Avian Species Research Articles

Challenges of Dermanyssus gallinae in Poultry: Biological Insights, Economic Impact and Management Strategies

Bird mites are parasites that feed on both wild and domesticated bird species, causing severe degradation in avian welfare. The chicken mite, Dermanyssus gallinae in particular, is a widespread ectoparasite in poultry, responsible for several challenges faced by the poultry industry, including poor animal health, which causes significant economic losses. This review, based on our current knowledge, aims to provide a comprehensive insight into the biology and distribution of these mites, as well as their impact on poultry health and production. It explores the most prevalent mites in avian species, with a focus on D. gallinae, and examines the different psychological and physiological alterations observed in infected stocks, such as decreased egg production, weight loss, and an increased susceptibility to diseases. This review will also cover existing control strategies, including chemical, biological, and environmental approaches, with attention to the growing concern around pesticide resistance. Additionally, it delves into genetic research conducted on these mites, primarily focusing on phylogenetic studies, which have provided insights into their evolutionary relationships and potential vulnerabilities. By compiling existing studies, this article underscores the urgent need for effective and sustainable countermeasures, as well as further genetic research to mitigate the substantial impact of D. gallinae on the poultry sector.

Decoding the role of ghrelin and its interactions with central signaling pathways in avian appetite regulation.

Ghrelin, a peptide hormone primarily produced in the enteroendocrine cells of the gastrointestinal tract, plays a vital role in regulating food intake, and energy balance in avian species. This review examines the complex interactions between ghrelin and the central signaling pathways associated with hunger regulation in birds. In contrast to mammals, where ghrelin typically promotes feeding behavior, its effects in birds appear more nuanced, exhibiting anorexigenic properties under certain conditions. The interactions of ghrelin with central signaling pathways, particularly within the hypothalamus, are explored, highlighting its influence on various neuropeptide systems, including GABAergic, corticotropinergic, opioidergic, dopaminergic, serotonergic, cannabinoidergic, and adrenergic pathways. This article synthesizes current knowledge regarding ghrelin's structure and physiological functions, as well as its interactions with other neuropeptides and hormones that collectively govern avian feeding behaviors. Furthermore, this review proposes future research directions aimed at elucidating the intricate mechanisms underlying appetite control in birds. Insights gained from this analysis may not only enhance our understanding of avian biology and the optimal regulation of their food intake but also inform wildlife management and conservation strategies in response to environmental changes.

North American avian species that migrate in flocks show greater long-term non-breeding range shift rates

Abstract Background Many species are exhibiting range shifts associated with anthropogenic change. For migratory species, colonisation of new areas can require novel migratory programmes that facilitate navigation between independently-shifting seasonal ranges. Therefore, in some cases range-shifts may be limited by the capacity for novel migratory programmes to be transferred between generations, which can be genetically and socially mediated. Methods Here we used 50 years of North American Breeding Bird Survey and Audubon Christmas Bird Count data to test the prediction that breeding and/or non-breeding range-shifts are more prevalent among flocking migrants, which possess a capacity for rapid social transmission of novel migration routes. Results Across 122 North American bird species, social migration was a significant positive predictor for the magnitude of non-breeding centre of abundance (COA) shift within our study region (conterminous United States and Southern Canada). Across a subset of 81 species where age-structured flocking was determined, migrating in mixed-age flocks produced the greatest shifts and solo migrants the lowest. Flocking was not a significant predictor of breeding COA shifts, which were better explained by absolute population trends and migration distance. Conclusions Our results suggest that social grouping may play an important role in facilitating non-breeding distributional responses to climate change in migratory species. We highlight the need to gain a better understanding of migratory programme inheritance, and how this influences spatiotemporal population dynamics under environmental change.

Identification of pennaceous barbule cell factor (PBCF), a novel gene with spatiotemporal expression in barbule cells during feather development.

Bird contour feathers exhibit a complex hierarchical structure composed of a rachis, barbs, and barbules, with barbules playing a crucial role in maintaining feather structure and function. Understanding the molecular mechanisms underlying barbule formation is essential for advancing our knowledge of avian biology and evolution. In this study, we identified a novel gene, pennaceous barbule cell factor (PBCF), using microarray analysis, RT-PCR, and in situ hybridization. PBCF is expressed in barbule cells adjacent to the ramus during pennaceous barbule formation, where these cells fuse with the ramus to establish the feather's branching structure. PBCF expression occurs transiently after melanin pigmentation of the barbule plates but before the expression of barbule-specific keratin 1 (BlSK1). Orthologues of PBCF, predicted to be secreted proteins, are conserved across avian species, with potential homologues detected in reptiles, suggesting an evolutionary lineage-specific adaptation. Additionally, PBCF is expressed in non-vacuolated notochord cells and the extra-embryonic ectoderm of the yolk sac, hinting at its broader developmental significance. The PBCF gene produces two mRNA isoforms via alternative splicing, encoding a secreted protein and a glycophosphatidylinositol (GPI)-anchored membrane-bound protein, indicating functional versatility. These findings suggest that PBCF may be involved as an avian-specific extracellular matrix component in cell adhesion and/or communication, potentially contributing to both feather development and embryogenesis. Further investigation of PBCF's role in feather evolution and its potential functions in other vertebrates could provide new insights into the interplay between development and evolution.

Evaluation and treatment of lead toxicosis in rehabilitated avian species: 95 cases (2014-2023).

To evaluate avian patients presented to a wildlife rehabilitation facility with confirmed lead toxicity for clinical signs associated with blood lead level groups, efficacy of subcutaneous chelation therapy with calcium disodium EDTA, and case outcome based on presenting blood lead levels. A retrospective record review of 95 avian cases representing 19 species treated for lead toxicosis from a wildlife rehabilitation center in Wisconsin between 2014 and 2023 was conducted. Data were evaluated for presenting complaints, clinical signs, radiographic findings, chelation therapy protocol, clinical pathology data, and case outcome. A low lead level of < 20 µg/dL was the most commonly diagnosed level in avian patients. The presence of neurologic disease was found most commonly in birds with higher blood lead levels, whereas poor body condition, trauma, and anemia were most common in birds with low lead levels. Bald eagles (Haliaeetus leucocephalus) and tundra swans (Cygnus columbianus) were the most prevalent species presented. All methods of chelation therapy evaluated resulted in a reduction of blood lead levels. Patients with intake blood lead levels > 60 µg/dL were more likely to die or be euthanized while in care. A bird with a blood lead level > 60 µg/dL is more likely to present with neurologic disease and have a poor case outcome. Diluted calcium disodium EDTA was clinically effective when administered SC. Initial blood lead level, in conjunction with species, clinical signs, and radiographic changes, can help guide clinical decision-making for avian patients with lead toxicosis.

Evaluation of a Point-of-Care-Viscoelastic Coagulation Device in Hispaniolan Amazon Parrots (Amazona ventralis).

Viscoelastic testing evaluates the formation and lysis of a clot over time, allowing more complete assessment of patient hemostasis in real time, whereas traditional tests, such as prothrombin time and partial thromboplastin time, only measure coagulation factor function. Patient-side viscoelastic coagulation monitors are easy to use, portable, and provide faster turnaround time than commercial laboratories. Viscoelastic testing requires only 0.2 mL of blood and is useful in diagnosing and treating hemostatic disorders. Currently, there is no standardized coagulation testing method across bird species. In this cross-sectional study, a viscoelastic coagulation device, the Entegrion Viscoelastic Coagulation Monitor-Vet (VCM-Vet), was evaluated. Blood samples were obtained from 26 Hispaniolan Amazon parrots (HAPs) (Amazona ventralis) under manual restraint. Results were recorded on the device as graphical output with quantitative viscoelastic measurements. Results were reported using standard rotational thromboelastometry terminology, including clotting time, clot formation time, alpha angle, maximum clot firmness, clot firmness amplitude at 10 and 20 minutes after clot formation, and clot lysis at 30 and 45 minutes. The median clotting time was 463 seconds (reference interval: 56-1635 seconds), the mean clot formation time was 704.7 seconds (reference interval: 172-1697 seconds), the mean alpha angle was 27.3 (reference interval: 7-60), and the mean maximum clot firmness was 15.4 (reference interval: 7-25). Statistical analysis found that all parameters were normally distributed aside from clotting time in seconds. There was no appreciable breakdown of the clot during the 60-minute device runtime, and there was no significant difference in any parameter based on sex. The VCM-Vet produced clotting times for this population of HAPs and enabled the creation of reference intervals. Based on our findings, the VCM-Vet can be used to assess clot potential in HAPs and possibly other avian species.

Avian species and functional diversity in the Yellow River Wetland Nature Reserve of Henan Province

Avian species and functional diversity in the Yellow River Wetland Nature Reserve of Henan Province

Hummingbirds use compensatory eye movements to stabilize both rotational and translational visual motion.

To maintain stable vision, behaving animals make compensatory eye movements in response to image slip, a reflex known as the optokinetic response (OKR). Although OKR has been studied in several avian species, eye movements during flight are expected to be minimal. This is because vertebrates with laterally placed eyes typically show weak OKR to nasal-to-temporal motion (NT), which simulates typical forward locomotion, compared with temporal-to-nasal motion (TN), which simulates atypical backward locomotion. This OKR asymmetry is also reflected in the pretectum, wherein neurons sensitive to global visual motion also exhibit a TN bias. Hummingbirds, however, stabilize visual motion in all directions through whole-body movements and are unique among vertebrates in that they lack a pretectal bias. We therefore predicted that OKR in hummingbirds would be symmetrical. We measured OKR in restrained hummingbirds by presenting gratings drifting across a range of speeds. OKR in hummingbirds was asymmetrical, although the direction of asymmetry varied with stimulus speed. Hummingbirds moved their eyes largely independently of one another. Consistent with weak eye-to-eye coupling, hummingbirds also exhibited disjunctive OKR to visual motion simulating forward and backward translation. This unexpected oculomotor behaviour, previously unexplored in birds, suggests a potential role for compensatory eye movements during flight.

Strategic analysis of avian conservation within key areas and key species - A case study of Baiyangdian, China.

Global climate change and extensive human activities are causing rapid transformations in natural ecosystems, leading to the rapid loss of suitable habitats for wildlife, which urgently requires measures to protect global biodiversity. In the past decade, China has invested heavily in ecological restoration, but current projects often do not prioritize biodiversity conservation. Therefore, developing systematic conservation strategies and using quantitative methods to identify conservation key areas and key species within a regional scale is of great importance for current ecological restoration. In this study, we focused on avian species, using an Ensemble Species Distribution Model to identify bird distribution hotspots and accordingly proposed conservation key areas in Baiyangdian. Additionally, the AHP-EWM-TOPSIS method and ENMTools were utilized to select flagship bird species with strong umbrella effects and to determine conservation key species. The results indicate that the Fuhe wetland, southwest of ZaoZaDian, central and northern of ShaoCheDian, northwest of Beitian Village and Datian Village, northern of XiaoBaiYangDian, and the Xiaoyihe wetland should be designated as the birdconservation key areas. The key birds should include Aythya baeri, Ardea alba, Phasianus colchicus, Falco tinnunculus, Upupa epops and Paradoxornis heudei, with higher priority given to A. baeri, A. alba, P. colchicus and F. tinnunculus. This study aims to provide a systematic framework for identifying conservation key areas and key species, facilitating the efficient use of public funding by local governments, and providing scientific guidance for conserving the bird diversity of Baiyangdian.

FKBP5 as a key regulator of metabolic processes in birds: Insights from chicken pectoral muscle.

FK506-binding protein 5 (FKBP5) is a negative regulator of the glucocorticoid response and may play an important role in regulating metabolic homeostasis in birds. However, limited information is available regarding its role in avian species. This study aimed to clarify the spatiotemporal characteristics of chicken FKBP5 and investigate the effects of exogenous stimuli on its expression. Real-time quantitative PCR (RT-qPCR) was utilized to analyze the spatiotemporal expression patterns of FKBP5 in chickens. Additionally, the impact of exogenous stimuli, including fasting, energy restriction, and insulin/pyruvate/glucose injections, on FKBP5 expression in the pectoral muscle was investigated. The results showed that FKBP5 is broadly expressed in various bird tissues, with dominant expression in insulin-sensitive tissues. The FKBP5 levels in birds are dramatically modulated during development in insulin-sensitive tissues, with the highest expression observed in striated muscle and liver at embryonic day 19 (E19) (P < 0.01). The basal level of FKBP5 in the pectoral muscle of broilers is higher than that in Silky chickens. Insulin administration leads to a rapid drop in blood glucose levels in both breeds, with a slower recovery in AA broilers (P < 0.01). However, FKBP5 expression in the pectoral muscle initially shows a slight drop, followed by a sharp increase over time after insulin administration (P < 0.01). Additionally, breed heterogeneity in FKBP5 expression was observed in the pectoral muscle upon insulin stimulation, with broilers showing stronger insulin sensitivity compared to Silky chickens. A 24-hour fasting period downregulated blood glucose levels (P < 0.01) and FKBP5 expression in the pectoral muscle of AA broilers (P < 0.01). A 30% energy restriction over three weeks slightly reduced blood glucose levels (P = 0.075) and significantly decreased FKBP5 levels in the pectoralis muscle of broilers. In addition, pyruvate increased blood glucose and pectoralis FKBP5 transcription levels at 60 min (P < 0.01), whereas glucose increased blood glucose levels but had no effect on FKBP5 expression. Overall analysis showed a negative correlation between FKBP5 expression in the pectoral muscle and blood glucose levels (ρ = -0.405, P < 0.001). In conclusion, FKBP5 is a key player in the metabolic regulation of birds, with its expression being highly dynamic and tissue-specific. Insulin regulates FKBP5 expression in pectoral muscles in a time-dependent manner, while pyruvate increases FKBP5 levels and fasting/energy restriction reduces FKBP5 mRNA expression in the pectoral muscles.

Brodifacoum causes coagulopathy, hemorrhages, and mortality in rainbow trout (Oncorhynchus mykiss) at environmentally relevant hepatic residue concentrations.

Widely used second-generation anticoagulant rodenticides like brodifacoum are classified as persistent, bioaccumulative, and toxic. Widespread exposure of terrestrial and avian non-target species is well-known and recently hepatic anticoagulant rodenticide residues have been detected in wild fish. However, no sufficient data exist to interpret the effects of these findings on fish health. In order to assess the potential impact of rodenticide residues on fish, we exposed rainbow trout (Oncorhynchus mykiss) to brodifacoum-spiked feed. In a first experiment, individually kept trout (body weight ca. 200 g) were exposed to a single dose of brodifacoum and observed for 15 days. In a second experiment, fish (body weight ca. 330 g) were kept in groups and fed every 7 or 8 days with brodifacoum-spiked feed for up to 60 days. Sampling of trout every 15 days over the 60 days period allowed monitoring of brodifacoum concentrations in serum, liver, and muscle tissue, as well as occurring effects over the course of the experiment. In both experiments, brodifacoum doses of ≥ 75 µg/kg body weight caused prolonged or non-measurable blood coagulation times. Disturbed hemostasis led to hemorrhages and anemia with significantly decreased albumin levels. In the 60 days-experiment, brodifacoum doses ≥ 100 µg/kg body weight caused additionally discoloration, apathy, and anorexia, resulting in reduced weight gain, and ultimately mortality. The delay until the onset of overt symptoms (14-17 days) highlights the importance of test duration while investigating effects of anticoagulant rodenticides in fish. The lowest hepatic brodifacoum concentration associated with effects in trout was on average 122.6 ng/g liver wet weight, which is in the range of previously reported brodifacoum residues in wild fish. These findings illustrate the risks associated with the use of anticoagulant rodenticides for freshwater fish and reinforce the need to stipulate all available and appropriate risk mitigation measures to prevent emissions at source.

The Flame of the Forest (Butea monosperma) and its Mutualistic Interaction with Birds in Summer from Jamkhed Tahsil, Dist. Ahmednagar.

The flame of the forest (Butea monosperma), a species native to the Indian subcontinent, play a vital role in supporting biodiversity, particularly in its interactions with avian species in rural and semi-arid areas like Jamkhed tahsil in Ahmednagar district, Maharashtra. This study aims to explore the avian fauna of Jamkhed and the importance of butea monosperma in sustaining bird populations during summer season. We emphasize conservation efforts and ecological singnificance by highlighting the relationships between the region’s flora and fauna through this investigation. Field surveys were conducted during early morning and late afternoon from February-April 2024.Total 56 bird species was recorded. Through field observation explores the butea monosperma role as a food source, nesting and roosting habitat for birds. Result highlight that Butea monosperma is a keystone species in supporting avian population by providing nector during the dry season, shelter for nesting and promoting ecological balance through bird-mediated pollination. Birds contribute to the genetic diversity of Butea monosperma by facilitating cross-pollination between individual trees. This interaction ensures the tree's reproductive success and enhances its ability to regenerate and persist in the ecosystem.

Cross-species regulatory network analysis identifies FOXO1 as a driver of ovarian follicular recruitment

The transcriptional regulation of gene expression in the latter stages of follicular development in laying hen ovarian follicles is not well understood. Although differentially expressed genes (DEGs) have been identified in pre-recruitment and pre-ovulatory stages, the master regulators driving these DEGs remain unknown. This study addresses this knowledge gap by utilizing Master Regulator Analysis (MRA) combined with the Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNe) for the first time in laying hen research to identify master regulators that are controlling DEGs in pre-recruitment and pre-ovulatory phases. The constructed ARACNe network included 10,466 nodes and 292,391 edges. The ARACNe network was then used in conjunction with the Virtual Inference of Protein-activity by Enriched Regulon (VIPER) for the MRA to identify top up- and down-regulated master regulators. VIPER analysis revealed FOXO1 as a master regulator, influencing 275 DEGs and impacting pathways related to apoptosis, proliferation, and hormonal regulation. Additionally, CLOCK, known as a crucial regulator of circadian rhythm, emerged as an upregulated master regulator in the pre-ovulatory stage. These findings provide new insights into the transcriptional landscape of laying hen ovarian follicles, offering a foundation for further exploration of follicle development and enhancing reproductive efficiency in avian species.

Generation of transgenic chicken through ovarian injection.

Traditional DNA microinjection methods used in mammals are difficult to apply to avian species due to their unique reproductive characteristics. Genetic manipulation in chickens, particularly involving immature follicles within living ovaries, has not been extensively explored. This study seeks to establish an efficient method for generating transgenic chickens through ovarian injection, potentially bypassing the challenges associated with primordial germ cell (PGC) manipulation and fertilized egg microinjection. Hens were anesthetized and underwent a surgical procedure to access the ovary for DNA injection into immature follicles. The study used liposomes to deliver GFP-expressing plasmids at various dosages. After injection, hens recovered, and their eggs were fertilized through artificial insemination. Transgenic chickens were successfully generated in one generation without needing G0 founders. The injection of 20 μg plasmid yielded the highest transgenic efficiency at 12.1%. GFP-positive embryos were confirmed through microscopy, and successful transgene expression was validated at the tissue level using immunostaining. TERT and GFP elements introduced in the G1 generation resulted in 4.1% positive transgene rates, as confirmed by PCR and Southern blotting. This ovarian injection method offers a promising alternative for avian genetic manipulation, bypassing complex PGC procedures and enabling direct generation of G1 transgenic chickens. This technique simplifies the transgenic process for chickens and has the potential to be adapted for other avian species, especially those without established PGCs culture systems.

Avifaunal diversity and conservation significance of coastal ecosystems on Rameswaram Island, Tamil Nadu, India

Biodiversity-rich areas tied to heritage, religious tourism, and ecotourism, often face changes to their landscapes due to infrastructure development. Such activities may threaten the species survival and disrupt the delicate ecosystems in these regions. Hence it becomes imperative to build up baseline species data from such areas for biodiversity conservation and management interventions. Towards achieving this objective, avifaunal inventories were documented from Kothandaramar Lagoon, Dhanushkodi Lagoon, and the Arichalmunai beach in Rameswaram Island, Ramanathapuram District, Tamil Nadu, which is an important site for winter migrants. A total of 147 avian species belonging to 17 orders and 45 families from August 2021 to July 2023 were recorded. Order-wise, Charadriiformes (52 species) dominated the area, followed by Passeriformes (27 species) and Pelecaniformes (21 species). According to the IUCN Red List of Threatened Species, 11 ‘Near Threatened’, three ‘Vulnerable’, two ‘Endangered’ (Great Knot Calidris tenuirostris and Siberian Sandplover Anarhynchus mongolus), and one unassessed species (Hanuman Plover Charadrius seebohmi) were recorded. The relative abundance based on the frequency of observations indicated that 61% (90 species) were common, 22% (32 species) were uncommon, and 17% (25 species) were rare. Winter visitors constituted 42% (62 species) and one was a passage migrant (Rosy Starling Pastor roseus). Coastal lagoons of this region comprise diverse habitats that play a vital role for birds, which provide places for nesting, roosting, and foraging. This baseline data emphasizes the importance of Dhanushkodi Lagoon along with adjacent areas as an important wintering site on the southeastern coast of India for migratory shorebirds as well as highlights the importance of adjoining small forested patches thus required to be declared as a protected area.

Association of Hepatic Gene Expression with Chemical Concentrations in Wild-Collected Double-Crested Cormorant Embryos using an EcoToxChip Gene Array.

Contaminant monitoring programs use wild bird eggs, but determining whether measured concentrations elicit adverse effects relies on extrapolation from toxicity studies with avian model species. Here, we directly evaluated the relationships between whole embryo contaminant concentrations and mRNA expression in liver tissue of the double-crested cormorant (Nannopterum auritum). Eggs collected from three North American sites (one from Lake Erie and two from the Salish Sea) were artificially incubated until pipping. Hepatic mRNA was analyzed with an EcoToxChip quantitative polymerase chain reaction (qPCR) array containing 354 target genes. The remaining embryo was analyzed for mercury and 95 persistent organic contaminants. Lake Erie embryos had higher concentrations of most organic contaminants than those from the Salish Sea. Sparse partial least-squares regression analysis of contaminant and gene expression data indicated that chlorinated hydrocarbons, especially polychlorinated biphenyls (PCBs), were associated with variation in gene expression. Linear correlations revealed consistent pairwise associations between chlorinated contaminants and the expression of nine genes (seven genes with PCBs and two with β-hexachlorocyclohexane). Partial least-squares discriminant analysis identified embryos from the Lake Erie site accurately. Overall, gene expression in embryos from wild-collected eggs was associated with tissue contaminant concentrations, and thus, transcriptomic measurements may serve to identify individuals or populations affected biologically by contaminants.

Comparative genomics of the sexually transmitted parasite Trichomonas vaginalis reveals relaxed and convergent evolution and genes involved in spillover from birds to humans.

Trichomonas vaginalis is the causative agent of the venereal disease trichomoniasis which infects men and women globally and is associated with serious outcomes during pregnancy and cancers of the human reproductive tract. Trichomonads parasitize a range of hosts in addition to humans including birds, livestock, and domesticated animals. Recent genetic analysis of trichomonads recovered from columbid birds has provided evidence that these parasite species undergo frequent host-switching, and that a current epoch spillover event from columbids likely gave rise to T. vaginalis in humans. We undertook a comparative evolutionary genomics study of seven trichomonad species, generating chromosome-scale reference genomes for T. vaginalis and its avian sister species Trichomonas stableri, and assemblies of five other species that infect birds and mammals. Human-infecting trichomonad lineages have undergone recent and convergent genome size expansions compared to their avian sister species, and the major contributor to their increased genome size is increased repeat expansions, especially multicopy gene families and transposable elements, with genetic drift likely a driver due to relaxed selection. Trichomonads have independently host-switched twice from birds to humans, and genes implicated in the transition to the human host include those associated with host tissue adherence and phagocytosis, extracellular vesicles, and CAZyme virulence factors.

Avian Reovirus: From Molecular Biology to Pathogenesis and Control.

Avian reoviruses (ARVs) represent a significant economic burden on the poultry industry due to their widespread prevalence and potential pathogenicity. These viruses, capable of infecting a diverse range of avian species, can lead to a variety of clinical manifestations, most notably tenosynovitis/arthritis. While many ARV strains are asymptomatic, pathogenic variants can cause severe inflammation and tissue damage in organs such as the tendons, heart, and liver. In broilers and turkeys, ARVs can induce severe arthritis/tenosynovitis, characterized by swollen hock joints and lesions in the gastrocnemius tendons. Additionally, ARVs have been implicated in other diseases, although their precise role in these conditions remains to be fully elucidated. In recent years, ARV cases have surged in the United States, emphasizing the need for effective control measures. Routine vaccination with commercial or autogenous vaccines is currently the primary strategy for mitigating ARV's impact. Future research efforts should focus on enhancing our understanding of ARV-induced pathogenesis, identifying host factors that influence disease severity, and developing novel vaccines based on ongoing surveillance of circulating ARV strains. This review aims to explore the molecular aspects of ARV, including virus structure, replication, molecular epidemiology, the roles of its encoded proteins in host pathogenesis, and the immune response to ARV infection. Furthermore, we discuss the diagnostic approaches of avian reovirus and the potential biosecurity measures and vaccination trials in combating ARV and developing effective antiviral strategies.

Black fly diversity and molecular detection of blood parasites in Simulium khelangense (Diptera, Simuliidae) from Laos

Abstract Black flies (Diptera: Simuliidae) are significant pests and vectors transmitting pathogens to humans and other animals. However, knowledge of species diversity as well as their role as pests and vectors in Laos is limited, despite the country having abundant suitable lotic habitats, that is, running water. In this study, we collected wild adult black fly specimens from Laos. Both morphology and genetic data supported that they were Simulium khelangense Takaoka, Srisuka and Saeung, and therefore, a new distribution record for this species. Screening of the blood protozoa from 106 females detected Leucocytozoon (n = 7) and Trypanosoma (n = 9). Identifications of Leucocytozoon based on cytochrome b sequences in MalAvi database indicated that 5 specimens had identical sequences to those of 4 lineages (GALLUS17 [n = 2], GALLUS35 [n = 1], GALLUS37 [n = 1], and GALLUS41 [n = 1]) of unidentified species (i.e., Leucocytozoon sp.). The remaining 2 had no identical sequences but were very similar (99%) to GALLUS34 and GALLUS41 lineages. Identifications of Trypanosoma based on the small subunit rRNA indicated that all were T. avium. The results presented here further support the role of S. khelangense as a potential vector of Leucocytozoon and Trypanosoma as well as being a possible pest of domestic avian species.

Mammalian ZAP and KHNYN independently restrict CpG-enriched avian viruses.

Zoonotic viruses are an omnipresent threat to global health. Influenza A virus (IAV) transmits between birds, livestock, and humans. Proviral host factors involved in the cross-species interface are well known. Less is known about antiviral mechanisms that suppress IAV zoonoses. We observed CpG dinucleotide depletion in human IAV relative to avian IAV. Notably, human ZAP selectively depletes CpG-enriched viral RNAs with its cofactor KHNYN. ZAP is conserved in tetrapods but we uncovered that avian species lack KHNYN. We found that chicken ZAP does not affect IAV (PR8) or CpG enriched IAV. Human ZAP or KHNYN independently restricted CpG enriched IAV by overexpression in chicken cells or knockout in human cells. Additionally, mammalian ZAP-L and KHNYN also independently restricted an avian retrovirus (ROSV). Curiously, platypus KHNYN, the most divergent from eutherian mammals, was also capable of direct restriction of multiple diverse viruses. We suggest that mammalian KHNYN may be a bona fide restriction factor with cell-autonomous activity. Furthermore, we speculate that through repeated contact between avian viruses and mammalian hosts, protein changes may accompany CpG-biased mutations or reassortment to evade mammalian ZAP and KHNYN.