Birds possess the most diverse assemblage of haemosporidian parasites, although the true diversity is unknown due to high genetic diversity and insufficient sampling across all avian clades. Waterfowl (Order Anseriformes) are an ideal group to discover hidden parasite diversity and examine the role of host ecology in parasite transmission. Waterfowl contain 2 distinct feeding guilds, dabbling and diving, which differ in niche utilization that likely alters vector encounter rates and haemosporidian parasite risk. To determine the role of feeding guild in haemosporidian parasitism we analysed 223 blood samples collected by hunters from the upper Midwest of the United States from 2017 to 2019. Fifty-four individuals were infected by haemosporidian parasites (24·2% prevalence). Infection prevalence differed significantly between dabbling (34·9%, n = 109) and diving (14·0%, n = 114) ducks. Feeding guild was the only host trait that could predict haemosporidian infection risk, with a significantly higher risk in dabbling ducks. Twenty-four haemosporidian lineages were identified, with 9 identified for the first time. Thirteen lineages were found only in dabbling ducks, 5 only in diving ducks and 6 in both feeding guilds. Community analysis showed that each feeding guild harboured a unique parasite community. There was no phylogenetic signal of feeding guild within a phylogenetic reconstruction of North American waterfowl haemosporidian lineages. Our results demonstrate that waterfowl contain a diverse and distinct community of haemosporidian parasites. The unique composition of each feeding guild determines not only haemosporidian infection risk but also community structure. This is the first report of such an impact for waterfowl feeding guilds.

Scabies is a neglected tropical disease caused by the ectoparasitic mite, Sarcoptes scabiei var. hominis (S. scabiei). Common scabies, the most prevalent clinical subtype of scabies, is characterized by pruritus, multiple skin lesions and low mite burden. In contrast, crusted scabies, an extremely contagious variant, is characterized by hyperkeratosis and high mite burden, with or without pruritus. Scabies can be diagnosed based on clinical manifestations, with confirmation obtained through microscopic identification of diagnostic features of S. scabiei. However, owing to the diversity and non-specific nature of its clinical manifestations and insufficient knowledge regarding early-stage clinical manifestations, the diagnosis of crusted scabies continues to be delayed. Herein, we present three cases of scabies with varying degrees of crusting and mite burden. Three patients with physical and microscopic results suggesting scabies were selected for this study. Case 1 had mild crusting and low mite burden, case 2 had severe crusting and high mite burden and case 3 had mild crusting and high mite burden. In this case report, ‘the initial stage of crusted scabies’ refers to the progression from common to crusted scabies. The discussion regarding the diagnostic characteristics of the initial stage of crusted scabies is expected to aid the early diagnosis of crusted scabies.

In this first report of endoparasites from endemic land-mammals of the Galápagos Islands, we describe a new species of cestode of the genus Raillietina (Cyclophyllidea: Davaineidae) from a species of Nesoryzomys and summarize the extent of helminth parasitism in both oryzomyine endemics and introduced species of Rattus. Up to the current time, no helminth parasites have been reported from rodents of the Galápagos, and little work has yet been done describing and synthesizing Galápagos parasite diversity. In historical times, several species of autochthonous rodents have occupied the islands including: Nesoryzomys narboroughi Heller 1904, N. fernandinae Hutterer and Hirsch 1979, N. swarthi Orr, 1938, and Aegialomys galapagoensis (Waterhouse, 1839). Colonization of the islands by humans brought 3 known species of synanthropic rodents: Rattus rattus, R. norvegicus, and Mus musculus which are suspected to have caused the extinction of at least 3 other oryzomyines in historical times.

Plant secondary metabolites (PSMs) may improve gastrointestinal health by exerting immunomodulatory, anti-inflammatory and/or antiparasitic effects. Bark extracts from coniferous tree species have previously been shown to reduce the burden of a range of parasite species in the gastrointestinal tract, with condensed tannins as the potential active compounds. In the present study, the impact of an acetone extract of pine bark (Pinus sylvestris) on the resistance, performance and tolerance of genetically diverse mice (Mus musculus) was assessed. Mice able to clear an infection quickly (fast responders, BALB/c) or slowly (slow responders, C57BL/6) were infected orally with 200 infective third-stage larvae (L3) of the parasitic nematode Heligmosomoides bakeri or remained uninfected (dosed with water only). Each infection group of mice was gavaged for 3 consecutive days from day 19 post-infection with either bark extract or dimethyl sulphoxide (5%) as vehicle control. Oral administration of pine bark extract did not have an impact on any of the measured parasitological parameter. It did, however, have a positive impact on the performance of infected, slow-responder mice, through an increase in body weight (BW) and carcase weight and reduced feed intake by BW ratio. Importantly, bark extract administration had a negative impact on the fast responders, by reducing their ability to mediate the impact of parasitism through reducing their performance and tolerance. The results indicate that the impact of PSMs on parasitized hosts is affected by host's genetic susceptibility, with susceptible hosts benefiting more from bark extract administration compared to resistant ones.

Avian Plasmodium parasites can be pathogenic to their vertebrate hosts. Although cases of anaemia are frequently reported in parasitized birds, the potential damage caused by the parasite during the exoerythrocytic reproduction phase remains poorly investigated. Here, we report 2 individuals of red-legged seriemas (Cariama cristata) infected with 2 different lineages of Plasmodium huffi, one of them exhibiting potential malarial-compatible tissue lesions in the spleen, liver, brain and lungs, alongside molecular confirmation of parasite presence in the spleen. Previously classified as specific to birds from the order Piciformes, this parasite has shown different associated lineages amplified across diverse host orders in South America (Anseriformes, Charadriiformes, Columbiformes, Galliformes, Pelecaniformes and Passeriformes). Those infections, however, were defined as abortive due to the absence of gametocytes visualized in blood smear slides. Herein, we confirm P. huffi as a generalist parasite based on the first morphological characterization in the peripheral blood of a bird outside the Piciformes order. This is also the first morphological and molecular description of a Plasmodium species in Cariamiformes. In addition to the morphological analyses, we have also proposed a novel phylogenetic hypothesis based on the partial cytb gene and the near-complete mitochondrial genome of this parasite. Our findings support that the division of the genus Plasmodium into subgenera is not monophyletic, as P. (Huffia) huffi and its associated lineages cluster more closely with Plasmodium (Haemamoeba) gallinaceum than with Plasmodium (Huffia) elongatum.

Coinfection of a host by more than 1 parasite is more common than single infection in wild environments and can have differing impacts, although coinfections have relatively rarely been quantified. Host immune responses to coinfection can contribute to infection costs but are often harder to predict than those associated with single infection, due to the influence of within-host parasite–parasite interactions on infection virulence. To first quantify coinfection in a common bird species, and then to test for immune-related impacts of coinfection, we investigated the prevalence and immune response to avian haemosporidian (genera: Plasmodium, Haemoproteus and Leucocytozoon) coinfection in wild blackbirds. Coinfection status was diagnosed using a 1-step multiplex polymerase chain reaction, immune response was quantified through white blood cell counts and heterophil: lymphocyte ratios, and parasitaemia was quantified for each infected sample. We detected high rates of haemosporidian infection and coinfection, although neither impacted immune activity, despite a significantly higher parasitaemia in individuals experiencing double vs single infection. This suggests that immune-related costs of haemosporidian single and coinfection are low in this system. This could be due to long-term host–parasite coevolution, which has decreased infection virulence, or a consequence of reduced costs associated with chronic infections compared to acute infections. Alternatively, our results may obscure immune-related costs associated with specific combinations of coinfecting haemosporidian genera, species or lineages. Future research should investigate interactions that occur between haemosporidian parasites within hosts, as well as the ways in which these interactions and resulting impacts may vary depending on parasite identity.

The crayfish plague pathogen Aphanomyces astaci (Oomycota: Saprolegniales) is native to North America but expanded with its crayfish hosts to other regions. In most of its invaded range, A. astaci haplotypes are associated with specific American crayfish, probably due to introduction bottlenecks, but haplotype diversity is higher and clear host-specific associations are lacking in its native range. However, little is known about the infection rate and load of this pathogen in North America. We investigated the distribution, prevalence and genetic variation of A. astaci in Pennsylvania (eastern USA), where multiple native and introduced crayfish species (family Cambaridae) occur. We used A. astaci-specific quantitative PCR to screen 533 individuals representing 8 crayfish species (2 Cambarus and 6 Faxonius) from 49 sites. Faxonius limosus, an American species first introduced to Europe and carrier of A. astaci genotype group E, was of particular interest. We confirmed A. astaci infections in 76% of sites in all but 1 host taxon, with the pathogen infection rate and load comparable to established populations of North American crayfish studied in Europe and Japan. Despite the absence of highly infected hosts, we genotyped A. astaci from 14 sites. We only detected 2 mitochondrial haplotypes, but nuclear markers indicated the presence of at least 4 distinct pathogen genotypes, none documented from invaded areas in Europe or Asia. Genotype group E was not detected in F. limosus, possibly due to limited spatial distribution of the original strain. Our results highlight both benefits and limitations of combining multiple pathogen genotyping methods.

Different agencies have emphasized the need to evaluate current serological methods for screening patients with suspected urogenital schistosomiasis. However, there is still a lack of evidence regarding the most appropriate methods for this purpose. Here we assessed the diagnostic efficacy of a newly developed serological technique that utilizes the recombinant protein Sh-TSP-2, applied to the urine and serum of migrants suspected of having urogenital schistosomiasis. The sensitivity, specificity, positive and negative predictive values of an in-house enzyme-linked immunosorbent assay (ELISA) using the recombinant protein Sh-TSP-2 were analysed and compared with other commercial serological methods. Due to the limitations of microscopy as a perfect reference method, a latent class analysis (LCA) and composite reference standard (CRS) approach was used to determine the sensitivity and specificity of each test. According to the LCA model, the commercial tests NovaLisa® and immunochromatography test (ICT) immunoglobulin G–immunoglobulin M (IgG–IgM) presented the highest sensitivity (100%), whereas the Sh-TSP-2 serum ELISA test had 79.2%. The Sh-TSP-2 urine and serum ELISA tests had the highest specificities among the serological methods (87.5 and 75%, respectively). CRS modelling showed that the ICT IgG–IgM, NovaLisa® and Sh-TSP-2 serum tests led in sensitivity at 97.1, 88.6 and 71.4%, respectively, with all tests except that the ICT IgG–IgM test having a specificity >90%. Sh-TSP-2 has been validated as a screening tool for patients suspected of having urogenital schistosomiasis. Although commercial serological tests have shown higher sensitivities, Sh-TSP-2 could be valuable for confirming results from tests with lower specificity. Nevertheless, further studies with larger patient cohorts are necessary to fully verify its potential.

Generalist parasites experience selective pressures from the various host species they infect. However, it is unclear if parasite transmission among host species precludes the establishment of host-specific adaptations and population genetic structure. We assessed the population genetic structure of the vector-transmitted avian haemosporidian parasite Haemoproteus majoris (lineage WW2; n = 34 infections) in a single site in southern Sweden among 10 of its host species. The 2 best-sampled host genera were Phylloscopus (2 species, n = 15 infections) and Sylvia (4 species, n = 15). We designed a sequence capture protocol to isolate 1.13 Mbp (ca. 5%) of the parasite genome and identified 1399 variable sites among the sequenced infections. In a principal components analysis, infections of Phylloscopus and Sylvia species mostly separated along the first 2 principal components. Sites with the highest FST values between the genera were found in genes that have mostly not been implicated in infection pathways, but several sites code for amino acid changes. An analysis of molecular variance confirmed significant variation among host genera, but not among host species within genera. The distribution of Tajima’s D among sequenced loci was negatively skewed, plausibly reflecting a history of bottleneck followed by population expansion. Tajima’s D was lower in infections of Phylloscopus than Sylvia, plausibly because WW2 began infecting Phylloscopus hosts after it was already a parasite of Sylvia hosts. Our results provide evidence of vector-transmitted parasite population differentiation among host species in a single location. Future work should focus on identifying the mechanisms underlying this genetic population structure.

Members of Sinistroporomonorchis Wee, Cutmore, Pérez-del-Olmo & Cribb, 2020 represent a small group of trematodes belonging to the Monorchiidae Odhner, 1911 with 5 species described from mugilid hosts. Specimens consistent with the generic concept of Sinistroporomonorchis were obtained from Floridichthys polyommus (Cyprinodontidae); most of them were juveniles from 4 localities within the Yucatán Peninsula. After a detailed morphological examination including scanning electron microscopy images and a principal component analysis, the specimens collected represented a new species, Sinistroporomonorchis bolini n. sp. The new species can be differentiated by the presence of an overall large pharynx including the proportion of pharynx width to oral sucker width, a uterus arranged in 2 main lateral fields, and by presenting robust caeca. In addition, sequences of the 28S of large subunit of nuclear ribosomal RNA and cox1 of the mitochondrial DNA were obtained. Phylogenetic trees inferred from each dataset, placed all the specimens in a monophyletic clade, confirming that the isolates belonged to the same species. The new species is the sixth described for the genus Sinistroporomonorchis, the fifth described from the Yucatán Peninsula and the first described from a non-mugilid host.

The aim was to assess the efficacy of ivermectin vs moxidectin for treating Strongyloides stercoralis infection. Ovid MEDLINE, Embase and Web of Science databases were searched for studies comparing ivermectin and moxidectin from inception to February 2024. The outcomes: elimination of infection or parasitological cure, mortality and serious adverse events. We calculated odds ratios (ORs) with 95% confidence intervals (CIs) for dichotomous data. Heterogeneity was assessed using Chi2 test for statistical heterogeneity and results of the I2 statistic. Two trials met the inclusion criteria that included 821 adult participants. Both studies were conducted in southeast Asia (Cambodia and Laos). Neither trial included immunocompromised patients. The mean age of the participants ranged from 40 to 45 years old, with a similar distribution of males and females. For all participants, S. stercoralis infection was confirmed by Baermann method. The evidence was moderate for parasitological cure rate. Certainty was downgraded by 1 level because of imprecision. Moxidectin was not inferior to ivermectin: OR 0.67, 95% CI 0.36–1.25 (P = 0.21), I2 = 0%, 821 participants. No deaths were reported in either trial. One trial reported mild adverse events. In total, 153/726 (21%) participants had an adverse event. The most reported symptoms were abdominal pain and headache. There is evidence for moderate quality that moxidectin is non-inferior to, and as safe as ivermectin; however, more high-quality and well-designed trials are needed. For patients with some underlying immunosuppressive disorder, or in patients who are very young or very old, current data are insufficient to be recommended.

The nutria was introduced to Europe from South America and kept for the fur industry. This semiaquatic rodent became a well-established species in the Czech Republic; however, it still poses a significant threat to the native fauna, not only as a natural competitor but also as a vector of non-indigenous parasites. Our research aimed to investigate the diversity of endoparasitic helminths in nutria, with a particular focus on assessing the risk posed by helminth species with zoonotic potential. A total of 46 nutria cadavers were collected at 8 locations in the Morava River basin and examined using standard parasitological post-mortem procedures. Additionally, coprological and molecular methods were used to identify the parasites. The presence of 6 helminth species was revealed. The highest prevalence was observed for Strongyloides myopotami (78.3%) and Trichuris myocastoris (37.0%), both of which are host-specific nematodes of nutria. Only 2 trematode taxa were recorded (Echinostoma sp. and a representative of the family Psilostomidae). The presence of alveolar hydatid cysts of Echinococcus multilocularis in the livers of 5 nutria specimens was also recorded. Herein, we provide novel molecular data for each parasite species collected, which is valuable for future phylogenetic analyses. Our findings also demonstrate that nutria in the Czech Republic serve as a carrier of helminths with zoonotic potential, particularly E. multilocularis and S. myopotami. Although the nutria is a relatively new species in local fauna, its synanthropic behaviour raises concerns about potential threats to human health, underscoring the importance of exercising caution when handling these animals.

Gastrointestinal infections constitute a significant global health concern, particularly in tropical and subtropical regions, caused by various pathogens. Among these, Cryptosporidium spp. and Giardia duodenalis are noteworthy due to their zoonotic potential. In Algeria, molecular epidemiological data on cryptosporidiosis and giardiasis are limited. To fill this gap, the present study aimed to examine the transmission dynamics of Cryptosporidium spp., and Giardia duodenalis in various households. A total of 216 samples were collected from the rural Guelma and Souk Ahras provinces, located in the eastern part of Algeria. These included human and animal faeces, as well as water and soil samples. DNA was extracted, followed by nested PCR targeting the SSU rRNA gene to detect Cryptosporidium spp., while the gp60 gene was amplified for subtyping. Detection of G. duodenalis was performed by qPCR targeting the SSU rRNA gene, followed by amplification of tpi, bg and gdh genes for genotyping and subtyping. Several Cryptosporidium species, including C. bovis, C. ryanae, C. andersoni and C. parvum, were identified in human, animal and environmental samples. The zoonotic C. parvum subtype IIaA17G2R1 was detected in human, animal and soil samples. Giardia duodenalis assemblage B was detected in a human sample, while assemblage E was found in cattle and sheep. The current investigation underscores the importance of the One Health approach in addressing issues related to intestinal parasites, highlighting the need for improved surveillance and control measures in rural settings.

Elevated levels of IL-6 in plasma are associated with the severity of visceral leishmaniasis (VL). The clinical manifestations of VL vary among patients, influenced by host factors and the virulence of the Leishmania infantum parasite. Considering that severe VL may result from an exaggerated inflammatory response, this study investigated whether IL-6 could serve as a biomarker to identify pro-inflammatory virulence factors. We conducted a genome-wide association study (GWAS) analysis on L. infantum isolates from patients with VL, whose IL-6 concentrations were measured. The analysis revealed that the relationship between IL-6 levels and clinical outcomes (survival vs mortality) had an area under the curve (AUC) of 0.67 (95% CI 0.52–0.81). A cut-off of 391.7 pg mL−1 for IL-6 was established to conduct a logistic regression analysis. We identified 10 029 single nucleotide variants (SNVs) across 62 genomes, resulting in 6,948 SNVs after filtering, of which 6,341 are located in protein-coding regions. The association analysis with PLINK identified 722 variants, of which 35 showed significant associations, with odds ratios ≥3.3, primarily in coding regions. These findings demonstrate that IL-6 levels tended to be associated with the fatal outcome of VL and highlight 35 novel genetic variants that could serve as potential biomarkers for prognosis. Further research into the biological role of these variants may lead to new therapeutic targets and improve the clinical management of VL, especially in identifying high-risk patients.

Identifying factors that drive among-individual variation in mixed parasitic infections is fundamental to understanding the ecology and evolution of host–parasite interactions. However, a lack of non-invasive diagnostic tools to quantify mixed infections has restricted their investigation for host populations in the wild. This study applied DNA metabarcoding on parasite larvae cultured from faecal samples to characterize mixed strongyle infections of 320 feral horses on Sable Island, Nova Scotia, Canada, in 2014 to test for the influence of host (age, sex and reproductive/social status) and environmental (location, local density and social group membership) factors on variation. Twenty-five strongyle species were identified, with individual infections ranging from 3 to 18 species with a mean richness (±1 s.d.) of 10.8 ± 3.1. Strongyle eggs shed in faeces were dominated by small strongyle (cyathostomins) species in young individuals, transitioning to large strongyles (Strongylus spp.) in adults. Egg counts were highest in young individuals and in the west or centre of the island for most species. Individuals in the same social group had similar parasite communities, supporting the hypothesis that shared environment may drive parasite assemblages. Other factors such as local horse density, sex, date and reproductive/social status had minimal impacts on infection patterns. This study demonstrates that mixed infections can be dynamic across host ontogeny and space and emphasizes the need to consider species-specific infection patterns when investigating mixed infections.

The migration of Mongolian gazelles (Procapra gutturosa) poses a potential risk of outbreak for zoonotic intestinal protozoan parasite infections. This study aims to investigate the infection status of zoonotic intestinal protozoan parasites in these migratory Mongolian gazelles. We collected 120 fecal samples from Mongolian gazelles during their migration from Mongolia to China in December 2023. These samples were analysed using amplification and sequencing of partial SSU rRNA genes to detect the 4 presence of zoonotic intestinal protozoan parasites and characterize their genotypes. Our analysis revealed the presence of several zoonotic intestinal protozoan parasites in the sampled Mongolian gazelles. Cryptosporidium spp. was detected in 14.17% (17/120) of the samples, followed by Cystoisospora belli in 13.33% (16/120), Blastocystis sp. in 16.67% (20/120) and Cyclospora cayetanensis in 30.00% (36/120). Moreover, we identified novel host-adapted genotypes of Cryptosporidium spp. and C. belli, as well as the presence of ST2 and ST13 Blastocystis sp. subtypes, while distinct genotypes were found in Blastocystis sp. and C. cayetanensis. This study revealed the status of 4 prevalent zoonotic intestinal protozoan parasite infections in Mongolian gazelles and provided crucial insights into their characteristics. The prevalence of these parasites in the population highlights the potential risk of cross-border transmission of infectious diseases associated with long-distance migration. Furthermore, the identification of novel genotypes contributes to our understanding of the genetic diversity and adaptation of these parasites. These findings can inform the development of protective measures to mitigate the impact of these infections on the health and survival of Mongolian gazelles.

The functional diversity structure of a community can be represented as a combination of three additive components (species dominance D, functional redundancy R, and functional diversity Q) (DRQ approach in which different facets of functional differences between species are considered simultaneously). We applied this concept to assemblages of fleas and gamasid mites parasitic on small mammals at continental (across regions of the Palearctic) and regional (across sampling sites in Slovakia) scales and asked: What are the relative effects of host species, biome/habitat type, and geographic locality on the DRQ composition of a parasite assemblage? At the continental scale, regions were partitioned according to predominant biome or geographic position in a continental section. At the regional scale, sampling sites were partitioned according to habitat type or geographic locality. We tested for differences in the functional diversity structure (measured as the DRQ composition) of an ectoparasite assemblage (a) within a host species between biomes/habitat types or continental sections/localities and (b) between host species within a biome/habitat type or a continental section/locality. At both scales, the functional diversity structure of both flea and mite assemblages differed mainly between host species within a biome/habitat or geographic regions/locations, whereas differences in the DRQ composition between biomes/habitats or geographic regions/locations were only detected in a few host species. We compare our results with the results of earlier studies and conclude that the DRQ approach has an advantage over a single diversity metric and allows a better understanding of spatial variation in different facets of ectoparasite diversity.

Paleoparasitological studies have made important contributions to our understanding of the past epidemiology of parasites, infection in past populations and lifestyle in the past. In some cases, these ancient parasites can also provide evidence for long distance travel or migration of people in the past. Three sediment samples from a 15th–16th c. CE latrine from the Spanish nation house in Bruges, Belgium were analysed for preserved helminth eggs using microscopy. Bruges was a major trading centre in medieval Europe, thus it was home to a large merchant population with extensive trading networks. Paleoparasitological analysis revealed a preserved parasite egg from Schistosoma mansoni, which causes intestinal schistosomiasis. Roundworm, whipworm, liver fluke and Taenia tapeworm eggs were also found in the latrine which is consistent with parasites previously found in the local population in the medieval period. These new data provide direct evidence for the movement of S. mansoni outside of its endemic area. Today the vast majority of S. mansoni infections occur in Sub-Saharan Africa, with additional endemic areas in the Arabian peninsula and South America. The introduction of S. mansoni into South America is proposed to have occurred relatively recently in human history, as the result of forced movement of people from Africa to the Americas with the Atlantic slave trade. Thus, this infection may have occurred in a merchant who acquired the parasite during trade voyages to Africa or in an individual living in Africa who migrated to Bruges.