Parasite Diversity Research Articles

Loss of species and genetic diversity during colonization: Insights from acanthocephalan parasites in northern European seals.

Studies on host-parasite systems that have experienced distributional shifts, range fragmentation, and population declines in the past can provide information regarding how parasite community richness and genetic diversity will change as a result of anthropogenic environmental changes in the future. Here, we studied how sequential postglacial colonization, shifts in habitat, and reduced host population sizes have influenced species richness and genetic diversity of Corynosoma (Acanthocephala: Polymorphidae) parasites in northern European marine, brackish, and freshwater seal populations. We collected Corynosoma population samples from Arctic, Baltic, Ladoga, and Saimaa ringed seal subspecies and Baltic gray seals, and then applied COI barcoding and triple-enzyme restriction-site associated DNA (3RAD) sequencing to delimit species, clarify their distributions and community structures, and elucidate patterns of intraspecific gene flow and genetic diversity. Our results showed that Corynosoma species diversity reflected host colonization histories and population sizes, with four species being present in the Arctic, three in the Baltic Sea, two in Lake Ladoga, and only one in Lake Saimaa. We found statistically significant population-genetic differentiation within all three Corynosoma species that occur in more than one seal (sub)species. Genetic diversity tended to be high in Corynosoma populations originating from Arctic ringed seals and low in the landlocked populations. Our results indicate that acanthocephalan communities in landlocked seal populations are impoverished with respect to both species and intraspecific genetic diversity. Interestingly, the loss of genetic diversity within Corynosoma species seems to have been less drastic than in their seal hosts, possibly due to their large local effective population sizes resulting from high infection intensities and effective intra-host population mixing. Our study highlights the utility of genomic methods in investigations of community composition and genetic diversity of understudied parasites.

Increasing Prevalence of Artemisinin-Resistant HRP2-Negative Malaria in Eritrea

BackgroundAlthough the clinical efficacy of antimalarial artemisinin-based combination therapies in Africa remains high, the recent emergence of partial resistance to artemisinin in Plasmodium falciparum on the continent is troubling, given the lack of alternative treatments.MethodsIn this study, we used data from drug-efficacy studies conducted between 2016 and 2019 that evaluated 3-day courses of artemisinin-based combination therapy (artesunate–amodiaquine or artemether–lumefantrine) for uncomplicated malaria in Eritrea to estimate the percentage of patients with day-3 positivity (i.e., persistent P. falciparum parasitemia 3 days after the initiation of therapy). We also assayed parasites for mutations in Pfkelch13 as predictive markers of partial resistance to artemisinin and screened for deletions in hrp2 and hrp3 that result in variable performance of histidine rich protein 2 (HRP2)–based rapid diagnostic tests for malaria.ResultsWe noted an increase in the percentage of patients with day-3 positivity from 0.4% (1 of 273) in 2016 to 1.9% (4 of 209) in 2017 and 4.2% (15 of 359) in 2019. An increase was also noted in the prevalence of the Pfkelch13 R622I mutation, which was detected in 109 of 818 isolates before treatment, from 8.6% (24 of 278) in 2016 to 21.0% (69 of 329) in 2019. The odds of day-3 positivity increased by a factor of 6.2 (95% confidence interval, 2.5 to 15.5) among the patients with Pfkelch13 622I variant parasites. Partial resistance to artemisinin, as defined by the World Health Organization, was observed in Eritrea. More than 5% of the patients younger than 15 years of age with day-3 positivity also had parasites that carried Pfkelch13 R622I. In vitro, the R622I mutation conferred a low level of resistance to artemisinin when edited into NF54 and Dd2 parasite lines. Deletions in both hrp2 and hrp3 were identified in 16.9% of the parasites that carried the Pfkelch13 R622I mutation, which made them potentially undetectable by HRP2-based rapid diagnostic tests.ConclusionsThe emergence and spread of P. falciparum lineages with both Pfkelch13-mediated partial resistance to artemisinin and deletions in hrp2 and hrp3 in Eritrea threaten to compromise regional malaria control and elimination campaigns. (Funded by the Bill and Melinda Gates Foundation and others; Australian New Zealand Clinical Trials Registry numbers, ACTRN12618001223224, ACTRN12618000353291, and ACTRN12619000859189.)

Zoonotic simian malaria parasites in free-ranging Macaca fascicularis macaques and human malaria patients in Thailand, with a note on genetic characterization of recent isolates

Despite the natural occurrences of human infections by Plasmodium knowlesi, P. cynomolgi, P. inui, and P. fieldi in Thailand, investigating the prevalence and genetic diversity of the zoonotic simian malaria parasites in macaque populations has been limited to certain areas. To address this gap, a total of 560 long-tailed macaques (Macaca fascicularis) and 20 southern pig-tailed macaques (M. nemestrina) were captured from 15 locations across 10 provinces throughout Thailand between 2018 and 2021 for investigation of malaria, as were 15 human samples residing in two simian-malaria endemic provinces, namely Songkhla and Satun, who exhibited malaria-like symptoms. Using PCR techniques targeting the mitochondrial cytb and cox1 genes coupled with DNA sequencing, 40 long-tailed macaques inhabiting five locations had mono-infections with one of the three simian malaria species. Most of the positive cases of macaque were infected with P. inui (32/40), while infections with P. cynomolgi (6/40) and P. knowlesi (2/40) were less common and confined to specific macaque populations. Interestingly, all 15 human cases were mono-infected with P. knowlesi, with one of them residing in an area with two P. knowlesi-infected macaques. Nucleotide sequence analysis showed a high level of genetic diversity in P. inui, while P. cynomolgi and P. knowlesi displayed limited genetic diversity. Phylogenetic and haplotype network analyses revealed that P. inui in this study was closely related to simian and Anopheles isolates from Peninsular Malaysia, while P. cynomolgi clustered with simian and human isolates from Asian countries. P. knowlesi, which was found in both macaques and humans in this study, was closely related to isolates from macaques, humans, and An. hackeri in Peninsular Malaysia, suggesting a sylvatic transmission cycle extending across these endemic regions. This study highlights the current hotspots for zoonotic simian malaria and sheds light on the genetic characteristics of recent isolates in both macaques and human residents in Thailand.

Intra-host Trypanosoma cruzi strain dynamics shape disease progression: the missing link in Chagas disease pathogenesis.

Chronic Chagasic cardiomyopathy develops years after infection in 20-40% of patients, but disease progression is poorly understood. Here, we assessed Trypanosoma cruzi parasite dynamics and pathogenesis over a 2.5-year period in naturally infected rhesus macaques. Individuals with better control of parasitemia were infected with a greater diversity of parasite strains compared to those with increasing parasitemia over time. Also, the in vivo parasite multiplication rate decreased with increasing parasite diversity, suggesting competition among strains or a stronger immune response in multiple infections. Significant differences in electrocardiographic (ECG) profiles were observed in Chagasic macaques compared to uninfected controls, suggesting early conduction defects, and changes in ECG patterns over time were observed only in macaques with increasing parasitemia and lower parasite diversity. Disease progression was also associated with plasma fibronectin degradation, which may serve as a biomarker. These data provide a novel framework for the understanding of Chagas disease pathogenesis, with parasite diversity shaping disease progression.IMPORTANCEChagas disease progression remains poorly understood, and patients at increased risk of developing severe cardiac disease cannot be distinguished from those who may remain asymptomatic. Monitoring of Trypanosoma cruzi strain dynamics and pathogenesis over 2-3 years in naturally infected macaques shows that increasing parasite diversity in hosts is detrimental to parasite multiplication and Chagasic cardiomyopathy disease progression. This provides a novel framework for the understanding of Chagas disease pathogenesis.

Gastrointestinal parasites of domestic sheep from Patagonia throughout historical times: A paleoparasitological approach.

Sheep husbandry in Patagonia, Argentina, started at the beginning of the 20th century from European settlers. Sanitary management is minimal, which has serious implications for the sheep health. Sheep can be infested by diverse parasites, with well over 150 species of internal and external parasites reported worldwide. Gastrointestinal parasitism is one of the most common and important infections in sheep concerning the health status, and is the cause of significant morbidity and mortality, which generates considerable production losses. The present work is the first paleoparasitological study of sheep coprolites from Patagonia throughout historical times. Fifty-seven coprolites from the 'Cueva Peligro' archaeological site (Patagonia, Argentina) were analyzed using the Lutz spontaneous sedimentation technique and the modified Faust flotation technique. Ancient DNA (aDNA) study was carried out in order to identify the zoological origin of coprolites. The results obtained from Cytb analysis confirmed the identity of the host as Ovis aries (domestic sheep). A total of 39 coprolites examined were positive for parasites by at least one of the studied methods. Thirty eight samples were positive by spontaneous sedimentation and 10 samples were positive by the modified Faust technique. The parasitic fauna found was Trichuris sp. (Trichinellida: Trichuridae), Nematodirus sp., Nematodirus spathiger (Strongylida, Trichostrongyloidea), two unidentified Strongylida-type egg morphotypes, Fasciola hepatica (Trematoda: Digenea) and coccidia oocysts of Eimeria spp. (Apicomplexa: Eimeriidae). The modified Faust technique provided satisfactory results in terms of sensitivity for the detection of Eimeria spp. The use of this methodology as a routine procedure enables the processing of ancient samples, in order to increase recoveries. These results show the importance of integrating different diagnostic approaches in order to optimize parasitic findings. The recorded parasite diversity appears to have not changed over the last 120years. The study displayed the presence of different parasitic species which suggests potential exposure to parasitic diseases through the historical times, both for sheep and for other domestic and wild mammals from Patagonia. Also, suggests the presence of fasciolosis, a zoonotic disease that implies a potential risk for Patagonian populations in the past.

Genetic diversity and molecular evolution of Plasmodium vivax Duffy Binding Protein and Merozoite Surface Protein-1 in northwestern Thailand.

The local diversity and population structure of malaria parasites vary across different regions of the world, reflecting variations in transmission intensity, host immunity, and vector species. This study aimed to use amplicon sequencing to investigate the genotypic patterns and population structure of P. vivax isolates from a highly endemic province of Thailand in recent years. Amplicon deep sequencing was performed on 70 samples for the 42-kDa region of pvmsp1 and domain II of pvdbp. Unique haplotypes were identified and a network constructed to illustrate genetic relatedness in northwestern Thailand. Based on this dataset of 70 samples collected between 2015 and 2021, 16 and 40 unique haplotypes were identified in pvdbpII and pvmsp142kDa, respectively. Nucleotide diversity was higher in pvmsp142kDa than in pvdbpII (π=0.027 and 0.012), as was haplotype diversity (Hd=0.962 and 0.849). pvmsp142kDa also showed a higher recombination rate and higher levels of genetic differentiation (Fst) in northwestern Thailand versus other regions (0.2761-0.4881). These data together suggested that the genetic diversity of P. vivax in northwestern Thailand at these two studied loci evolved under a balancing selection, most likely host immunity. The lower genetic diversity of pvdbpII may reflect its stronger functional constrain. In addition, despite the balancing selection, a decrease in genetic diversity was observed. Hd of pvdbpII decreased from 0.874 in 2015-2016 to 0.778 in 2018-2021; π of pvmsp142kDa decreased from 0.030 to 0.022 over the same period. Thus, the control activities must have had a strong impact on the parasite population size. The findings from this study provide an understanding of P. vivax population structure and the evolutionary force on vaccine candidates. They also established a new baseline for tracking future changes in P. vivax diversity in the most malarious area of Thailand.

DNA metabarcoding reveals spatial and temporal variation of fish eye fluke communities in lake ecosystems

Eye flukes (Diplostomidae) are diverse and abundant trematode parasites that form multi-species communities in fish with negative effects on host fitness and survival. However, the environmental factors and host-related characteristics that determine species diversity, composition, and coexistence in such communities remain poorly understood. Here, we developed a cost-effective cox1 region-specific DNA metabarcoding approach to characterize parasitic diplostomid communities in two common fish species (Eurasian perch and common roach) collected from seven temperate lakes in Estonia. We found considerable inter- and intra-lake, as well as inter-host species, variation in diplostomid communities. Sympatric host species characterization revealed that parasite communities were typically more diverse in roach than perch. Additionally, we detected five positive and two negative diplostomid species associations in roach, whereas only a single negative association was observed in perch. These results indicate that diplostomid communities in temperate lakes are complex and dynamic systems exhibiting both spatial and temporal heterogeneity. They are influenced by various environmental factors and by host-parasite and inter-parasite interactions. We expect that the described methodology facilitates ecological and biodiversity research of diplostomid parasites. It is also adaptable to other parasite groups where it could serve to improve current understanding of diversity, distribution, and interspecies interactions of other understudied taxa.

Exploring the genetic diversity of Eimeria acervulina: A polymerase chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) approach

Eimeria, protozoan parasites that can cause the disease coccidiosis, pose a persistent challenge to poultry production and welfare. Control is commonly achieved using good husbandry supplemented with routine chemoprophylaxis and/or live parasite vaccination, although widespread drug resistance and challenges to vaccine supply or cost can prove limiting. Extensive effort has been applied to develop subunit anticoccidial vaccines as scalable, cost-effective alternatives, but translation to the field will require a robust understanding of parasite diversity. Using a new Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) panel we begin to describe the genetic diversity of Eimeria acervulina populations in Africa and Europe. PCR-RFLP genotyping E. acervulina populations sampled from commercial broiler and layer chickens reared in Nigeria or the United Kingdom (UK) and Republic of Ireland (RoI) revealed comparable levels of haplotype diversity, in direct contrast to previous descriptions from the close relative E. tenella. Here, 25 distinct PCR-RFLP haplotypes were detected from a panel of 42 E. acervulina samples, including 0.7 and 0.5 haplotypes per sample in Nigeria (n = 20) and the UK/RoI (n = 14), respectively. All but six haplotypes were found to be country-specific. The PCR-RFLP markers immune mapped protein 1 (IMP1) and heat shock protein 90 (HSP90) were most informative for Nigerian E. acervulina, while microneme protein 3 (MIC3) and HSP90 were most informative in UK/RoI populations. High haplotype diversity within E. acervulina populations may indicate frequent genetic exchange and potential for rapid dissemination of genetic material associated with escape from selective barriers such as anticoccidial drugs and future subunit vaccines.

Demographic, environmental and physiological predictors of gastrointestinal parasites in urban raccoons.

Raccoons are host to diverse gastrointestinal parasites, but little is known about the ecology of these parasites in terms of their interactions with each other during coinfections, their interactions with host physiology and environmental factors, and their impact on raccoon health and survival. As a first step, we investigated the patterns of parasite infection and their demographic distribution in an urban-suburban population of raccoons trapped in the summers and autumns of 2018 and 2019. We collected faecal samples, demographic data, morphometric measurements, and blood smears, and used GPS data to classify trapping location by land cover type. Faecal floats were performed to detect and quantify gastrointestinal nematode eggs and coccidia oocysts, and white blood cell differentials were performed on blood smears to characterise white blood cell distributions. Data were analysed cross-sectionally and, where possible, longitudinally, using generalised linear models. Overall, 62.6% of sampled raccoons were infected with gastrointestinal nematodes, and 82.2% were infected with gastrointestinal coccidia. We analysed predictors of infection status and faecal egg count for three different morphotypes of nematode-Baylisascaris, strongyle, and capillariid nematodes-and found that infection status and egg count varied with Year, Month, Age class, Land cover, and coinfection status, though the significance of these predictors varied between nematode types. Gastrointestinal coccidia prevalence varied with Year, Month, Age class, strongyle infection status, and capillariid infection status. Coccidia oocyst counts were lower in adults and in October, but higher in females and in raccoons trapped in areas with natural land cover; furthermore, coccidia oocysts were positively associated with capillariid faecal egg counts. We found no evidence that gastrointestinal parasites influenced raccoon body condition or overwinter mortality, and so conclude that raccoons, though harbouring diverse and abundant gastrointestinal parasites, may be relatively tolerant of these parasites.

Toxoplasma gondii and related Sarcocystidae parasites in harvested caribou from Nunavik, Canada.

Caribou are keystone species important for human harvest and of conservation concern; even so, much is unknown about the impact of parasites on caribou health and ecology. The aim of this study was to determine the seroprevalence, tissue prevalence, and diversity of tissue-dwelling coccidian parasites (including Toxoplasma gondii, Neospora caninum and Sarcocystis spp.) in 88 migratory caribou (Rangifer tarandus) harvested for human consumption in two communities in Nunavik, Québec, Canada. Both T. gondii and N. caninum have potential to cause abortions and neurological disease in caribou. Seroprevalence for antibodies to T. gondii using ELISA on fluid from thawed hearts was 18% overall, and no DNA of T. gondii was detected in tissues, which has positive implications for food safety since this parasite is zoonotic. Seroprevalence for antibodies to N. caninum using competitive ELISA was 5%, and DNA of N. caninum was detected in only one heart sample. DNA of Sarcocystis, a non-zoonotic, related coccidian, was detected in tissue samples from 85% of caribou, with higher prevalence in heart (82%) than skeletal muscle (47%). This is the first time that Sarcocystis spp. from caribou in Canada have been identified to species level, many of which have been described in reindeer from Fennoscandia. The high prevalence and diversity of Sarcocystis spp. suggests intact trophic relationships between canids and caribou in Nunavik. Besnoitia spp. was serendipitously detected in three muscle samples, a parasite previously associated with skin lesions in caribou in Nunavik. Community-level differences in T. gondii exposure and prevalence of Sarcocystis spp. in skeletal muscle tissues may reflect differences in hunter selection of individual animals and muscles, or possibly regional differences in the ecology of carnivore definitive hosts for these parasites. Further work is needed to explore effects of tissue coccidians in caribou, their taxonomic classifications, and community level differences in parasite prevalence and diversity.

Parasite Diversity in a Freshwater Ecosystem.

Parasites are a significant component of biodiversity. They negatively affect fish appearance, growth, and reproduction. In this study, the prevalence of infection, diversity, and mean intensity of parasites were examined in 9 freshwater fish species (45 samples per fish species). Ecto-parasites were examined on the skin, gills, and fins with a hand lens. Wet mounts were prepared using mucosal scrapings from all the external and internal organs of the sampled fish. Microscopy, muscle compression, and the pepsin-HCL artificial digestion technique were also performed. In this study, 26 species of parasites were identified including three taxa belonging to 9 species of protozoan parasites, 11 treamtodes, and 6 monogenean parasites. The identified protozoan parasites were Entamoeba histolitica, Chilodonella sp., Coccidia sp., Costia sp., Cryptobia sp., Ichthyopthiris-multifilis, Microsporidia, Piscinoodinium sp., and Ichthyobodo necator. The identified trematode parasites were Fasciola gigantica, Echinostoma revolutum, Fasciola hepatica, Haplorchis pumilio, Brachylaima cribbi, Echinostoma cinetorchis, Neascus sp., Deropegus sp., Trematode Soldier, Centrocestus formosanus, and Clinostomum marginatum. The identified monogenean parasites were Dactylogyrus limipopoensis, Dactylogyrus anchoratus, Dactylogyrus myersi, Dactylogyrus vastator, Gyrodactylus salaris, and Ancyrocephalus. The diversity of parasites was maximum at the Okara site. The host's organs that were targeted for parasitic infection included the intestine, liver, gills, fins, skin, and kidneys. The majority of the parasites were identified in Labeo rohita followed by Hypophthalmichthys molitrix, Ctenopharyngodon idella, Oreochromis niloticus, Cyprinus carpio, and Wallagu attu. Two species appeared to be resistant species because none of the parasites were observed in Notopterus notopterus or Sperata seenghala. This study also concluded that the prevalence of parasites increased with increasing length, size, and age of fish.

Diversity of myxozoans (Cnidaria) infecting Neotropical fishes in southern Mexico

Myxozoans are a unique group of microscopic parasites that infect mainly fishes. These extremely reduced cnidarians are highly diverse and globally distributed in freshwater and marine habitats. Myxozoan diversity dimension is unknown in Mexico, a territory of an extraordinary biological diversity. This study aimed to explore, for the first time, myxozoan parasite diversity from fishes of the Neotropical region of Mexico. We performed a large morphological and molecular screening using host tissues of 22 ornamental and food fish species captured from different localities of Veracruz, Oaxaca and Chiapas. Myxozoan infections were detected in 90% of the fish species, 65% of them had 1 or 2 and 35% had 3 and up to 8 myxozoan species. Forty-one putative new species were identified using SSU rDNA phylogenetic analyses, belonging to two main lineages: polychaete-infecting (5 species) and oligochaete-infecting (36 species) myxozoans; from those we describe 4 new species: Myxidium zapotecus sp. n., Zschokkella guelaguetza sp. n., Ellipsomyxa papantla sp. n. and Myxobolus zoqueus sp. n. Myxozoan detection increased up to 6 × using molecular screening, which represents 3.7 × more species detected than by microscopy. This study demonstrated that Neotropical fishes from Mexico are hosts of a multitude of myxozoans, representing a source of emerging diseases with large implications for economic and conservation reasons.

Phylogeography and host‐shift speciation in the vampirecups, an enigmatic clade of endophytic holoparasitic plants

AbstractAimDiversification of obligate parasites is often closely associated with historical shifts among host species. This phenomenon is well‐documented in animal parasites but still poorly understood for parasitic plants. We studied the associations between host shifts, biogeography and diversification in Cytinus, a genus of endophytic holoparasitic plants which show a remarkable disjunct distribution.LocationMediterranean Basin, southern Africa, Madagascar.TaxonCytinus.MethodsWe sampled numerous populations in South Africa and the western Mediterranean Basin, as well as a few populations in Madagascar where the genus is rare. We amplified two nuclear (ITS and SSU) and two mitochondrial (matR and nad1) loci, to infer its evolutionary history using maximum likelihood and time‐calibrated Bayesian analyses, to elucidate the factors responsible for its current distribution and to assess whether host switching is a main driver of speciation.ResultsAll genes recover lineages corresponding to the three geographic areas of Cytinus and sublineages associated with specific host plants, although they disagree on their deep‐level relationships. Ribosomal nuclear genes support an initial split of the Malagasy lineage and an Afrotropical origin of Cytinus before colonization of warm temperate latitudes. Mitochondrial genes support an initial split of the Mediterranean and Afro‐Malagasy lineages and a later split between the South African and Malagasy clades. Introgressive hybridization is the most likely explanation for this discrepancy, while horizontal gene transfers from hosts is less likely. We found strong support for cryptic host‐specific diversity, with five and eight host races in the Mediterranean and South Africa respectively, and a strong phylogenetic signal in the host–parasite associations suggestive of parasite diversification via phylogenetic host tracking.Main ConclusionsThese dated phylogenies indicate that radiation through long‐distance dispersal events and adaptation to new hosts best explain the disjunct distribution of Cytinus. We emphasize the importance of host specificity and host‐switching in the diversification and biogeography of plant endoparasites.

Microfauna community assembly and cascading relationship with microflora in cropland ecosystems along a latitudinal gradient

Cropland ecosystems are environmentally more homogeneous than natural ecosystems due to anthropogenic management. However, it is unclear whether there is similar convergence in soil fauna diversity and community assembly in croplands with different latitudes. Therefore, the study on the latitudinal pattern and community assembly processes of soil microfauna across a transect spanning 3200 km of croplands was conducted. The results indicated that the β diversity of plant parasites, fungivores, and bacterivores showed a decreasing trend and that of omnivores-predators at higher levels followed a unimodal distribution along a latitudinal gradient. The dissimilarity of soil microfauna communities increased with geographical distance, which exhibited a strong distance decay pattern. The β diversity partitioning analysis suggested that species replacement had the greatest influence for all trophic groups, except for omnivores-predators that were driven by a combination of richness differences and species replacement. The stochastic processes shaping the microfauna assembly prevailed over deterministic processes. Ecological drift and homogenizing dispersal of the stochastic processes accounted for 50.4% and 37% of total variations respectively, and heterogeneous selection of the deterministic processes for 10%. Both soil and climatic factors had a direct impact on soil microflora and plant parasites, and indirect impact on bacterivores, fungivores, and omnivores-predators through mediating microflora communities. The partial least squares path modeling and co-occurrence analysis all showed that the soil microfauna assembly was inextricably linked to soil microflora and their network complexity exhibited a significant increasing trend along the latitudinal gradient. Further studies are needed to optimize the molecular database of soil microfauna and construct models for predicting their community distribution patterns.

Bird community effects on avian malaria infections

In community assembly processes, interspecific interactions play an important role in shaping community diversity, especially at the local scale. Changes in species richness or abundance can modify local infectious disease dynamics, either reducing or increasing the risk of transmission within the community. This study evaluates the effects of bird community on avian haemosporidians infections in a Neotropical region. Bird samples were collected from areas surrounding three dams, and molecular analysis were performed to identify blood-parasitic haemosporidia infecting the birds. Generalized linear models were used to analyze the relationships between the bird community and the prevalence, number of infections, and richness of avian haemosporidian lineages. Non-significant effects of bird community dominance and richness on the prevalence of avian parasites and the number of infections of Haemoproteus were found. However, there was evidence of an amplification effect. Host dominance was associated with the total number of infections, the number Plasmodium infections and the expected richness of Plasmodium lineages, while the expected richness of Haemoproteus lineages was associated with the richness of bird species. These findings highlight the role of host community dominance and richness in the dynamics of parasite infections, potentially influenced by the availability of competent hosts. This study contributes significantly to our understanding of blood parasite diversity in tropical birds within a relatively understudied region of South America.

Coevolution With Host Fishes Shapes Parasitic Life Histories in a Group of Freshwater Mussels (Unionidae: Quadrulini).

Ecological interactions among species often lead to parasitic lineages coevolving with host resources, which is often suggested as the primary driver of parasite diversification. Freshwater mussels are bivalves that possess a parasitic life cycle requiring larval encystment on freshwater vertebrates to complete metamorphosis. The North American freshwater mussel tribe Quadrulini has a suite of life history adaptations including highly specialized patterns of host use, infection strategies, and variable larval morphologies. However, the evolution of life histories has yet to be explored using phylogenetic comparative methods. In this study, we use a holistic approach incorporating biogeographical, ecological, molecular, and morphological datasets to reconstruct the evolution of Quadrulini. Comparative phylogenetic analyses suggested the diversification of Quadrulini has been driven, at least in part, by codiversification with their primary host fishes in Ictaluridae. Major diversification events in both ictalurids and quadrulines were estimated to have occurred in the Mississippi River basin throughout the Miocene. Life history characteristics associated with parasitism were supported to have coevolved with host repertories, supporting the hypothesis that ecological interactions with host fishes have shaped the evolution of highly specialized traits in this group. Our findings demonstrate the importance of ecological interactions with host resources in shaping the evolutionary history of freshwater mussels.

Bird species with wider geographical ranges have higher blood parasite diversity but not prevalence across the African-Eurasian flyway

Avian blood parasites, from the genera Plasmodium, Haemoproteus and Leucocytozoon, are predicted to alter their range and prevalence as global temperatures change, and host and vector ranges shift. Understanding large-scale patterns in the prevalence and diversity of avian malaria and malaria-like parasites is important due to an incomplete understanding of their effects in the wild, where studies suggest even light parasitaemia can potentially cause rapid mortality, especially in naïve populations. We conducted phylogenetically controlled analyses to test for differences in prevalence and lineage diversity of haemoparasite infection (for Plasmodium, Haemoproteus and Leucocytozoon) in and between resident and migratory species along the African-Eurasian flyway. To test whether migratory strategy or range size drives differences in parasite prevalence and diversity between resident and migrant species, we included three categories of resident species: Eurasian only (n = 36 species), African only (n = 41), and species resident on both continents (n = 17), alongside intercontinental migrants (n = 64), using a subset of data from the MalAvi database comprising 27,861 individual birds. We found that species resident on both continents had a higher overall parasite diversity than all other categories. Eurasian residents had lower Plasmodium diversity than all other groups, and both migrants and species resident on both continents had higher Haemoproteus diversity than both African and Eurasian residents. Leucocytozoon diversity did not differ between groups. Prevalence patterns were less clear, with marked differences between genera. Both Plasmodium and Leucocytozoon prevalence was higher in species resident on both continents and African residents than in migrants and Eurasian residents. Haemoproteus prevalence was lower in Eurasian residents than species resident on both continents. Our findings contrast with previous findings in the North-South American flyway, where long-distance migrants had higher parasite diversity than residents and short-distance migrants, although we found contrasting patterns for parasite diversity to those seen for parasite prevalence. Crucially, our results suggest that geographic range may be more important than migratory strategy in driving parasite diversity within species along the African-Palaearctic flyway. Our findings differ between the three parasite genera included in our analysis, suggesting that vector ecology may be important in determining these large-scale patterns. Our results add to our understanding of global patterns in parasite diversity and abundance, and highlight the need to better understand the influence of vector ecology to understand the drivers of infection risk and predict responses to environmental change.

Prevalence and diversity of malaria parasites (genus Plasmodium) in the imperiled Saltmarsh Sparrow are greater at northern sites

Abstract Malaria parasites (genus Plasmodium) are important agents of infectious disease in birds and multiple factors, including warming temperatures and environmental contamination, may act to increase their geographic and host ranges. Here, we examined the role of geographical variation and environmental mercury exposure in malaria parasite infection dynamics in an imperiled songbird species with high mercury exposition, the Saltmarsh Sparrow (Ammospiza caudacutus). Using polymerase chain reaction (PCR) methods, we screened 280 Saltmarsh Sparrows from across their breeding range for malaria parasite infection. We detected malaria parasites in 17% of sampled birds and a total of 6 Plasmodium lineages. Prevalence of infection and diversity of parasite lineages varied across the breeding range of the Saltmarsh Sparrow and increased at more northern latitudes. Although mercury is a known immunosuppressant and has been documented to alter an individual’s susceptibility to pathogens, we did not find a significant difference in blood mercury levels between infected and not infected birds, perhaps due to sampling methods and/or small sample sizes. As a specialist of coastal wetlands, the Saltmarsh Sparrow is an excellent indicator species for ecological health, and the patterns of malaria parasite infection with host distribution and mercury suggest that birds at northern latitudes are at greater risk of disease and should be priorities for conservation, habitat, and pathogen monitoring.

INTESTINAL PARASITES IN PECARI TAJACU AND SUS SCROFA DOMESTICUS IN THE CAATINGA FROM SOUTHEASTERN PIAUÍ, BRAZIL.

This study identifies gastrointestinal parasites in the feces of Pecari tajacu (caititu) and Sus scrofa domesticus (domestic pig) in southeastern Piauí, Brazil. The region covers 2 protected areas, Serra da Capivara National Park and Serra das Confusões National Park, and surrounding communities. Fecal samples from 64 animals, 42 from domestic swine and 22 from caititu, collected between 1985 and 2013, were analyzed by optical microscopy. Helminths and/or protozoa were found in 64% of the domestic pig samples and 27% of the caititu samples, totaling 18 morphospecies: Nematoda, Spirurida (2 morphospecies), Trichostrongyloidea, Eimeriidae, Aspidodera sp., Bertiella sp., Metastrongylus sp., Trichostrongylus sp., Moniezia sp., Gongylonema sp., Trichuris suis, Spirocerca lupi, Macracanthorhyncus hirudinaceus, Globocephalus urosubulatus, Strongyloides cf ransomi, Balantioides coli, and Eimeria cf scabra. The highest parasite diversity was obtained in the pig samples, totaling 15 morphospecies, compared to only 6 in caititus, with S. cf ransomi, G. urosubulatus, and S. lupi present in both hosts. We discuss the presence of parasites associated with domestic animals around the Protected Areas and potentially zoonotic parasites close to human communities, which raise concerns about the conservation of wildlife, human health, and livestock in the region.

Discovery of a Digenean (Cryptogonimidae) Living in a Cleft-Lipped Goby, Sicyopterus cynocephalus (Teleostei: Gobiidae) from Ranongga Island, Solomon Islands: Analysis of Multiple Ribosomal DNA Regions.

This study results from a continued investigation of the occurrence and diversity of parasites of freshwater fish in the Solomon Islands. Thus, we revealed a new host as well as a new site of infection and a new geographical area for the cryptogonimid parasite, Stemmatostoma cribbi (Digenea: Cryptogonimidae). The cryptogonimid species was identified based on general morphology and on molecular data of metacercariae found in the gills of the cleft-lipped goby, Sicyopterus cynocephalus, from Ranongga Island, Western Province of the Solomon Islands. This is the first report of a Stemmatostoma sp. digenean parasitizing fish of the genus Sicyopterus in the Indo-Pacific region and the first report of S. cribbi infection in a fish from the Solomon Islands. Phylogenetic analysis performed by Bayesian inference and maximum likelihood confirmed the presence of the cryptogonimid in a well-supported subclade of Stemmatostoma spp.