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Natural selection should favour parents that are able to adjust their offspring's life-history strategy and resource allocation in response to changing environmental and social conditions. Pathogens impose particularly strong and variable selective pressure on host life histories, and parental genes will benefit if offspring are appropriately primed to meet the immunological challenges ahead. Here, we investigated transgenerational immune priming by examining reproductive resource allocation by female mice in response to direct infection with Babesia microti prior to pregnancy. Female mice previously infected with B. microti gained more weight over pregnancy, and spent more time nursing their offspring. These offspring generated an accelerated response to B. microti as adults, clearing the infection sooner and losing less weight as a result of infection. They also showed an altered hormonal response to novel social environments, decreasing instead of increasing testosterone production upon social housing. These results suggest that a dominance-resistance trade-off can be mediated by cues from the previous generation. We suggest that strategic maternal investment in response to an infection leads to increased disease resistance in the following generation. Offspring from previously infected mothers downregulate investment in acquisition of social dominance, which in natural systems would reduce access to mating opportunities. In doing so, however, they avoid the reduced disease resistance associated with increased testosterone and dominance. The benefits of accelerated clearance of infection and reduced weight loss during infection may outweigh costs associated with reduced social dominance in an environment where the risk of disease is high. [ABSTRACT FROM AUTHOR]

Abstract: The major human soil-transmitted helminths (STH), Ascaris lumbricoides, hookworms (Necator americanus and Ancylostoma duodenale) and Trichuris trichiura have a marked impact on human health in many parts of the world. Current efforts to control these parasites rely predominantly on periodic mass administration of anthelmintic drugs to school age children and other at-risk groups. After many years of use of these same drugs for controlling roundworms in livestock, high levels of resistance have developed, threatening the sustainability of these livestock industries in some locations. Hence, the question arises as to whether this is likely to also occur in the human STH, thereby threatening our ability to control these parasites. This is particularly important because of the recent increase in mass control programmes, relying almost exclusively on benzimidazole anthelmintics. It will be important to ensure that resistance is detected as it emerges in order to allow the implementation of mitigation strategies, such as use of drug combinations, to ensure that the effectiveness of the few existing anthelmintic drugs is preserved. In this review we address these issues by firstly examining the efficacy of anthelmintics against the human STH, and assessing whether there are any indications to date that resistance has emerged. We then consider the factors that influence the effect of current drug-use patterns in selecting for resistant parasite populations. We describe the tools currently available for resistance monitoring (field-based coprological methods), and those under development (in vitro bioassays and molecular tests), and highlight confounding factors that need to be taken into account when interpreting such resistance-monitoring data. We then highlight means to ensure that the currently available tools are used correctly, particularly with regard to study design, and we set appropriate drug-efficacy thresholds. Finally, we make recommendations for monitoring drug efficacy in the field, as components of control programmes, in order to maximise the ability to detect drug resistance, and if it arises to change control strategy and prevent the spread of resistance. [Copyright &y& Elsevier]

The article discusses the results of a study on the sequences of betaherpesvirus in eastern spiny mice and Wagner's dipodils. The sequences are unusually similar and herpesvirus are normally very host specific, suggesting a cross-species transmission event. It mentions the existence of a carrier state of infection and that immunsuppression of the host may result in recrudescence of viral replication and a variety of disease syndromes.

Two recent papers published in Immunity and Cell Host & Microbe underline the great importance of B cells and of antibodies (Abs) in orchestrating crucial T helper cell type 2 (Th2) protective immune responses to gastrointestinal nematodes. The findings in animal models now raise major questions as to how B cells and Abs carry out these functions in humans. Here we discuss recent technological advances in humanizing animal models at the level of both Abs and their Fc-receptors, that might provide some answers. [Copyright &y& Elsevier]

Abstract: Babesia microti (Apicomplexa, Piroplasmida) is one of the aetiological agents of human babesiosis, maintained in nature by complex zoonotic transmission cycles, involving small wild mammals as hosts and hard ticks (Ixodidae) as vectors. We previously reported that the B. microti strain commonly encountered among Microtus rodents in Poland is not zoonotic and that it is therefore most unlikely that it represents a risk to public health. Here, we analysed the contribution of four rodent species, Myodes glareolus, Apodemus flavicollis, Microtus arvalis, and Mi. oeconomus as hosts for two species of locally abundant ticks (Ixodes ricinus and Dermacentor reticulatus) and the rodent infective B. microti. Studies were carried out in the Mazury Lakes District of north-eastern Poland in 2005 and 2006. Infestation prevalence and abundance of both species of ticks (altogether 5674) collected from 781 rodent hosts, including 61 A. flavicollis, 495 My. glareolus, 99 Mi. arvalis, and 126 Mi. oeconomus from two different habitats, were determined. A. flavicollis and My. glareolus from the woodland habitat were more frequently infested with larvae and nymphs of I. ricinus ticks (96.7% and 87.9%, respectively) than the other species of hosts. In contrast, a higher percentage (>30%) of the other two species of rodents (Mi. arvalis, Mi. oeconomus) from fallow lands were infested with larvae and nymphs of D. reticulatus ticks (31.3% and 68.3%, respectively). Pronounced co-infestation rates (36.3%) of I. ricinus and D. reticulatus ticks (larvae and nymphs) were recorded on Mi. oeconomus. B. microti infections in blood samples of hosts and in ticks collected from hosts were examined by PCR, followed by sequence analysis. The prevalence of B. microti in hosts from the fallow lands (Mi. arvalis and Mi. oeconomus) was much higher than that in hosts from woodland (A. flavicollis and My. glareolus). However, the overall prevalence of B. microti in ticks collected from rodents was quite low, and varied from 3.4% for larvae to 4.8% for nymphs of I. ricinus and 11.8% for larvae to 4.0% for nymphs of D. reticulatus. The present study revealed for the first time the presence of B. microti DNA in partly engorged immature I. ricinus, but also in partly engorged larvae and nymphs of D. reticulatus. Furthermore, our results suggest widely differing roles of various rodent host species from two different habitats in maintaining zoonotic transmission of B. microti. [Copyright &y& Elsevier]

The results of a longitudinal epidemiological survey in two contrasting habitats in an area of the Mazury Lakes district of Poland indicate that both host and vector (Ixodes ricinus) densities, may be the most important risk factors for the tick-transmitted spirochetes of Borrelia burgdirferi s.l. However, the results also highlight that even related host species, such as the wild rodents Apodemus flavicollis and Clethrionomys glareolus that share the same habitat, can show quite different dynamics of tick infestation. We provide evidence that the woodland populations of A. flavicollis and C. glareolus are more frequently infested with larvae than nymphs, and more frequently with both stages than M. arvalis in the neighbouring open fallow lands. The prevalence of infestation with larvae varied from 92% for A. flavicollis, and 76% for C. glareolus to 37% for M. arvalis. Other factors, such as population age structure and sex, were also shown to impact on tick densities on hosts at particular times of the year and hence on the zoonotic risk. Moreover, particular species of rodents from different habitats, A. flavicollis (woodlands) and Microtus arvalis (fallow lands) carry infected immature I. ricinus ticks more frequently than C. glareolus voles (woodlands). Thus, the relative contribution of each species to the cumulative reservoir competence differs among species living in the woodland habitats and in relation to voles living in the fallow lands. It follows, therefore, that any factor which reduces the relative density of A. flavicollis in comparison to other hosts in the wild rodent community, will reduce also the risk of human exposure to Lyme borreliosis spirochetes. [ABSTRACT FROM AUTHOR]

Fine mapping of quantitative trait loci (QTL) associated with resistance to the gastrointestinal parasite Heligmosomoides polygyrus was achieved on F6/F7 offspring (1076 mice) from resistant (SWR) and susceptible (CBA) mouse strains by selective genotyping (top and bottom 20% selected on total worm count in week 6). Fecal egg counts were recorded at weeks 2, 4, and 6, and the average was also analyzed. Blood packed cell volume in weeks 3 and 6 and five immunological traits (mucosal mast cell protease 1, granuloma score, IgG1 against adult worm, IgG1, and IgE to L4 antigen) were also recorded. On Chromosome 1 single-trait analyses identified a QTL with effects on eight traits located at about 24 cM on the F2 mouse genome database (MGD) linkage map, with a 95% confidence interval (CI) of 20-32 cM established from a multitrait analysis. On Chromosome 17 a QTL with effects on nine traits was located at about 18 cM on the MGD map (CI 17.9-18.4 cM). Strong candidate genes for the QTL position on Chromosome 1 include genes known to be involved in regulating immune responses and on Chromosome 17 genes within the MHC, notably the Class II molecules and tumor necrosis factor. [ABSTRACT FROM AUTHOR]

Abstract: Infections of Babesia microti (Apicomplexa, Piroplasmida), a common erythroparasitic protozoon of Holarctic rodents, are not widely acknowledged in Poland. The presence of this parasite in various species of wild rodents has been well documented throughout the northern temperate zone of North America, Europe, and Eurasia. However, human babesiosis attributable to infection with B. microti has been reported only from the north-eastern and upper midwestern United States and Japan. We recently carried out an epizootiological survey investigating the prevalence of B. microti both in the tick Ixodes ricinus and in wild rodents in north-eastern Poland. Blood samples were collected from a total of 483 animals comprising three species: Apodemus flavicollis, Microtus arvalis, and Microtus oeconomus trapped at Urwitałt near Mikołajki in the Mazury Lakes District. Questing adult I. ricinus ticks were collected in the study sites by blanket dragging of vegetation in heterogeneous, deciduous woodland, and, in addition, rodents were carefully examined for feeding larvae and nymphs. Altogether, B. microti was detected in 9 out of 1513 I. ricinus ticks (0.6%) examined by PCR. This included 163 adults (92 females and 71 males), 50 nymphs, and 1300 larvae 3%, 8%, and 0% of which were PCR-positive, respectively. Of 85 A. flavicollis, 374 M. arvalis and 24 M. oeconomus, 1%, 12.8%, and 42% were parasitaemic, respectively, as determined by microscopic examination of blood smears stained with Giemsa. B. microti DNA, extracted from 53 M. arvalis and 5 M. oeconomus and examined by nested PCR, targeting a piroplasm-specific portion of the 18S ribosomal DNA, revealed 72% and 40%, respectively, to be PCR positive. Sequence analysis showed that all PCR-positive samples had rDNA sequences identical (100% homology) to that of the Munich B. microti strain (GenBank Accession no. AB071177) isolated from Mus musculus. The results of this study indicate that the B. microti commonly encountered among Microtus spp. rodents is probably not a zoonotic strain and, therefore, that it is most unlikely to represent a risk to public health in the Mazury Lakes District of north-eastern Poland. [Copyright &y& Elsevier]

Some humans are persistently more susceptible to gastrointestinal nematodes than others. Here, for the first time, susceptibility to reinfection has been linked to host cytokine responses. Ascaris lumbricoides and Trichuris trichiura abundance was assessed immediately before and 8-9 months after deworming in a Cameroonian population (starting n = 191 ). Profiles of whole-blood cytokine responses to parasite antigens (for interleukin [IL]-5, IL-13, IL-10, IL-12p40, tumor necrosis factor-α, and interferon-γ), assayed before treatment, were significantly related both to an overall measure of host susceptibility and to susceptibility to reinfection. Significant effects were primarily due to a negative association between IL-13 and IL-5 responses and infection. Persistently susceptible individuals were, therefore, characterized by a weak T helper cell type 2 response. The apparent plasticity of age-specific cytokine response-worm abundance relationships between different populations is also discussed. [ABSTRACT FROM AUTHOR]