Morphological and genetic characterization of Porrocaecum angusticolle (Molin, 1860) (Nematoda: Ascaridomorpha) from the common buzzard Buteo buteo (Linnaeus) (Accipitriformes: Accipitridae) in Czech Republic

Nematodes and acanthocephalans of buzzards (Buteo spp.): Checklist of species in Europe and new host-parasite associations in Romania

Various species of nematodes and acanthocephalans are frequently encountered in birds from the genus Buteo. In Romania, three species of buzzards are present: the Eurasian buzzard (Buteo buteo), the long-legged buzzard (B. rufinus), and the rough-legged buzzard (B. lagopus). This study represents the first comprehensive research on roundworms and acanthocephalans parasitizing birds from genus Buteo in Romania. Between 2017 and 2024, 88 Eurasian buzzards, two long-legged buzzards, and three rough-legged buzzards which were found dead were collected from various localities in Romania. All specimens were necropsied and examined for nematodes and acanthocephalans, which later on were divided equally and preserved in 100 % ethanol for molecular identification and 4 % formaldehyde for morphological identification. Morphological identification revealed three species of acanthocephalans from the family Centrorhynchidae and 12 species of nematodes belonging to seven families: four species from Capillariidae, two species from each Tetrameridae and Toxocaridae, and one species from each Acuariidae, Habronematidae, Physalopteridae, and Syngamidae families. This study provides new data about the diversity of nematodes and acanthocephalan parasitizing B. buteo, B. lagopus and B. rufinus in Romania. To our best knowledge, this study reports B. lagopus as a new host for Eucoleus contortus, Procyrnea leptoptera, and Microtetrameres sp. and B. rufinus as a new host of P. leptoptera.

Integrated evidence reveals a new subspecies of the genus Seuratascaris (Nematoda: Ascaridomorpha), with characterization of the complete mitochondrial genome

Species of Seuratascaris Sprent, 1985 are a rarely reported group of ascaridoid nematodes, parasitising various frogs and toads. In the present study, a new subspecies of Seuratascaris, S. physalis bazhaiensis n. subsp. was described using integrated taxonomic methods, based on specimens collected from Odorrana graminea (Anura: Ranidae) in Guangxi Zhuang Autonomous Region, China. Results of the Assemble Species by Automatic Partitioning (ASAP) and Bayesian inference based on the mitochondrial cox1, cox2 and rrnS data all supported S. physalis bazhaiensis representing a distinct taxon from the nominate subspecies S. physalis physalis. Supplementary morphometric and genetic data of S. phy. physalis are presented based on newly collected material from Odorrana tiannanensis (Anura: Ranidae) and Rhacophorus sp. (Anura: Rhacophoridae) in Yunnan Province, China. A key to species of Seuratascaris is provided. The complete mitochondrial genome of S. physalis bazhaiensis was sequenced and annotated, and represents the first mitogenomic data for the genus Seuratascaris. This mitogenome has only 13,628 bp (including 12 protein-coding genes, 22 tRNA genes, 2 ribosomal RNAs, and only 1 non-coding region), and is the smallest of the reported ascaridoid mitogenomes so far.

Morphological and genetic characterization of Contracaecum and Porrocaecum species from the wild birds in Turkey

The superfamily Ascaridoidea are parasitic nematodes in vertebrates, including birds and humans. In order to investigate the presence and distribution of these parasitic nematodes in birds acting as the definitive host, 157 birds of 64 bird species belonging to 16 orders were collected and necropsied in the Kızılırmak Delta area in the Bafra district of Samsun province. The parasites collected were fixed in 70% ethyl alcohol and identified under a light microscope, and morphologically important regions were photographed for identification. The parasitological examination determined morphologically that Ardea purpurea was infected with Contracaecum rudolphii; Accipiter nisus, Buteo buteo, and B. rufinus with Porrocaecum angusticolle; Aythya ferina with P. crassum; Egretta garzetta with P. depressum; and Turdus merula with P. ensicaudatum. ITS-1 gene region was preferred for molecular analyses of all identified species, and morphological findings were confirmed. C. rudolphii, P. depressum, and P. ensicaudatum were described molecularly for the first time in Turkey, while P. angusticolle and P. crassum were described both molecularly and morphologically.

First report of Hexametra angusticaecoides Chabaud & Brygoo, 1960 (Nematoda: Ascarididae) in a population of captive central bearded dragons, Pogona vitticeps Ahl (Squamata: Agamidae)

Between 2022 and 2023 ascaridoid nematodes of the genus Hexametra were recovered from two captive central bearded dragons (Pogona vitticeps Ahl) in the Extremadura region of Spain. These nematodes were identified by an integrative approach combining morpho-anatomical and molecular data. We used two rRNA regions (D2-D3 expansion segments of the 28S, and ITS fragments), and the partial region of the cytochrome oxidase I gene (COI mtDNA) sequences. Hexametra angusticaecoides Chabaud & Brygoo, 1960 (Ascarididae) was morphologically characterized and illustrated using light and scanning electron microscopy. Bayesian inference (BI) and Maximum Likelihood (ML) phylogenetic trees for these genetic markers established relationships that highlight the importance of using molecular and phylogenetic data for accurate species identification within the genus Hexametra. Phylogenetic trees indicated that the Spanish isolates of H. angusticaecoides were clustered in a well-supported clade together with other isolates from Central Europe of the same species. Molecular phylogenetic findings also reflect that there was a higher intraspecific variation for ITS genetic markers at the intraspecific level. Phylogenetic results based on 28S rRNA suggest that Ascarididea was divided into three monophyletic major clades. To our knowledge, this is the first report of this species parasitizing bearded dragons, extending the host range of this species. These findings represent the first formal record of H. angusticaecoides in Spain.

Mitogenomic phylogenies suggest the resurrection of the subfamily Porrocaecinae and provide insights into the systematics of the superfamily Ascaridoidea (Nematoda: Ascaridomorpha), with the description of a new species of Porrocaecum

BACKGROUND

The family Toxocaridae is a group of zooparasitic nematodes of veterinary, medical and economic significance. However, the evolutionary relationship of Porrocaecum and Toxocara, both genera currently classified in Toxocaridae, and the monophyly of the Toxocaridae remain under debate. Moreover, the validity of the subgenus Laymanicaecum in the genus Porrocaecum is open to question. Due to the scarcity of an available genetic database, molecular identification of Porrocaecum nematodes is still in its infancy.

METHODS

A number of Porrocaecum nematodes collected from the Eurasian marsh harrier Circus aeruginosus (Linnaeus) (Falconiformes: Accipitridae) in the Czech Republic were identified using integrated morphological methods (light and scanning electron microscopy) and molecular techniques (sequencing and analyzing the nuclear 18S, 28S and ITS regions). The complete mitochondrial genomes of the collected nematode specimens and of Porrocaecum (Laymanicaecum) reticulatum (Linstow, 1899) were sequenced and annotated for the first time. Phylogenetic analyses of ascaridoid nematodes based on the amino acid sequences of 12 protein-coding genes of mitochondrial genomes were performed using maximum likelihood and Bayesian inference.

RESULTS

A new species of Porrocaecum, named P. moraveci n. sp., is described based on the morphological and genetic evidence. The mitogenomes of P. moraveci n. sp. and P. reticulatum both contain 36 genes and are 14,517 and 14,210 bp in length, respectively. Comparative mitogenomics revealed that P. moraveci n. sp. represents the first known species with three non-coding regions and that P. reticulatum has the lowest overall A + T content in the mitogenomes of ascaridoid nematodes tested to date. Phylogenetic analyses showed the representatives of Toxocara clustered together with species of the family Ascarididae rather than with Porrocaecum and that P. moraveci n. sp. is a sister to P. reticulatum.

CONCLUSIONS

The characterization of the complete mitochondrial genomes of P. moraveci n. sp. and P. reticulatum is reported for the first time. Mitogenomic phylogeny analyses indicated that the family Toxocaridae is non-monophyletic and that the genera Porrocaecum and Toxocara do not have an affinity. The validity of the subgenus Laymanicaecum in Porrocaecum was also rejected. Our results suggest that: (i) Toxocaridae should be degraded to a subfamily of the Ascarididae that includes only the genus Toxocara; and (ii) the subfamily Porrocaecinae should be resurrected to include only the genus Porrocaecum. The present study enriches the database of ascaridoid mitogenomes and provides a new insight into the systematics of the superfamily Ascaridoidea.

First reported Porrocaecum angusticolle infection in Griffon vulture (Gyps fulvus) in China

This present study is the first case of a Porrocaecum angusticolle (P. angusticolle) infection reported in Griffon vulture (Gyps fulvus) in China. This study aimed to identify the nematode species and explore the genetic evolution of worms infecting Gyps fulvus (G.fulvus). Clinical examination revealed several milky white parasites in the stomach and intestinal tract. Polymerase chain reaction and partial 18S gene sequencing analyses identified these worms to be P. angusticolle (SD isolates). Further phylogenetic analyses revealed that they shared the highest genetic identity (99.9%) with a P. angusticolle isolate (EU004820.1) from Germany. Our study is the first report on the identification and characterization of P. angusticolle infecting G.fulvus in China, based on clinical findings and molecular diagnosis. Therefore, our study provides novel insights for the diagnosis of P. angusticolle infections and the prevention of nematode transmission in wild and domestic animals.

Molecular data reveal a new species of Seuratascaris Sprent, 1985 (Nematoda: Ascaridoidea) from Quasipaa exilispinosa (Liu & Hu) (Amphibia: Anura)

The genus Seuratascaris Sprent, 1985 is a group of obligate nematode parasites of amphibians. In the present study, a new species of Seuratascaris, S. physalis sp. n. was described using light and scanning electron microscopy based on specimens collected from Quasipaa exilispinosa (Liu & Hu) (Amphibia: Anura) in China. The new species differs from S. numidica (Seurat, 1917) by the cuticle of the cervical region distinctly inflated to form a cephalic vesicle-like structure and the absence of single medio-ventral precloacal papilla. The molecular characterization of the nuclear large ribosomal DNA (28S) and internal transcribed spacer (ITS) and the mitochondrial cytochrome c oxidase subunit 1 (cox1), cytochrome c oxidase subunit 2 (cox2) and 12S small subunit ribosomal RNA gene of S. physalis sp. n., together with the 28S, cox2 and 12S of S. numidica are provided for the first time. Molecular analysis revealed the presence of high level of interspecific genetic variation between the two species in the ITS (5.50%), cox1 (13.3%), cox2 (10.6%) and 12S regions (10.5%), which strongly supported that S. physalis sp. n. represented a different species from S. numidica. Angusticaecum ranae Wang, Zhao & Chen, 1978 reported from the frog Quasipaa spinosa (David) (Anura: Dicroglossidae) in China was transferred into the genus Seuratascaris as S. ranae (Wang, Zhao & Chen, 1978) comb. n. based on the morphology of lips and the presence of very short and robust spicules without alae and small numbers of precloacal papillae. The present study provided useful genetic data for molecular identification of species of Seuratascaris and provides the foundation for being able to determine if S. numidica represents a species complex of some sibling species or a single species.

Morphological and molecular identification of third-stage larvae of Anisakis typica (Nematoda: Anisakidae) from Red Sea coral trout, Plectropomus areolatus

Anisakidosis is a foodborne zoonotic infection induced by members of the family Anisakidae via the consumption of raw or undercooked fish such as sushi and sashimi. Identifying anisakid larval species is critical for the epidemiology and diagnosis of diseases caused by them. This study aimed at identifying Anisakis larvae collected from marine fish in Egyptian waters based on morphological characteristics and molecular analysis. Thirty marine fish coral trout, Plectropomus areolatus, were collected from Hurghada, Red Sea, Egypt, to investigate larval nematodes of the genus Anisakis. The larvae were detected encapsulated in the peritoneal cavity and muscle of the fish host. This examination revealed that anisakid larvae naturally infected 19 fish specimens with a prevalence of 63.33% and a mean intensity of 4.1 ± 0.40. Most of them (68 larvae: 71.57%) were found in the musculature. Morphological and morphometric analyses using light and scanning electron microscopy revealed a head region with a prominent boring tooth, inconspicuous lips, and a characteristic protruded cylindrical mucron. All larvae in this study possessed the same morphology as Anisakis Larval type I. Molecular analysis based on ITS region using maximum likelihood and Bayesian phylogenetic methods confirmed them as Anisakis typica. This is the first study to identify A. typica larvae from the commercial fish coral trout P. areolatus in Egyptian waters using morphological and molecular methods.

Parasites, Bacteria, and Associated Pathological Changes in the Digestive System of Diurnal and Nocturnal Raptors in Central Italy

The knowledge of raptor pathogens and associated lesions may be extremely important to enhancing raptor conservation efforts and reducing pathogen spillover to humans and domesticated animals and vice versa. Parasite infections of the digestive system and associated bacteria and pathological changes were evaluated in deceased diurnal and nocturnal raptors in central Italy. Overall, the prevalence of parasites (nematodes, cestodes, trematodes, acanthocephalans, and protozoa) identified in the examined birds was 72.41%, and most of the positive raptors (71.42%) showed multiple parasite infections. Among bacteria, Salmonella typhimurium, Salmonella enterica subspecies diarizonae, Escherichia coli, Clostridium perfringens, Yersinia enterocolitica, and Pasteurella multocida were identified. The results obtained showed that both parasites and bacteria may cause severe lesions in the digestive system of diurnal and nocturnal raptors; parasites and bacteria may concur in causing these lesions; most severe lesions are caused by the interaction of multiple pathogens, both parasites and bacteria; and the same pathogen taxa are frequently associated with the same pathological changes. This study is the first report of S. typhimurium and S. enterica subspecies diarizonae in Buteo buteo, while Andracantha mergi, Spirocerca spp., Sarcocystis dispersa,Sarcocystis columbae, and Eumonospora spp. were recorded for the first time in Italy.