Birds in arid regions have depauperate louse communities: Climate change implications?

Environmental factors such as temperature and humidity influence the distribution of free-living organisms. As climates change, the distributions of these organisms change along with their associated parasites, mutualists and commensals. Less studied, however, is the possibility that environmental conditions may directly influence the distribution of these symbionts even if the hosts are able to persist in altered environments. Here, we investigate the diversity of parasitic lice (Insecta: Phthiraptera) on birds in arid Utah compared to the humid Bahamas. We quantified the parasite loads of 500 birds. We found that the prevalence, abundance and richness of lice was considerably lower among birds in Utah, compared to the Bahamas, despite sampling greater host taxonomic richness in Utah. Our data suggest that as climates change, birds in arid regions will have less diverse louse communities over time, potentially relieving birds of some of the cost of controlling these ectoparasites. Conversely, birds in more humid regions will see an increase in louse diversity, which may require them to invest more time and energy in anti-parasite defense. Additional research with other ectoparasites of birds and mammals across different environmental conditions is needed to more fully understand how climate change may reshape parasite communities, and how these changes could influence their hosts.

Seasonal Effects on Health Status and Parasitological Traits of an Invasive Minnow in Iberian Waters.

Biological invasions are of special conservation concern in the Iberian Peninsula and other regions with high levels of endemism. Environmental variability, such as the seasonal fluctuations of Mediterranean streams, is a key factor that affects the spread of aquatic species in novel habitats. Fish parasites have a great potential to reflect such changes in the habitat features of freshwater ecosystems. The aim of this study consisted of seasonally analysing the health status and parasitological traits of non-native fish in Iberian waters. In particular, a strongly invasive population of Languedoc minnow Phoxinus septimaniae (leuciscid species native to south-east France) was assessed in Tordera Stream (north-eastern Iberian Peninsula, Mediterranean conditions). Fish were sampled in April, July, and October 2023 by electrofishing. Health status (external/internal organs) was significantly better in autumn (HAI = 28.8) than spring (HAI = 35.6). Life-cycle complexity was higher in spring (LCI = 1.98), whereas parasite abundance and Shannon diversity were significantly lower in autumn (TA = 19.6 and H' = 2.15, respectively). In October (more 'benign' environmental conditions in Iberian streams), minnows could display elevated foraging activity, with fish increasing their health condition and level of parasite resistance/tolerance. Overall results showed a particular seasonal profile of health and parasite infra-communities that allow this minnow species to thrive under highly fluctuating habitat conditions. This information could help environmental managers to control non-native fish in Mediterranean streams.

Assessing global drivers of parasite diversity: host diversity and body mass boost avian haemosporidian diversity.

Biodiversity varies worldwide and is influenced by multiple factors, such as environmental stability and past historical events (e.g. Panama Isthmus). At the same time, organisms with unique life histories (e.g. parasites) are subject to unique selective pressures that structure their diversity patterns. Parasites represent one of the most successful life strategies, impacting, directly and indirectly, ecosystems by cascading effects on host fitness and survival. Here, I focused on a highly diverse, prevalent and cosmopolitan group of parasites (avian haemosporidians) to investigate the main drivers (e.g. host and environmental features) of regional parasite diversity on a global scale. To do so, I compiled data from 4 global datasets on (i) avian haemosporidian (malaria and malaria-like) parasites, (ii) bird species diversity, (iii) avian functional traits and (iv) climate data. Then, using generalized least square models, I evaluated the effect of host and environmental features on haemosporidian diversity. I found that haemosporidian diversity mirrors host regional diversity and that higher host body mass increases haemosporidian diversity. On the other hand, climatic conditions had no effect on haemosporidian diversity in any model. When evaluating Leucocytozoon parasites separately, I found parasite diversity was boosted by a higher proportion of migratory hosts. In conclusion, I demonstrated that haemosporidian parasite diversity is intrinsically associated with their hosts' diversity and body mass.

Urbanization correlates with the prevalence and richness of blood parasites in Eurasian Blackbirds (Turdus merula).

Urbanization is increasing worldwide, producing severe environmental impacts. Biodiversity is affected by the expansion of cities, with many species being unable to cope with the different human-induced stressors present in these landscapes. However, this knowledge is mainly based on research from taxa such as plants or vertebrates, while other organisms like protozoa have been less studied in this context. The impact of urbanization on the transmission of vector-borne pathogens in wildlife is still unclear despite its relevance for animal and human health. Here, we investigated whether cities are associated with changes in the prevalence and richness of lineages of three vector-borne protozoans (Plasmodium, Haemoproteus and Leucocytozoon) in Eurasian blackbirds (Turdus merula) from multiple urban and forest areas in Europe. Our results show important species-specific differences between these two habitat types. We found a significant lower prevalence of Leucocytozoon in urban birds compared to forest birds, but no differences for Plasmodium and Haemoproteus. Furthermore, the richness of parasite lineages in European cities was higher for Plasmodium but lower for Leucocytozoon than in forests. We also found one Plasmodium lineage exclusively from cities while another of Leucocytozoon was only found in forests suggesting a certain level of habitat specialization for these protozoan vectors. Overall, our findings show that cities provide contrasting opportunities for the transmission of different vector-borne pathogens and generate new scenarios for the interactions between hosts, vectors and parasites.

Species of Dactylogyridae (Platyhelminthes: Monogenoidea) infecting marine fishes of Moreton Bay, Queensland, Australia, with proposals of Pleuronectitrema n. gen. and Ecnomotrema n. gen. and descriptions of 13 new species.

Twenty-nine dactylogyrid species were reported from teleosts collected during a survey of the parasites of fishes of Moreton Bay, Queensland, Australia, in 2016. Two new genera, Ecnomotrema n. gen. and Pleuronectitrema n. gen., were proposed, and 13 new species were illustrated and described: Atherinicus difficilis n. sp., Diversohamulus similis n. sp., and Ecnomotrema cetiosum n. sp. from Atherinomorus vaigiensis; Haliotrema apiculum n. sp. from Pempheris schwenkii; Haliotrema tugulduriforme n. sp. from Scarus ghobban; Lethrinitrema australiense n. sp., and Lethrinitrema lituus n. sp. from Lethrinus nebulosus; Tetrancistrum siganioides n. sp. from Siganus fuscescens; Ligophorus bostrychus n. sp. from Planiliza subviridis; Neohaliotrema gemmula n. sp. from Abudefduf vaigiensis; Neohaliotrema moretonense n. sp. from Ab. vaigiensis and Ab. bengalensis; and Pleuronectitrema spirula n. sp. from Pseudorhombus arsius (all from Moreton Bay); Pleuronectitrema kuwaitense Kritsky & Sey n. sp. was described from specimens collected from P. arsius in Kuwait during 1996. Ten new host records were recorded: Chauhanellus duriensis Lim, 1994 and Hamatopeduncularia thalassini Bychowsky & Nagibina, 1969 from Pararius proximus; Diplectanotrema sp. 1 and sp. 2 from Sillago maculata and Goniistius vestitus, respectively; Diversohamulus tricuspidatus Bychowsky & Nagibina, 1969 from At. vaigiensis; Hal. cf. dempsteri (Mizelle & Price, 1964) Young, 1968 from Prionurus microlepidotus; Hal. spirale Yamaguti, 1968 from Upeneus tragula; Ligophorus kaohsianghsieni (Gussev, 1962) Gussev, 1985 from Planiliza subviridis; and Neohaliotrema malayense Lim & Gibson, 2010 from Ab. bengalensis and Ab. whitleyi. Twenty-five new faunal records for Moreton Bay were recorded, including the new species listed above and C. duriensis, Diplectanotrema sp. 1 and sp. 2, Diversohamulus tricuspidatus Bychowsky & Nagibina, 1969, Glyphidohaptor phractophallus Kritsky, Galli, & Yang, 2007, Hal. cf. dempsteri, Hal. johnstoni Bychowsky & Nagibina, 1970, Hal. spirale, Yamaguti, 1968 Hamatopeduncularia thalassini Bychowsky & Nagibina, 1969, Lethrinitrema nebulosum Sun, Li, & Yang, 2014, Ligophorus kaohsianghsieni (Gussev, 1962) Gussev, 1985, Ligophorus parvicopulatrix Soo & Lim, 2012, and Neohaliotrema malayense Lim & Gibson, 2010. Three new combinations were proposed: Hal. spariense Roubal, 1981 as Euryhaliotrema spariense (Roubal, 1981) n. comb.; and Hal. arsiosa Venkatanarasaiah, 1984 and Hal. youngi Venkatanarasaiah, 1984 as Pleuronectitrema arsiosa (Venkatanarasaiah, 1984) n. comb. and Pleuronectitrema youngi (Venkatanarasaiah, 1984) n. comb., respectively; Haliotrema sp. of Zhang is transferred to Pleuronectitrema as Pleuronectitrema sp. Hal. ctenochaeti Yamaguti, 1968 was replaced with Hal. asymphylum n. nom. to remove it from homonymy with Hal. ctenochaeti Young, 1968. Pseudohaliotrematoides zancli Yamaguti, 1968 was transferred to Haliotrema as Haliotrema hawaiiense n. nom. Hal. zancli Yamaguti, 1968 was considered a junior subjective synonym of Hal. dempsteri.

Title: Espèces de Dactylogyridae (Platyhelminthes, Monogenoidea) infectant les poissons marins de Moreton Bay, Queensland, Australie, avec la proposition de Pleuronectitrema n. gen. et Ecnomotrema n. gen. et la description de 13 nouvelles espèces. Abstract: Vingt-neuf espèces de Dactylogyridae sont signalées chez des téléostéens collectés lors d'une étude des parasites des poissons de Moreton Bay, Queensland, Australie, en 2016. Deux nouveaux genres, Ecnomotrema n. gen. et Pleuronectitrema n. gen., sont proposés, et 13 nouvelles espèces sont illustrées et décrites : Atherinicus difficilis n. sp., Diversohamulus similis n. sp., et Ecnomotrema cetiosum n. sp. d'Atherinomorus vaigiensis ; Haliotrema apiculum n. sp. de Pempheris schwenkii ; Haliotrema tugulduriforme n. sp. de Scarus ghobban ; Lethrinitrema australiense n. sp. et Lethrinitrema lituus n. sp. de Lethrinus nebulosus, Tetrancistrum siganioides n. sp. de Siganus fuscescens ; Ligophorus bostrychus n. sp. de Planiliza subviridis ; Neohaliotrema gemmula n. sp. d'Abudefduf vaigiensis ; Neohaliotrema moretonense n. sp. d'Ab. vaigiensis et Ab. bengalensis ; et Pleuronectitrema spirula n. sp. de Pseudorhombus arsius (tous de Moreton Bay). Pleuronectitrema hawaiiense Kritsky & Sey n. sp. est décrit à partir de spécimens collectés de P. arsius au Koweït en 1996. Dix nouvelles combinaisons parasites-hôtes sont répertoriées : Chauhanellus duriensis Lim, 1994 et Hamatopeduncularia thalassini Bychowsky & Nagibina, 1969 de Pararius proximus ; Diplectanotrema sp. 1 et sp. 2, respectivement de Sillago maculata et Goniistius vestitus ; Diversohamulus tricuspidatus Bychowsky & Nagibina, 1969 d'At. vaigiensis ; Hal. cf. dempsteri (Mizelle & Price, 1964) Young, 1968 de Prionurus microlepidotus ; Hal. spirale Yamaguti, 1968 d'Upeneus tragula ; Ligophorus kaohsianghsieni (Gussev, 1962) Gussev, 1985 de Planiliza subviridis ; et Neohaliotrema malayense Lim & Gibson, 2010 d'Ab. bengalensis et Ab. whitleyi. Vingt-cinq nouveaux signalements fauniques pour la baie Moreton sont rapportés, y compris les nouvelles espèces énumérées ci-dessus et C. duriensis, Diplectanotrema sp. 1 et sp. 2, Diversohamulus tricuspidatus Bychowsky & Nagibina, 1969, Glyphidohaptor phractophallus Kritsky, Galli et Yang, 2007, Hal. cf. dempsteri, Hal. johnstoni Bychowsky et Nagibina, 1970, Hal. spirale, Hamatopeduncularia thalassini Bychowsky & Nagibina, 1969, Lethrinitrema nebulosum Sun, Li, & Yang, 2014, Ligophorus kaohsianghsieni (Gussev, 1962) Gussev, 1985, Ligophorus parvicopulatrix Soo & Lim, 2012, et Neohaliotrema malayense Lim et Gibson, 2010. Trois nouvelles combinaisons sont proposées : Hal. spariense Roubal, 1981 comme Euryhaliotrema spariense (Roubal, 1981) n. comb. ; Hal. arsiosa Venkatanarasaiah, 1984 et Hal. youngi Venkatanarasaiah, 1984, respectivement comme Pleuronectitrema arsiosa (Venkatanarasaiah, 1984) n. comb. et Pleuronectitrema youngi (Venkatanarasaiah, 1984) n. comb. ; Haliotrema sp. de Zhang est transféré à Pleuronectitrema sous le nom de Pleuronectitrema sp. Hal. ctenochaeti Yamaguti, 1968 est remplacé par Hal. asymphylum n. nom. pour supprimer l'homonymie avec Hal. ctenochaeti Young, 1968. Pseudohaliotrematoides zancli Yamaguti, 1968 est transféré à Haliotrema sous le nom de Haliotrema hawaiiense n. nom. Hal. zancli Yamaguti, 1968 est considéré comme un synonyme subjectif junior de Hal. dempsteri.

Prevalence and genetic diversity of avian haemosporidian parasites in islands within a mega hydroelectric dam in the Brazilian Amazon.

The Brazilian Amazon supports an extremely diverse avifauna and serves as the diversification center for avian malaria parasites in South America. Construction of hydroelectric dams can drive biodiversity loss by creating islands incapable of sustaining the bird communities found in intact forest sites. Besides anthropogenic actions, the presence of parasites can also influence the dynamics and structure of bird communities. Avian malaria (Plasmodium) and related haemosporidian parasites (Haemoproteus and Leucocytozoon) are a globally distributed group of protozoan parasites recovered from all major bird groups. However, no study to date has analyzed the presence of avian haemosporidian parasites in fragmented areas such as land bridge islands formed during artificial flooding following the construction of hydroelectric dams. The aim of this study is to assess the prevalence and molecular diversity of haemosporidians in bird communities inhabiting artificial islands in the area of the Balbina Hydroelectric Dam. The reservoir area covers 443,700 ha with 3546 islands on the left bank of the Uatumã River known to contain more than 400 bird species. We surveyed haemosporidian infections in blood samples collected from 445 understory birds, belonging to 53 species, 24 families, and 8 orders. Passeriformes represented 95.5% of all analyzed samples. We found a low overall Plasmodium prevalence (2.9%), with 13 positive samples (two Plasmodium elongatum and 11 Plasmodium sp.) belonging to eight lineages. Six of these lineages were previously recorded in the Amazon, whereas two of them are new. Hypocnemis cantator, the Guianan Warbling Antbird, represented 38.5% of all infected individuals, even though it represents only 5.6% of the sampled individuals. Since comparison with Plasmodium prevalence data prior to construction of Balbina is not possible, other studies in artificially flooded areas are imperative to test if anthropogenic flooding may disrupt vector-parasite relationships leading to low Plasmodium prevalence.

Parasites indicate trophic complexity and faunal succession in restored oyster reefs over a 22-year period.

Foundation species like the eastern oyster (Crassostrea virginica) create complex habitats for organisms across multiple trophic levels. Historic declines in oyster abundance have prompted decades of restoration efforts. However, it remains unclear how long it takes for restored reefs to resemble the trophic complexity of natural reefs. We used a space-for-time approach to examine community succession of restored reefs ranging in age from 3 to 22 years old in coastal North Carolina, surveying both free-living taxa and parasite communities and comparing them to natural reefs that are decades old. Trophically transmitted parasites can serve as valuable biodiversity surrogates, sometimes providing greater information about a system or question than their free-living counterparts. We found that the diversity of free-living taxa was highly variable and did not differ among new (<10 years), old (20 years), and natural reefs. Conversely, parasite diversity increased with elapsed time after restoration, and parasite communities in older restored reefs resembled those found in natural reefs. Our study also revealed that oyster toadfish (Opsanus tau) act as a key host species capable of facilitating parasite transmission and trophic ascent in oyster reef food webs. Overall, our results suggest that trophic complexity in restored oyster reefs requires at least 8 years to resemble that found in natural reefs. This work adds to a growing body of evidence demonstrating how parasites can serve as biodiversity surrogates, proxies for the presence of additional taxa that are often difficult or impractical to sample. Given the multiplicity of links formed with their hosts, parasites offer a powerful tool for quantifying diversity and trophic complexity in environmental monitoring studies.

Diversity, distribution, and methodological considerations of haemosporidian infections among Galliformes in Alaska.

Using samples spanning 10-degrees of latitude in Alaska, we provide the first comparative assessment of avian haemosporidia distribution of Arctic Alaska with subarctic host populations for four species of grouse and three species of ptarmigan (Galliformes). We found a high overall prevalence for at least one haemospordian genus (88%; N = 351/400), with spruce grouse (Canachites canadensis) showing the highest prevalence (100%; N = 54/54). Haemoproteus and Plasmodium lineages were only observed within grouse, while Leucocytozoon species were found within both grouse and ptarmigan. Further, different Leucocytozoon lineages were obtained from blood and tissue samples from the same individual, potentially due to the differential timing and duration of blood and tissue stages. Using different primer sets, we were able to identify different Leucocytozoon lineages within 55% (N = 44/80) of sequenced individuals, thereby detecting coinfections that may have otherwise gone undetected. The commonly used Haemoproteus/Plasmodium primers amplified Leucocytozoon for 90% (N = 103/115) of the products sequenced, highlighting the potential value of alternate primers to identify intra-genus coinfections and the importance of obtaining sequence information rather than relying solely on PCR amplification to assess parasite diversity. Overall, this dataset provides baseline information on parasite lineage distributions to assess the range expansion associated with climate change into Arctic regions and underscores methodological considerations for future studies.

Ceratonova shasta: a cnidarian parasite of annelids and salmonids.

The myxozoan Ceratonova shasta was described from hatchery rainbow trout over 70 years ago. The parasite continues to cause severe disease in salmon and trout, and is recognized as a barrier to salmon recovery in some rivers. This review incorporates changes in our knowledge of the parasite's life cycle, taxonomy and biology and examines how this information has expanded our understanding of the interactions between C. shasta and its salmonid and annelid hosts, and how overarching environmental factors affect this host­parasite system. Development of molecular diagnostic techniques has allowed discrimination of differences in parasite genotypes, which have differing host affinities, and enabled the measurement of the spatio-temporal abundance of these different genotypes. Establishment of the C. shasta life cycle in the laboratory has enabled studies on host­parasite interactions and the availability of transcriptomic data has informed our understanding of parasite virulence factors and host defences. Together, these advances have informed the development of models and management actions to mitigate disease.

Disentangling direct from indirect effects of habitat disturbance on multiple components of biodiversity.

Human habitat disturbance affects both species diversity and intraspecific genetic diversity, leading to correlations between these two components of biodiversity (termed species-genetic diversity correlation, SGDC). However, whether SGDC predictions extend to host-associated communities, such as the intestinal parasite and gut microbial diversity, remains largely unexplored. Additionally, the role of dominant generalist species is often neglected despite their importance in shaping the environment experienced by other members of the ecological community, and their role as source, reservoir and vector of zoonotic diseases. New analytical approaches (e.g. structural equation modelling, SEM) can be used to assess SGDC relationships and distinguish among direct and indirect effects of habitat characteristics and disturbance on the various components of biodiversity. With six concrete and biologically sound models in mind, we collected habitat characteristics of 22 study sites from four distinct landscapes located in central Panama. Each landscape differed in the degree of human disturbance and fragmentation measured by several quantitative variables, such as canopy cover, canopy height and understorey density. In terms of biodiversity, we estimated on the one hand, (a) small mammal species diversity, and, on the other hand, (b) genome-wide diversity, (c) intestinal parasite diversity and (d) gut microbial heterogeneity of the most dominant generalist species (Tome's spiny rat, Proechimys semispinosus). We used SEMs to assess the links between habitat characteristics and biological diversity measures. The best supported SEM suggested that habitat characteristics directly and positively affect the richness of small mammals, the genetic diversity of P. semispinosus and its gut microbial heterogeneity. Habitat characteristics did not, however, directly impact intestinal parasite diversity. We also detected indirect, positive effects of habitat characteristics on both host-associated assemblages via small mammal richness. For microbes, this is likely linked to cross species transmission, particularly in shared and/or anthropogenically altered habitats, whereas host diversity mitigates parasite infections. The SEM revealed an additional indirect but negative effect on intestinal parasite diversity via host genetic diversity. Our study showcases that habitat alterations not only affect species diversity and host genetic diversity in parallel, but also species diversity of host-associated assemblages. The impacts from human disturbance are therefore expected to ripple through entire ecosystems with far reaching effects felt even by generalist species.

Las perturbaciones antropogénicas sobre los hábitats naturales pueden afectar tanto a la diversidad de las especies como a la diversidad genética intraespecífica, dando lugar a correlaciones entre estos dos elementos de la biodiversidad (denominados correlación de la diversidad genética de las especies, SGDC por sus siglas en inglés). Sin embargo, todavía queda sin explorar si las predicciones de la SGDC afectan a las comunidades de parásitos y microorganismos intestinales asociadas al hospedador. Adicionalmente, el rol que juegan las especies generalistas, especialmente aquéllas dominantes, suele ser descuidado, a pesar de la importancia de control que ejercen sobre la estructura de la comunidad, y su rol como fuente, reservorio y vector de enfermedades zoonóticas. Para poder evaluar las relaciones de SGDC y distinguir entre los efectos directos e indirectos que tienen las características del hábitat y las perturbaciones sobre los distintos componentes de la biodiversidad, se pueden utilizar nuevos enfoques analíticos como por ejemplo los modelos de ecuaciones estructurales (SEM, por sus siglas en inglés). Considerando seis modelos específicos y biológicamente sólidos, recopilamos las características del hábitat de 22 sitios ubicados en cuatro paisajes distintos situados en el centro de Panamá. Cada paisaje difería en el grado de perturbación antropogénica y fragmentación, medido por diferentes variables cuantitativas, como la cobertura del dosel, la altura del dosel y la densidad del sotobosque. En términos de biodiversidad, por un lado estimamos (1) la diversidad de especies de pequeños mamíferos y, por otro lado (2) la diversidad del genoma completo, (3) la diversidad de parásitos intestinales, y (4) la heterogeneidad de las comunidades microbianas del intestino de la especie generalista más dominante, la rata espinosa de Tomes Proechimys semispinosus. Para evaluar los vínculos entre las características del hábitat y las medidas de diversidad biológica se utilizó el modelado SEM. El SEM mejor apoyado sugirió que las características del hábitat afectan directa y positivamente a la abundancia de pequeños mamíferos, a la diversidad genética de P. semispinosus y a la heterogeneidad microbiana intestinal. Sin embargo, se observó que las características del hábitat no tienen un efecto directo en la diversidad de parásitos intestinales. Aparte de estos efectos directos, detectamos efectos indirectos y positivos de las características del hábitat en ambos conjuntos asociados al hospedador (diversidad de parásitos y microorganismos intestinales) a través de la abundancia de pequeños mamíferos. En el caso de las comunidades microbianas, esto está probablemente relacionado con la transmisión interespecífica, especialmente en hábitats compartidos y/o antropogénicamente alterados; mientras que la diversidad de hospedadores mitiga las infecciones de parásitos. El SEM reveló un efecto indirecto adicional pero negativo sobre la diversidad de parásitos intestinales a través de la diversidad genética de los hospedadores. Nuestro estudio muestra que los patrones de SGDC se filtran a través de las varias capas de diversidad biológica, añadiendo los ensamblajes asociados al hospedador como componentes biológicos afectados por las alteraciones del hábitat.

Microsporidian diversity in the aquatic isopod Asellus aquaticus.

We conducted a molecular survey on microsporidian diversity in different lineages (operational taxonomic units = OTUs) of Asellus aquaticus from 30 sites throughout Europe. Host body length was determined, and DNA was extracted from host tissue excluding the intestine and amplified by microsporidian-specific primers. In total, 247 A. aquaticus specimens were analysed from which 26.7% were PCR-positive for microsporidians, with significantly more infections in larger individuals. Prevalence ranged between 10 and 90%. At 9 sites, no microsporidians were detected. A significant relationship was found between the frequency of infected individuals and habitat type, as well as host OTU. The lowest proportion of infected individuals was detected in spring-habitats (8.7%, n = 46) and the highest in ponds (37.7%, n = 53). Proportion of infected individuals among host OTUs A, D and J was 31.7, 21.7 and 32.1%, respectively. No infections were detected in OTU F. Our results are, however, accompanied by a partially low sample size, as only a minimum of 5 individuals was available at a few locations. Overall, 17 different microsporidian molecular taxonomic units (MICMOTUs) were distinguished with 5 abundant isolates (found in 4­17 host individuals) while the remaining 12 MICMOTUs were "rare" and found only in 1­3 host individuals. No obvious spatio-genetic pattern could be observed. The MICMOTUs predominantly belonged to Nosematida and Enterocytozoonida. The present study shows that microsporidians in A. aquaticus are abundant and diverse but do not show obvious patterns related to host genetic lineages or geography.

Gastrointestinal Parasite Community and Phenotypic Plasticity in Native and Introduced Alien Lagomorpha.

The Convention on Biological Diversity classifies "Invasive Alien Species" as those whose introduction and spread represents a threat for biodiversity. Introduction of alien pathogens, including parasites, is one of the main consequences of the introduction of invasive alien species. The objective of this work was to assess the parasite community composition in native lagomorphs (Lepus europaeus and Lepus timidus varronis) in sympatric and non-sympatric conditions with an alien lagomorph (Sylvilagus floridanus), and to evaluate the phenotypic traits of exotic parasites in such conditions. We firstly describe the characteristics of the parasite community in the different host species (richness, prevalence, abundance and intensity), and, secondly, the phenotypic traits of the observed parasite species in each host. Nine helminths were reported on: eight nematodes (Obeliscoides cuniculi, Trichostrongylus calcaratus, Trichostrongylus retortaeformis, Trichostrongylus affinis, Trichuris leporis, Trichostrongylus colubriformis, Passalurus ambiguus, and Nematodirus sp.) and one unidentified cestode. In addition, exotic parasites showed significantly different phenotypic plasticity after spillover from S. floridanus to L. europaeus, whereas endemic parasite species were not isolated in the alien S. floridanus. Our results highlight that the community of autochthonous and allochthonous Lagomorpha in northwestern Italy represents an extremely interesting system for modelling ecological and evolutionary interactions between parasites and their hosts.

Diversity and dynamics in larval digenean assemblages parasitizing Heleobia parchappii in a freshwater shallow lake from the Southeastern Pampa plain, Argentina.

Digeneans have important roles within ecosystems; however, it is estimated that only 14% of the species have been described. Therefore, before being able to detail their role, digenean species' identification and the diversity present in the ecosystems must be known. In this study, the diversity and the temporal-spatial dynamics of larval digeneans in the freshwater snail Heleobia parchappii were analysed in a shallow lake. Specimens of H. parchappii were collected seasonally at three points during one year and a total of 2871 molluscs were analysed. A total of 23 species of digenea were registered and both the overall prevalence and the composition of the assemblages presented temporal and spatial variations, responding to the differential environmental conditions characteristics (anthropic effect, presence of native forests, and differential use of the habitat by the definitive hosts) of three sampled sites. The assemblages of larval digenean in their first intermediate host support the idea that this area is of great importance in biodiversity, and could be endemic areas of some species of digenean that use reptiles, amphibians and bats as hosts, groups that are at risk of conservation. Protection of these environments is a fundamental pillar in the policies for the conservation of wild flora and fauna.

Human parasites as tracers of the evolution of their hosts.

Because parasite data reveal essential information about the behavior and history of their hosts, it is possible to use them as tracers of host evolution. A table built from the analysis of the data contained in the book by Ashford and Crewe "The Parasites of Homo sapiens" allows counting and cross comparing the parasites according to the main descriptors used by the authors: Taxonomic groups, for each group number of parasites species identified in humans; Status, numbers of reported human cases and their dispersion; Geographic distribution, parasite specific richness recorded in biogeographic regions; Habitat, parasite location in or on the human body; Transmission, contamination pathways to man; Hosts, non-human hosts, which have a role in the maintenance of a parasite; Host-specificity status, relative role of man or other hosts in the maintenance of parasite populations. A strong positive correlation is observed between the number of parasites species recorded in humans and the global parasite species richness for each taxonomic group. About 74% of the parasites recorded in humans are rare, sporadic or nowhere common; 10% only are common or abundant worldwide. The Palearctic exhibits the highest parasite species diversity; the Oriental, Nearctic, Neotropical and Aethiopian regions have roughly similar richness values; the Australian Region is the poorest. Earliest domesticated animals, such as dog, cat, cattle or pig, share more parasite species with Humans than tardily domesticated as horse, rabbit or camel. More than one third of our parasites have elected our alimentary canal as a home and about two third are using the digestive tract path for contamination. Time of occupancy of new territories, diversity in feeding habits and commensalism with other animals, widely explain Human particular parasite richness. As suggested by the authors: "There must be few parasitic species which have never had the opportunity to infect a human".

Host foraging behavior and nest type influence prevalence of avian haemosporidian parasites in the Pantanal.

Avian haemosporidians from the genera Plasmodium and Haemoproteus are vector transmitted parasites. A growing body of evidence suggests that variation in their prevalence within avian communities is correlated with a variety of avian ecological traits. Here, we examine the relationship between infection probability and diversity of haemosporidian lineages and avian host ecological traits (average body mass, foraging stratum, migratory behavior, and nest type). We used molecular methods to detect haemosporidian parasites in blood samples from 642 individual birds of 149 species surveyed at four localities in the Brazilian Pantanal. Based on cytochrome b sequences, we recovered 28 lineages of Plasmodium and 17 of Haemoproteus from 31 infected avian species. Variation in lineage diversity among bird species was not explained by avian ecological traits. Prevalence was heterogenous across avian hosts. Bird species that forage near the ground were less likely to be infected by Haemoproteus, whereas birds that build open cup nests were more likely infected by Haemoproteus. Furthermore, birds foraging in multiple strata were more likely to be infected by Plasmodium. Two other ecological traits, often related to host resistance (body mass and migratory behavior), did not predict infection probability among birds sampled in the Pantanal. Our results suggest that avian host traits are less important determinants of haemosporidian diversity in Pantanal than in other regions, but reinforces that host attributes, related to vector exposure, are to some extent important in modulating infection probability within an avian host assemblage.

Metazoan endoparasite fauna and feeding ecology of commercial fishes from Java, Indonesia.

Despite being an important component of the marine ecosystem and posing health risks to human seafood consumers, fish parasites in Indonesia have yet to be adequately described. Here, we analyzed the diet and metazoan parasite fauna of seven commercial fish species (Alectis indica, Carangoides chrysophrys, Johnius borneensis, Mene maculata, Trichiurus lepturus, Upeneus asymmetricus, U. moluccensis) landed in Java, Indonesia. We isolated 11 endoparasite species, established 22 new host and 14 new locality records, and extended parasitological records of A. indica by 24%, C. chrysophrys by 25%, J. borneensis by 40%, M. maculata by 44%, U. asymmetricus by 100%, and U. moluccensis by 17%. We genetically identified the trematode Stephanostomum cf. uku (of Bray et al. 2005) from Alecta indica for the first time in Indonesia and provided the sequence of its 28S marker. Stomach content analysis revealed seven different prey items, and the examined fish species were grouped into four feeding categories, which differed significantly in their respective endoparasite fauna. All but two examined fish species hosted potentially zoonotic nematodes, which reveal a risk for parasite-borne diseases in Indonesian food fishes and call for more consequent monitoring with regard to seafood safety in this region. With this study, we were able to establish an association between the feeding ecology and the endoparasite fauna of marine fishes which will help to better understand the transmission pathways of (potentially zoonotic) parasites in food fishes in tropical waters.

Age-specific patterns of DBLα var diversity can explain why residents of high malaria transmission areas remain susceptible to Plasmodium falciparum blood stage infection throughout life.

Immunity to Plasmodium falciparum is non-sterilising, thus individuals residing in malaria-endemic areas are at risk of infection throughout their lifetime. Here we seek to find a genomic epidemiological explanation for why residents of all ages harbour blood stage infections despite lifelong exposure to P. falciparum in areas of high transmission. We do this by exploring, for the first known time, the age-specific patterns of diversity of variant antigen encoding (var) genes in the reservoir of infection. Microscopic and submicroscopic P. falciparum infections were analysed at the end of the wet and dry seasons in 2012-2013 for a cohort of 1541 residents aged from 1 to 91 years in an area characterised by high seasonal malaria transmission in Ghana. By sequencing the near ubiquitous Duffy-binding-like alpha domain (DBLα) that encodes immunogenic domains, we defined var gene diversity in an estimated 1096 genomes detected in sequential wet and dry season sampling of this cohort. Unprecedented var (DBLα) diversity was observed in all ages with 42,399 unique var types detected. There was a high degree of maintenance of types between seasons (>40% seen more than once), with many of the same types, especially upsA, appearing multiple times in isolates from different individuals. Children and adolescents were found to be significant reservoirs of var DBLα diversity compared with adults. Var repertoires within individuals were highly variable, with children having more related var repertoires compared to adolescents and adults. Individuals of all ages harboured multiple genomes with var repertoires unrelated to those infecting other hosts. High turnover of parasites with diverse isolate var repertoires was also observed in all ages. These age-specific patterns are best explained by variant-specific immune selection. The observed level of var diversity for the population was then used to simulate the development of variant-specific immunity to the diverse var types under conservative assumptions. Simulations showed that the extent of observed var diversity with limited repertoire relatedness was sufficient to explain why adolescents and adults in this community remain susceptible to blood stage infection, even with multiple genomes.

Diversity of Trypanosoma cruzi parasites infecting Triatoma dimidiata in Central Veracruz, Mexico, and their One Health ecological interactions.

Triatoma dimidiata is the main vector of Trypanosoma cruzi parasites in Veracruz, Mexico, and its association with human housing appears variable. Also, in spite of a high seroprevalence of T. cruzi infection in humans, parasite transmission remains poorly understood. Therefore, we aimed to identify T. dimidiata blood feeding sources and its parasite and microbial diversity to reconstruct T. cruzi parasite transmission ecology in central Veracruz, Mexico, within a One Health/Ecohealth framework. We used a metabarcoding and deep sequencing approach of specific markers for the simultaneous identification of T. dimidiata haplogroup (ITS-2), vertebrate blood meals (12 s gene), T. cruzi parasites (mini-exon gene), and gut microbiota (bacterial 16 s). Twelve species of domestic/synanthropic animals and humans were identified as blood sources, with multiple feeding on 4.2 ± 0.4 hosts per bug. The feeding/parasite transmission network was strongly centered on humans, emphasizing a significant risk of infection. We also unambiguously confirmed the presence of TcI, TcII, TcV and TcVI DTUs in T. dimidiata, and sequences from Veracruz tended to cluster apart from parasites from other regions, suggesting some level of local differentiation. Analysis of T. dimidiata microbiota suggested that several bacterial families may be associated with the presence/absence of T. cruzi, and some of these associations may also be parasite DTU-specific. Such integrative approaches within the EcoHealth/One Health framework provide key insights on T. cruzi transmission and potential novel strategies for disease control.

Host migration and environmental temperature influence avian haemosporidians prevalence: a molecular survey in a Brazilian Atlantic rainforest.

Avian haemosporidians are parasites with great capacity to spread to new environments and new hosts, being considered a good model to host-parasite interactions studies. Here, we examine avian haemosporidian parasites in a protected area covered by Restinga vegetation in northeastern Brazil, to test the hypothesis that haemosporidian prevalence is related to individual-level traits (age and breeding season), species-specific traits (diet, foraging strata, period of activity, species body weight, migratory status, and nest shape), and climate factors (temperature and rainfall). We screened DNA from 1,466 birds of 70 species captured monthly from April 2013 to March 2015. We detected an overall prevalence (Plasmodium/Haemoproteus infection) of 22% (44 host species) and parasite's lineages were identified by mitochondrial cyt b gene. Our results showed that migration can be an important factor predicting the prevalence of Haemoproteus (Parahaemoproteus), but not Plasmodium, in hosts. Besides, the temperature, but not rainfall, seems to predict the prevalence of Plasmodium in this bird community. Neither individual-level traits analyzed nor the other species-specific traits tested were related to the probability of a bird becoming infected by haemosporidians. Our results point the importance of conducting local studies in particular environments to understand the degree of generality of factors impacting parasite prevalence in bird communities. Despite our attempts to find patterns of infection in this bird community, we should be aware that an avian haemosporidian community organization is highly complex and this complexity can be attributed to an intricate net of factors, some of which were not observed in this study and should be evaluated in future studies. We evidence the importance of looking to host-parasite relationships in a more close scale, to assure that some effects may not be obfuscated by differences in host life-history.

Molecular ecology of Triatoma dimidiata in southern Belize reveals risk for human infection and the local differentiation of Trypanosoma cruzi parasites.

OBJECTIVE: In Belize, the main vector for Trypanosoma cruzi, the agent of Chagas disease, is Triatoma dimidiata, but transmission cycles and the risk for human infection are unclear. Therefore, the aim of this study was to identify T. dimidiata blood feeding sources and its parasite and microbial diversity, in order to reconstruct T. cruzi parasite transmission ecology in southern Belize. METHODS: A metabarcoding approach based on deep sequencing of markers was used for bug taxonomy, blood meal sources, T. cruzi genotypes, and microbiota composition. Bugs were collected in 13 villages of Toledo district. RESULTS: Bugs fed on at least 13 species, from domestic hosts such as humans, dogs, cows, and pigs, to synanthropic species such as mice, rats, and opossums, and sylvatic species such as deer, peccary, and kinkajou, in agreement with an opportunistic feeding behavior. Nonetheless, most feeding focused on a few species, including humans. Infection with T. cruzi was detected in 24 of 39 bugs (62%), and the analysis of 242 T. cruzi mini-exon sequences (average 10 ± 5 haplotypes per bug) indicated the presence of TcI and TcIV parasite discrete typing units (DTUs). However, for both DTUs, sequences from Belize mostly clustered apart from sequences from North and South America, suggesting the local differentiation of parasites. T. dimidiata also harbored a diverse bacterial microbiota, with ontogenic changes suggesting microbiota maturation during nymphal development. CONCLUSIONS: Together, these results indicate a significant risk for T. cruzi infection in humans. They also highlight the need to better characterize the diversity of T. cruzi strains in the region and its impact on disease epidemiology.