingfisher lice, Alcedoffula and Alcedoecus. These phylogenies included 47 kingfisher lice sampled from 11 of the 19 currently recognized genera of kingfishers. We compared louse phylogenies to host phylogenies to reconstruct their cophylogenetic history. Two distinct clades occur within Alcedoffula, one that infests Alcedininae and a second that infests Cerylinae. All species of Alcedoecus were found only on host species of the subfamily Halcyoninae. Cophylogenetic analysis indicated that Alcedoecus, as well as the clade of Alcedoffula occurring on Alcedininae, do not show evidence of cospeciation. In contrast, the clade of Alcedoffula occurring on Cerylinae showed strong evidence of cospeciation.

The epidermis of Diplectanum aequans has, in general, been found to be similar to the epidermis of other monogeneans, consisting of a syncytial outer epidermis and sunken sub-epidermal nucleated regions. However, the epidermis of D. aequans differs from that of other monogeneans in 3 respects. These are, the presence of large areas of granular cytoplasm within the outer epidermis, the presence of myofibres invaginating into the epidermal matrix and, in the posterior regions of the epidermis, the presence of epidermal scales. These scales occur within the epidermal cytoplasm, beneath the outer membrane, and are composed of moderately electron-dense material. Also present beneath the outer membrane in the more anterior regions of the epidermis are small scale-like sclerites of a similar electron density to the epidermal scales.

Surface antigens of Schistosoma haematobium were identified by 125I-surface labelling of schistosomula followed by immunoprecipitation of the solubilized, labelled surfaces. The major antigens, after electrophoresis, formed a continuous smear corresponding to a molecular weight in the range 35–24000; in addition, a 17000 antigen was also identified. These surface antigens, in contrast to somatic antigens, were species-specific, as judged by immunoprecipitation with human anti-S. mansoni serum and serum from mice vaccinated with highly irradiated S. mansoni cercariae. S. haematobium surface antigens, however, were recognized to some extent by serum from mice chronically infected with S. mansoni. It is suggested that this cross-reactivity may reflect the heterologous immunity demonstrated experimentally between these two species, whilst the species-specificity of vaccine sera to surface antigens may mirror the highly specific immunity induced by vaccination.

A survey was carried out to determine values for the prevalence and intensity of infection of intestinal helminths in children living in Cocle Province, Republic of Panama. The data set consisted of the results of microscopic examinations (modified Kato Katz technique) of stool samples collected in November 1987 from 661 children attending primary schools in 4 communities in the province. The overall prevalences of Ascaris lumbricoides, hookworm and Trichuris trichiura infections were found to be 18·2, 12·0 and 27·5% respectively. There were significant differences between the infection prevalence values for children attending the different schools, but not with respect to age or sex. Positive associations were detected between particular pairs of infections and these were most evident when Trichuris trichiura was involved. The data revealed evidence of a positive association between siblings at one school only for each helminth infection.

Neck samples from 54 badgers and 32 tongue samples of the same badgers (Meles meles), collected in the Lothians and Borders regions of Scotland, were tested using polymerase chain reactions (PCRs) directed against the 18S ribosomal DNA and the internal transcribed spacer (ITS1) region of protozoan parasites of the family Sarcocystidae. Positive results were obtained from 36/54 (67%) neck and 24/32 (75%) tongue samples using an 18S rDNA PCR. A 468 base pair consensus sequence that was generated from the 18S rDNA PCR amplicons (KX229728) showed 100% identity to Sarcocystis lutrae. The ITS1 PCR results revealed that 12/20 (60%) neck and 10/20 (50%) tongue samples were positive for Sarcocystidae DNA. A 1074 bp consensus sequence was generated from the ITS1 PCR amplicons (KX431307) and showed 100% identity to S. lutrae. Multiple sequence alignments and phylogenetic analysis support the finding that the rDNA found in badgers is identical to that of S. lutrae. This parasite has not been previously reported in badgers or in the UK. Sarcocystis lutrae has previously only been detected in tongue, skeletal muscle and diaphragm samples of the Eurasian otter (Lutra lutra) in Norway and potentially in the Arctic fox (Vulpes lagopus).

In the present study we have used antibodies to Leishmania major promastigote antigens which were eluted from a glutathione-agarose column (LmGbp) and could identify several parasite components among different Leishmania species by using immunoprecipitation and Western blot techniques. The results also showed that some of LmGbp are present among the molecules released into the culture medium. Moreover, immunofluorescence assays clearly demonstrated that LmGbp are expressed by intracellular amastigotes. The electron micrographs of thawed cryosections of L. major-infected cells revealed that the antigens were associated with the membrane of the phagocytic vacuole. Moreover, the Western blot technique allowed us to identify, using other Leishmania species extracts and anti-LmGbp antibodies, a major polypeptide of an apparent molecular mass of 66 kDa. Immunofluorescence studies suggested that the 66 kDa polypeptide is associated with intracytoplasmic vesicles. Cryosections of Leishmania promastigotes improved the fine structure preservation of the organelles and enabled a number of features to be seen, particularly the structures considered as vesicles, which appeared as a complex tubulo-vesicular structure resembling mammalian cell endosomes and Leishmania organelles previously named ‘megasomes’. Further studies using antibodies against the native 66 kDa protein will be needed to investigate the localization of the protein at the ultrastructural level and to follow its intracellular vesicular traffic.

Amblyomma dissimile Koch is well known to science and previous accounts of its biology have already appeared. Newstead (1909) made some observations on its habits in Jamaica. Hooker, Bishopp, and Wood (1912) give an exact account of its life cycle worked out in confinement in the Southern United States of America. These authors do not refer to the occurrence of parthenogenesis in this species.

Schistosomiasis and malnutrition are often overlapped in poor communities, resulting in disproportionately high mortality rates. Currently, fragmented data make it difficult to define the relationship between diet and schistosomiasis. Thus, we systematically review the preclinical evidence on the impact of diet in Schistosoma mansoni infection. From a structured search, we recovered 27 original articles. All studies used mice and most of them investigated hypoproteic (70.37%), hyperlipidic (22.22%) or vitamin-deficient (7.41%) diets. Diets based on carbohydrate, zinc or milk supplementation were investigated at a reduced frequency (3.70% each). Hypoproteic diets attenuated parasitic load and granulomatous inflammation, but also reduced host resistance to S. mansoni infection, determining higher mortality rates. By stimulating steatohepatitis, parasitic load and granulomatous inflammation, hyperlipidic diets increase organ damage and mortality in infected animals. Although a high-sugar diet and vitamin restriction potentiate and zinc supplementation attenuates S. mansoni infection, the current evidence for these diets remains inconclusive. Analysis of methodological quality indicated that the current evidence is at high risk of bias due to incomplete characterization of the experimental design, diet composition and treatment protocols. From the bias analysis, we report methodological limitations that should be considered to avoid systematic reproduction of inconsistent and poorly reproducible experimental designs.

The ability of certain species of trypanosomes (T. lewisi and T. equiperdum) to ingest previously stained oil drops which occurred simultaneously in the blood has been observed.

Tryparsamide incorporated in dyed (Sudan IV) cod-liver oil.when administered orally, was found to be effective against T. equiperdum infections in mice.

Trichomonas vaginalis (Tv) induces host cell damage through cysteine proteinases (CPs) modulated by iron. An immunoproteomic analysis showed that trichomoniasis patient sera recognize various CPs, also some of them are present in vaginal washes (VWs). Thus, the goal of this work was to determine whether TvCP2 is expressed during infection and to assess the effect of iron on TvCP2 expression, localization and contribution to in vitro cellular damage. Western-blotting (WB) assays using TvCP2r and vaginitis patient serum samples showed that 6/9 Tv (+) but none of the Tv (−) patient sera recognized TvCP2r. WB using an anti-TvCP2r antibody and VWs from the same patients showed that in all of the Tv (+) but none of the Tv (−) VWs, the anti-TvCP2r antibody detected a 27 kDa protein band that corresponded to the mature TvCP2, which was confirmed by mass spectrometry analysis. Iron decreased the amount of TvCP2 mRNA and the protein localized on the parasite surface and cytoplasmic vesicles concomitant with the cytotoxic effect of TvCP2 on HeLa cells. Parasites pretreated with the anti-TvCP2r antibody also showed reduced levels of cytotoxicity and apoptosis induction in HeLa cell monolayers. In conclusion, these results show that TvCP2 is expressed during trichomonal infection and plays an important role in the in vitro HeLa cell cytotoxic damage under iron-restricted conditions.

1. During the period November 1936 to February 1937, eighty rabbits were examined, whilst from August 1937 to July 1938 another 446 were examined for nematodes. The following nematodes were found: Graphidium strigosum, Passalurus ambiguus, Trichostrongylus retortaeformis.

2. The incidence of the above three nematodes is given, and their seasonal incidence is discussed, with special reference to its ecological implication.

3. Evidence of host and age resistance is also demonstrated in infections with Graphidium strigosum, Passalarus ambiguus and Trichostrongylus retortaeformis.

4. The proportion of the sexes in Graphidium strigosum was found to be constant during both periods. The percentage of males in 1936–7 was 45·6 and 45·96 in 1937–8. In Passalurus ambiguus, however, the proportion of the sexes varied to a large extent.

The copepod described in this paper has been found in Strangford Lough, Co. Down, an area which has already proved rich in ascidicolous copepods of the suborder Notodelphyoida (Gotto, 1952). The present species, however, belongs to the section Poecilostoma of the suborder Cyclopoida, many members of which are associated with marine animals of several different groups. The extremes of retrogressive specialization which characterize many of the notodelphyoids are not, on the whole, so apparent in these cyclopoids, their associative habits often being inferred from general structure rather than proved occurrence with any particular host. Thus a fair number of the types described have been found unattached in dredged material, the possible host being any one of several species taken in the same haul. Associations of an apparently loose nature are therefore sufficiently frequent to render the present form of particular interest since it has so far been found exclusively in the compound ascidian Trididemnum tenerum (Verrill), in which it is localized in the extensive cloacal cavities. Further search may of course reveal alternative hosts, since the family Lichomolgidae, to which it undoubtedly belongs, has a wide range of acceptable hosts. Indeed the genus Lichomolgus is known to occur in association with sponges, polychaets, nudibranchs, gasteropods, cephalopods, holothurians and ascidians—and one species, L. agilis (Leydig) has been recorded from a score of different nudibranchs.