The results of the study on the digestion of Gastrophilus larvae may be summarized as follows:

(1) Pepsin-like enzymes are totally absent.

(2) The salivary glands secrete a proteolytic enzyme, which has no effect on the digestion of casein, gelatine and fibrin, but acts on milk alone.

(3) The midgut is capable of secreting amylolytic, proteolytic and lipolytic enzymes.

(4) The body fluid contains a strong reducing substance.

(5) The body fluid, as was shown by Khemnitz (1914), contains an amylolytic enzyme which is also capable of converting glycogen into glucose.

(6) Free glycogen and glucose circulate in the body fluid of the larva during the prepupal and possibly the pupal stage also.

(7) The larva of Gastrophilus does not feed on blood, but lives on the fluid material partly digested by its host in the stomach.

(8) For this reason the horses do not show any symptoms even when there is a heavy infestation.

The genus Crenosoma was founded by Molin in 1861 for two species of nematodes, Strongylus canis vulpis Rud., 1819, from the lungs of a fox (Vulpes vulpes L.), and Strongylus striatus Zeder, 1800, from the bronchi of a hedgehog (Erinaceus europaeus L.).

Alveolar echinococcosis (AE) is an emerging zoonotic disease caused by the cestode Echinococcus multilocularis. The secondary infection model of AE is based on intraperitoneal injection of disease-causing metacestodes into the peritoneal cavity of mice, which allows investigations on novel drugs or immunotherapeutical treatment options in vivo. So far, such in vivo studies assessed exclusively the parasite weight at the endpoint of a given treatment period. We here developed an ultrasound (US)-based scoring system that allows to follow-up parasite development in the living animal, and provides insights into parasite growth during the treatment phase. By this method a statistically significant difference between untreated and medicated mice with E. multilocularis infection was observed at 2 months post-infection, and the growth curve of the parasite load was described by a linear mixed model. High correlation and similar levels of variation were observed for the standard method based on parasite weight measurement, the novel US-based scoring system, as well volume segmentation by post-mortem magnetic resonance imaging. Thus, US-based scoring in the live animal has the potential to assist the 3R concept by contributing to the refinement and reduction of animal use in experimental echinococcosis.

An enzyme-linked immunosorbent assay (ELISA) using crude worm extracts (CWE) and mixtures of these as antigens of five Spanish isolates (P, C, B1, B2 and W) was developed for detecting homologous and heterologous experimental infections with these isolates between – 14 and 82 days post-infection (p.i.) in white and Iberian pigs. A total of 243 pigs (Ilberian or cross-bred with this race) with numerous parasitic infections were also screened for the presence of antibodies to a mixture of CWE of C, B1 and B2 isolate. The test showed a specificity of 93·1–98·9% depending on the cut-off values and a maximum sensitivity of 92·8–100% between days 34 and 82 p.i. A low grade of infectivity was shown in the T3 isolates compared to the T1 isolates (P, C, B1 and B2) but high cross-reactions were observed between all the isolates with minor differences between P and W isolates. The highest antibody response was found in P infections and the lowest in pigs infected with the W isolate. A clear association between the presence of several parasitic infections and false positive reactions was not found, but an important relation was shown between high background levels and the Iberian race in experimentally and conventionally raised pigs

Levels of 2 Schistosoma circulating antigens, the circulating anodic antigen (CAA) and the circulating cathodic antigen (CCA), were determined in serum samples collected, on a monthly basis over a period of 1·5 years, from 32 farm animals of different ages and from 12 tracer calves exposed to Schistosoma mattheei infection on a Zambian farm. Faecal egg counts were monitored in all animals and worm burdens in tracers determined after perfusion. Antigen determination tests in serum, with sensitivities between 95 and 100% in heifers and adult cows, proved to be excellent tools for the diagnosis of cattle schistosomiasis. Also in young calves, some infections could be demonstrated earlier by CCA determination than by faecal egg examination. A poor correlation was seen between the data for faecal egg counts and for CAA and CCA levels. It therefore appears that circulating antigen measurements in serum are of limited value as indicators of the pathogenesis of infection in cattle. Although all tracer calves were found infected at perfusion, large variations were recorded in antigen levels. An unexpected finding was the observation in farm animals of a clear seasonal pattern in CAA levels, with significant increase between August and October during the second half of the dry season, when animals are subjected to heavy physical and nutritional stress. It therefore appears that, although circulating antigen determination may provide an indication of the worm burden in ageing infections, possible variations of antigen clearance rate with the physiological condition of the host may complicate the interpretation of the results.

Plasmodium falciparum is the main cause of severe malaria in humans that can lead to death. There is growing evidence of drug-resistance in P. falciparum treatment, and the design of effective vaccines remains an ongoing strategy to control the disease. On the other hand, the recognition of specific diagnostic markers for P. falciparum can accelerate the diagnosis of this parasite in the early stages of infection. Therefore, the identification of novel antigenic proteins especially by proteomic tools is urgent for vaccination and diagnosis of P. falciparum. The proteome diversity of the life cycle stages of P. falciparum, the altered proteome of P. falciparum-infected human sera and altered proteins in P. falciparum-infected erythrocytes could be proposed as appropriate proteins for the aforementioned aims. Accordingly, this review highlights and proposes different proteins identified using proteomic approaches as promising markers in the diagnosis and vaccination of P. falciparum. It seems that most of the candidates identified in this study were able to elicit immune responses in the P. falciparum-infected hosts and they also played major roles in the life cycle, pathogenicity and key pathways of this parasite.

Clonorchis sinensis (C. sinensis) is one of the most serious food-borne parasites, which can lead to liver fibrosis or cholangiocarcinoma. Effective measures for clonorchiasis prevention are still urgently needed. Bacillus subtilis (B. subtilis) is an effective antigen delivery platform for oral vaccines. Chonorchis sinensis serpin (CsSerpin) was proved to be potential vaccine candidates. In this study, CsSerpin3 was displayed on the surface of B. subtilis spore and recombinant spores were orally administrated to BALB/C mice. CsSerpin3-specific IgA levels in faecal, bile and intestinal mucous increased at 4–8 weeks after the first administration compared with those in control groups. The mucus production and the number of goblet cells in intestinal mucosa elevated in B.s-CotC-CsSerpin3 (CotC, coat protein of B. subtilis spore) spores treated group compared to those in blank control. No significant difference in the activities of glutamic-pyruvic transaminase/ alanine aminotransferase and glutamic oxalacetic transaminase/aspartate aminotransferase were observed between groups. There was no side effect inflammation and observable pathological damage in the liver tissue of mice after administration. Moreover, collagen deposition and Ishak score were statistically reduced in B.s-CotC-CsSerpin3 spores treated mice. In conclusion, B. subtilis spores displaying CsSerpin3 could be investigated further as an oral vaccine against clonorchiasis.

Phosphoenolpyruvate carboxykinase (PEPCK, EC 4.1.1.32) is an essential regulatory enzyme of glycolysis in helminths in contrast to its role in gluconeogenesis in their host. Previously we have reported that phytochemicals from Flemingia vestita (Family: Fabaceae), genistein in particular, have vermifugal action and are known to affect carbohydrate metabolism in the cestode, Raillietina echinobothrida. In order to determine the functional differences of PEPCK from the parasite and its avian host (Gallus domesticus), we purified the parasite enzyme apparently to homogeneity, and characterized it. The native PEPCK is a monomer with a subunit molecular weight of 65 kDa. The purified enzyme displayed standard Michaelis-Menten kinetics with Km value of 42·52 μM for its substrate PEP. The Ki for the competitive inhibitors GTP, GMP, ITP and IMP for the carboxylation reaction were determined and discussed. In order to identify putative modulators from plant sources, phytochemicals from F. vestita and Stephania glabra were tested on the purified PEPCK, which resulted in alteration of its activity. From our results, we hypothesize that PEPCK may be a potential target site for anthelmintic action.

Malaria remains a major cause of human morbidity and mortality worldwide. Plasmodium falciparum, the most virulent of the 4 human Plasmodium species causing malaria, is potentially life threatening, is increasing in prevalence and is becoming even more resistant to in-use drugs. In light of the growing problem of multi-drug resistance to malarial parasites, the development of new drugs or the use of a combination therapy is of primary importance. A previous report describes a remarkable synergistic antimalarial interaction between 2 structurally similar compounds, rufigallol, an anthraquinone derivative and exifone, a benzophenone derivative, in vitro. The synergistic antimalarial activity of exifone and vitamin C was also reported. To extend the same analogy to other ketones, we carried out antimalarial testing of 20 benzophenone derivatives, individually, in combination with rufigallol, and also in combination with vitamin C, in mice infected with Plasmodium berghei. Five ketones, out of 20, showed good antimalarial activity, in vivo, when tested individually. Nine ketones, out of 20, showed good antimalarial activity, in vivo, when tested in combination with rufigallol, indicating the synergism between them. However, synergism between ketones and vitamin C was not satisfactory since only 2 ketones showed good antimalarial activity when tested in combination with vitamin C.

The structure of H. placei adult worms, obtained from calves at 4, 7, 10 or 11–13 weeks after primary infection, has been studied. A reorganization of rough endoplasmic reticuhim in the cytoplasm of the gut cells was seen at 10 weeks and this was followed by marked vacuolation of many of these cells, associated with an increase in lipid production. Increases of lipid were also found in the hypodermis, lateral cords and occasionally muscle cells of worms examined at 11–13 weeks after infection.

It is suggested that these changes are the result of the host immune response, because they resemble changes which occur in the rat nematode Nippostrongylus brasiliensis and which are known to be caused by host immunity.

Experimentally infected female mice and naturally infected female jackrabbits are more susceptible to infection with Taenia multiceps than males. It appears that cortisone has the greatest effect in altering rates in mice when injected between days 1 and 14 following exposure of mice. Cortisone elevates infection rates in male mice but not in females. Cortisone does, however, alter the distribution pattern in a similar manner in both sexes. The biology of coenuriasis in rabbits and mice is discussed and compared.

I wish to thank Dr J. R. Egerton of the Merck Institute, Rahway, New Jersey, for supplying cortisone used in this study. I also thank Dr Robert Sullivan and Dr Ralph Amen for their criticisms and suggestions in the preparation of this manuscript.

A novel DNA-binding peptide of Mr∼30 kDa was documented for the first time in the excretory–secretory (E–S) products of the infective-stage larvae of Trichinella pseudospiralis. Larvae recovered from muscles of infected mice were maintained for 48 h in DMEM medium. E–S products of worms extracted from the medium were analysed for DNA-binding activity by the electrophoretic mobility shift assay (EMSA). Multiple DNA-protein complexes were detected. A comparison of the Mr of proteins in the complexes indicated that they could bind to the target DNA as a dimer, tetramer or multiples of tetramers. Site selection and competition analysis showed that the binding has a low specificity. A (G/C-rich)-gap-(G/T-rich)-DNA sequence pattern was extracted from a pool of degenerate PCR fragments binding to the E–S products. Results of immunoprecipitation and electrophoretic mobility supershift assay confirmed the authenticity of the DNA-binding protein as an E–S product.

An extract of blood from Aotus monkeys infected with Plasmodium falciparum contained all the clones of malaria precipitins so far identified in human blood.

We are grateful to the Medical Research Council and Overseas Development Administration of Great Britain and to the World Health Organization for their financial assistance.

The infected termite was collected in Samoa by Dr P. A. Buxton and was identified by Mr G. F. Hill, Melbourne, who noticed “foreign bodies” attached to the forelegs. These bodies proved to be fructifications, in the form of small apothecia, of a fungus to which the name Ectomyces caloterni n.g., n.sp., has been given. The two infected legs comprised all the available material, and, as they were preserved in alcohol, cultivation of the fungus could not be attempted.

1. Two specimens of Coenurus serialis in the rabbit are described.

2. The duration of infection is estimated at 18–24 months.

3. Secondary external daughter coenuri had developed within the same adventitious cyst of host tissue as the primary coenuri.

4. No internal daughter coenuri were found within the primary coenuri.

5. Both primary coenuri contained some scolices which had developed vesicles (ranging from 3 to 30mm.) in their ‘neck’ region. These vesicular scolices remain attached to the germinal layer until the vesicle is 4–5 mm. in diameter, when they become detached. These would appear to be the internal daughter coenuri of many authors but are here shown to be degenerating scolices.

The taxonomy of larval and nymphal stages of H. savignyi, H. detritum, H. marginatum, H. dromedarii and the nymph of H. aegyptium are described.

The material for the first four species was obtained from laboratory-bred specimens. The bionomics of these species was studied in the laboratory. Their behaviour under natural conditions still remains to be studied.

The mouse type 2 Alu (B2) sequence was detected in both DNAs of Schistosoma mansoni and S. japonicum except for the cercarial stage by the polymerase chain reaction (PCR). Using several kinds of mouse STMS (sequence tagged microsatellite site) primer sets, PCR products related to the host were found in the DNAs of S. mansoni as well as of S. japonicum. Products could be detected only in the DNA of S. japonicum using certain STMS primer sets. The fact that no products could be amplified from the DNAs of both parasites when other kinds of STMS primer sets were used suggests unequal incorporation of the host DNA into the schistosomes. Furthermore, the sequence of the N-terminal domain of H-2, the mouse major histocompatibility complex (MHC), was detected in the DNAs from S. mansoni miracidium, male adult and S. japonicum adults, whereas the sequence of the C2 domain of H-2 was found only in the DNAs of S. japonicum adults. This evidence that host DNA sequences, including the class I MHC, exist heterogeneously in the DNAs of schistosomes might provide an important insight for further understanding of host-parasite immune interactions.

Phthirus pubis is not known to serve as a vector of any infective disease.

The pathological effects of its parasitism on man are on the whole of slight degree. Some persons are more sensitive than others to its presence; on the one hand the louse may produce no reaction by its bite or it may be tolerated upon the person for years, on the other hand it may induce pruritus of a more or less severe character, especially in parts of the body that are most infested and where the skin is most delicate, i.e. about the genitalia, the axillae, and eyelids. All grades of pruritus are observable, scratching of which the individual is unconscious may occur, or in the severest cases the scratching goes on day and night, so that by day it may be evident to spectators and aid in diagnosis. The scratching may only begin from the moment when a person realizes that he is infested.

The pale bluish-grey maculae are a specific sign of the presence of Phthirus upon man, but they are not always present. They are induced by the adult louse, are few in number, painless, deep seated, do not disappear on pressure, and measure 0·2–3 cm. in diameter. The maculae mark the site of the insect's bite; they appear 8–24 hours after the louse commences to feed on the spot affected. The bites of P. humanus do not produce maculae caeruleae. The salivary glands of Phthirus and Pediculus give correspondingly positive and negative results when inoculated subcutaneously. The maculae disappear usually within a week after the removal of the offending parasite, and they disappear more rapidly when the skin is irritated. The nature of the maculae remains to be determined, they may be due to extravasated and altered blood.

Apart from the maculae, Phthirus, like P. humanus, fleas and mosquitoes, may cause a febrile condition owing to skin irritation, although this appears to be rare; with the removal of the lice, the fever promptly subsides. Papular eruptions and eczematous inflammation may supervene upon the presence of the louse, but they appear to be largely due to the added insult of scratching the infested skin. The melanism is of non-specific origin, being due to continued scratching which leads to hyperaemia, pigmentation and desquamation. The lesions induced thereby may lead to secondary skin infection with pyogenic bacteria.