Paraiotonchium autumnale (Nickle) (Tylenchida: Iotonchiidae) causes parasitic sterilization in female Musca autumnalis DeGeer (Diptera: Muscidae). In addition to sterilization, P. autumnale causes physiological and behavioural changes within its host. However, there have been no records of reduced host lifespan in this system. Studies were conducted in 2009 and 2010 with wild M. autumnalis collected as larvae from cow dung pats from Browns Valley, California, USA. Field-collected larvae were reared to adulthood and flies of the same eclosion dates were caged together, regardless of whether or not they were parasitized. Dead flies were collected daily, and parasitism status was confirmed by dissection. Due to the very different effects of P. autumnale-parasitism on male versus female face flies, flies were analysed separately by sex. Kaplan-Meier analysis revealed a non-significant difference in longevity between non-parasitized and parasitized flies for female and male flies in 2009. In 2010, however, significant differences (P < 0·05) were found between parasitized and non-parasitized female and male flies. In 2010, the median time to death for non-parasitized female flies was 20 days and 15 days for parasitized females. The 2010 median survival time for non-parasitized male flies was 33 days and 15 days for parasitized males. This is a parasite-mediated cost to the host that has not been recorded previously. Based on our results and results from another published study we suggest that the potential for sterilizing parasites to alter host longevity is condition dependent.

Phylogenetic and geographical overlaps in host distributions influence the compositional similarity of ectoparasite fauna in a host–parasite system. In these systems, hosts that are more closely related (phylogenetically) are expected to share more parasitic species than more distantly related hosts. Similarly, hosts sharing a larger geographical distribution overlap are expected to have similar ectoparasites. This study investigated the influence of phylogeny (divergence time) and geographical overlap of some neotropical sigmodontine rodent species on the similarities among their ectoparasite fauna (Mesostigmata and Siphonaptera), using a partial Mantel test. Divergence time was the only significant factor that influenced the similarity among the ectoparasites, when mites and fleas were analysed together. Host species that had diverged more recently displayed ectoparasite fauna that were similar. The similarities of the flea species showed similar results in both separate and joint analyses, but neither phylogenetic nor geographical overlap influenced the similarity in mite species. Fleas were shown to be more host-specific than were mesostigmate mites, probably because of the increased influence of host phylogeny.

Landscape epidemiology and landscape genetics combine advances in molecular techniques, spatial analyses and epidemiological models to generate a more real-world understanding of infectious disease dynamics and provide powerful new tools for the study of RNA viruses. Using dog rabies as a model we have identified how key questions regarding viral spread and persistence can be addressed using a combination of these techniques. In contrast to wildlife rabies, investigations into the landscape epidemiology of domestic dog rabies requires more detailed assessment of the role of humans in disease spread, including the incorporation of anthropogenic landscape features, human movements and socio-cultural factors into spatial models. In particular, identifying and quantifying the influence of anthropogenic features on pathogen spread and measuring the permeability of dispersal barriers are important considerations for planning control strategies, and may differ according to cultural, social and geographical variation across countries or continents. Challenges for dog rabies research include the development of metapopulation models and transmission networks using genetic information to uncover potential source/sink dynamics and identify the main routes of viral dissemination. Information generated from a landscape genetics approach will facilitate spatially strategic control programmes that accommodate for heterogeneities in the landscape and therefore utilise resources in the most cost-effective way. This can include the efficient placement of vaccine barriers, surveillance points and adaptive management for large-scale control programmes.

The antimalarial drug mefloquine has promising antischistosomal properties killing haematophagous adult schistosomes as well as schistosomula. The mode of action and involved drug targets of mefloquine in Schistosoma mansoni schistosomula are unknown. In order to identify mefloquine-binding proteins and thus potential drug targets, mefloquine affinity chromatography with S. mansoni schistosomula crude extracts was performed. We found one specific mefloquine-binding protein that was identified by mass spectrometry as the glycolytic enzyme enolase (Q27877). Enolase activity assays were performed on schistosomula crude extracts and on the recombinant enolase Q27877 expressed in Escherichia coli. In schistosomula crude extracts enolase activity was inhibited by mefloquine and by the enolase inhibitor sodium fluoride, while activity of the recombinant enolase was not affected. In contrast to enolase from crude extracts, recombinant Q27877 did not bind to mefloquine-agarose. Using isothermal microcalorimetry, we next investigated the metabolic inhibition of mefloquine and 3 known glycolytic inhibitors in Schistosoma spp., namely sodium fluoride, 3-bromopyruvate and menadione on schistosomula in the presence or absence of glucose. We found that in the presence of glucose, schistosomula were less affected by mefloquine, sodium fluoride and 3-bromopyruvate, whereas glucose had no protective effect when schistosomula had been exposed to menadione. These results suggest a potential role of mefloquine as an inhibitor of glycolysis, at least in stages where other targets like haem degradation are not relevant.

The objective of the present study was to evaluate the anticoccidial effect of different concentrations of the herbal complex of 4 plants (leaves of Azadirachta indica and Nicotiana tabacum, flowers of Calotropis procera and seeds of Trachyspermum ammi) in broiler chickens in comparison with amprolium anticoccidial. Three concentrations (2 g, 4 g and 6 g) of herbal complex were given to the experimental groups once a day and amprolium (at the dose rate of 125 ppm) was given orally in drinking water from the 14th to the 21st days of age. One group was kept as infected, non-medicated control and one as non-infected, non-medicated control. All groups were inoculated orally with 75 000 sporulated oocysts on the 14th day of age except the non-infected, non-medicated control. Among herbal complex medicated groups, the maximum anticoccidial effect was seen in the group medicated with 6 g herbal complex followed by 4 g and 2 g herbal complex medicated groups. Treatment with 6 g of the herbal complex significantly reduced the negative performance and pathogenic effects associated with Eimeria tenella challenge at a level that was comparable with amprolium when using a largely susceptible recent field isolate. In summary, concentration-dependent anticoccidial activity of the studied herbal complex suggests its use as an alternative anticoccidial agent to chemotherapeutic drugs for Eimeria tenella control.

Haemonchus contortus is one of the most pathogenic parasites of small ruminants (e.g. sheep and goat). The treatment of haemonchosis is complicated because of recurrent resistance of H. contortus to common anthelmintics. The aim of this study was to compare the metabolism of the anthelmintic drug flubendazole (FLU) and the activities of selected biotransformation enzymes towards model xenobiotics in 4 different strains of H. contortus: the ISE strain (susceptible to common anthelmintics), ISE-S (resistant to ivermectin), the BR strain (resistant to benzimidazole anthelmintics) and the WR strain (resistant to all common anthelmintics). H. contortus adults were collected from the abomasums from experimentally infected lambs. The in vitro as well as ex vivo experiments were performed and analysed using HPLC with spectrofluorimetric and mass-spectrometric detection. In all H. contortus strains, 4 different FLU metabolites were detected: FLU with a reduced carbonyl group (FLU-R), glucose conjugate of FLU-R and 2 glucose conjugates of FLU. In the resistant strains, the ex vivo formation of all FLU metabolites was significantly higher than in the susceptible ISE strain. The multi-resistant WR strain formed approximately 5 times more conjugates of FLU than the susceptible ISE strain. The in vitro data also showed significant differences in FLU metabolism, in the activities of UDP-glucosyltransferase and several carbonyl-reducing enzymes between the susceptible and resistant H. contortus strains. The altered activities of certain detoxifying enzymes might protect the parasites against the toxic effect of the drugs as well as contribute to drug-resistance in these parasites.

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.

Since 2004 there has been a remarkable increment in our knowledge of the proteins and glycans that reside at, or are released from the surfaces of schistosomes in the mammalian host. Initial characterization of the soluble proteome permits distinctions to be made between the parasite secretome and its necrotome. The principal proteins secreted by the cercaria to gain access to the skin have been described as well as those released by migrating schistosomula. An inventory of transporters, enzymes and structural proteins has been shown to reside the tegument surface, but also immunoglobulins, complement factors and host CD44. The secreted membranocalyx that overlies the plasma membrane may contain a small number of proteins, not simply acting as physical barrier, but its lipid composition remains elusive. Analysis of worm vomitus has provided insights into blood feeding, increasing the number of known lysosomal hydrolases, and identifying a series of carrier proteins potentially involved in uptake of lipids and inorganic ions by the gut epithelium. The egg secretions that aid escape from the tissues include a mixture of MEG-2 and MEG-3 family variant proteins. The utility of identified proteins for the development of new diagnostics, and their potential as vaccines candidates is evaluated.

Draft genome sequences for Schistosoma japonicum and S. mansoni are now available. The schistosome genome encodes ∼13 000 protein-encoding genes for which the functions of few are well understood. Nonetheless, the new genes represent potential intervention targets, and molecular tools are being developed to determine their importance. Over the past 15 years, noteworthy progress has been achieved towards development of tools for gene manipulation and transgenesis of schistosomes. A brief history of genetic manipulation is presented, along with a review of the field with emphasis on reports of integration of transgenes into schistosome chromosomes.

Temperature can be a limiting factor on parasite development. Riccardoella limacum, a haematophagous mite, lives in the mantle cavity of helicid land snails. The prevalence of infection by R. limacum in populations of the land snail Arianta arbustorum is highly variable (0–78%) in Switzerland. However, parasitic mites do not occur in host populations at altitudes of 1290 m or higher. It has been hypothesized that the host's hibernation period might be too long at high elevations for mites and their eggs to survive. To test this hypothesis, we experimentally infected snails and allowed them to hibernate at 4°C for periods of 4–7 months. Winter survival of host snails was negatively affected by R. limacum. The intensity of mite infection decreased with increasing hibernation duration. Another experiment with shorter recording intervals revealed that mites do not leave the host when it buries in the soil at the beginning of hibernation. The number of mites decreased after 24 days of hibernation, whereas the number of eggs attached to the lung tissue remained constant throughout hibernation. Thus, R. limacum survives the winter in the egg stage in the host. Low temperature at high altitudes may limit the occurrence of R. limacum.

We tested the hypothesis that compositional and/or phylogenetic dissimilarity of host assemblages affect compositional and/or phylogenetic dissimilarity of parasite assemblages, to different extents depending on scale, using regional surveys of fleas parasitic on small mammals from 4 biogeographical realms. Using phylogenetic community dissimilarity metric, we calculated the compositional and phylogenetic dissimilarity components between all pairs of host and parasite communities within realms and hemispheres. We then quantified the effect of compositional or phylogenetic dissimilarity in host regional assemblages, and geographical distance between assemblages, on the compositional or phylogenetic dissimilarity of flea regional assemblages within a realm, respectively. The compositional dissimilarity in host assemblages strongly affected compositional dissimilarity in flea assemblages within all realms and within both hemispheres. However, the effect of phylogenetic dissimilarity of host assemblages on that of flea assemblages was mostly confined to the Neotropics and Nearctic, but was detected in both the Old and New World at the higher scale, possibly because of phylogenetic heterogeneity in flea and host faunas between realms. The clearer effect of the compositional rather than the phylogenetic component of host community dissimilarity on flea community dissimilarity suggests important roles for host switching and ecological fitting during the assembly history of flea communities.

Parasite ecologists are often interested in the repeatability of patterns in parasite communities in space and/or time, because of implications for the dynamics of host-parasite interactions. Field studies usually examine temporal and spatial variation in isolation or limit themselves to a small number of host populations. Here, we studied the macroparasite communities of 12 populations of three-spined stickleback, Gasterosteus aculeatus L., on North Uist, Scotland, separated by small geographical distances, during the breeding season in 2 consecutive years (2007 and 2008) to determine: (1) the extent of spatial variation in macroparasite communities, (2) whether this variation is consistent across years, and (3) whether habitat characteristics can explain differences in macroparasite community composition among populations. We found substantial variation in parasite communities among populations. Generally, measures of parasite community composition were higher in 2008 than in 2007, but this effect of year was consistent across populations, such that the relative differences in these measures among populations changed little between years. These data suggest that there is short-term stability in the spatial variation in macroparasite communities of North Uist sticklebacks. However, none of the 5 habitat characteristics measured explained spatial variation in any measure of parasite community composition.

Although clam populations in France are known to be infected with protozoans of the genus Perkinsus, no molecular characterization was previously performed on these parasites. Considering that several members of this genus have been associated with mortalities of molluscs worldwide, a study was undertaken in order to characterize these parasites in France. For that purpose, clams, Ruditapes philippinarum and R. decussatus, collected from different production areas and found to be infected with Perkinsus sp. in thioglycolate culture medium, were selected for PCR-RFLP tests and sequencing. Perkinsus olseni was detected in all the investigated areas and results also suggested the presence of P. chesapeaki in Leucate, a lagoon on the Mediterranean coast and in Bonne Anse in Charente Maritime, on the Atlantic coast. Clonal cultures from both detected species were produced in order to describe and compare in vitro stages. Differences in size between both Perkinsus spp. were noticed especially for schizonts and zoosporangia. Lastly, in situ hybridization tests allowed confirmation of the presence of both species in the same R. decussatus population and even in same clams. This is the first detection of P. chesapeaki in Ruditapes species and outside North America, which questions its introduction into Europe.

The first UK epizootic of highly pathogenic (HP) H5N1 influenza in wild birds occurred in 2008, in a population of mute swans that had been the subject of ornithological study for decades. Here we use an innovative combination of ornithological, phylogenetic and immunological approaches to investigate the ecology and age structure of HP H5N1 in nature. We screened samples from swans and waterbirds using PCR and sequenced HP H5N1-positive samples. The outbreak's origin was investigated by linking bird count data with a molecular clock analysis of sampled virus sequences. We used ringing records to reconstruct the age-structure of outbreak mortality, and we estimated the age distribution of prior exposure to avian influenza. Outbreak mortality was low and all HP H5N1-positive mute swans in the affected population were <3 years old. Only the youngest age classes contained an appreciable number of individuals with no detectable antibody responses to viral nucleoprotein. Phylogenetic analysis indicated that the outbreak strain circulated locally for ∼1 month before detection and arrived when the immigration rate of migrant waterbirds was highest. Our data are consistent with the hypothesis that HP H5N1 epizootics in wild swans exhibit limited mortality due to immune protection arising from previous exposure. Our study population may represent a valuable resource for investigating the natural ecology and epidemiology of avian influenza.

Parasitic nematodes are significant pathogens of humans and other animals. The molecular and genetic basis of animal parasitism is not yet fully understood. Strongyloides spp. are a genus of gastrointestinal nematodes of which species infect approximately 100–200 million people worldwide. S. ratti is a natural parasite of the rat, and a useful and amenable laboratory model. Previous EST and microarray analyses of the S. ratti life cycle have identified genes whose expression was specific, or biased, to the parasitic adult stage, suggesting that they may play a key role in parasitism in this species. Here we have further investigated the expression of these genes (by RT-PCR) throughout the S. ratti life-cycle. We produced recombinant proteins in vitro for a subset of these genes, which were used in Western blot analyses to investigate the distribution of the gene products among different stages of the S. ratti life cycle. We tested the efficacy of these recombinant proteins as anti-S. ratti vaccines. One of the proteins was detected in the excretory/secretory products of the parasitic stages.

In parasitological research, significant progress has been made with respect to genomics and transcriptomics but transgenic systems for functional gene analyses are mainly restricted to the protozoan field. Gene insertion and knockout strategies can be applied to parasitic protozoa as well as gene silencing by RNA interference (RNAi). By contrast, research on parasitic helminthes still lags behind. Along with the major advances in genome and transcriptome analyses e.g. for schistosomes, methods for the functional characterization of genes of interest are still in their initial phase and have to be elaborated now, at the beginning of the post-genomic era. In this review we will summarize attempts made in the last decade regarding the establishment of protocols to transiently and stably transform or transfect schistosomes. Besides approaches using particle bombardment, electroporation or virus-based infection strateies to introduce DNA constructs into adult and larval schistosome stages to express reporter genes, first approaches have also been made in establishing protocols based on soaking, lipofection, and/or electroporation for RNA interference to silence gene activity. Although in these cases remarkable progress can be seen, the schistosome community eagerly awaits major breakthroughs especially with respect to stable transformation, but also for silencing or knock-down strategies for every schistosome gene of interest.

Between December 2007 and March 2009, small mammals were captured in 6 Atlantic Forest patches in Brazil. We assessed tick-host associations and whether they differ among forest strata, sites, seasons, and host age classes or between sexes. Moreover, we assessed the exposure of animals to Rickettsia spp. In total, 432 animals were captured and 808 ticks were found on 32·9% of them. Significant differences were found among host species, collection sites, and forest strata; microhabitat preference was a strong risk factor for tick infestation. The highest tick density rates were recorded in forest fragments settled in rural areas; 91·3% of the ticks were collected from animals trapped in these forest fragments. A high prevalence (68·8%) of antibodies to Rickettsia spp. was detected among animals. This study suggests that disturbed Atlantic Forest fragments provide an environment for ticks and small mammals, which are highly exposed to rickettsiae. It also indicates that forest patches settled in rural areas are usually associated with higher small mammal diversity as well as with higher tick density rates.

A traditional assumption is that schistosome cercariae lose their tails at the onset of penetration. It has, however, recently been demonstrated that, for Schistosoma mansoni, cercarial tails were not invariably being shed as penetration took place and a high proportion of tails entered human skin under experimental conditions. This phenomenon was termed delayed tail loss (DTL). In this paper, we report that DTL also happens with S. japonicum cercariae during penetration of mouse skin. It occurred at all cercarial densities tested, from as few as 10 cercariae/2·25 cm2 of mouse skin up to 200 cercariae. Furthermore, it was demonstrated that there was a density-dependent increase in DTL as cercarial densities increased. No such density-dependent enhancement was shown for percentage attachment over the same cercarial density range.

Cell death mechanisms in Trypanosoma cruzi have not been disclosed in detail though different conventional techniques have been used in the classification of parasite-cell death type. Nuclear magnetic resonance (NMR) has successfully been used as a tool to evaluate the onset of apoptosis in a number of higher eukaryote-cell models analysing the ratio of CH2/CH3 integration from the visible mobile lipids (VML). Surprisingly, this versatile non-invasive spectroscopy technique has never been employed with this purpose in T. cruzi. In the present study it is shown that under different parasite death-conditions the ratio CH2/CH3 varied drastically. Thus, T. cruzi epimastigotes in apoptotic conditions increase significantly this ratio while in necrotic as well as in autophagic situations the parasites maintain the VML, CH2/CH3 ratio, in normal values. Additionally, other VML markers commonly used in these studies, such as the change in the region of methyl-choline moiety, -N+(CH3)3, exhibited different particular patterns according to the type of cell death. Our results suggest that the 1H NMR-VML technique is an adequate tool to discriminate different T. cruzi death pathways.

Species introduced into new areas often show a reduction in parasite and genetic diversity associated to the limited number of founding individuals. In this study, we compared microsatellite and parasite diversity in both native (lower Danube) and introduced populations of 4 Ponto-Caspian gobies, including those (1) introduced from within the same river system (middle Danube; Neogobius kessleri and N. melanostomus), and (2) introduced from a different river system (River Vistula; N. fluviatilis and N. gymnotrachelus). Microsatellite data confirmed the lower Danube as a source population for gobies introduced into the middle Danube. Both native and introduced (same river system) populations of N. kessleri and N. melanostomus had comparable parasite species richness and microsatellite diversity, possibly due to multiple and/or continual migration/introduction of new individuals and the acquisition of local parasites. Reduced parasite species richness and microsatellite diversity were observed in introduced (different river system) populations in the Vistula. A low number of colonists found for N. fluviatilis and N. gymnotrachelus in the Vistula potentially resulted in reduced introduction of parasite species. Insufficient adaptation of the introduced host to local parasite fauna, together with introduction into an historically different drainage system, may also have contributed to the reduced parasite fauna.