The Anaplasma species are important globally distributed tick-transmitted bacteria of veterinary and public health importance. These pathogens, cause anaplasmosis in domestic and wild animal species including humans. Rhipicephalus, Ixodes, Dermacentor and Amblyomma genera of ticks are the important vectors of Anaplasma. Acute anaplasmosis is usually diagnosed upon blood smear examination followed by antibodies and nucleic acid detection. All age groups are susceptible but prevalence increases with age. Serological cross-reactivity is one of the important issues among Anaplasma species. They co-exist and concurrent infections occur in animals and ticks in same geographic area. These are closely related bacteria and share various common attributes which should be considered while developing vaccines and diagnostic assays. Movement of susceptible animals from non-endemic to endemic regions is the major risk factor of bovine/ovine anaplasmosis and tick-borne fever. Tetracyclines are currently available drugs for clearance of infection and treatment in humans and animals. Worldwide vaccine is not yet available. Identification, elimination of reservoirs, vector control (chemical and biological), endemic stability, habitat modification, rearing of tick resistant breeds, chemotherapy and tick vaccination are major control measures of animal anaplasmosis. Identification of reservoirs and minimizing the high-risk tick exposure activities are important control strategies for human granulocytic anaplasmosis.

Anaplasmosis is caused by a group of obligate intracellular bacteria in the genus Anaplasma, which are transmitted by ticks and infect humans, domestic animals and wildlife. This study was conducted to determine the prevalence and molecular characterization of Anaplasma spp. in semi-wild white yaks sampled in Tianzhu Tibetan Autonomous County, northwest China. Out of 332 samples tested, 35 (10·9%) were positive for Anaplasma spp. The positive rates were 6·2% (20/322) and 5·3% (17/322) for Anaplasma bovis and Anaplasma phagocytophilum in white yaks, respectively. None of the sample was positive for Anaplasma marginale. Two (0·6%) samples were simultaneously positive to A. bovis and A. phagocytophilum. Sequence analysis of the 16S rRNA gene revealed two genotypes (ApG1 and ApG2) of A. phagocytophilum and two sequence types (ST1 and ST2) of A. bovis in white yaks. This study is the first to document the presence of Anaplasma in white yaks. Our findings extend the host range for Anaplasma species and provide more valuable information for the control and management of anaplasmosis in white yaks.

Leishmania (L.) amazonensis [L. (L.) amazonensis] is widely distributed in Brazil and its symptomatic infections usually lead to few localized lesions and sometimes to diffuse cutaneous form, with nodules throughout the body, anergy to parasite antigens and poor therapeutic response. The variability of these manifestations draws attention to the need for studies on the pathophysiology of infection by this species. In this study, we analysed the course and immunological aspects of L. (L.) amazonensis infection in BALB/c and C57BL/6 strains, both susceptible, but displaying different clinical courses, and athymic BALB/c nude, to illustrate the role of T cell dependent responses. We analysed footpad thickness and parasite burden by in vivo imaging. Furthermore, we evaluated the cellular profile and cytokine production in lymph nodes and the inflammatory infiltrates of lesions. Nude mice showed delayed lesion development and less inflammatory cells in lesions, but higher parasite burden than BALB/c and C57BL/6. BALB/c and C57BL/6 mice had similar parasite burdens, lesion sizes and infiltrates until 6 weeks after infection, and after that C57BL/6 mice controlled the infection. Small differences in parasite numbers were observed in C57BL/6 macrophages in vitro, indicating that in vivo milieu accounts for most differences in infection. We believe our results shed light on the role of host immune system in the course of L. (L.) amazonensis infection by comparing three mouse strains that differ in parasitaemia and inflammatory cells.

Transforming growth factor beta (TGF-β) cytokine is involved in Chagas disease establishment and progression. Since Trypanosoma cruzi can modulate host cell receptors, we analysed the TGF-β receptor type II (TβRII) expression and distribution during T. cruzi – cardiomyocyte interaction. TβRII immunofluorescent staining revealed a striated organization in cardiomyocytes, which was co-localized with vinculin costameres and enhanced (38%) after TGF-β treatment. Cytochalasin D induced a decrease of 45·3% in the ratio of cardiomyocytes presenting TβRII striations, demonstrating an association of TβRII with the cytoskeleton. Western blot analysis showed that cytochalasin D significantly inhibited Smad 2 phosphorylation and fibronectin stimulation after TGF-β treatment in cardiomyocytes. Trypanosoma cruzi infection elicited a decrease of 79·8% in the frequency of cardiomyocytes presenting TβRII striations, but did not interfere significantly in its expression. In addition, T. cruzi-infected cardiomyocytes present a lower response to exogenous TGF-β, showing no enhancement of TβRII striations and a reduction of phosphorylated Smad 2, with no significant difference in TβRII expression when compared to uninfected cells. Together, these results suggest that the co-localization of TβRII with costameres is important in activating the TGF-β signalling cascade, and that T. cruzi-derived cytoskeleton disorganization could result in altered or low TGF-β response in infected cardiomyocytes.

Previous work has highlighted increased opportunities for the transmission of Syngamus trachea within pheasant release pens, due in part to high levels of environmental contamination around communal areas. Despite this, the distribution of adult worms within their definitive hosts is not significantly different from predicted distributions under Taylor's power law. Therefore, density-dependent processes are probably acting to regulate S. trachea population dynamics. Patterns of nematode fecundity were investigated in a semi-naturally occurring population of ring-necked pheasants (Phasianus colchicus) and a wild population of carrion crows (Corvus carone). Worm length was a reliable indicator of nematode fecundity, and a negative association between mean worm length and mean worm burden was identified within both the species. The stunting of worms at greater parasite densities was present in both immunologically naïve and previously exposed pheasants, so is unlikely to be a function of age-dependent acquired immunity. Interestingly, the effect of parasite crowding in the crow population explained more of the variation in mean worm length, apparently driven by a greater mean worm burden when compared with pheasants. The findings of the present study suggest that fecundity is a function of parasite density, i.e. parasite-mediated competition and not host-mediated heterogeneities in immunocompetence.

We tested Szidat's rule (the more primitive the host, the more primitive the parasites it harbours) by analysing the relationships between phylogenetic clade ranks of fleas and their small mammalian hosts in four biogeographic realms (Afrotropics, Neotropics, Nearctic and Palearctic). From the host perspective, we tested the association between host clade rank and the mean clade rank of all fleas collected from this host. From the flea perspective, we tested the relationships between flea clade rank and the mean clade rank of hosts on which this flea was recorded. First, we tested whether the analysis of the relationships between host and flea clade ranks should be controlled for phylogenetic dependence among either host or flea species. Then, we tested for the associations between host and flea clade ranks separately for each realm using either a phylogenetic general least-squares analysis or an ordinary least-squares analysis. In all realms, the mean clade rank of fleas parasitic on a given host increased with an increase of this host's clade rank, and the mean clade rank of hosts recorded on a given flea increased with an increase of this flea's clade rank, suggesting that Szidat's rule, at least to some extent, holds for fleas.

Myxozoans have been successfully used as tags for fish stock identification around the world. However, few studies using myxozoan tags have been carried out in the Southern Atlantic, a region with complex oceanography that constitutes a potentially suitable scenario for testing the utility of myxozoans as indicators. Its usefulness was tested using six samples of Merluccius hubbsi in two different regions of the Argentine Sea. Generalized linear models were performed to assess the effects of fish size and sex, and year and region of capture and selected using the Information Theoretic approach. Three myxozoan species were recorded: Kudoa rosenbuschi, Myxoproteus meridionalis and Fabespora sp. Results of modelling species individually showed differential capabilities for detecting geographical population structure at different spatial scales, with K. rosenbuschi and Fabespora sp. allowing the discrimination of northern and southern stocks, but Fabespora sp. also as a promissory indicator of intrapopulation sub-structure due to different migratory routes during non-reproductive periods. This work confirms that myxozoans offer a set of suitable markers at different spatial scales, which can be selected individually or in any combination, depending on the geographical extent of the study, constituting tools adaptable to the objectives of further research on fish population structure.

To address the molecular diversity and occurrence of pathogenic species of the genus Entamoeba spp. in wild non-human primates (NHP) we conducted molecular-phylogenetic analyses on Entamoeba from wild chimpanzees living in the Issa Valley, Tanzania. We compared the sensitivity of molecular [using a genus-specific polymerase chain reaction (PCR)] and coproscopic detection (merthiolate-iodine-formaldehyde concentration) of Entamoeba spp. We identified Entamoeba spp. in 72 chimpanzee fecal samples (79%) subjected to species-specific PCRs for six Entamoeba species/groups (Entamoeba histolytica, Entamoeba nuttalli, Entamoeba dispar, Entamoeba moshkovskii, Entamoeba coli and Entamoeba polecki ST2). We recorded three Entamoeba species: E. coli (47%), E. dispar (16%), Entamoeba hartmanni (51%). Coproscopically, we could only distinguish the cysts of complex E. histolytica/dispar/moshkovskii/nuttalli and E. coli. Molecular prevalence of entamoebas was higher than the prevalence based on the coproscopic examination. Our molecular phylogenies showed that sequences of E. dispar and E. coli from Issa chimpanzees are closely related to sequences from humans and other NHP from GenBank. The results showed that wild chimpanzees harbour Entamoeba species similar to those occurring in humans; however, no pathogenic species were detected. Molecular-phylogenetic methods are critical to improve diagnostics of entamoebas in wild NHP and for determining an accurate prevalence of Entamoeba species.

The sexual stages and new oocysts development of Cryptosporidium parvum were investigated in a cell-free culture system using transmission electron microscopy (TEM). Sexual development was extremely rapid after inoculation of oocysts into the medium. The process began within 1/2–12 h and was completed with new oocyst formation 120 h post-inoculation. The macrogamonts were bounded by two membranes and had amylopectin granules and two distinct types of wall-forming bodies. The microgamonts had a large nucleus showing lobe projections and condensation of chromatin, giving rise to peripherally budding microgametes. The microgametes contained a large area of granular substance containing groups of microtubules surrounding the electron-dense nucleus. In some instances, the dividing microgamy was observed in cell-free cultures with no preceding merogonic process. Fertilization was observed with the bullet-shaped microgamete penetrating an immature macrogamont at 24 and 216 h. The new thin- and thick-walled oocysts had a large residuum with polysaccharide granules and sporogony noted inside these oocysts. Novel immature four-layer walled thick oocysts with irregular knob-like protrusions on the outer layer resembling the immature Eimeria oocysts were also observed. The present study confirms the gametogony and sporogony of C. parvum in cell-free culture and describes their ultra-structure for the first time.

Sarcocystis neurona is a terrestrial parasite that can cause fatal encephalitis in the endangered Southern sea otter (Enhydra lutris nereis). To date, neither risk factors associated with marine contamination nor the route of S. neurona infection to marine mammals has been described. This study evaluated coastal S. neurona contamination using California mussels (Mytilus californianus) as sentinels for pathogen pollution. A field investigation was designed to test the hypotheses that (1) mussels can serve as sentinels for S. neurona contamination, and (2) S. neurona contamination in mussels would be highest during the rainy season and in mussels collected near freshwater. Initial validation of molecular assays through sporocyst spiking experiments revealed the ITS-1500 assay to be most sensitive for detection of S. neurona, consistently yielding parasite amplification at concentrations ⩾5 sporocysts/1 mL mussel haemolymph. Assays were then applied on 959 wild-caught mussels, with detection of S. neurona confirmed using sequence analysis in three mussels. Validated molecular assays for S. neurona detection in mussels provide a novel toolset for investigating marine contamination with this parasite, while confirmation of S. neurona in wild mussels suggests that uptake by invertebrates may serve as a route of transmission to susceptible marine animals.

Chicory is a perennial crop that has been investigated as a forage source for outdoor-reared ruminants and pigs, and has been reported to have anthelmintic properties. Here, we investigated in vitro anthelmintic effects of forage chicory-extracts against the highly prevalent swine parasites Ascaris suum and Oesophagostomum dentatum. Methanol extracts were prepared and purified from two different cultivars of chicory (Spadona and Puna II). Marked differences were observed between the anthelmintic activity of extracts from the two cultivars. Spadona extracts had potent activity against A. suum third (L3) and fourth (L4) – stage larvae, as well as O. dentatum L4 and adults, whereas Puna II extracts had less activity against A. suum and no activity towards O. dentatum L4. Transmission-electron microscopy of A. suum L4 exposed to Spadona extracts revealed only subtle changes, perhaps indicative of a specific anthelmintic effect rather than generalized toxicity. Ultra-high liquid chromatography-mass spectrometry analysis revealed that the purified extracts were rich in sesquiterpene lactones (SL), and that the SL profile differed significantly between cultivars. This is the first report of anthelmintic activity of forage chicory towards swine nematodes. Our results indicate a significant anthelmintic effect, which may possibly be related to SL composition.

Gastrointestinal nematodes are compromising productivity of grazing sheep and goats. Therefore, scientists have been looking for cost-effective alternative options. Forage legumes (Fabacea Family) contain tannins that could improve livestock performance and their health as well. The present study aimed to (i) determine the in vitro anthelmintic (AH) activity of 19 acetonic extracts of Hedysarum carnosum Desf on Haemonchus contortus by a larval exsheathment assay (LEA); (ii) test the anthelmintic activity of condensed tannins using a deactivating reagent, polyvinylpolypyrrolidone (PVPP); (iii) study the effect of location and the phenological stage on the percentage of exsheathment. The LEA was used at different concentrations (150, 300, 600, 1200 µg mL−1 of acetonic extract/mL of purified buffer solution (PBS)). The larval exsheathment is concentration, location, phenological stage dependent. All extracts, caused a delay of the percentage of exsheathment over 50% so the AH activity of H. carnosum was confirmed. After addition of PVPP, the % exsheathment was similar to the 150 µg mL−1 concentration. The biplot showed that Loc1(S), Loc4(B), Loc 5(PF), Loc 6(BM) and Loc 6(PF) were isolated from other plant extract sample. Our in vitro study showed that H. carnosum seems to be a promising alternative to AH drugs.

Heterogeneities in parasite infection among conspecific hosts often manifest as sex- or size-biased infections, which are typically attributed to differential host susceptibility and exposure. Since parasite fitness is often tied to host quality, host preference by parasites is likely to be under strong selection. We test the hypothesis that host preference is sufficient to generate variability in infection rate among conspecifics. Specifically, we ask whether the mite Macrocheles muscaedomesticae is able to discriminate between Drosophila hydei hosts of different sex and size, while explicitly accounting for the potential confounding effects of these two factors. Our results indicate a preference for female hosts, but this preference appears to be driven by size and not sex per se. When differences in body size were controlled for, the sex-biased infection disappeared, while mites presented with the choice of two female flies of disparate sizes were more likely to select the larger host. Across the distribution of fly body weight in this study, mites preferentially attached to flies of intermediate size. This study provides evidence that mite choice for certain host types can play an important role in parasite transmission, even in the absence of differential susceptibility or exposure among hosts.

The accumulation of heavy metals in macroparasites of fish has been widely studied in freshwater environments. Less is known about metal uptake in cestodes parasitizing marine fish. Lacistorhynchus dollfusi is a common larval cestode parasite of Pacific sanddab (Citharichthys sordidus), a flatfish species inhabiting Santa Monica Bay. The ability of this cestode to concentrate metals in its tissues was compared with metal levels in its sanddab host. Fish and cestode tissue were analysed for 14 elements using Inductively Coupled Plasma Mass Spectrometry. The elements analysed were silver (Ag), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), potassium (K), lead (Pb), rubidium (Rb), selenium (Se), strontium (Sr), titanium (Ti) and zinc (Zn). Three of the 14 metals (Cu, Hg and Zn) were significantly greater in concentration in L. dollfusi compared with their levels in the liver, intestine and muscle of their fish host. They ranked in concentration from highest to lowest as follows: Zn > Cu > Hg. The ability of the cestode L. dollfusi to uptake metals at higher concentrations than its host warrants its consideration as a candidate for a heavy metal accumulation indicator of pollution exposure in Pacific sanddab.