Objective. We used data on fleas and gamasid mites parasitic on 8 species of small mammals to test whether (a) species composition of ectoparasite infracommunities may be used to predict host habitat occupancy and (b) the accuracy of this prediction differs between ectoparasite taxa, host genders and seasons. Methods. We used a Random Forests algorithm that is based on the methodology of classification trees. Results. The accuracy of prediction of habitat occupancy was relatively low and varied substantially among host species. The combined rate of the correct prediction of host habitat occupancy from data on ectoparasites was significantly higher than 50%, albeit being relatively low. The accuracy of prediction (a) did not differ between male and female hosts when it was based on species composition of fleas in summer or of mites in summer and winter, (b) was significantly higher in male hosts than in female hosts when the winter data on fleas were used and (c) was significantly higher for flea than mite assemblages. The effect of season was found in mites but not in fleas with the accuracy of prediction being significantly higher in summer than in winter assemblages. Conclusions. Ectoparasites appeared to be not especially useful as biological markers for distinguishing host populations in different habitats in temperate zones.

The shaping of a child's immune system starts in utero, with possible long-term consequences in later life. This review highlights the studies conducted on the development of the immune system in early childhood up to school-age, discussing the impact that environmental factors may have. Emphasis has been put on studies conducted in geographical regions where exposure to micro-organisms and parasites are particularly high, and the effect that maternal exposures to these may have on an infant's immune responses to third-party antigens. In this respect we discuss the effect on responses to vaccines, co-infections and on the development of allergic disorders. In addition, studies of the impact that such environmental factors may have on slightly older (school) children are highlighted emphasizing the need for large studies in low to middle income countries, that are sufficiently powered and have longitudinal follow-up components to understand the immunological footprint of a child and the consequences throughout life.

Immunohistochemistry and immunogold labelling techniques were used to localize the EG95 vaccine antigen in Echinococcus granulosus oncospheres. In non-activated oncospheres, the cytoplasm of 2 pairs of bilateral cells exhibited specific positive labelling for the presence of EG95. No surface localization was seen in non-activated or recently activated oncospheres. Besides the staining of 2 pairs of bilateral cells, there was also a generalized distribution of specific staining for EG95 throughout the parenchyma of activated oncospheres. Immunogold labelling of non-activated oncosphere revealed specific reactivity for EG95 involving 2 pairs of bilateral cells and the ultrastructural characteristics of these cells were consistent with them being penetration gland cells. No other oncospheral structures stained specifically for the presence of EG95. The absence of surface location of EG95 in oncospheres suggests that the parasite may not be susceptible to vaccine-induced antibody and complement mediated attack until some post-oncospheral development has occurred. Further studies would be required to determine when the EG95 antigen associates with the parasite's surface, thus making them susceptible to immune attack.

We recovered larval trombiculid mites (i.e. chiggers), vectors of scrub typhus, from small mammal hosts in Taiwan, and compared the relative degree of engorgement (RDE) of the dominant chigger (Leptotrombidium imphalum) from different hosts. Naturally occurring chiggers recovered from Rattus losea and Bandicota indica were 1·4x and 1·3x as engorged as those from Apodemus agrarius. Within each host species, RDE was negatively related to chigger loads, but was mostly unrelated to gender or to body or reproductive condition of hosts. We documented significant variation in chigger engorgement both within and among host species; to the extent that RDE is a proxy for fitness, this contradicts predictions of the Ideal Free Distribution (IFD) that the per capita fitness of vectors should be similar among hosts. Failure to meet predictions of the IFD may reflect the limited mobility of chiggers, which consequently must be less selective in the hosts on which they feed. Further disease control efforts should consider vector feeding success in addition to vector abundance and may be able to capitalize on the unsuitability of certain hosts in supporting disease vectors.

Whole blood collected from koalas admitted to the Australian Zoo Wildlife Hospital (AZWH), Beerwah, QLd, Australia, during late 2006–2009 was tested using trypanosome species-specific 18S rDNA PCRs designed to amplify DNA from Trypanosoma irwini, T. gilletti and T. copemani. Clinical records for each koala sampled were reviewed and age, sex, blood packed cell volume (PCV), body condition, signs of illness, blood loss, trauma, chlamydiosis, bone marrow disease, koala AIDS and hospital admission outcome (‘survival’ / ‘non-survival’) were correlated with PCR results. Overall 73·8% (439/595) of the koalas were infected with at least 1 species of trypanosome. Trypanosoma irwini was detected in 423/595 (71·1%), T. gilletti in 128/595 (21·5%) and T. copemani in 26/595 (4·4%) of koalas. Mixed infections were detected in 125/595 (21%) with co-infections of T. irwini and T. gilletti (101/595, 17%) being most common. There was a statistical association between infection with T. gilletti with lower PCV values and body condition scores in koalas with signs of chlamydiosis, bone marrow disease or koala AIDS. No association between T. gilletti infection and any indicator of health was observed in koalas without signs of concurrent disease. This raises the possibility that T. gilletti may be potentiating other disease syndromes affecting koalas.

Mathematical models predict that the future of epidemics of drug-resistant pathogens depends in part on the competitive fitness of drug-resistant strains. Considering metacyclogenesis (differentiation process essential for infectivity) as a major contributor to the fitness of Leishmania donovani, we tested its relationship with pentavalent antimony (SbV) resistance in clinical lines. Different methods for the assessment of metacyclogenesis were cross-validated: gene expression profiling (META1 and SHERP), morphometry (microscopy and FACS), in vitro infectivity to macrophages and resistance to complement lysis. This was done on a model constituted by 2 pairs of reference strains cloned from a SbV-resistant and -sensitive isolate. We selected the most adequate parameter and extended the analysis of metacyclogenesis diversity to a sample of 20 clinical lines with different in vitro susceptibility to the drug. The capacity of metacyclogenesis, as measured by the complement lysis test, was shown to be significantly higher in SbV-resistant clinical lines of L. donovani than in SbV-sensitive lines. Together with other lines of evidence, it is concluded that L. donovani constitutes a unique example and model of drug-resistant pathogens with traits of increased fitness. These findings raise a fundamental question about the potential risks of selecting more virulent pathogens through massive chemotherapeutic interventions.

The number of facilities in which customers make contact with cats before eating and drinking, called ‘cat cafés’, has recently increased in Tokyo, Japan. In a survey to clarify the possibility of zoonotic transmission in Giardia duodenalis, the infection rates of G. duodenalis in 321 stool samples of cats from 16 cat cafés, 31 pet shops, and the Animal Care and Consultation Center of Tokyo were 19·1% (22/115), 1·2% (1/85), and 2·5% (3/121), respectively. In the molecular analysis of 26 G. duodenalis isolates, 6 samples from 2 cat cafés belonged to the zoonotic genotype assemblage A I, and 20 other samples were of assemblage F. Moreover, phylogenetic analysis of glutamate dehydrogenase (GDH) and triosephosphate isomerase (TPI) genes of the 20 assemblage F isolates revealed 2 major lineages. The 6 assemblage A isolates belonged to the same cluster with regard to the GDH gene; however, 2 of the 6 isolates belonged to a different cluster from the other 4 isolates with regard to the TPI gene. Therefore, a risk of transmission from cats to humans is suggested because of the detection of zoonotic Giardia genotypes in cat cafés.

It is suspected that host-parasite interactions are influenced by climatic oscillations such as the North Atlantic Oscillation (NAO). However, the effects of climatic oscillations on host-parasite interactions have never been investigated. A long-term (1982–1999) dataset of the host snail Lymnaea stagnalis and trematode metacercariae infection has been collected for Lake Chany in Western Siberia. Using this dataset, we estimated the impact of the NAO on the population dynamics of hosts and parasites as well as their interactions. The results of general linear models showed that the abundance of dominant parasite species and the total parasite abundance significantly increased with NAO, with the exception of Moliniella anceps. Other climatic and biological factors were relatively weak to explain the abundance. There was no significant relationship between NAO and the population density of host snails. The prevalence of infection was related to the total abundance of parasites, but not to the NAO. Thus, the responses to the NAO differed between the host and parasites, indicating mismatching in host-parasite interactions. Therefore, climatic oscillations, such as the NAO, influence common parasitism.

Objective. Ornithonyssus sylviarum (northern fowl mite) and Menacanthus stramineus (chicken body louse) are key poultry pests currently controlled by exclusion or pesticide application. We studied how host beak condition affected their populations over time and how the lice and mites might interact on a host. Methods. Beak-trimmed or beak-intact white leghorn hens were infested initially with either mites or lice and subsequently challenged using the alternate ectoparasite species (reciprocal transfer), while other hens harboured only the initial ectoparasite species. Results. Beak-trimmed hens had far higher ectoparasite numbers relative to beak-intact hens, and the 2 ectoparasites showed evidence of grooming-mediated competitive asymmetry. On beak-trimmed hens, larger numbers of lice quickly nearly completely excluded mites in competition for enemy-free space (lower abdomen), while in the reciprocal transfer mites did not affect louse numbers on beak-trimmed hosts. The 2 ectoparasites co-existed on beak-intact hens, which were better able to defend the lower abdomen habitat by grooming. Conclusion. Lice are somewhat less damaging and much easier to control relative to mites, and might be used to eliminate mites in commercial, beak-trimmed flocks. Beak trimming impairs host grooming and contributes greatly to the high ectoparasite populations seen in commercial flocks. The study adds incentives for poultry breeders to develop more docile hen strains that can be held without beak trimming. This has advantages both to welfare advocates and producers who may no longer need to use insecticides for pest control or be concerned about worker exposure to pesticides.

Objective: Conventional wisdom suggests that parasites evolve increased host specialization over time. Host specificity, which describes the number of host species parasitized, is one aspect of host specialization. Recent studies of vertebrate parasites indicate that highly host-specific parasite lineages are not, in fact, evolutionary dead ends; host generalists can evolve from host specialists.

Methods: Using phylogenetic reconstruction methods, we evaluate these patterns in the body lice (Insecta: Phthiraptera) of pigeons and doves, which are permanent ectoparasites that complete their entire life cycle on the body of the host.

Results: We find that species of body lice that parasitize more than one species of host (generalists) are invariably derived from lice parasitizing only one species of host (specialists). A previous study of the wing lice of pigeons and doves also found that generalists were derived from specialists, and that these changes were correlated with the presence of a potentially competing species of wing louse on the same host. For body lice we did not find such a correlation with competition. Instead, the evolution of host generalists in body lice was correlated with host ecology. When we compared body lice that parasitize terrestrial versus arboreal hosts, we found that the evolution of host generalists was associated with terrestrial hosts. In contrast, wing lice showed no correlation between the evolution of generalists and host ecology.

Conclusion: The correlation in body lice suggests that dispersal between host species may occur via the ground. This, in turn, suggests that body lice may fall to the ground more often than wing lice. To test this hypothesis, we conducted an experiment to compare the rate at which body and wing lice are dislodged from the bodies of preening pigeons. Interestingly, our results showed that body lice are dislodged four times more often than wing lice. Therefore, species of terrestrial doves are far more likely to encounter body lice than wing lice on the ground.

The aim of this study was to evaluate the activity of delta-aminolevulinate dehydratase (δ-ALA-D) in red blood cells of rats infected with Trypanosoma evansi and establish its association with haematocrit, serum levels of iron and zinc and lipid peroxidation. Thirty-six male rats (Wistar) were divided into 2 groups with 18 animals each. Group A was non-infected while Group B was intraperitoneally infected, receiving 7·5×106 trypomastigotes per animal. Each group was divided into 3 subgroups of 6 rats and blood was collected during different periods post-infection (p.i.) as follows: day 5 (A1 and B1), day 15 (A2 and B2) and day 30 PI (A3 and B3). Blood samples were collected by cardiac puncture to estimate red blood cell parameters (RBC), δ-ALA-D activity and serum levels of iron, zinc and thiobarbituric acid reactive substances (TBARS). Rats in group B showed a significant (P<0·05) reduction of RBC count, haemoglobin concentration and haematocrit at days 5 and 15 p.i. The activity of δ-ALA-D in blood was significantly (P<0·001) increased at days 15 and 30 p.i. δ-ALA-D activity in blood had a significant (P<0·05) negative correlation with haematocrit (r=−0·61) and haemoglobin (r=−0·70) at day 15 p.i. There was a significant (P<0·05) decrease in serum iron and zinc levels and an increase in TBARS levels (P<0·05) during infection. The δ-ALA-D activity in blood was negatively correlated with the levels of iron (r=−0·68) and zinc (r=−0·57) on day 30 p.i. It was concluded that the increased activity of δ-ALA-D in blood might have occurred in response to the anaemia in remission as heme synthesis was enhanced.

An evaluation of the genetic diversity within Fasciola hepatica (liver fluke) may provide an insight into its potential to respond to environmental changes, such as anthelmintic use or climate change. In this study, we determined the mitochondrial DNA haplotypes of >400 flukes from 29 individual cattle, from 2 farms in the Netherlands, as an exemplar of fasciolosis in a European context. Analysis of this dataset has provided us with a measure of the genetic variation within infrapopulations (individual hosts) and the diversity between infrapopulations within a herd of cattle. Temporal sampling from one farm allowed for the measurement of the stability of genetic variation at a single location, whilst the comparison between the two farms provided information on the variation in relation to distance and previous anthelmintic regimes. We showed that the liver fluke population in this region is predominantly linked to 2 distinct clades. Individual infrapopulations contain a leptokurtic distribution of genetically diverse flukes. The haplotypes present on a farm have been shown to change significantly over a relatively short time-period.

Melarsomine hydrochloride can cure Trypanosoma evansi infection in camels at a dose of 0·25 mg/kg, but at that dose relapses occur in cattle. In our study, the efficacy of an intramuscular injection of melarsomine hydrochloride at 0·5 mg/kg was assessed in 3 normal and 3 splenectomized dairy cattle experimentally infected with a stock of T. evansi from Thailand. The animals were monitored for 5 months by haematocrit centrifugation, blood- or cerebrospinal fluid-mouse inoculation, polymerase chain reaction, the card agglutination test (CATT) for T. evansi, and the enzyme-linked immunosorbent assay‑T. evansi. Parasitological and DNA tests became and remained negative just after treatment. By the end of the experiment, CATT was negative and ELISA scores were below or very close to the cut-off value. One of the splenectomized cattle died from anaplasmosis during the experiment, but tested negative for surra. It was concluded that the parasites had been cleared from the cattle, and melarsomine hydrochloride at 0·5 mg/kg can be recommended for treatment against T. evansi infection in dairy cattle in Thailand. Further work is necessary to validate the efficacy of the treatment in the event of confirmed CSF-infection.

Cadmium and lead concentrations were compared in tissues of cutlassfish, Trichiurus lepturus L., its intestinal nematode Hysterothylacium sp. type MB larvae, and in water from the same location in the Sea of Oman. Metal accumulation in hosts, parasites and sea water was measured by ICP-OES. Hysterothylacium larvae from the intestinal lumen and visceral cavity showed much higher metal concentrations than in host tissues or sea water. Statistical analyses revealed no significant differences in metal accumulation between infected and uninfected hosts. Cadmium concentration in the host muscle was lower than in intestine, liver and gonad tissues. The mean concentrations of lead and cadmium in nematodes were 289·03 and 81·5 times higher than in host intestine, 188·4 and 225 times higher than in host muscle, 108·6 and 65·3 times higher than in host gonads, 70·5 and 19·5 times higher than in host liver and 3351 and 148 times higher than in sea water. The results show the value of this and possibly related nematodes as bioindicators of heavy metals and their potential use in environmental studies.

A study has been carried out to determine whether the action of triclabendazole (TCBZ) against the liver fluke, Fasciola hepatica is altered by inhibition of the cytochrome P450 (CYP 450)-mediated drug metabolism pathway. The Oberon TCBZ-resistant and Cullompton TCBZ-susceptible fluke isolates were used for these experiments, the basic design of which is given in the paper by Devine et al. (2010a). Piperonyl butoxide (PB) was the CYP P450 inhibitor used. Morphological changes resulting from drug treatment and following metabolic inhibition were assessed by means of transmission electron microscopy. After treatment with either TCBZ or TCBZ.SO on their own, there was greater disruption to the TCBZ-susceptible than TCBZ–resistant isolate. However, co-incubation with PB+TCBZ, but more particularly PB+TCBZ.SO, led to greater changes to the TCBZ-resistant isolate than with each drug on its own, with blebbing of the apical plasma membrane, severe swelling of the basal infolds and their associated mucopolysaccharide masses in the syncytium and flooding in the internal tissues. Golgi complexes were greatly reduced or absent in the tegumental cells and the synthesis and production of secretory bodies were badly disrupted. The mitochondria were swollen throughout the tegumental system and the somatic muscle blocks were disrupted. With the TCBZ-susceptible Cullompton isolate, there was a limited increase in drug action following co-incubation with PB. The results provide evidence that the condition of a TCBZ-resistant fluke can be altered by inhibition of drug metabolism. Moreover, they support the concept that altered drug metabolism contributes to the mechanism of resistance to TCBZ.

Experiments on hybridization between Fasciola hepatica and Fasciola gigantica were carried out to clarify whether a reproductive isolating mechanism appears between the two Fasciola species. Molecular evidence for hybridization was based on the DNA sequence of the internal transcribed spacer 1 (ITS1) region in nuclear ribosomal DNA, which differs between the species. The results suggested that there were not pre-mating but post-mating isolating mechanisms between the two species. However, viable adults of the hybrids F1 and F2 were produced from both parental F. hepatica and F. gigantica. The hybrids inherited phenotypic characteristics such as ratio of body length and width and infectivity to rats from parental Fasciola hepatica and F. gigantica. These findings suggest that reproductive isolation is incomplete between Fasciola hepatica and F. gigantica. Adults of the hybrids F1 and F2 were completely different in mode of reproduction from aspermic Fasciola forms that occur in Asia and seem to be offspring originated from hybridization between F. hepatica and F. gigantica and to reproduce parthenogenetically.

Five novel species, Auerbachia scomberoidi n. sp., Auerbachia chaetodoni n. sp., Auerbachia caranxi n. sp., Coccomyxa colurodontidis n. sp. and Coccomyxa gobiodoni n. sp. are described from the gall bladders of marine teleosts. These species descriptions provide the first record of Auerbachia from Australian waters. Each species is characterized morphologically, including additional measurements for Auerbachia spp. and small subunit ribosomal DNA (SSU rDNA) sequences were determined for molecular phylogenetic analyses. All 5 species were each recovered from a single (and different) species of host. Phylogenetic analyses revealed a close genetic relatedness between members of Auerbachia and Coccomyxa. Based on these phylogenetic data, on obvious paraphyly displayed by the Myxidiidae and on priority, we propose the re-establishment of the family Coccomyxidae to house all species of the genera, Coccomyxa, Auerbachia and Globospora.

Buffalo-adapted Theileria parva causes Corridor disease in cattle. Strict control measures therefore apply to the movement of buffalo in South Africa and include mandatory testing of buffalo for the presence of T. parva. The official test is a real-time hybridization PCR assay that amplifies the V4 hypervariable region of the 18S rRNA gene of T. parva, T. sp. (buffalo) and T. sp. (bougasvlei). The effect that mixed T. parva and T. sp. (buffalo)-like infections have on accurate T. parva diagnosis was investigated in this study. In vitro mixed infection simulations indicated PCR signal suppression at 100 to 1000-fold T. sp. (buffalo) excess at low T. parva parasitaemia. Suppression of PCR signal was found in field buffalo with mixed infections. The T. parva-positive status of these cases was confirmed by selective suppression of T. sp. (buffalo) amplification using a locked nucleic acid clamp and independent assays based on the p67, p104 and Tpr genes. The incidence of mixed infections in the Corridor disease endemic region of South Africa is significant, while the prevalence in buffalo outside the endemic area is currently low. A predicted increase of T. sp. (buffalo)-like infections can affect future diagnoses where mixed infections occur, prompting the need for improvements in current diagnostics.

NK cells represent one of the first lines of defence in the immune reaction after invasion of Leishmania parasites. Depletion of mouse natural killer (NK) cells dramatically enhances susceptibility of normally resistant mice. In this study we evaluated the fate of NK cells and parasites after contact formation. The hydrophilic fluorescent dye CMFDA (chloro-methylfluorescin diacetate) that allows analysis of cytotoxicity in flow cytometry and microscopy was used. Furthermore, these findings were confirmed with scanning and transmission electron microscopy. Direct contact points were found between Leishmania promastigotes and naïve human NK cells. These contacts were associated with transfer of cytosol by membrane bridges and cytotoxicity of NK cells against Leishmania. However, in contrast to other target cells which allow repeated exocytosis of lytic granules, contact with Leishmania causes immediate destruction of NK cells in a non-apoptotic way. Our results give a reasonable explanation for ex vivo observations of reduced NK cell numbers and impaired NK response in patients with acute cutaneous leishmaniasis. Animal models have clearly shown that NK cells play a key role in the induction and direction of the immune response. Thus inhibition of NK cells at the onset of infection would be advantageous for the survival of the parasite.