The current World Health Organization strategic plan targets the elimination of schistosomiasis as a public health problem by 2025 and accurate diagnostics will play a pivotal role in achieving this goal. DNA-based detection methods provide a viable alternative to some of the commonly used tests, notably microscopy and serology, for the diagnosis of schistosomiasis. The detection of parasite cell-free DNA in different clinical samples is a recent valuable advance, which provides significant benefits for accurate disease diagnosis. Here we validated a novel duplex droplet digital PCR assay for the diagnosis of Chinese (SjC) and Philippine (SjP) strains of Schistosoma japonicum infection in a mouse model. The assay proved applicable for both SjC and SjP infections and capable of detecting infection at a very early intra-mammalian stage in conveniently obtainable samples (urine and saliva) as well as in serum and feces. The target DNA copy numbers obtained in the assay showed a positive correlation with the infection burden assessed by direct traditional parasitology. The potential to detect parasite DNA in urine and saliva has important practical implications for large-scale epidemiological screening programmes in the future, particularly in terms of logistical convenience, and the assay has the potential to be a valuable additional tool for the diagnosis of schistosomiasis japonica.

Over the last decade, One Health has attracted considerable attention from researchers and policymakers. The concept argues that the fields of human, animal and environmental health ought to be more closely integrated. Amid a flurry of conferences, projects and publications, there has been substantial debate over what exactly One Health is and should be. This review summarizes the main trends in this emerging discussion, highlighting the fault lines between different perspectives on One Health. Some have shown that One Health's call to synthesize knowledge from different disciplines can lead to better interventions. Others, however, argue that One Health's challenge to existing practice must go further, and set out a vision that foregrounds the social and economic drivers of disease. Meanwhile, recent examples of One Health in practice highlight the potential but also the challenges of institutionalizing cooperation. We also discuss the promise and pitfalls of using complexity theory to tackle multifaceted problems, and consider how the One Health concept has been brought to bear on other issues, such as emerging new technologies. Ultimately, One Health is an important and worthwhile goal, and requires a debate that clarifies both the competing uses and the political nature of the project.

Fascioliasis is a condition caused by the trematode Fasciola hepatica. In this paper, the spatial distribution of F. hepatica in bovines in Brazil was modelled using a decision tree approach and a logistic regression, combined with a geographic information system (GIS) query. In the decision tree and the logistic model, isothermality had the strongest influence on disease prevalence. Also, the 50-year average precipitation in the warmest quarter of the year was included as a risk factor, having a negative influence on the parasite prevalence. The risk maps developed using both techniques, showed a predicted higher prevalence mainly in the South of Brazil. The prediction performance seemed to be high, but both techniques failed to reach a high accuracy in predicting the medium and high prevalence classes to the entire country. The GIS query map, based on the range of isothermality, minimum temperature of coldest month, precipitation of warmest quarter of the year, altitude and the average dailyland surface temperature, showed a possibility of presence of F. hepatica in a very large area. The risk maps produced using these methods can be used to focus activities of animal and public health programmes, even on non-evaluated F. hepatica areas.

The majority of the 30–100 million people infected with Strongyloides stercoralis, a soil transmitted intestinal nematode, have subclinical (or asymptomatic) infections. These infections are commonly chronic and longstanding because of the autoinfective process associated with its unique life cycle. A change in immune status can increase parasite numbers, leading to hyperinfection syndrome, dissemination, and death if unrecognized. Corticosteroid use and HTLV-1 infection are most commonly associated with the hyperinfection syndrome. Strongyloides adult parasites reside in the small intestine and induce immune responses both local and systemic that remain poorly characterized. Definitive diagnosis of S. stercoralis infection is based on stool examinations for larvae, but newer diagnostics – including new immunoassays and molecular tests – will assume primacy in the next few years. Although good treatment options exist for infection and control of this infection might be possible, S. stercoralis remains largely neglected.

Trichinella spiralis is a parasitic helminth that can infect almost all mammals, including humans. Trichinella spiralis infection elicits a typical type 2 immune responses, while suppresses type 1 immune responses, which is in favour of their parasitism. DNA vaccines have been shown to be capable of eliciting balanced CD4+ and CD8+ T cell responses as well as humoral immune responses in small-animal models, which will be advantage to induce protective immune response against helminth infection. In this study, serine protease (Ts-NBLsp) was encoded by a cDNA fragment of new-born T. spiralis larvae, and was inserted after CMV promoter to construct a DNA vaccine [pcDNA3·1(+)-Ts-NBLsp]. Ts-NBLsp expression was demonstrated by immunofluorescence. Sera samples were obtained from vaccinated mice, and they showed strong anti-Ts-NBLsp-specific IgG response. Mice immunized with the pcDNA3·1(+)-Ts-NBLsp DNA vaccine showed a 77·93% reduction in muscle larvae (ML) following challenge with T. spiralis ML. Our results demonstrate that the vaccination with pcDNA3·1(+)-Ts-NBLsp plasmid promoted the balance of type 1 and 2 immune responses and produced a significant protection against T. spiralis infection in mice.

Neck samples from 54 badgers and 32 tongue samples of the same badgers (Meles meles), collected in the Lothians and Borders regions of Scotland, were tested using polymerase chain reactions (PCRs) directed against the 18S ribosomal DNA and the internal transcribed spacer (ITS1) region of protozoan parasites of the family Sarcocystidae. Positive results were obtained from 36/54 (67%) neck and 24/32 (75%) tongue samples using an 18S rDNA PCR. A 468 base pair consensus sequence that was generated from the 18S rDNA PCR amplicons (KX229728) showed 100% identity to Sarcocystis lutrae. The ITS1 PCR results revealed that 12/20 (60%) neck and 10/20 (50%) tongue samples were positive for Sarcocystidae DNA. A 1074 bp consensus sequence was generated from the ITS1 PCR amplicons (KX431307) and showed 100% identity to S. lutrae. Multiple sequence alignments and phylogenetic analysis support the finding that the rDNA found in badgers is identical to that of S. lutrae. This parasite has not been previously reported in badgers or in the UK. Sarcocystis lutrae has previously only been detected in tongue, skeletal muscle and diaphragm samples of the Eurasian otter (Lutra lutra) in Norway and potentially in the Arctic fox (Vulpes lagopus).

Cyclin-dependent kinases (CDKs) have important roles in regulating key checkpoints between stages of the cell cycle. Their activity is tightly regulated through a variety of mechanisms, including through binding with cyclin proteins and the Cdc2/Cdc28 kinase subunit (CKS), and their phosphorylation at specific amino acids. Studies of the components involved in cell cycle control in parasitic protozoa are limited. Trichomonas vaginalis is the causative agent of trichomoniasis in humans and is therefore important in public health; however, some of the basic biological processes used by this organism have not been defined. Here, we characterized proteins potentially involved in cell cycle regulation in T. vaginalis. Three genes encoding protein kinases were identified in the T. vaginalis genome, and the corresponding recombinant proteins (TvCRK1, TvCRK2, TvCRK5) were studied. These proteins displayed similar sequence features to CDKs. Two genes encoding CKSs were also identified, and the corresponding recombinant proteins were found to interact with TvCRK1 and TvCRK2 by a yeast two-hybrid system. One putative cyclin B protein from T. vaginalis was found to bind to and activate the kinase activities of TvCRK1 and TvCRK5, but not TvCRK2. This work is the first characterization of proteins involved in cell cycle control in T. vaginalis.

FK506 and rapamycin (Rap) are immunosuppressive drugs that act principally on T-lymphocytes. The receptors for both drugs are FK506-binding proteins (FKBPs), but the molecular mechanisms of immunosuppression differ. An FK506–FKBP complex inhibits the protein phosphatase calcineurin, blocking a key step in T-cell activation, while the Rap –FKBP complex binds to the protein kinase target of rapamycin (TOR), which is involved in a subsequent signalling pathway. Both drugs, and certain non-immunosuppressive compounds related to FK506, have potent antimalarial activity. There is however conflicting evidence on the involvement of Plasmodium calcineurin in the action of FK506, and the parasite lacks an apparent TOR homologue. We therefore set out to establish whether inhibition of the Plasmodium falciparum FKBP PfFKBP35 itself might be responsible for the antimalarial effects of FK506 and Rap. Similarities in the antiparasitic actions of FK506 and Rap would constitute indirect evidence for this hypothesis. FK506 and Rap acted indistinguishably on: (i) specificity for different intra-erythrocytic stages in culture, (ii) kinetics of killing or irreversible growth arrest of parasites and (iii) interactions with other antimalarial agents. Furthermore, PfFKBP35's inhibitory effect on calcineurin was independent of FK506 under a range of conditions, suggesting that calcineurin is unlikely to be involved in the antimalarial action of FK506.

Numerous studies have been conducted on the cellular morphology of Cryptocaryon irritans. However, details regarding the tomont stage of its life cycle remain lacking. In this study, we investigated the morphology of the tomont stage throughout encystment and cell division using light and electron microscopy. Results showed that there was no secretion of encystation-specific secretory vesicles or extrusomes during formation of the cyst wall. Instead, the synthesis and construction of the C. irritans cyst wall materials may involve molecular events at the pellicle. The somatic cilia and the cytostome were present during encystment and covered by the newly formed cyst wall. New somatic cilia were continuously created between old cilia and showed various lengths during cell division, a process that was similar to morphogenesis in many free-living ciliates. During cell division inside the tomont, dividing daughter cells formed temporary cell chains with no oral primordia before separating from each other into dissociative tomite precursors. The process of cell division may not be accompanied by stomatogenesis, and new oral primordia in offspring cells likely formed before the dividing cell chains split into dissociative spherical tomites. Mitochondrial autophagy was observed in encysting C. irritans cells. Numerous endosymbionts and Golgi structures were observed in the tomont cytoplasm. Cellular metabolic activity in the C. irritans tomont was quite high, with large amounts of materials or cellular organelles potentially being synthesized and prepared for the following infective theront stage.

Knowing the determinants of the geographic ranges of parasites is important for understanding their evolutionary ecology, epidemiology and their potential to expand their range. Here we explore the determinants of geographic range in the peculiar case of a parasite species – the microsporidian Hamiltosporidium tvaerminnensis – that has a limited geographic distribution in a wide-spread host – Daphnia magna. We conducted a quantitative trait loci (QTLs) analysis with monoclonal F2D. magna populations originating from a cross between a susceptible northern European genotype and a resistant central European genotype. Contrary to our expectations, long-term persistence turned out to be a quantitative trait across the F2 offspring. Evidence for two QTLs, one epistatic interaction and for further minor QTL was found. This finding contrasts markedly with the previously described bimodal pattern for long-term parasite persistence in natural host genotypes across Europe and leaves open the question of how a quantitative genetic trait could determine the disjunct geographic distribution of the parasite across Europe.

Famous for the discovery of the parasite, Leishmania, named after him, and the invention of Leishman's stain, William Boog Leishman should perhaps be better known for his work in military and public health, particularly the prevention of typhoid. Leishman was a Medical Officer in the British Army from 1887 until his death in 1926. His early research was on diseases affecting troops posted to stations within the British Empire. He saw cases of Leishmaniasis while stationed in India, and was able to identify the causative organism from his detailed records of his observations. Leishman's most important contribution to public health, however, was his work with typhoid, a major cause of morbidity and mortality in the army. Leishman planned experiments and the collection of data to demonstrate the efficacy of anti-typhoid inoculation and, using his considerable political skills, advocated the adoption of the vaccine. He planned for the inoculation of troops in an emergency so, when war broke out in 1914, the vaccine was available to save thousands of lives. Leishman's colleagues and mentors included Ronald Ross and Almroth Wright. Leishman was less outspoken than either Ross or Wright; this paper shows how the different contributions of the three men overlapped.

Genome assemblies can form the basis of comparative analyses fostering insight into the evolutionary genetics of a parasite's pathogenicity, host–pathogen interactions, environmental constraints and invasion biology; however, the length and complexity of many parasite genomes has hampered the development of well-resolved assemblies. In order to improve Trichinella genome assemblies, the genome of the sylvatic encapsulated species Trichinella murrelli was sequenced using third-generation, long-read technology and, using syntenic comparisons, scaffolded to a reference genome assembly of Trichinella spiralis, markedly improving both. A high-quality draft assembly for T. murrelli was achieved that totalled 63·2 Mbp, half of which was condensed into 26 contigs each longer than 571 000 bp. When compared with previous assemblies for parasites in the genus, ours required 10-fold fewer contigs, which were five times longer, on average. Better assembly across repetitive regions also enabled resolution of 8 Mbp of previously indeterminate sequence. Furthermore, syntenic comparisons identified widespread scaffold misassemblies in the T. spiralis reference genome. The two new assemblies, organized for the first time into three chromosomal scaffolds, will be valuable resources for future studies linking phenotypic traits within each species to their underlying genetic bases.

Species composition of wild reservoir hosts can influence the transmission and maintenance of multi-host vector borne pathogens. The ‘pace of life’ hypothesis proposes that the life history strategy of reservoir hosts can influence pathogen transmission of vector borne generalist pathogens. We use empirical data to parameterize a mathematical model that investigates the impacts of host life history traits on vector transmission dynamics of the vector-borne multi-host parasite Trypanosoma cruzi in habitats characterized by different degrees of deforestation and varying host community structure. The model considers susceptible and infected vector and host populations. When comparing the proportion of vectors infected with T. cruzi predicted by the model with empirical data, we found a trend of increasing vector infection as anthropogenic landscape disturbance increases for both data and model output. The model's vector infection rates were significantly lower than empirical results, but when incorporating host congenital transmission in the model, vector infection approaches field data. We conclude that intervened habitats associated with r-selected host species communities predict higher proportions of infected vectors.

Little is known about the genetic diversity of the protozoan parasite, Giardia duodenalis, infecting humans in Queensland, Australia. The present study typed 88 microscopically Giardia-positive isolates using assemblage-specific primers at the triose phosphate isomerase (tpi) gene and sequenced a subset of isolates at the glutamate dehydrogenase (gdh) gene (n = 30) and tpi locus (n = 27). Using the tpi-assemblage specific primers, G. duodenalis assemblage A and assemblage B were detected in 50% (44/88) and 38·6% (34/88) of samples, respectively. Mixed infections with assemblages A and B were identified in 4·5% (4/88) and assemblage E was identified in 6·8% (6/88) of samples. Sequence analysis at the gdh and tpi loci also confirmed the presence of assemblage E in these isolates. Cyst numbers per gram of feces (g−1) were determined using quantitative polymerase chain reaction and of the isolates that were typed as assemblage E, cyst numbers ranged 13·8–68·3 × 106 cysts g−1. This is the first report of assemblage E in humans in Australia, indicating that in certain settings, this assemblage may be zoonotic.

This paper reviews the occurrence and impact of threadworms, Strongyloides spp., in companion animals and large livestock, the potential zoonotic implications and future research. Strongyloides spp. infect a range of domestic animal species worldwide and clinical disease is most often encountered in young animals. Dogs are infected with Strongyloides stercoralis while cats are infected with different species according to geographical location (Strongyloides felis, Strongyloides tumefaciens, Strongyloides planiceps and perhaps S. stercoralis). In contrast to the other species, lactogenic transmission is not a primary means of infection in dogs, and S. stercoralis is the only species considered zoonotic. Strongyloides papillosus in calves has been linked to heavy fatalities under conditions of high stocking density. Strongyloides westeri and Strongyloides ransomi of horses and pigs, respectively, cause only sporadic clinical disease. In conclusion, these infections are generally of low relative importance in livestock and equines, most likely due to extensive use of macrocyclic lactone anthelmintics and/or improved hygiene. Future prevalence studies need to include molecular typing of Strongyloides species in relation to different hosts. More research is urgently needed on the potential zoonotic capacity of Strongyloides from dogs and cats based on molecular typing, information on risk factors and mapping of transmission routes.

Human population increases, with greater food demands, have resulted in a rapid evolution of livestock food systems, leading to changes in land and water use. The scale of global livestock systems mean that changes in animal health status, particularly in parasite levels, have impacts that go beyond farm and sector levels. To quantify the true impact of parasites in livestock, frameworks that look at both resources and services valued in markets and those that have no true market value are required. Mitigating the effects of parasitic disease in livestock will not only increase productivity, but also improve animal welfare and human health, whilst reducing the environmental burden of livestock production systems. To measure these potential benefits, a One Health approach is needed. This paper discusses the types of methods and the data collection tools needed for a more holistic perspective and provides a framework with its application to coccidiosis in poultry. To build a body of knowledge that allows the ranking of parasite diseases in a wider animal health setting, such One Health frameworks need to be applied more frequently and with rigour. The outcome will improve the allocation of resources to critical constraints on parasite management.

Entamoeba histolytica is the causative agent of amoebic liver abscess (ALA), which course with an uncontrolled inflammation and nitro-oxidative stresses, although it is well known that amoeba has an effective defence mechanisms against this toxic environment, the underlying molecular factors responsible for progression of tissue damage remain largely unknown. The purpose of the present study was to determine during the acute stage of ALA in hamsters, the involvement of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and nuclear factor-kappa B (NF-κB), which are activated in response to oxidative stress. From 12 h post-infection the ALA was visible, haematoxylin-eosin and Masson's trichrome stains were consistent with these observations, and alanine aminotransferase, alkaline phosphatase and γ-glutamyl transpeptidase serum activities were increased too. At 48 h after infection, liver glycogen content was significantly reduced. Western blot analyses showed that 4-Hydroxy-2-nonenal peaked at 12 h, while glycogen synthase kinase-3β, cleaved caspase-3, pNF-κB, interleukin-1β and tumour necrosis factor-α were overexpressed from 12 to 48 h post-infection. Otherwise, Nrf2 and superoxide dismutase-1, decreased at 48 h and catalase declined at 36 and 48 h. Furthermore, heme oxygenase-1 was increased at 12 and 24 h and decreased to normal levels at 36 and 48 h. These findings suggest for the first time that the host antioxidant system of Nrf2 is influenced during ALA.

Plant cysteine proteinases (CPs) from Carica papaya kill parasitic and free-living nematodes in vitro by hydrolysis of the worm cuticle, a mechanism that is different to all commercially available synthetic anthelmintics. We have developed a cheap and effective, rapid-throughput Caenorhabditis elegans-based assay for screening plant CP extracts for anthelmintic activity targeting cuticular integrity. The assay exploits colorimetric methodology for assessment of cuticular damage, and is based on the ability of viable cells to incorporate and bind Neutral red dye within lysosomes and to release the dye when damaged. Living worms are pre-stained with the dye, exposed to CPs and then leakage of the dye through the damaged cuticle is quantified by spectrophotometry. In contrast to motility assays and semi-subjective interpretation of microscopical images, this colorimetric assay is independent of observer bias. Our assay was applied to a series of C. elegans bus mutant strains with leaky cuticles and to cystatin knockout mutants. At ambient temperature and over 0.5–24 h, both bus mutants and the cystatin knockouts were highly susceptible to CPs, whereas wild-type Bristol N2 worms were essentially unstained by Neutral red and unaffected by CPs, providing validation for the utility of this assay.

Syngamid strongylids of the genus Mammomonogamus undoubtedly belong among the least known nematodes with apparent zoonotic potential and the real diversity of the genus remains hard to evaluate without extensive molecular data. Eggs of Mammomonogamus sp. are frequently found in feces of African forest elephants (Loxodonta cyclotis) and western lowland gorillas (Gorilla gorilla gorilla) in Dzanga-Sangha Protected Areas. Using sedimentation-based coproscopic techniques, we found the eggs of Mammomonogamus in 19·7% elephant and 54·1% gorilla fecal samples with 8–55 and 1–24 eggs per gram of fecal sediment for elephants and gorillas, respectively. We used a combination of light microscopy, scanning electron microscopy and analysis of cytochrome c oxidase subunit I (cox1) and a partial sequence of 18S rDNA isolated from single eggs to test the hypothesis of possible Mammomonogamus conspecificity in gorillas and elephants. Whereas 18S rDNA sequences were identical in both gorillas and elephants, we distinguished seven different haplotypes within the cox1. Two haplotypes were found in both gorillas and elephants suggesting sharing of Mammomonogamus. Assignment of the parasite to M. loxodontis is proposed. Provided sequences represent the first genomic data on Mammomonogamus spp.

Paramphistomoids are ubiquitous and widespread digeneans that infect a diverse range of definitive hosts, being particularly speciose in ruminants. We collected adult worms from cattle, goats and sheep from slaughterhouses, and cercariae from freshwater snails from ten localities in Central and West Kenya. We sequenced cox1 (690 bp) and internal transcribed region 2 (ITS2) (385 bp) genes from a small piece of 79 different adult worms and stained and mounted the remaining worm bodies for comparisons with available descriptions. We also sequenced cox1 and ITS2 from 41 cercariae/rediae samples collected from four different genera of planorbid snails. Combining morphological observations, host use information, genetic distance values and phylogenetic methods, we delineated 16 distinct clades of paramphistomoids. For four of the 16 clades, sequences from adult worms and cercariae/rediae matched, providing an independent assessment for their life cycles. Much work is yet to be done to resolve fully the relationships among paramphistomoids, but some correspondence between sequence- and anatomically based classifications were noted. Paramphistomoids of domestic ruminants provide one of the most abundant sources of parasitic flatworm biomass, and because of the predilection of several species use Bulinus and Biomphalaria snail hosts, have interesting linkages with the biology of animal and human schistosomes to in Africa.