This is a systematic review on the role of metalloproteases in the pathogenicity of the American tegumentary leishmaniasis (ATL) caused by New World Leishmania species. The review followed the PRISMA method, searching for articles in PubMed, EMBASE, LILACS and ISI Web of Science, by employing the following terms: ‘leishmaniasis’, ‘cutaneous leishmaniasis’, ‘mucocutaneous leishmaniasis’, ‘diffuse cutaneous leishmaniasis’, ‘Leishmania’ and ‘metalloproteases’. GP63 of New World Leishmania species is a parasite metalloproteases involved in the degradation and cleavage of many biological molecules as kappa-B nuclear factor, fibronectin, tyrosine phosphatases. GP63 is capable of inhibiting the activity of the complement system and reduces the host's immune functions, allowing the survival of the parasite and its dissemination. High serological/tissue levels of host matrix metalloproteases (MMP)-9 have been associated with tissue damage during the infection, while high transcriptional levels of MMP-2 related with a satisfactory response to treatment. Host MMPs serological and tissue levels have been investigated using Western Blot, zymography, and Real Time polymerase chain reaction. GP63 detection characterizes species and virulence in promastigotes isolated from lesions samples using techniques mentioned previously. The monitoring of host MMPs levels and GP63 in Leishmania isolated from host samples could be used on the laboratory routine to predict the prognostic and treatment efficacy of ATL.

Australian tea tree oil (TTO) and its extract terpinen-4-ol (T4O) are found to be effective in moderating demodex-related diseases. Their possible effects are lowering the mite counts, relieving the demodex-related symptoms and modulating the immune system especially the inflammatory response. This review summarizes the topical treatments of TTO and T4O in human demodicosis, their possible mechanism of actions, side-effects and potential resistance in treating this condition. Although current treatments other than TTO and T4O are relatively effective in controlling the demodex mite population and the related symptoms, more research on the efficacy and drug delivery technology is needed in order to assess its potential as an alternative treatment with minimal side-effect profile, low toxicity and low risk of demodex resistance.

Extracellular vesicles (EVs) are released by a wide number of cells including blood cells, immune system cells, tumour cells, adult and embryonic stem cells. EVs are a heterogeneous group of vesicles (~30–1000 nm) including microvesicles and exosomes. The physiological release of EVs represents a normal state of the cell, raising a metabolic equilibrium between catabolic and anabolic processes. Moreover, when the cells are submitted to stress with different inducers or in pathological situations (malignancies, chronic diseases, infectious diseases.), they respond with an intense and dynamic release of EVs. The EVs released from stimulated cells vs those that are released constitutively may themselves differ, both physically and in their cargo. EVs contain protein, lipids, nucleic acids and biomolecules that can alter cell phenotypes or modulate neighbouring cells. In this review, we have summarized findings involving EVs in certain protozoan diseases. We have commented on strategies to study the communicative roles of EVs during host–pathogen interaction and hypothesized on the use of EVs for diagnostic, preventative and therapeutic purposes in infectious diseases. This kind of communication could modulate the innate immune system and reformulate concepts in parasitism. Moreover, the information provided within EVs could produce alternatives in translational medicine.

Due to the lack of an effective prophylactic intervention and diagnosis, human liver fluke Clonorchis sinensis continues to afflict a large human population, causing a chronic inflammatory bile duct disease. With an aim to identify target antigens for sensitive serodiagnosis, adenylate kinase 3 of C. sinensis (CsAK3) was successfully expressed in soluble form in Escherichia coli by fusion to an RNA-interacting domain derived from human Lys-tRNA synthetase and purified by Ni2+-affinity chromatography. Anti-CsAK3 serum was raised by immunization of mice, and Western blotting confirmed that CsAK3 was expressed in adult-stage C. sinensis. Histochemical analysis showed that CsAK3 was localized to the subtegumental tissue of C. sinensis and was excreted into the bile duct of the host. When tested against sera from various parasite-infected patients by enzyme-linked immunosorbent assay, the recombinant CsAK3 elicited a specific response to C. sinensis-infected sera. The results suggest that CsAK3, either alone or in combination with other antigens, could be used for improving the clinical diagnosis of clonorchiasis.

Camelids (llama, alpaca, vicunãs, guanacos) are important for the economy of South America and Eimeria infections are an important cause of mortality in camelids. Of the six species of Eimeria in camelids, Eimeria macusaniensis, considered the most pathogenic, is distinctive; its oocysts are the largest among all Eimeria species in animals, its prepatent period is more than 1 month, and its oocysts have been found in mummies from prehistoric times. Although, E. macusaniensis gametogonic stages are found associated with enteritis in naturally infected camelids, the schizogonic stages are unknown and clinical disease has been reported in some camelids with no oocysts in feces. Described herein are morphological details of gametogonic development and oocyst formation of E. macusaniensis in a naturally infected llama (Lama lama), solely infected with this parasite. Microgamonts, macrogamonts and oocysts were located in large (up to 300 µm diameter) parasitophorous vacuoles of enterocytes in the ileum. Schizonts were not found. Review of previous reports suggests that multinucleated microgamonts have been mistaken for schizonts. Gametogonic development described in the present study can serve as a guide for differential diagnosis of Eimeria species in the histological sections of intestines.

Avian trichomonosis is an architypal disease of wild columbids and those birds that predate them. Increasingly though, it has been reported in passerines; a recent and ongoing epidemic in the chaffinches and greenfinches of Europe and outbreaks amongst house finches, American goldfinches and purple finches in North America. The parasite, Trichomonas gallinae, causes lesions in the upper respiratory tract which can cause mortality associated with dehydration and emaciation. This paper reports for the first time, the widespread, endemic and often asymptomatic infection of common mynah (Acridotheres tristis) around the Faisalabad District, Pakistan. Parasite typing was used to investigate the potential for transmission among the frequently sympatric species. Type C parasites were found in mynah, and while this is analagous to the pandemic finch strain which is Type A, it is the first known example of passerine infections of this parasite genotype. Subtype analysis showed the strain to be C4 a subtype which has a widespread distribution in columbids.

Orca (Orcinus orca) strandings are rare and post-mortem examinations on fresh individuals are scarce. Thus, little is known about their parasitological fauna, prevalence of infections, associated pathology and the impact on their health. During post-mortem examinations of two male neonatal orcas stranded in Germany and Norway, lungworm infections were found within the bronchi of both individuals. The nematodes were identified as Halocercus sp. (Pseudaliidae), which have been described in the respiratory tract of multiple odontocete species, but not yet in orcas. The life cycle and transmission pathways of some pseudaliid nematodes are incompletely understood. Lungworm infections in neonatal cetaceans are an unusual finding and thus seem to be an indicator for direct mother-to-calf transmission (transplacental or transmammary) of Halocercus sp. nematodes in orcas.

Mermithid nematodes (Nematoda: Mermithida: Mermithidae) parasitize a wide range of both terrestrial and aquatic invertebrate hosts, yet are recorded in bumble bees (Insecta: Hymenoptera: Apidae: Bombus) only six times historically. Little is known about the specific identity of these parasites. In a single-season nationwide survey of internal parasites of 3646 bumble bees, we encountered six additional instances of mermithid parasitism in four bumble bee species and genetically characterized them using two regions of 18S to identify the specific host–parasite relationships. Three samples from the northeastern USA are morphologically and genetically identified as Mermis nigrescens, whereas three specimens collected from a single agricultural locality in the southeast USA fell into a clade with currently undescribed species. Nucleotide sequences of the V2–V6 region of 18S from the southeastern specimens were 2.6–3.0% divergent from one another, and 2.2–4.0% dissimilar to the nearest matches to available data. The dearth of available data prohibits positive identification of this parasite and its affinity for specific bumble bee hosts. By doubling the records of mermithid parasitism of bumble bee hosts and providing genetic data, this work will inform future investigations of this rare phenomenon.

Parasites are known to have direct negative effects on host fitness; however, the indirect effects of parasitism on host fitness sans infection are less well understood. Hosts undergo behavioural and physiological changes when in proximity to parasites. Yet, there is little experimental evidence showing that these changes lead to long-term decreases in host fitness. We aimed to determine if parasite exposure affects host fitness independent of contact, because current approaches to parasite ecology may underestimate the effect of parasites on host populations. We assayed the longevity and reproductive output of Drosophila nigrospiracula exposed or not exposed to ectoparasitic Macrocheles subbadius. In order to preclude contact and infection, mites and flies were permanently separated with a mesh screen. Exposed flies had shorter lives and lower fecundity relative to unexposed flies. Recent work in parasite ecology has argued that parasite–host systems show similar processes as predator–prey systems. Our findings mirror the non-consumptive effects observed in predator–prey systems, in which prey species suffer reduced fitness even if they never come into direct contact with predators. Our results support the perspective that there are analogous effects in parasite–host systems, and suggest new directions for research in both parasite ecology and the ecology of fear.

In order to analyse the effect of hosts’ relationships and the helminthic load on the switching of parasites between native and introduced hosts, we sampled rodents belonging to two suborders from Central Chile. We compared the number of helminthic species shared between murids (introduced) and cricetid (native, same suborder) rodents to those shared between murids and hystricomorphs (native, different suborder), and we assessed the association between parasitic presence, abundance and geographical dispersion in source hosts to the presence and abundance in recipient hosts. Introduced rodent species shared more helminth species with cricetid rodents than with non-cricetids. Presence and abundance in recipient hosts was not associated with the prevalence and mean abundance in source hosts’ population. The mean abundance of parasites in source hosts throughout the territory and wider dispersion was positively associated with the likelihood of being shared with a recipient host. Closer relationships between native and introduced hosts and high parasitic abundance and dispersion could facilitate host switching of helminths between native and introduced rodents. This work provides the first documentation of the importance of parasitic abundance and dispersion on the switching of parasites between native and introduced hosts.

To date, genotyping data on giardiasis have not been available in the Czech Republic. In this study, we characterized 47 human isolates of Giardia intestinalis from symptomatic as well as asymptomatic giardiasis cases. Genomic DNA from trophozoites was tested by PCR-sequence analysis at three loci (β-giardin, glutamate dehydrogenase and triose phosphate isomerase). Sequence analysis showed assemblages A and B in 41 (87.2%) and six (12.8%) isolates, respectively. Two of the 41 assemblage A samples were genotyped as sub-assemblage AI, and 39 were genotyped as sub-assemblage AII. Four previously identified multilocus genotypes (MLGs: AI-1, AII-1, AII-4 and AII-9) and six likely novel variations of MLGs were found. In agreement with previous studies, sequences from assemblage B isolates were characterized by a large genetic variability and by the presence of heterogeneous positions, which prevent the definition of MLGs. This study also investigated whether there was a relationship between the assemblage and clinical data (including drug resistance). However, due to the large number of genotypes and the relatively small number of samples, no significant associations with the clinical data were found.

Genotypes of the myxosporean parasite Ceratonova shasta are defined by the number of ATC repeats in the parasite's ribosomal DNA internal transcribed spacer region 1. These genotypes correlate with specific salmonid fish hosts. We observed coho salmon (Oncorhynchus kisutch) and rainbow trout (Oncorhynchus mykiss) with mixtures of genotypes II and III, and assumed that this was a consequence of fish having an aggregate infection from multiple individual parasites. We hypothesized that although multiple ITS copies are present within a parasite spore, the DNA sequences of these copies are identical, and thus individual C. shasta spores are a single genotype. We tested this by extracting and sequencing DNA from individual myxospores. We trialed three approaches for in-tube DNA extraction; digestion with proteinase K was superior to simply rehydrating spores, or incubation in the buffer. Sequences from 14 myxospores were each a mixture of genotypes II and III. Therefore, intra-genomic ribosomal DNA variants exist within individual parasite spores, and II and III should no longer be regarded as discrete C. shasta genotypes. This single-spore genotyping approach will be a useful tool for testing validity of other C. shasta genotypes, and for correctly matching genotype with phenotype for mixed infections of other myxozoan species.

The use of chimeric molecules fusing several antigenic determinants is a promising strategy for the development of low-cost, standardized and reliable kits to determine specific antibodies. In this study, we designed and assessed a novel recombinant chimera that complements the performance of our previously developed chimera, CP1 [FRA and SAPA antigens (Ags)], to diagnose chronic Chagas disease. The new chimeric protein, named CP3, is composed of MAP, TcD and TSSAII/V/VI antigenic determinants. We compared the performance of both chimeric Ags using a panel of 67 Trypanosoma cruzi-reactive sera and 67 non-reactive ones. The sensitivity of CP3 vs CP1 was 100 and 90.2%, and specificity was 92.5 and 100%, respectively. The mixture of CP1 + CP3 achieved 100% of sensitivity and specificity. More importantly, an additional subset of 17 sera from patients with discordant results of conventional serological methods was analysed; the CP1 + CP3 mixture allowed us to accurately classify 14 of them with respect to IIF, the usual technique used in most of the reference centres. These results show an improved performance of the CP1 + CP3 mixture in comparison with enzyme-linked immunosorbent assay and indirect haemagglutination commercial assays.

Ribosome assembly is critical for translation and regulating the response to cellular events and requires a complex interplay of ribosomal RNA and proteins with assembly factors. We investigated putative participants in the biogenesis of the reduced organellar ribosomes of Plasmodium falciparum and identified homologues of two assembly GTPases – EngA and Obg that were found in mitochondria. Both are indispensable in bacteria and P. berghei EngA is among the ‘essential’ parasite blood stage proteins identified recently. PfEngA and PfObg1 interacted with parasite mitoribosomes in vivo. GTP stimulated PfEngA interaction with the 50S subunit of Escherichia coli surrogate ribosomes. Although PfObg1–ribosome interaction was independent of nucleotide binding, GTP hydrolysis by PfObg1 was enhanced upon ribosomal association. An additional function for PfObg1 in mitochondrial DNA transactions was suggested by its specific interaction with the parasite mitochondrial genome in vivo. Deletion analysis revealed that the positively-charged OBG (spoOB-associated GTP-binding protein) domain mediates DNA-binding. A role for PfEngA in mitochondrial genotoxic stress response was indicated by its over-expression upon methyl methanesulfonate-induced DNA damage. PfEngA had lower sensitivity to an E. coli EngA inhibitor suggesting differences with bacterial counterparts. Our results show the involvement of two important GTPases in P. falciparum mitochondrial function, with the first confirmed localization of an EngA homologue in eukaryotic mitochondria.

Cystic echinococcosis (CE) is a severe parasitic disease caused by the species complex Echinococcus granulosus sensu lato. Human infections are most commonly associated with E. granulosus sensu stricto (s.s.), comprising genotypes G1 and G3. The objective of the current study was to provide first insight into the genetic diversity and phylogeography of genotype G3. Despite the epidemiological importance of the genotype, it has remained poorly explored due to the ambiguity in the definition of the genotype. However, it was recently demonstrated that long sequences of mitochondrial DNA (mtDNA) provide a reliable method to discriminate G1 and G3 from each other. Therefore, we sequenced near-complete mtDNA of 39 G3 samples, covering most of the known distribution range and host spectra of the genotype. The phylogenetic network revealed high genetic variation within E. granulosus s.s. G3 and while G3 is significantly less prevalent worldwide than G1, the genetic diversity of both of the genotypes is equally high. We also present the results of the Bayesian phylogeographic analysis, which yielded several well-supported diffusion routes of genotype G3 originating from Turkey and Iran, suggesting the Middle East as the origin of the genotype.

To understand existence, patterns and mechanisms behind phylogenetic heritability in the geographic range size (GRS) of parasites, we measured phylogenetic signal (PS) in the sizes of both regional (within a region) and continental (within a continent) geographic ranges of fleas in five regions. We asked whether (a) GRS is phylogenetically heritable and (b) the manifestation of PS varies between regions. We also asked whether geographic variation in PS reflects the effects of the environment's spatiotemporal stability (e.g. glaciation disrupting geographic ranges) or is associated with time since divergence (accumulation differences among species over time). Support for the former hypothesis would be indicated by stronger PS in southern than in northern regions, whereas support for the latter hypothesis would be shown by stronger PS in regions with a large proportion of species belonging to the derived lineages than in regions with a large proportion of species belonging to the basal lineages. We detected significant PS in both regional and continental GRSs of fleas from Canada and in continental GRS of fleas from Mongolia. No PS was found in the GRS of fleas from Australia and Southern Africa. Venezuelan fleas demonstrated significant PS in regional GRS only. Local Indicators of Phylogenetic Association detected significant local positive autocorrelations of GRS in some clades even in regions in which PS has not been detected across the entire phylogeny. This was mainly characteristic of younger taxa.

Although Varroa destructor is the most serious ecto-parasite to the honeybee, Apis mellifera L., some honeybee populations such as Apis mellifera scutellata in Kenya can survive mite infestations without treatment. Previously, we reported that grooming behaviour could be a potential tolerant mechanism expressed by this honeybee subspecies towards mite infestation. However, both hygienic and grooming behaviours could not explain the lower mite-infestation levels recorded in these colonies. Here, we investigated the involvement of other potential resistant mechanisms including suppression of mite reproduction in worker brood cells of A. m. scutellata to explain the low mite numbers in their colonies. High infertility rates (26–27%) and percentages of unmated female offspring (39–58%) as well as low fecundity (1.7–2.2, average offspring produced) were identified as key parameters that seem to interact with one another during different seasons to suppress mite reproduction in A. m. scutellata colonies. We also identified offspring mortality in both sexes and absence of male offspring as key factors accounting for the low numbers of mated daughter mites produced in A. m. scutellata colonies. These results suggest that reduced mite reproductive success could explain the slow mite population growth in A. m. scutellata colonies.