The rickettsial bacterium Ehrlichia ruminantium is the causative agent of heartwater, a serious tick-borne disease in ruminants. The genetic diversity of organisms in the field will have implications for cross-protective capacities of any vaccine developed, and for an effective vaccine design strategy proper genotyping and understanding of existing genetic diversity in the field is necessary. We searched for variable-number tandem-repeat (VNTR) loci for use in a multi-locus VNTR analysis (MLVA). Sequencing analysis of 30 potential VNTRs using a panel of 17 reference strains from geographically diverse origins identified 12 VNTRs with allelic profiles differing between strains. Application of MLVA to 38 E. ruminantium-infected Amblyomma variegatum collected from indigenous cattle in 6 different districts of Uganda identified 21 MLVA types. The discriminatory power of MLVA was greater than that of map1 PCR-restriction fragment length polymorphism analysis, with which only 6 genotypes were obtained. The high discriminatory power as well as cost- effective performance of MLVA provide the potential for this technique to be applied in the future with respect to optimizing vaccine trials by identifying local strain diversity, and also raise the possibility of exploring the association between E. ruminantium genotypes and phenotypes such as pathological outcome in the ruminant host.

The impact of Toxocara canis infection of Balb/c mice mothers on the future immune response of their offspring towards reinfection with the same parasite was studied. Two groups of offspring, the first originating from the mothers infected with a single dose of 1000 Toxocara canis eggs and the second from non-infected mothers, were both challenged with 500 T. canis eggs per animal at 6 weeks of age. The proportions of spleen CD4+ and CD8+ T lymphocytes, the level of serum cytokines IFN-γ and IL-5, eosinophilia in peripheral blood, the production of specific antibodies and the number of migrating larvae were monitored. In both groups of offspring, the challenge infection resulted in an increase in CD4+ T-cell subtype in comparison with the non-infected healthy control, although after an initial decline a subsequent increase in CD8+ was observed. The immunoregulation index (CD4+/CD8+) was lower in the group of mice originating from infected mothers throughout the whole experiment compared to the offspring of non-infected mothers as well as in healthy control mice of the same age. In the offspring of infected mothers mainly, a reduced production of IFN-γ and of IL-5, suppressed eosinophilia and a higher level of protective antibodies was detected, compared to the control second group, in which the INF-γ concentration significantly increased after day 42 p.i. In the first group of offspring before challenge, 12·7±2·5 larvae in the brains and 32±2·1 larvae in the muscles transmitted from the infected mothers were detected. There was a significant reduction in larval recovery from brain on days 42 and 49 p.i. (56·7 and 56·8%, respectively), while from muscles in the same time there was a reduction of 46·7 and 39%, respectively, compared to the offspring of non-infected mothers. These results indicate a significant protective memory of immune mechanisms against T. canis induced in offspring of Toxocara-infected mother mice.

Chagas disease (CD) is caused by the intracellular protozoan parasite Trypanosoma cruzi and affects more than 10 million people in poor areas of Latin America. There is an urgent need for alternative drugs with better safety, broader efficacy, lower costs and shorter time of administration. Thus the biological activity of viniconazole, a chloroaryl-substituted imidazole was investigated using in vitro and in vivo screening models of T. cruzi infection. Ultrastructural findings demonstrated that the most frequent cellular damage was associated with plasma membrane (blebs and shedding events), Golgi (swelling aspects) and the appearance of large numbers of vacuoles suggesting an autophagic process. Our data demonstrated that although this compound is effective against bloodstream and intracellular forms (16 and 24 μ m, respectively) in vitro, it does not present in vivo efficacy. Due to the urgent need for novel agents against T. cruzi, the screening of natural and synthetic products must be further supported with the aim of finding more selective and affordable drugs for CD.

The causal chain of parasite–host–environment interactions, the so-called ‘dual parasite environment’, makes studying parasites more complicated than other wild organisms. A sample of 65 282 fleas taken from 336 different locations were analysed for changes in the distribution, diversity and compensation of flea communities found on small mammals along an elevational diversity gradient ranging from the Pannonian Plain to the base of the Carpathian summits. The fleas were divided into four groups, which were derived from changes in abundance and occurrence determined from cluster analysis. They are (1) flea species whose range seems unrelated to any change in elevation; (2) species that avoid high altitudes; (3) a group that can be subdivided into two types: (i) host-specific fleas and (ii) mountains species and (4) species opting for high altitudes on the gradient or preferring lower to middle elevations below 1000 m. Our study showed a unimodal pattern of flea diversity along the elevational gradient. It indicated that seasonality significantly conditions changes in biodiversity and patterns of spatial change along the elevational gradient, with specific flea species influenced by their host, while the impact of environmental conditions is more pronounced in opportunistic flea species.

Leishmania infantum immunoelectrophoretic antigen 24 (AG 24), a visceral leishmaniasis associated immunodominant antigen, has been characterized with a monospecific antiserum by combining SDS–PAGE, immunoblotting, metabolic labelling, radio-immunoprecipitation and in vitro poly A+ mRNA translation. AG 24 appeared to correspond to a multi-antigen family of 6–9 members ranging from 20 to 31 kDa and proteinic by nature with no post-translational modifications. A similar banding pattern was recognized by infection sera. AG 24 was not found exposed on the cell surface.

The anterior adhesive mechanism was studied for Merizocotyle icopae (Monogenea: Monocotylidae). Adult anterior apertures can open and close. In addition, duct endings terminating within the apertures are everted or retracted depending on the stage of attachment. Adhesive in adults is synthesized from all 3 secretory types (rod-shaped, small and large spheroidal bodies) found within anterior apertures. All exit together and undergo mixing to produce the adhesive matrix, a process that depletes duct contents. A greater number of ducts carrying rod-shaped bodies is depleted than ducts containing spheroidal bodies which changes the ratio of secretory types present on detachment. Detachment involves elongation of duct endings and secretion of additional matrix as the worm pulls away from the substrate. The change in secretory type ratio putatively modifies the properties of the secreted matrix enabling detachment. Only after detachment do ducts refill. During attachment, individual secretory bodies undergo morphological changes. The larval and adult adhesive matrix differs. Anterior adhesive in oncomiracidia does not show fibres with banding whereas banded fibres comprise a large part of adult adhesive. The data suggest that this is the result of adult spheroidal secretions modifying the way in which the adult adhesive matrix forms.

Fragmented habitats generally harbour small populations that are potentially more prone to local extinctions caused by biotic factors such as parasites. We evaluated the effects of botflies (Cuterebra apicalis) on naturally fragmented populations of the gracile mouse opossum (Gracilinanus agilis). We examined how sex, food supplementation experiment, season and daily climatic variables affected body condition and haemoglobin concentration in animals that were parasitized or not by botflies. Although parasitism did not affect body condition, haemoglobin concentrations were lower in parasitized animals. Among the non-parasitized individuals, haemoglobin concentration increased with the increase of maximum temperature and the decrease of relative humidity, a climatic pattern found at the peak of the dry season. However, among parasitized animals, the opposite relationship between haemoglobin concentration and relative humidity occurred, as a consequence of parasite-induced anaemia interacting with dehydration as an additional stressor. We conclude that it is critical to assess how climate affects animal health (through blood parameters) to understand the population consequences of parasitism on the survival of individuals and hence of small population viability.

Many protease genes have previously been shown to be involved in parasitism and in the development of Steinernema carpocapsae, including a gene predicted to encode an aspartic protease, Sc-ASP110, which was cloned and was analysed in this study. A cDNA encoding Sc-ASP110 was cloned based on an expressed sequence tag (EST) fragment from our EST library. The full-length cDNA of Sc-ASP110 consists of 1112 nucleotides with a catalytic aspartic domain (aa18–337). The putative 341 amino acid residues have a calculated molecular mass of 37·1 kDa and a theoretical pI of 4·7. BLASTp analysis of the Sc-ASP110 amino acid sequence showed 45–77% amino acid sequence identity to parasitic and non-parasitic nematode aspartic proteases. An expression analysis showed that the sc-asp110 gene was upregulated during the late parasitic stage, L4, and 24 h after induction of in vitro nematodes. A sequence comparison revealed that Sc-ASP110 was a member of an aspartic protease family; additionally, a phylogenetic analysis indicated that Sc-ASP110 was clustered with the closely related nematode Steinernema feltiae. In situ hybridization showed that sc-asp110 was expressed in the body walls of dorsal cells. The upregulated Sc-ASP110 expression revealed that this protease could play a role in the late parasitic process. In this study, we have cloned and analysed the gene transcript of Sc-ASP110 in S. carpocapsae.

The effects of a liposomal preparation of lipophilic immunomodulator β-D-GlcNstearoyl-(1-4)-norMurNAc-L-Abu-D-isoGln (N-L18-norAbu-GMDP) were investigated on resistance to Cryptosporidium parvum infection in neonatal kids. The liposomal preparation was administered subcutaneously or intranasally/orally (i.n./p.o.) twice at doses of 100 μg, 200 μg, or 1000 μg per kid pre-infection challenge. The treatment schemes were (i) 72 and 24 h pre-infection challenge, (ii) 24 h pre-infection challenge and 24 h post-infection challenge (oral inoculation with 1×107 oocysts of C. parvum in 5 ml of PBS). Administration of liposomal N-L18-norAbu-GMDP by i.n./p.o. route at the cumulative dose of 2000 μg per kid 72 and 24 h pre-infection challenge, lead to substantially increased clearance of coccidian parasites from various parts of the intestine. On the basis of histological examination, the distribution of cryptosporidia in the intestine and the severity of the infection, treated kids were classified on day 5 as having a strong reduction in infection in comparison to the control group (P<0·05). No cryptosporidia were found on the mucosal surface of treated kids by day 10, while the intestines of the control kids were still infected. All doses and routes of administration were judged effective with respect to suppression of cryptosporidia infections.

Many different drug-resistant lines of rodent malaria are available as screening models. It is obligatory to screen new compounds for antimalarial activity against a series of resistant lines in order to identify a compound with potential for the treatment of multi-drug resistant (MDR) malaria infections. Instead of using a battery of resistant lines, a single MDR Plasmodium yoelii nigeriensis strain that shows a wide spectrum of drug resistance to high doses of chloroquine, mepacrine, amodiaquine, mefloquine, quinine, quinidine, halofantrine as well as tetracyclines, fluoroquinolines and erythromycin, was used to assess the blood schizontocidal efficacy of a new macrolide azithromycin and other antibiotics. The present study shows that only azithromycin has the potential to control an MDR P. y. nigeriensis infection in Swiss mice, provided the treatment with a dose of 50–100 mg/kg/day by oral route is continued for a period of 7 days. Tetracycline, oxytetracycline, doxycyline, erythromycin, ciprofloxacin and norfloxacin, although active in vitro, failed to protect the mice. Tetracycline, ciprofloxacin and norfloxacin combinations with chloroquine did not control the infection. Additionally, the antimalarial efficacy of azithromycin can be potentiated with the addition of arteether, which is an ethyl ether derivative of artemisinin. A total (100%) curative effect has been obtained with a shorter regimen of 4 days only.

For parasites in natural systems, the most common pattern of spatial distribution is aggregation among hosts. The main causes of such aggregation are variable exposure of hosts to parasites and heterogeneity in host susceptibility. The objective of this study was to determine if there are differences in the aggregation pattern of two species of ectoparasitic flies between the Pantanal and Cerrado regions of Brazil on the bat Artibeus planirostris. We collected the ectoparasites from bats captured between 2002 and 2017 with mist nets in 21 sites in the Pantanal and 15 sites in the surrounding plateaus. The results showed that the aggregation of ectoparasitic flies in Pantanal was more pronounced than in Cerrado. The discrepancy aggregation index (D) of the bat fly Megistopoda aranea was 0.877 in Pantanal and 0.724 in Cerrado. The D values of Aspidoptera phyllostomatis was even higher, with 0.916 and 0.848 in the Pantanal and Cerrado, respectively. Differences in the shelters used may be the main factor shaping variation in aggregation, since the Pantanal does not have rock formations, with only foliage, crowns and hollow tree trunks. These differences likely affect host exposure to the parasites, leading to an increase in parasite aggregation.

A trispanning orphan receptor (TOR) has been described in Schistosoma haematobium and S. mansoni. Here we report the complete molecular organization of the S. mansoni TOR gene, also known as SmCRIT (complement C2 receptor inhibitor trispanning). The SmTOR gene consists of 4 exons and 3 introns as shown by cloning the single exons from S. mansoni genomic DNA and the corresponding cDNA from the larval stage (cercaria) and the adult worm. The SmTOR ORF consists of 1260 bp and is longer than previously reported, with a fourth trans-membrane domain (proposed new name: Tetraspanning Orphan Receptor) and with, however, an unchanged C2-binding domain on the extracellular domain 1 (ed1). This domain differs in S. japonicum. A protein at the approximate expected molecular weight (55 kDa) was detected in adult worm extracts with polyclonal and monoclonal antibodies, and was found to be expressed on the tegumental surface of cercariae.

The larvae and puparia of Limnophora exurda are to be found in tufts of wet moss or liverworts in or near small waterfalls.

The larvae are carnivorous and exhibit the characteristic morphological characters of carnivorous anthomyid larvae.

1. The parasitization of the slugs Milax sowerbii and Agriolimax reticulatus by a brachylaemid trematode in an area in Durham, during the period 1949–53, is described. Evidence is given that M. sowerbii is a natural intermediate host of the parasite.

2. Seasonal fluctuations in the incidence of infestation are described, including the fluctuations in the incidence of the four developmental stages of the metacercariae. Primary (spring) and secondary (autumnal) infestations of the molluscs are described.

3. The implications of an unexplained decline in parasite density during 1953 are noted.

4. A life history for the parasite, involving a small mammal as the vertebrate host, is postulated.

Cattle were inoculated with dilutions of Theileria parva (Muguga) stabilate without concurrent antibiotic treatment. The dilutions were selected to induce severe East Coast fever infections, which in some cases would lead to death. Serum samples were collected and the complement fixation (CF), indirect haemagglutination (IHA) and indirect immunofluorescence (IFA) tests were used to detect T. parva serum antibodies. Sera were fractionated on Sephadex G200 to determine the activities of specific immunoglobulin fractions. Sequential production of IgM antibody followed by 7SIg antibody was demonstrated by the IHA and CF tests. All IFA activity was restricted to the 7SIg fraction. Serologic reactions in the IHA test were detected as early as 4 days after inoculation of the stabilate, CF activity after 8 days and IFA activity after 21 days.

1. Cysts of Trichomonas batrachorum have never been found in repeated examinations of faeces nor of cultures made from them from Bufo vulgaris and Rana temporaria.

2. In dilutions of cultures in rain water with large surfaces exposed to the air Trichomonas batrachorum dies in forty-eight hours; but in long columns of water and absence of oxygen they live, in some cases, for months.

3. T. batrachorum will not live at 37° C., and T. hominis, though it lives at room temperature, will not multiply.

4. Tadpoles of Rana temporaria and Bufo vulgaris and larvae of Salamandra maculosa have been reared free from Protozoa.

5. Tadpoles of all three species of Amphibia have been infected with Trichomonas by feeding them on cultures free from cysts.

6. Tadpoles of Rana temporaria can be infected with Trichomonas batrachorum isolated from Bufo vulgaris, and tadpoles of B. vulgaris with Trichomonas from Rana temporaria. It is concluded therefore that Trichomonas batrachorum in frogs and toads is one true species.

7. Trichomonas sp. isolated from Lacerta viridis will not infect tadpoles of Bufo vulgaris and Rana temporaria.

8. Cultures of Trichomonas batrachorum from Bufo vulgaris will infect larvae of Salamandra maculosa though this species of Trichomonas has not been described from this amphibian.

1. Different extracts of adult worms of S. mansoni and F. hepatica have been examined in the C.F.T. for bilharziasis. Extracts of S. mansoni worms in Coca's solution, alcohol-ether and absolute alcohol after acetone extraction possess high antigenic activity, the first being the most specific but less sensitive than the others. Extracts in Coca's solution of alcohol-ether insoluble residues still showed slight activity while acetone and polysaccharide (formamide) extracts showed none.

2. Using the Coca's extract of S. mansoni worms, the C.F.T. was positive in 83% of sera of untreated patients and 58% of treated. The figures using the alcohol-ether extract were 13 and 4% respectively and, for the alcoholic extract of acetone insoluble residue, 42 and 13%.

3. Extracts of F. hepatica worms showed the same general trend, but even in the two extracts to show activity (alcohol-ether and alcohol extract of acetone insoluble material) the titre was too low for use in the test.

4. Of rabbits immunized with three different fractions of S. mansoni worms only that given the Coca extract showed complement-fixing antibodies and then only with the homologous antigen. Skin tests on the rabbits were negative to each of the antigens used.

5. The nature of the antigen in the C.F.T. is discussed, and it is suggested that the active portion is lipo-protein in nature or more than one substance is involved. For use in clinical diagnosis, an extract of S. mansoni worms in Coca's solution is recommended.

Our grateful thanks are due to Mr O. D. Standen of the Wellcome Laboratories of Tropical Medicine, London, for his generous gift of worm powder, and to Professor G. Witenberg of the Hebrew University for his interest in our work.

In February 1928 I obtained from a ♂ Scyllium canicula, taken at Plymouth, a ♀ Lernaeopoda scyllicola bearing a younger and better preserved male than any I had hitherto observed. It is the first time in this genus that a male has been found anywhere other than on the female's shoulder, namely on one of the abdominal appendages, and the male was probably alive at the moment of fixation. The heads of the sexes point in opposite directions so that in Fig. 1 the abdominal appendage is “upside down,” and the genital process of the male is near a vulva of the female which is however fertilised since it bears egg-strings. I am now fortunate in having the kind services of Miss E. C. Humphreys to illustrate this male which is not shrunk into its carapace and desire that Figs 1. and 2 shall supersede my figures of 1918. The near second maxilla has been omitted to show the method of attachment of the male.

1. Oxynema crassispiculum (Sonsino, 1889) has been redescribed and shown to possess two spicules.

2. The genus Numidica Barreto, 1919 has been shown to be synonymous with the genus Oxynema von Linstow, 1899.

3. The genus Oxynema has been redefined and a synonymic list is given of the species that it now contains.

4. Oxynema typicum Kreis, 1940 is considered to be a species incertae sedis.

5. Baylisnumidica petrodromi (Baylis, 1934) has been redescribed and shown to belong to the genus Parasubulura Berghe & Vuylsteke, 1938.

6. The family Parasubuluridae is reduced to subfamily rank, and placed in the family Subuluridae.

1. In a mixed infection in which Haemonchus contortus, Ostertagia circumcincta and O. trifurcata predominated, the lengths were plotted against widths of eggs obtained from faeces.

2. Two-dimensional groups approximating to normal frequency distributions, showing little overlap, were observed.

3. The statistical ranges of means plus and minus twice the standard deviation for the two groups barely touched. These were, to the nearest micron, 68–84 by 41–51 for Haemonchus contortus and, for the Ostertagia group, 83–103 by 46–52.