Morphological and molecular data establishes Clinostomum dolichorchum n. sp. (Digenea: Clinostomidae) in the great blue heron Ardea herodias L. and American bullfrog Rana catesbeiana Shaw.

Clinostomum is a cosmopolitan genus of trematodes that infect piscivorous birds, freshwater molluscs, freshwater fish and amphibians. Herein, a novel species of Clinostomum is described based on morphological and molecular data from an adult in the oral cavity of the great blue heron Ardea herodias and metacercariae collected from the gills and skin of American bullfrog tadpoles Rana catesbeiana. The novel species shares similar qualitative and quantitative morphological features with a congener, Clinostomum marginatum, which has overlap in host and geographic distribution. The most notable morphological difference when compared to C. marginatum is the greater posterior testis length of the novel species. Molecular data resolved similarities with morphological comparisons to nominal species and supports the establishment of a novel species. Molecular data include partial small ribosomal subunit (18S rRNA gene), ribosomal internal transcribed spacer regions (ITS1, 5.8S rRNA gene, and ITS2), partial large ribosomal subunit (28S rRNA gene), cytochrome c oxidase subunit 1 gene (cox1), and nicotinamide adenine dinucleotide dehydrogenase subunit 1 gene (nad1) sequences. Phylogenetic analyses place the novel species in a sister clade to C. marginatum. Morphological and molecular data, combined with phylogenetic analyses support the establishment of Clinostomum dolichorchum n. sp.

Contributions to our knowledge on avian louse flies (Hippoboscidae: Ornithomyinae) with the first European record of the African species Ornithoctona laticornis.

BACKGROUND: Louse flies (Diptera, Hippoboscidae) are important blood-sucking parasites of birds and mammals with a worldwide distribution. The aim of our study was to collect louse flies from birds across multiple sites in Hungary and evaluate the effects of avian traits on louse fly-host relationships. METHODS: Between 2015 and 2022, 237 louse flies were collected from birds at multiple locations in Hungary. The louse flies were identified to species level by morphological and molecular methods. Louse fly species and their seasonal dynamics were analyzed. RESULTS: Six louse fly species were identified: Ornithomya avicularia, Ornithomya fringillina, Ornithomya biloba, Ornithomya chloropus, Ornithoica turdi and Ornithoctona laticornis. Results of statistical analyses indicated that habitat, migration habits and the feeding places of birds have significant effects on their possible role as hosts of O. avicularia, O. fringillina and O. turdi. Analysis of the temporal distribution of avian louse flies showed different seasonal patterns according to species. Phylogenetic analyses highlighted that O. turdi clustered separately from other members of the subfamily Ornithomyinae which thus did not form a monophyletic group. CONCLUSIONS: This study presents one of the longest continuous collections of ornithophilic louse fly species in Europe so far. Avian traits were shown to influence louse-fly infestation. To our best knowledge, this is the first report on O. laticornis in Europe. The ability of this African louse fly species to survive in Europe, as demonstrated in the present study, may be an indication of its future establishment. Our findings, in accordance with previous reports, also indicated that the subfamily Ornithomyinae should be taxonomically revised.

Raising the bar: genus-specific nested PCR improves detection and lineage identification of avian haemosporidian parasites.

Avian haemosporidian parasites are useful model organisms to study the ecology and evolution of parasite-host interactions due to their global distribution and extensive biodiversity. Detection of these parasites has evolved from microscopic examination to PCR-based methods, with the mitochondrial cytochrome b gene serving as barcoding region. However, standard PCR protocols used for screening and identification purposes have limitations in detecting mixed infections and generating phylogenetically informative data due to short amplicon lengths. To address these issues, we developed a novel genus-specific nested PCR protocol targeting avian haemosporidian parasites. The protocol underwent rigorous testing utilizing a large dataset comprising blood samples from Malagasy birds of three distinct Passeriformes families. Furthermore, validation was done by examining smaller datasets in two other laboratories employing divergent master mixes and different bird species. Comparative analyses were conducted between the outcomes of the novel PCR protocol and those obtained through the widely used standard nested PCR method. The novel protocol enables specific identification of Plasmodium, Haemoproteus (Parahaemoproteus), and Leucocytozoon parasites. The analyses demonstrated comparable sensitivity to the standard nested PCR with notable improvements in detecting mixed infections. In addition, phylogenetic resolution is improved by amplification of longer fragments, leading to a better understanding of the haemosporidian biodiversity and evolution. Overall, the novel protocol represents a valuable addition to avian haemosporidian detection methodologies, facilitating comprehensive studies on parasite ecology, epidemiology, and evolution.

Indirect interaction between an endemic and an invading pathogen: A case study of Plasmodium and Usutu virus dynamics in a shared bird host population.

Infectious disease agents can influence each other's dynamics in shared host populations. We consider such influence for two mosquito-borne infections where one pathogen is endemic at the time that a second pathogen invades. We regard a setting where the vector has a bias towards biting host individuals infected with the endemic pathogen and where there is a cost to co-infected hosts. As a motivating case study, we regard Plasmodium spp., that cause avian malaria, as the endemic pathogen, and Usutu virus (USUV) as the invading pathogen. Hosts with malaria attract more mosquitoes compared to susceptible hosts, a phenomenon named vector bias. The possible trade-off between the vector-bias effect and the co-infection mortality is studied using a compartmental epidemic model. We focus first on the basic reproduction number R0 for Usutu virus invading into a malaria-endemic population, and then explore the long-term dynamics of both pathogens once Usutu virus has become established. We find that the vector bias facilitates the introduction of malaria into a susceptible population, as well as the introduction of Usutu in a malaria-endemic population. In the long term, however, both a vector bias and co-infection mortality lead to a decrease in the number of individuals infected with either pathogen, suggesting that avian malaria is unlikely to be a promoter of Usutu invasion. This proposed approach is general and allows for new insights into other negative associations between endemic and invading vector-borne pathogens.

Ticks (Acari: Ixodidae) on resident and migratory wild birds in Orinoquia region, Colombia.

Several species of hard ticks, including those of the genera Ixodes, Haemaphysalis, Amblyomma, and Rhipicephalus, are of medical and veterinary importance and have been reported in association with Neotropical wild birds. Colombia, known for its great bird diversity, has 57 confirmed tick species. However, there are few studies on the association between wild birds and ticks in Colombia. The Orinoquia region, a migratory center in Colombia, provides a unique opportunity to study wild bird-tick associations and their implications for tick-borne disease dynamics. Our study, conducted between October and December 2021, aimed to identify hard ticks infesting resident and migratory wild birds in the department of Arauca and to assess the presence of bacteria from the genera Anaplasma, Borrelia, Ehrlichia, Rickettsia, and piroplasms. A total of 383 birds were examined, of which 21 were infested. We collected 147 ticks, including Amblyomma dissimile (larvae), Amblyomma longirostre (nymphs), Amblyomma mixtum (adults), and Amblyomma nodosum (larvae and nymphs). We did not detect bacterial DNA in the tested ticks; however, piroplasm DNA was detected in ticks from three of the infested birds. Of the 21 bird-tick associations, six are new to the Americas, and interesting documentation of piroplasm DNA in A. longirostre, A. nodosum, and A. dissimile ticks from wild birds in the region. This study provides valuable insights into the ticks associated with wild birds and their role in the dispersal of ticks and pathogens in Colombia, enhancing our understanding of tick life cycles and tick-borne disease dynamics.

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.

Molecular detection of Toxoplasma gondii and Neospora caninum in seabirds collected along the coast of Santa Catarina, Brazil.

Toxoplasma gondii and Neospora caninum are two closely related protozoans that infect a wide range of animals, including birds. However, the occurrence of N. caninum and T. gondii in seabirds is unknown. Therefore, this study aimed to determine the presence of T. gondii and N. caninum DNA in tissue samples of seabirds. Tissue samples of the pectoral muscles, heart, and brain were collected from 47 birds along the coastline of Santa Catarina State, SC, Brazil. The DNA was extracted from the tissues and screened using nested-PCR (nPCR) targeting internal transcribed spacer 1 (ITS1). T. gondii DNA was detected in tissues from seven seabirds (7/47, 14.8%), kelp gull (Larus dominicanus) (5/21), and Manx shearwater (Puffinus puffinus) (2/8). N. caninum DNA was detected in tissues of nine seabirds (9/47, 19.1%), the kelp gull (L. dominicanus) (4/21), Manx shearwater (P. puffinus) (2/8), neotropic cormorant (Phalacrocorax brasilianus) (1/4), brown booby (Sula leucogaster) (1/5), and white-chinned petrel (Procellaria aequinoctialis) (1/1); however, no co-infection was observed. In conclusion, this study showed the circulation of N. caninum and T. gondii in seabirds along the coastline of Santa Catarina State. Further studies are required to clarify the role of these birds in the epidemiology of neosporosis and toxoplasmosis.

Expanding the swimmer's itch pool of the Benelux: a first record of the neurotropic Trichobilharzia regenti and potential link to human infection.

BACKGROUND: Swimmer's itch, an allergic contact dermatitis caused by avian and mammalian blood flukes, is a parasitic infection affecting people worldwide. In particular, avian blood flukes of the genus Trichobilharzia are infamous for their role in swimmer's itch cases. These parasites infect waterfowl as a final host, but incidental infections by cercariae in humans are frequently reported. Upon accidental infections of humans, parasite larvae will be recognized by the immune system and destroyed, leading to painful itchy skin lesions. However, one species, Trichobilharzia regenti, can escape this response in experimental animals and reach the spinal cord, causing neuroinflammation. In the last few decades, there has been an increase in case reports across Europe, making it an emerging zoonosis. METHODS: Following a reported case of swimmer's itch in Kampenhout in 2022 (Belgium), the transmission site consisting of a private pond and an adjacent creek was investigated through a malacological and parasitological survey. RESULTS: Six snail species were collected, including the widespread Ampullaceana balthica, a well-known intermediate host for Trichobilharzia parasites. Shedding experiments followed by DNA barcoding revealed a single snail specimen to be infected with T. regenti, a new species record for Belgium and by extension the Benelux. Moreover, it is the most compelling case to date of the link between this neurotropic parasite and cercarial dermatitis. Additionally, an Echinostomatidae sp. and Notocotylus sp. were isolated from two other specimens of A. balthica. However, the lack of reference DNA sequences for these groups in the online repositories prevented genus- and species-level identification, respectively. CONCLUSIONS: The presence of T. regenti in Belgium might have severe clinical implications and its finding highlights the need for increased vigilance and diagnostic awareness among medical professionals. The lack of species-level identification of the other two parasite species showcases the barcoding void for trematodes. Overall, these findings demonstrate the need for a Belgian framework to rapidly detect and monitor zoonotic outbreaks of trematode parasites within the One Health context.

Brain parasites and misorientation of migratory birds.

Haemoproteus blood parasites of birds are thought to be relatively benign. Recent findings show that infections may develop in the brain of birds, possibly distorting their orientation sense. Misdirected migration may lead migrants outside their range where they are recognized as vagrants and can transmit parasites to novel hosts.

First Report of Intestinal Cestode Infection in a Berylline Hummingbird (Saucerottia beryllina) in Mexico.

BACKGROUND: Up to now, five cestode species have been reported infecting five hummingbird species. To date, there have been no reports of cestode infections in hummingbirds in Mexico. METHODS: A Berylline hummingbird (Saucerottia beryllina) was found dead in a backyard at Toluca City, Mexico, and a window collision was assumed as the cause of death. The bird was preserved in 10% neutral buffered formalin for routine histological examination. RESULTS: At the histological study, liver parenchymal disruption was observed. This lesion could be the result of the assume collision. No lesions were observed in other tissues examined. Conspicuous cestode structures were observed in the lumen of the small intestine. Structure of cestodes, as revealed from histological sections, suggests their position in the genus Anonchotaenia Cohn, 1900 (family Paruterinidae). CONCLUSION: This is the first report of intestinal cestodosis in a Berylline hummingbird (S. beryllina) in Mexico.

Large-scale spatial drivers of avian schistosomes in Northern Michigan inland lakes.

Avian schistosomes are snail-borne trematode parasites (Trichobilharzia spp.) that can cause a nasty skin rash in humans when their cercariae mistake us for their normal bird hosts. We sought to investigate drivers of the spatial distribution of Trichobilharzia cercaria abundance throughout Northern Michigan lakes. For 38 sites on 16 lakes, we assessed several dozen potential environmental predictors that we hypothesized might have direct or indirect effects on overall cercaria abundance, based on known relationships between abiotic and biotic factors in wetland ecosystems. We included variables quantifying local densities of intermediate hosts, temperature, periphyton growth rates, human land use and hydrology. We also measured daily abundance of schistosome cercariae in the water over a 5-week period, supported by community scientists who collected and preserved filtered water samples for qPCR. The strongest predictor of cercaria abundance was Lymnaea host snail density. Lymnaea density was higher in deeper lakes and at sites with more deciduous tree cover, consistent with their association with cool temperature habitats. Contrary to past studies of human schistosomes, we also found a significant negative relationship between cercaria abundance and submerged aquatic vegetation, possibly due to vegetation blocking cercaria movement from offshore snail beds. If future work shows that these effects are indeed causal, then these results suggest possible new approaches to managing swimmer's itch risk in northern MI lakes, such as modifying tree cover and shallow-water vegetation at local sites.

Parasite escape mechanisms drive morphological diversification in avian lice.

Organisms that have repeatedly evolved similar morphologies owing to the same selective pressures provide excellent cases in which to examine specific morphological changes and their relevance to the ecology and evolution of taxa. Hosts of permanent parasites act as an independent evolutionary experiment, as parasites on these hosts are thought to be undergoing similar selective pressures. Parasitic feather lice have repeatedly diversified into convergent ecomorphs in different microhabitats on their avian hosts. We quantified specific morphological characters to determine (i) which traits are associated with each ecomorph, (ii) the quantitative differences between these ecomorphs, and (iii) if there is evidence of displacement among co-occurring lice as might be expected under louse-louse competition on the host. We used nano-computed tomography scan data of 89 specimens, belonging to four repeatedly evolved ecomorphs, to examine their mandibular muscle volume, limb length and three-dimensional head shape data. Here, we find evidence that lice repeatedly evolve similar morphologies as a mechanism to escape host defences, but also diverge into different ecomorphs related to the way they escape these defences. Lice that co-occur with other genera on a host exhibit greater morphological divergence, indicating a potential role of competition in evolutionary divergence.

New insight into avian malaria vectors in New Zealand.

BACKGROUND: Mosquitoes (Culicidae) are vectors for most malaria parasites of the Plasmodium species and are required for Plasmodium spp. to complete their life cycle. Despite having 16 species of mosquitoes and the detection of many Plasmodium species in birds, little is known about the role of different mosquito species in the avian malaria life cycle in New Zealand. METHODS: In this study, we used nested polymerase chain reaction (PCR) and real-time PCR to determine Plasmodium spp. prevalence and diversity of mitochondrial cytochrome b gene sequences in wild-caught mosquitoes sampled across ten sites on the North Island of New Zealand during 2012-2014. The mosquitoes were pooled by species and location collected, and the thorax and abdomens were examined separately for Plasmodium spp. DNA. Akaike information criterion (AIC) modeling was used to test whether location, year of sampling, and mosquito species were significant predictors of minimum infection rates (MIR). RESULTS: We collected 788 unengorged mosquitoes of six species, both native and introduced. The most frequently caught mosquito species were the introduced Aedes notoscriptus and the native Culex pervigilans. Plasmodium sp DNA was detected in 37% of matched thorax and abdomen pools. When considered separately, 33% of abdomen and 23% of thorax pools tested positive by nested PCR. The MIR of the positive thorax pools from introduced mosquito species was 1.79% for Ae. notoscriptus and 0% for Cx. quinquefasciatus, while the MIR for the positive thorax pools of native mosquito species was 4.9% for Cx. pervigilans and 0% for Opifex fuscus. For the overall MIR, site and mosquito species were significant predictors of Plasmodium overall MIR. Aedes notoscriptus and Cx. pervigilans were positive for malaria DNA in the thorax samples, indicating that they may play a role as avian malaria vectors. Four different Plasmodium lineages (SYAT05, LINN1, GRW6, and a new lineage of P (Haemamoeba) sp. AENOT11) were identified in the pooled samples. CONCLUSIONS: This is the first detection of avian Plasmodium DNA extracted from thoraxes of native Culex and introduced Aedes mosquito species in New Zealand and therefore the first study providing an indication of potential vectors in this country.

Avian trematodes of central European corvids are heterogeneous regarding preferences for host species and age.

Corvids are highly adaptive birds that respond well to anthropogenic changes in their environment. Trematode communities of corvids were studied mainly in the 1950s through 1970s in regularly flooded parts of the Volga River delta in Russia; more recent studies and data from other regions where the corvids are in less contact with postflooding habitats are limited. Data for Corvus corax were lacking. Using our samples obtained from 1963 to 2023, we performed a large-scale analysis of trematode species composition and community structure in Corvus frugilegus, Corvus cornix, C. corax, Coloeus monedula, Pica pica, and Garrulus glandarius; all originated from the Czech Republic. We identified corvids as hosts of mutually overlapping component communities of only a few species of trematodes (Brachylecithum lobatum, Lyperosomum petiolatum, Lyperosomum longicauda, Tamerlania zarudnyi, Urogonimus macrostomus), with the presence of many rare and incidental findings of other trematode species. Only a few species used corvids as their core hosts (L. longicauda and B. lobatum). Trematode component communities in first-year birds included Prosthogonimus cuneatus, Prosthogonimus ovatus, Plagiorchis asperus, and Morishitium dollfusi due to an increased share of insects (intermediate hosts of Prosthogonimus and Plagiorchis) and snails (intermediate hosts of Morishitium) in the diet of juveniles. The trematode component communities of corvid species overlapped but were heterogeneous at the level of host individuals, likely reflecting differences in food sources related to the respective host ages and nesting sites.

Molecular characterization of Haemoproteus enucleator with emphasis on the host and geographic distribution.

Haemoproteus species (Haemosporida, Haemoproteidae) are cosmopolitan and highly diverse blood parasites of birds that have been neglected in avian medicine. However, recent discoveries based on molecular diagnostic markers show that these pathogens often cause marked damage to various internal organs due to exo-erythrocytic development, sometimes resulting in severe and even lethal avian haemoproteosis, including cerebral pathologies. Molecular markers are essential for haemoproteosis diagnostics, but the data is limited, particularly for parasites transmitted in tropical ecosystems. This study combined microscopic and molecular approaches to characterize Haemoproteus enucleator morphologically and molecularly. Blood samples were collected from the African pygmy kingfisher Ispidina picta in Cameroon, and the parasite was identified using morphological characters of gametocytes. The analysis of partial cytochrome b sequences (cytb) identified a new Haemoproteus lineage (hISPIC03), which was linked to the morphospecies H. enucleator. Illustrations of blood stages were provided and the phylogenetic analysis showed that the new lineage clustered with five other closely related lineages belonging to the same morphospecies (hALCLEU01, hALCLEU02, hALCLEU03, hISPIC01, and hALCQUA01), with a maximum genetic distance between these lineages of 1.5 % (7 bp difference) in the 478 bp cytb sequences. DNA haplotype network was developed and identified geographic and host distribution of all lineages belonging to H. enucleator group. These lineages were almost exclusively detected in African kingfishers from Gabon, Cameroon, South Africa, and Botswana. This study developed the molecular characterization of H. enucleator and provides opportunities for diagnostics of this pathogen at all stages of its life cycle, which remains undescribed in all its closely related lineages.

Severe decline in abundance of Cyathostoma lari, a parasite of the nasal and orbital sinuses of gulls, at their central European nesting grounds.

Cyathostoma lari is a parasite of the nasal and orbital sinuses of gulls and other hosts in Europe and Canada. Here, we provide an overview of previously published data on the prevalence and infection intensity of C. lari in gulls. Furthermore, based on our data, we analyze the spatiotemporal trends in the prevalence and intensity of infection by C. lari in Chroicocephalus ridibundus in Czechia (central Europe; data from 1964 to 2014) and compare them with those obtained from five species of gulls in Karelia (Northwest Russia; data from 2012-2020). Based on our preliminary observations, we hypothesized that C. lari is subject to a decline in certain regions, but this decline is not necessarily applicable throughout its distribution range. We found that the C. lari population crashed in specific parts of its distribution range. The reasons are unknown, but the observed population changes correspond with the diet switch of their core host in Czechia, C. ridibundus. We previously observed a diet switch in Czech C. ridibundus from earthworms (intermediate hosts of C. lari) to other types of food. This diet switch affected both young and adult birds. Nevertheless, it may not necessarily affect populations in other regions, where they depend less on earthworms collected from agrocenoses affected by agrochemicals and trampling. Correspondingly, we found that these changes were limited only to regions where the gulls feed (or fed) on arable fields. In Karelia, where arable fields are scarce, gulls likely continue to feed on earthworms and still display high infection rates by C. lari. Therefore, C. lari, a parasite of the nasal and orbital sinuses of gulls, nearly disappeared from their central European nesting grounds but is still present in better-preserved parts of its distribution range.

Gastrointestinal helminths of the Australasian harrier (Circus approximans Peale, 1848) in New Zealand, and description of a new species of nematode, Procyrnea fraseri n. sp. (Habronematidae).

The Australasian harrier Circus approximans, a native of Australia, New Zealand and the South Pacific, is an opportunistic hunter of small prey, although a large part of its diet consists of carrion, mainly from roadkill. Besides a record of a single, unnamed species of capillariid nematode there have been no investigations into the parasites of Australasian harriers in New Zealand. In this study, a helminthological survey of sixty-five deceased harriers from southern New Zealand uncovered a gastrointestinal helminth fauna consisting of six parasite species. Porrocaecum circinum (Nematoda) was previously described only from fragmented females, and a redescription is presented here. Procyrnea fraseri n. sp. (Nematoda) is described, and distinguished from its congeners by its slender body shape and shorter spicules. Strigea falconis (Trematoda) is reported for the first time in New Zealand. Cladotaenia anomalis (Cestoda) and Polymorphus circi (Acanthocephala) were previously described as new species elsewhere. An unnamed species of capillariid appears to be mainly confined to North Island and is rare in South Island. Prevalence and intensity metrics are given, and DNA sequences provided to accompany new re/descriptions. Potential intermediate hosts are discussed, and the origins of the helminths and their potential for pathogenicity are considered.

Global prevalence of Plasmodium infection in wild birds: A systematic review and meta-analysis.

Avian malaria is a vector-borne parasitic disease caused by Plasmodium infection transmitted to birds by mosquitoes. The aim of this systematic review was to analyze the global prevalence of malaria and risk factors associated with infection in wild birds. A systematic search of the databases CNKI, WanFang, VIP, PubMed, and ScienceDirect was performed from database inception to 24 February 2023. The search identified 3181 retrieved articles, of which 52 articles met predetermined inclusion criteria. Meta-analysis was performed using the random-effects model. The estimated pooled global prevalence of Plasmodium infection in wild birds was 16%. Sub-group analysis showed that the highest prevalence was associated with adult birds, migrant birds, North America, tropical rainforest climate, birds captured by mist nets, detection of infection by microscopy, medium quality studies, and studies published after 2016. Our study highlights the need for more understanding of Plasmodium prevalence in wild birds and identifying risk factors associated with infection to inform future infection control measures.

Seasonal Variation in Detection of Haemosporidia in a Bird Community: A Comparison of Nested PCR and Microscopy.

In a 2-yr study on prevalence of Haemosporidia in an avian community in Ithaca, New York, USA, we tested the hypothesis that apparent seasonal variation in prevalence is influenced by the detection protocol. We confirmed a higher detection of Haemosporidia using a molecular diagnosis technique (PCR) than by microscopy; this further increased when the PCR test was triplicated. Microscopic examination and PCR techniques have different specificity and sensitivity and therefore different probabilities of detecting hemoparasites. Birds with chronic infections or sampled during winter often have very low parasitemia, and such infections may be missed by microscopy but detected by PCR. Haemosporidian prevalence was higher during the breeding season than during the nonbreeding season regardless of the method used. Detection of Leucocytozoon spp. infection from blood smears using microscopy was challenging.

Avian haemosporidians of breeding birds in the Davis Mountains sky-islands of west Texas, USA.

Avian haemosporidians are protozoan parasites transmitted by insect vectors that infect birds worldwide, negatively impacting avian fitness and survival. However, the majority of haemosporidian diversity remains undescribed. Quantifying this diversity is critical to determining parasite­host relationships and host-switching potentials of parasite lineages as climate change induces both host and vector range shifts. In this study, we conducted a community survey of avian haemosporidians found in breeding birds on the Davis Mountains sky islands in west Texas, USA. We determined parasite abundance and host associations and compared our results to data from nearby regions. A total of 265 birds were screened and infections were detected in 108 birds (40.8%). Most positive infections were identified as Haemoproteus (36.2%), followed by Plasmodium (6.8%) and Leucocytozoon (0.8%). A total of 71 haemosporidian lineages were detected of which 39 were previously undescribed. We found that regional similarity influenced shared lineages, as a higher number of lineages were shared with avian communities in the sky islands of New Mexico compared to south Texas, the Texas Gulf Coast and central Mexico. We found that migratory status of avian host did not influence parasite prevalence, but that host phylogeny is likely an important driver.