Ecological immunology is based upon the notion that activation and use of the immune system is costly and should thus be traded off against other energy-demanding aspects of life history. Most of the studies on insects that have examined the possibility that mating results in trade-offs with immunity have shown that mating has immunosuppressive effects. The connection between mating and immunity has traditionally been investigated using indirect measures of immunity. However, studies that have assessed the effects of mating on the resistance against real pathogens have had conflicting results. A previous study on Tenebrio molitor showed that copulation decreases phenoloxidase activity in the haemolymph, and concluded that copulation corrupts immunity in this species. In the present study we tested whether mating also affects the ability of T. molitor to resist the entomopathogenic fungus, Beauveria bassiana. Interestingly, we found that mating enhanced resistance against the fungal infection and that the effect was stronger on males than females. Furthermore, we found that male beetles were overall more susceptible to the fungal infection than were females, indicating an immunological sex difference in immunity. Our study highlights the importance of the use of real pathogens and parasites in immuno-ecological studies.

The experimental studies of Brucei group trypanosomes presented here demonstrate that the balance of host and parasite factors, especially IFN-γ GPI-sVSG respectively, and the timing of cellular exposure to them, dictate the predominant MP and DC activation profiles present at any given time during infection and within specific tissues. The timing of changes in innate immune cell functions following infection consistently support the conclusion that the key events controlling host resistance occur within a short time following initial exposure to the parasite GPI substituents. Once the changes in MP and DC activities are initiated, there appears little that the host can do to reverse these changes and alter the final outcome of these regulatory events. Instead, despite the availability of multiple innate and adaptive immune mechanisms that can control parasites, there is an inability to control trypanosome numbers sufficiently to prevent the emergence and establishment of virulent trypanosomes that eventually kill the host. Overall it appears that trypanosomes have carefully orchestrated the host innate and adaptive immune response so that parasite survival and transmission, and alterations of host immunity, are to its ultimate benefit.

Introduction. Several reports indicate high prevalences of both onchocerciasis and epilepsy in some regions of Africa. This raises the question of whether these diseases are associated. We therefore investigated people with epilepsy and/or onchocerciasis living in an area in Tanzania endemic for Onchocerca volvulus (O. volvulus). Methods. We collected clinical information, skin snips, and blood from 300 individuals, and cerebrospinal fluid (CSF) from 197. Participants were allocated to 4 groups consisting of people with epilepsy and onchocerciasis (n=135), those with either epilepsy (n=61) or onchocerciasis only (n=35), and healthy individuals (n=69). Samples were evaluated for microfilaria, IgG4 antibodies against O. volvulus, O. volvulus antibody index (CSF/serum), and CSF routine parameters. Polymerase chain reaction (PCR) was performed on skin snips and CSF. Results. No difference was found in microfilarial density between participants with and without epilepsy (P=0·498). The antibody index was raised in 2 participants. CSF PCR was negative in all samples tested. Discussion. Our results do not give evidence of a relationship between O. volvulus and epilepsy. Despite the fact that 2 participants had raised antibody index, the existence of cerebral onchocerciasis caused by migration of microfilariae into the CSF appears unlikely. However, to date unexplored reactions to the infestation with O. volvulus causing epilepsy cannot be excluded.

We applied a combined molecular and morphological approach to resolve the taxonomic status of Saccocoelium spp. parasitizing sympatric mullets (Mugilidae) in the Mediterranean. Eight morphotypes of Saccocoelium were distinguished by means of multivariate statistical analyses: 2 of Saccocoelium obesum ex Liza spp.; 4 of S. tensum ex Liza spp.; and 2 (S. cephali and Saccocoelium sp.) ex Mugil cephalus. Sequences of the 28S and ITS2 rRNA gene regions were obtained for a total of 21 isolates of these morphotypes. Combining sequence data analysis with a detailed morphological and multivariate morphometric study of the specimens allowed the demonstration of cryptic diversity thus rejecting the hypothesis of a single species of Saccocoelium infecting sympatric mullets in the Mediterranean. Comparative sequence analysis revealed 4 unique genotypes, thus corroborating the distinct species status of Saccocoelium obesum, S. tensum and S. cephali and a new cryptic species ex Liza aurata and L. saliens recognized by its consistent morphological differentiation and genetic divergence. However, in spite of their sharp morphological difference the 2 morphotypes from M. cephalus showed no molecular differentiation and 4 morphotypes of S. tensum were genetically identical. This wide intraspecific morphological variation within S. tensum and S. cephali suggests that delimiting species of Saccocoelium using solely morphological criteria will be misleading.

Tick distribution depends on the drop-off rhythm of the previous stage and on the suitability for tick survival of the environment where they are disseminated. Studies were implemented in Burkina Faso to assess detachment pattern of engorged Amblyomma variegatum nymphs. Experiments were carried out with naturally infested cattle kept in a paddock or monitored when grazing community pasture. In the pasture, 80% of the nymphs detached between 14.00 h and 17.00 h while less than 25% did so in the paddock. Further investigation was implemented to assess whether the density of adult ticks might be modified by herd management. During the early dry season, zebus grazed in 4 plots fenced in natural savannahs and fallows. Two of the plots were used in the morning and the two others in the afternoon. Six months later, zebus were put in these plots, in turn, on 9 occasions. The number of A. variegatum adults picked up by the cattle in each plot was highly variable: they captured more ticks in the plots installed on good lush savannah and 3-fold more ticks in those where the herd had grazed in the afternoon during the previous dry season. An integrated tick control strategy taking these results into account is proposed.

Since its use as a model to study metazoan parasite culture and in vitro development, the plerocercoid of the tapeworm, Ligula intestinalis, has served as a useful scientific tool to study a range of biological factors, particularly within its fish intermediate host. From the extensive long-term ecological studies on the interactions between the parasite and cyprinid hosts, to the recent advances made using molecular technology on parasite diversity and speciation, studies on the parasite have, over the last 60 years, led to significant advances in knowledge on host-parasite interactions. The parasite has served as a useful model to study pollution, immunology and parasite ecology and genetics, as well has being the archetypal endocrine disruptor.

Entomopathogenic nematodes (EPN) are soil-transmitted parasites and their foraging strategies are believed to range from ‘ambush’ to ‘cruise’ foragers. However, research on their behaviour has not considered the natural habitat of these nematodes. We hypothesized that EPN behaviour would be influenced by soil habitat quality and tested this hypothesis using 2 EPN species Steinernema carpocapsae (an ‘ambusher’) and Heterorhabditis megidis (a ‘cruiser’) in 2 contrasting habitats, sand and peat. As predicted from previous studies, in sand most S. carpocapsae remained at the point of application and showed no taxis towards hosts, but in peat S. carpocapsae dispersed much more and showed a highly significant taxis towards hosts. H. megidis dispersed well in both media, but only showed taxis towards hosts in sand. In outdoor mesocosms in which both species were applied, S. carpocapsae outcompeted H. megidis in terms of host finding in peat, whereas the opposite was true in sand. Our data suggest that these 2 EPN may be habitat specialists and highlight the difficulties of studying soil-transmitted parasites in non-soil media.

The strengths and limitations of existing mass spectrometry methods for metabolite detection and identification are discussed. A brief review is made of the methods available for quenching and extraction of cells or organisms prior to instrumental analysis. The techniques available for carrying out mass spectrometry-based profiling of metabolomes are discussed using the analysis of extracts from trypanosomes to illustrate various points regarding methods of separation and mass spectrometric analysis. The advantages of hydrophilic interaction chromatography (HILIC) for the analysis of polar metabolites are discussed. The challenges of data processing are outlined and illustrated using the example of ThermoFisher's Sieve software. The existing literature on applications of mass spectrometry to the profiling of parasite metabolomes is reviewed.

In the field of molecular and epidemiological parasitology, characterization of fast evolving genetic markers appears as an important challenge to consider the diversity and genetic structure of parasites. The study of respective populations can help us to understand their adaptive strategies to survive and perpetuate the species within different host populations, all trying to resist infection. In the past, the relative monomorphic features of Echinococcus multilocularis, the causative agent of alveolar echinococcosis and a severe human parasitic disease, did not stimulate studies dealing with the genetic variability of Echinococcus species or respective populations. A recently developed, characterized and validated original multilocus microsatellite, named EmsB, tandemly repeated in the genome, offered an additional opportunity for this line of investigation. We have compiled in this review new insights brought by this molecular tracker on the transmission activity of Echinococcus among different hosts and at different geographical scales.

Schistosoma japonicum remains highly endemic in many counties in China and has recently re-emerged, to a large extent, in previously controlled areas. To test the hypothesis that small rodents and less agriculturally important domestic animals such as dogs and cats may play an important role in the transmission and potential re-emergence of this disease, an annual investigation of S. japonicum among humans, domestic animals and rodents, combined with detailed surveys of the snail intermediate host, was performed across 3 marshland villages and 3 hilly villages in Anhui province of China over 2 consecutive years. The highest infection prevalence and intensity observed across all mammals was in rodents in the hilly region; while in the marshland, bovines were suspected as the main reservoirs. However, relatively high infection prevalence levels were also found in dogs and cats in both regions. Such results may have implications for the current human- and bovine-oriented control policy for this medically and veterinarily important disease, particularly within the hilly regions of mainland China.

Experimental studies of parasite transmission are essential for advances in basic and applied parasitology. A survey of the results of published experiments can identify the determinants of both variation among studies in experimental design and of parasite infection success. Here, analyses are conducted on data compiled from a total of 106 metacercarial infection experiments (35 on Echinostomatidae, 37 on Fasciolidae, 34 on other trematodes) obtained from 83 studies. All of these involved experimental oral infection of individual definitive hosts by a single known dose of metacercariae under controlled conditions. Across these studies, the metacercarial dose used (i) was typically about 10 times higher than the average natural dose that could be acquired by feeding on intermediate hosts (for taxa other than Fasciolidae), and (ii) showed a positive relationship with the body mass of the definitive host, although this relationship was only significant for Fasciolidae. Although the chosen dose was rarely justified, the larger the definitive host, the more metacercariae it received. Among Echinostomatidae and Fasciolidae, there was also a significant dose-dependent effect on infection success: the higher the dose used in an experiment, the smaller the proportion of metacercariae recovered from the host. This effect was mitigated by definitive host body mass, with infection success being generally lower in larger definitive hosts. For Echinostomatidae, the taxonomic identity of the definitive host also mattered, with metacercariae achieving higher infection success in mammals than in birds. The present findings suggest that the design of experimental infection studies requires greater consideration if their results are to yield useful biological insights.

Objective. Expression of the gene encoding Der-p2 allergen-like protein in the castor bean tick Ixodes ricinus is induced by blood intake. Tick Der-p2 allergen-like protein belongs to a diverse family of ML proteins that includes major allergens of house dust mites, human MD-2 or similar proteins from Drosophila melanogaster. In ticks, genes encoding proteins belonging to the ML protein family were identified, but their protein products have not been characterized yet. Methods. A gene encoding tick Der-p2 allergen-like protein was amplified from cDNA of engorged I. ricinus female using the gene-specific primers designed on a basis of partial sequences of related allergen-like genes. The tissue and state specific patterns of expression of the gene were analysed. The IgE binding activity of the produced recombinant protein was studied by use of ELISA. Results. Analysis of the expression pattern showed that the gene encoding the tick Der-p2 allergen-like protein is strongly induced by the bloodmeal in gut and haemolymph throughout all tick developmental stages. Der-p2 allergen-like protein possesses a putative lipid-binding site, according to the comparisons with the related proteins. The ability of tick Der-p2 allergen-like protein to bind immunoglobulin E (IgE) was revealed. Discussion. The presence of a putative lipid-binding domain in Der-p2 allergen-like protein and its ability to interact with IgE might indicate the involvement of the protein in the tick's immune response.

This study examined concurrent stresses of nematode infection and pregnancy using pregnant and non-pregnant CD1 mice infected 3 times with 0, 50 or 100 Heligmosomoides bakeri larvae. Physiological, energetic, immunological and skeletal responses were measured in maternal and foetal compartments. Resting metabolic rate (RMR) was elevated by pregnancy, but not by the trickle infection. Energy demands during pregnancy were met through increased food intake and fat utilization whereas mice lowered their body temperature during infection. Both infection and pregnancy increased visceral organ mass and both altered regional bone area and mineralization. During pregnancy, lumbar mineralization was lower but femur area and mineralization were higher. On the other hand, infection lowered maternal femur bone area and this was associated with higher IFN-γ in maternal serum of heavily infected pregnant mice. Infection also reduced foetal crown-rump length which was associated with higher amniotic fluid IL-1β.

Patterns of infection among hosts in a population are often driven by intrinsic host features such as age or sex, as well as by positive or negative interactions between parasite species. We investigated helminth parasitism in 2 South American rodent species, Ctenomys australis and C. talarum (Octodontidae), to determine whether the unusual solitary and subterranean nature of these hosts would impact their patterns of infection. We applied generalized linear models to infection data on a total of 7 helminth species (1 in C. australis and 6 in C. talarum). Host age and season of capture influenced infection levels in some of the helminth species, but none were influenced by host body condition. In C. talarum, 4 pairs of helminth species showed significant associations, either asymmetrical or symmetrical, and with 3 of the 4 being positive; strong inter-specific facilitation appears likely in 1 case. Also, we found that female hosts, especially non-pregnant ones, harboured heavier infections of 2 nematode species than male hosts. This is in sharp contrast to the general male-bias reported for most studies of nematodes in wild mammals, and we develop explanations for these results based on the unusual ecology of these subterranean rodents.

The aim of this study was to evaluate the CD4+/CD8+ ratio in peripheral blood of dogs with localized and generalized demodicosis. Sixteen dogs were examined, 8 with localized and 8 with generalized demodicosis, while 8 healthy dogs were used as controls. Peripheral blood was obtained and CD4+ and CD8+ T cells were determined by flow cytometry. Significantly higher numbers of CD8+ T cells and lower numbers of CD4+ T cells were found in dogs with generalized demodicosis compared to dogs with localized demodicosis and healthy controls. Significantly higher numbers of CD8+ T cells and lower numbers of CD4+ T cells were also found in dogs with localized demodicosis compared to healthy controls. The CD4+/CD8+ ratio was also found to be significantly lower in dogs with generalized demodicosis in comparison with dogs with localized demodicosis and healthy controls. It is concluded that significant alteration in the CD4+/CD8+ ratio may be implicated in the pathogenesis of generalized canine demodicosis.

The tick Rhipicephalus (Boophilus) microplus is an important parasite of cattle in many areas of the tropics. Characterization of molecules involved in mechanisms such as vitellogenesis and embryo development may contribute to a better understanding of this parasite's physiology. The vitellin-degrading cysteine endopeptidase (VTDCE) is the most active enzyme involved in vitellin hydrolysis in R. microplus eggs. Here we show an association between VTDCE and vitellin in an additional site, apart from the active site. Our data also demonstrate cysteine endopeptidase activity in different tissues such as ovary, gut, fat body, salivary gland and female haemolymph, where it is controlled by a physiological inhibitor. In R. microplus female gut, VTDCE is localized in areas of protein synthesis and trafficking with the underlying haemolymph. VTDCE is also localized in the ovary basal region, in vesicle membranes of ovary pedicel cells and in oocyte cytosol. These results suggest that VTDCE plays a role in vitellin digestion during tick development.

The anthelmintic properties of tannin-rich plants are being explored as an alternative to chemical drugs. Most data have been acquired on legume forages, but only few on browse plants. The present study aimed to (i) screen the in vitro effects of extracts from 7 Mediterranean plants on Haemonchus contortus, (ii) verify the role of tannins using an inhibitor, polyvinyl polypyrrolidone (PVPP) and (iii) verify the in vivo effects of extracts from 4 plants. Significant inhibition was shown in vitro using a larval migration inhibition (LMI) assay for all extracts except that from Olea europaea var. koroneiki. After adding PVPP, the LMI values were restored to control levels for all plants except Pistacia lentiscus and Ceratonia siliqua, confirming a role for tannins in the activity. In the in vivo experiment, 48 lambs composed 6 groups, depending on diet. On Day 0, groups G1–G5 received H. contortus and Trichostrongylus colubriformis larvae and G6 remained uninfected. The various diets were distributed from Days 14 to 45: P. lentiscus (G1), Quercus coccifera (G2), C. siliqua (G3), Onobrychis viciifolia (G4), or Medicago sativa for the 2 control groups (G5, G6). Egg excretion, packed cell volumes (PCVs) and inorganic phosphate were measured weekly throughout the entire experimental period. At slaughter, the worms were enumerated and their fecundity assessed. Consumption of the 4 browser plants did not provoke differences in pathophysiological measurements but there were significant decreases in egg excretion, mainly explained by significant decreases in worm fecundity for both species, without any statistical difference in worm numbers.

Narrow site specificity in parasites is assumed to be associated with fitness benefits, such as higher reproductive success, although this is never quantified. We linked the body mass and combined mass of egg sacs of female copepods, Neobrachiella spinicephala, parasitic on the sandperch, Pinguipes brasilianus, to attachment sites on the host. Adult females attach permanently either on the lips, the margins of the operculum, or the base of pectoral or pelvic fins. In addition to influences of sampling site, season and host body length, our analyses revealed important fitness effects. First, attachment site significantly influenced copepod body mass; independent of other factors, copepods at the base of fins were 32% larger than those on the lips or operculum. Second, the mass of egg sacs was almost always greater if the copepod was attached at the base of fins rather than to the lip or operculum. Thus, a female weighing 6 mg would, on average, produce 40% larger egg sacs if attached to the base of fins. However, copepods were much more likely to attach at the base of fins on small fish, and on either the lip or the operculum on large fish. We propose that constraints varying with fish size account for the shift from optimal to suboptimal attachment sites as a function of increasing host size. By measuring differences in fitness components between attachment sites, our approach allows hypothesis testing regarding microhabitat selection.

Maternal effects occur when the maternal phenotype influences that of the offspring in addition to the effects of maternal genes, and may have a considerable influence on offspring parasite resistance. These effects, and the effects of early levels of reproduction and parasite resistance, may persist into later life and even influence ageing rates. Here we analyse a 20-year longitudinal data set collected on a free-living population of Soay sheep, to investigate the associations between a suite of maternal phenotypic traits and early-life performance on measures of parasite resistance across life. Our results show that maternal effects are important in determining offspring parasite resistance, since lambs born as twins and those born to the youngest and oldest mothers show higher parasite burdens. We show that the association between parasite resistance and natal litter size persists into adulthood. We also show that age-specific changes in parasite resistance in males are associated with natal litter size, and that age-specific changes in females are influenced by early-life levels of reproduction and parasite infection. These results add to the growing evidence that conditions experienced by individuals during development can have a profound influence on immediate and late-life performance and may even influence ageing.