Survey of the Prosthogonimus spp. metacercariae infection in the second intermediate host dragonfly in Heilongjiang Province, China.

Prosthogonimiasis poses a threat to the reproductive system of poultry and wild birds, which are the definitive hosts of the parasite causing this disease. However, the parasite infection of the second intermediate host (dragonfly), the primary vector of this pathogen, is rarely reported. In this study, the prevalence of Prosthogonimus infection in dragonflies was investigated from June 2019 to October 2022 in Heilongjiang Province, northeast China. The species of metacercariae isolated from dragonfly were identified by morphological characteristics, molecular biology techniques, and animal infection experiments. The results showed that 11 species of dragonflies and one damselfly were identified and among six of the dragonflies infected by Prosthogonimus metacercariae, Sympetrum depressiusculum (28.53%) had the highest infection rate among all positive dragonflies, followed by Sympetrum vulgatum (27.86%) and Sympetrum frequens (20.99%), which are preferred hosts, and the total prevalence was 20.39% (2061/10,110) in Heilongjiang Province. Three species of Prosthogoniumus metacercariae were isolated, including Prosthogonimus cuneatus, Prosthogonimus pullucidus, and Prosthogonimus sp., among which P. cuneatus was the dominant species in dragonflies in Heilongjiang Province. This is the first report on the prevalence of Prosthogonimus in dragonflies in China, which provides baseline data for the control of prosthogonimiasis in Heilongjiang Province and a reference for the prevention of prosthogonimiasis in other areas of China.

The complete mitochondrial genome of Prosthogonimus cuneatus and Prosthogonimus pellucidus (Trematoda: Prosthogonimidae), their features and phylogenetic relationships in the superfamily Microphalloidea.

Prosthogonimus cuneatus and Prosthogonimus pellucidus (Trematoda: Prosthogonimidae) are common flukes of poultry and other birds which can cause severe impacts on animal health and losses to the poultry industry. However, there are limited studies on the molecular epidemiology, population genetics, and systematics of Prosthogonimus species. In the present study, the complete mitochondrial (mt) genomes of P. cuneatus and P. pellucidus were determined to be 14,829 bp and 15,013 bp in length, respectively. Both mt genomes contain 12 protein-coding genes (PCGs) (cox1-3, nad1-6, nad4L, cytb, and atp6), 22 transfer RNA genes, two ribosomal RNA genes, and one non-coding region. Our comparative analysis shows that the atp6 genes of P. cuneatus and P. pellucidus are longer than any previously published atp6 genes of other trematodes. The lengths of the atp6 genes of P. cuneatus and P. pellucidus in this study seem unusual, and should therefore be studied further. The mt genes of P. cuneatus and P. pellucidus are transcribed in the same direction, and the gene arrangements are identical to those of Plagiorchis maculosus, Tamerlania zarudnyi, and Tanaisia sp., but different from those of Eurytrema pancreaticum, Dicrocoelium chinensis, and Brachycladium goliath. The mt genome A + T contents of P. cuneatus and P. pellucidus are 64.47% and 65.34%, respectively. In the 12 PCGs, ATG is the most common initiation codon, whereas TAG is the most common termination codon. The sequence identity of the same 12 PCGs among the eight trematodes (P. cuneatus, P. pellucidus, Pl. maculosus, D. chinensis, E. pancreaticum, B. goliath, T. zarudnyi, Tanaisia sp.) of Xiphidiata are 55.5%-81.7% at the nucleotide level and 43.9%-82.5% at the amino acid level. The nucleotide similarities among the complete mt genomes of the eight trematodes range from 54.1%-81.5%. Phylogenetic analysis based on the aligned concatenated amino acid sequences of the 12 PCGs shows that P. cuneatus and P. pellucidus cluster together and are sister to T. zarudnyi and Tanaisia sp., and this clade is more closely related to E. pancreaticum, Dicrocoelium spp. and Lyperosomum longicauda in the family Dicrocoeliidae, than it is to species in the families Plagiorchiidae and Brachycladiidae. These are the first reported complete mt genomes of Prosthogonimidae, and these data will provide additional molecular resources for further studies of Prosthogonimidae taxonomy, population genetics, and systematics.

Characterization of the mitochondrial genome of Tetrameres grusi and insights into the phylogeny of Spirurina.

Tetrameres grusi is a significant parasitic nematode of cranes that is classified into suborder Spirurina. However, for more than a century, this classification has been controversial. Mitochondrial genomes are valuable resources for parasite taxonomy, population genetics and systematics studies. Here, the mitochondrial genome of T. grusi was determined and subsequently compared with those from Spirurina species using concatenated datasets of amino acid sequences predicted from mitochondrial protein-coding genes. The complete mitochondrial genome of T. grusi is circular with 13,709 bp, and it contains 12 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and one non-coding region. All of the protein-coding genes are transcribed in the same direction. There were 18 intergenic spacers of 1-44 bp, and six locations with gene overlaps, ranging from 1 bp to 28 bp, in the mitochondrial genome of T. grusi. The AT content of this mitochondrial genome was 71.56%. This was similar to mitochondrial genomes of other Spirurina species, which also exhibited strong AT content bias, not only in the nucleotide composition but also in codon usage. The sequenced mitogenomes of the 25 Spirurina nematodes showed three classes of gene arrangements based on the 12 protein-coding genes, and the gene arrangement of the T. grusi mitochondrial genome belonged to the Class I. Phylogenetic analyses using mitochondrial genomes of 25 Spirurina nematodes revealed that T. grusi (Habronematoidea) was closer to Gongylonema pulchrum (Spiruroidea) than Spirocerca lupi (Thelazioidea). The availability of the complete mitochondrial genome sequence of T. grusi provides new and useful genetic markers for further studies on Spirurina nematodes.

An alternate and reversible method for flight restraint of cranes.

Flight restraint is important for zoos, safaris, and breeding centers for large birds. Currently used techniques for flight restraint include both surgical and non-surgical approaches. Surgical approaches usually cause permanent change to or removal of tendon, patagial membrane, or wing bones, and can cause pain and inflammation. Non-surgical approaches such as clipping or trimming feathers often alter the bird's appearance, and can damage growing blood feathers in fledglings or cause joint stiffness. We observed microstructure of primary feathers of the red-crowned crane (Grus japonensis) and found that the width of barbs is a determinative factor influencing vane stiffness and geometric parameters. We hypothesized that partial longitudinal excision of barbs on the ventral surface of the primary feathers would reduce the stiffness of the vane and render the feathers unable to support the crane's body weight during flight. Furthermore, we hypothesized that this modification of barbs would also change the aerodynamic performance of feathers such that they could not generate sufficient lift and thrust during flapping to enable the bird to fly. We tested this hypothesis on a red-crowned crane that had normal flight capability by excising the ventral margin of barbs on all 10 primaries on the left wing. The bird was unable to take off until the modified feathers were replaced by new ones. Removal of barbs proved to be a simple, non-invasive, low-cost and reversible method for flight restraint. It is potentially applicable to other large birds with similar structural characteristics of primary feathers.