Nothing can be more challenging for an author than trying to write a popular book on a subject that evokes disgust in the public at large. In his latest effort, Claude Combes attempts to sell parasites and their life-style to a lay audience. To readers of this journal, this may seem like a simple task; after all, we know that parasites are wonderful creatures. But convincing the average person of this simple fact is a monumental challenge indeed. On the whole, Combes achieves this superbly.

Ichthyosporean parasites (order Dermocystida) can cause morbidity and mortality in amphibians, but their ecology and epidemiology remain understudied. We investigated the prevalence, gross and histologic appearance, and molecular phylogeny of a novel dermocystid in the state-endangered silvery salamander (Ambystoma platineum) and the co-occurring, non-threatened small-mouthed salamander (Ambystoma texanum) from Illinois. Silvery salamanders (N = 610) were sampled at six ephemeral wetlands from 2016 to 2018. Beginning in 2017, 1–3 mm raised, white skin nodules were identified in 24 silvery salamanders and two small-mouthed salamanders from five wetlands (prevalence = 0–11.1%). Skin biopsy histology (N = 4) was consistent with dermocystid sporangia, and necropsies (N = 3) identified infrequent hepatic sporangia. Parasitic 18S rRNA sequences (N = 5) from both salamander species were identical, and phylogenetic analysis revealed a close relationship to Dermotheca viridescens. Dermocystids were not identified in museum specimens from the same wetlands (N = 125) dating back to 1973. This is the first report of Dermotheca sp. affecting caudates in the Midwestern United States. Future research is needed to determine the effects of this pathogen on individual and population health, and to assess whether this organism poses a threat to the conservation of ambystomatid salamanders.

My interest having been aroused in Calliobdella lophii, I requested all my friends engaged upon the sea to keep a look-out for any leeches that might come to hand and especially for Calliobdella. Accordingly on 6. VIII. 1914 I received a specimen of a leech, taken near St Margaret's Hope towards the north-east of S. Ronaldsay in the Isles of Orkney, which as far as I can discover has never been described before, and which presents peculiar and interesting features not wholly dissimilar from those of Calliobdella. I propose to name the leech Ganymedes (or, if this name should be pre-occupied, Ganymedebdella) cratere.

Bovine trichomoniasis is a notifiable, reproductive disease of cattle caused by the parasite Tritrichomonas foetus. Culturing with modified Diamond's medium (MDM) is required to increase the low number of organisms received from a preputial sample, but is limited in application to remote areas as it requires continuous cold chain storage. This study utilized lyophilization to sustain the viability of MDM during transport in lieu of a continuous cold chain. All lyophilized MDM was able to sustain T. foetus after storage for 42 days at 24 °C, and the results demonstrated that lyophilized MDM was equally as viable as refrigerated liquid MDM. Storage of lyophilized MDM at room temperature for 1 and 7 days did not impact T. foetus yield, both with and without exposure to light. A limitation of the lyophilized MDM was demonstrated with a significant decrease in T. foetus yield when the media was stored at 37 and 58 °C. The lyophilization of MDM provides a robust method of transporting and storing medium prior to reconstitution and inoculation, for use in T. foetus diagnosis and surveillance in remote areas.

Parasites often have reduced genomes as their own genes become redundant when utilizing their host as a source of metabolites, thus losing their own de novo production of metabolites. Primate malaria parasites can synthesize vitamin B1 (thiamine) de novo but rodent malaria and other genome-sequenced apicomplexans cannot, as the three essential genes responsible for this pathway are absent in their genomes. The unique presence of functional thiamine synthesis genes in primate malaria parasites and their sequence similarities to bacterial orthologues, have led to speculations that this pathway was horizontally acquired from bacteria. Here we show that the genes essential for the de novo synthesis of thiamine are found also in avian Plasmodium species. Importantly, they are also present in species phylogenetically basal to all mammalian and avian Plasmodium parasites, i.e. Haemoproteus. Furthermore, we found that these genes are expressed during the blood stage of the avian malaria infection, indicating that this metabolic pathway is actively transcribed. We conclude that the ability to synthesize thiamine is widespread among haemosporidians, with a recent loss in the rodent malaria species.

SMYB1 is a Schistosoma mansoni protein highly similar to members of the Y-box binding protein family. Similar to other homologues, SMYB1 is able to bind double- and single-stranded DNA, as well as RNA molecules. The characterization of proteins involved in the regulation of gene expression in S. mansoni is of great importance for the understanding of molecular events that control morphological and physiological changes in this parasite. Here we demonstrate that SMYB1 is located in the cytoplasm of cells from different life-cycle stages of S. mansoni, suggesting that this protein is probably acting in mRNA metabolism in the cytoplasm and corroborating previous findings from our group that showed its ability to bind RNA. Protein–protein interactions are important events in all biological processes, since most proteins execute their functions through large supramolecular structures. Yeast two-hybrid screenings using SMYB1 as bait identified a partner in S. mansoni similar to the SmD3 protein of Drosophila melanogaster (SmRNP), which is important in the assembly of small nuclear ribonucleoprotein complexes. Also, pull-down assays were conducted using immobilized GST-SMYB1 proteins and confirmed the SMYB1-SmRNP interaction. The interaction of SMYB1 with a protein involved in mRNA processing suggests that it may act in processes such as turnover, transport and stabilization of RNA molecules.

The in situ polymerase chain reaction (PCR) results revealed that mouse type A and type C retroviral sequences were transmitted horizontally from the host to schistosomes. The signals to these retroviral sequences were observed in the nuclei of the mesenchymal and reproductive cells of 8-week Schistosoma japonicum. These signals were also detected in the nuclei of the mesenchymal and reproductive cells and in the cytoplasm of the tegumental tubercles of 24-week S. mansoni. Furthermore, mouse type A retroviral sequence was detected in the DNA extracted from the cercariae of both species. However, mouse type C retroviral sequence and mouse type 2 Alu sequence (B2) were difficult to detect in the cercarial DNA of either species. These findings may indicate that some host sequences are propagated in the schistosome progeny, that is to say, not only horizontal but also vertical transfer of the host gene may occur in schistosomes.

The Leptomonas described in this paper has been studied principally in the gut contents and faeces of the larva of the fly, Leia sp., and in moisture obtained from the decaying vegetable matter within which the larvae grow and pupate. The incidence of infection of the larvae has been found to be almost 100 %, only one or two very young specimens being found unparasitized among the hundreds studied.

The following is a description of a Cysticercoid obtained during investigation of the larval cestode fauna of Dundee and Arbroath districts (Harper, 1930). The Cysticercoid was first obtained from Helodrilus (Allolobophora longus Cede) the host containing four larvae; later, two similar larvae were found in Lumbricus terrestris L. Many specimens of these hosts were dissected but only the above two infections were observed.

The two specimens of trematodes herein described were obtained from the intestine of an Indian Ruff, Philomachus pugnax. Of six birds examined, three harboured a few of both species. The genera to which these worms belong have not been hitherto recorded from India.

The new species herein described, collected by Mr Charles Elton in the course of ecological field work in Norway, was very kindly passed on by him to me for identification and description.

Premunition is the state in a disease where an existing infection protects the host from reinfection with the same species. The cause of premunition is not clearly understood. In this study, we hypothesized that kin-selection might be a contributing factor in premunition. To test this theory, sheep were infected either once with a linguiform or smooth vulval morphotype of Haemonchos contortus, twice with the same morphotype or twice with different morphotypes. All infections resulted in a similar number of adult parasites. However, there were differences in the morphotypes recovered providing potential evidence of kin selection. Negative interference competition might also contribute to the reduction of the incoming population. Allelopathic or physical interactions between the parasites may be the mechanism behind the observed phenomena.

Aquaporin (SmAQP) is the most abundant transmembrane protein in the tegument of Schistosoma mansoni. This protein is expressed in all developmental stages and seems to be essential in parasite survival since it plays a crucial role in osmoregulation, nutrient transport and drug uptake. In this study, we utilized the murine model to evaluate whether this protein was able to induce protection against challenge infection with S. mansoni cercariae. A chimeric (c) SmAQP was formulated with Freund's adjuvant for vaccination trial and evaluation of the host's immune response was performed. Our results demonstrated that immunization with cSmAQP induced the production of high levels of specific anti-cSmAQP IgG antibodies and a Th1/Th17 type of immune response characterized by IFN-γ, TNF-α and IL-17 cytokines. However, vaccination of mice with cSmAQP failed to reduce S. mansoni worm burden and liver pathology. Finally, we were unable to detect humoral immune response anti-cSmAQP in the sera of S. mansoni-infected human patients. Our results lead us to believe that SmAQP, as formulated in this study, may not be a good target in the search for an anti-schistosomiasis vaccine.

Visceral leishmaniasis is an endemic protozoonosis observed in over 60 countries, with over 500 000 new cases recorded annually. Although the diagnostic procedure of its symptomatic forms is well established, for asymptomatic patients, who represent about 85% of those infected, there is no consensus on the best method for its identification. Recent studies have presented molecular techniques as viable identification methods, with good sensitivity and specificity indices in asymptomatic individuals. Therefore, we aimed to use molecular methods to assess their effectiveness in identifying the presence of asymptomatic infection by Leishmania infantum (L. infantum) individuals from endemic regions of Brazil. Screening was performed by real-time polymerase chain reaction (qPCR) and confirmed by sequencing the cytochrome B gene. Of the 127 samples [from 608 blood donors who had participated in a previous study, of which 34 were positive by the enzyme-linked immunosorbent assay (ELISA) rK39] tested by qPCR, 31 (24.4%) were positive. In the sequencing of 10 qPCR-positive samples, five were identified as L. infantum. Complimentary samples of the ELISA rK39 and conventional PCR showed only reasonable and low agreement with qPCR, respectively. The qPCR confirmed the presence of infection in five of the 10 sequenced samples, ELISA confirmed three, and the conventional PCR confirmed none.