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(a) Pancreas, multifocal areas of necrosis of pancreatic acini (asterisk), H&E × 100. (b) Cerebrum, encephalomalacia (asterisk), H&E × 200.
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In winter 2016/2017, the highly pathogenic avian influenza virus H5N8 was detected in backyard poultry in Serbia for the first time. The second HPAI outbreak case in backyard poultry was reported in 2022, caused by subtype H5N1. This is the first study that documents the laboratory identification and pathology associated with highly pathogenic avia...
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... kidneys, hemorrhages, focal degeneration and necrosis of the renal tubular epithelial cells were observed. Although there were no macroscopic lesions in the pancreas, multifocal necrotic foci with mild to moderate mononuclear cell infiltrations were found (Figure 7a). In the exocrine pancreatic cells, vacuolization of the cytoplasm was detected. ...
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... the brain, lesions consisted of disseminated focal microgliosis, necrosis and infiltration of mononuclear cells around blood vessels. Non-suppurative meningitis, neuronophagia and encephalomalacia were observed in ten cases (Figure 7b). Mild lymphocytic infiltration in the lamina propria was present in the intestines. ...
Citations
... Similarly, H5N1 HPAI was able to replicate in the renal tubular epithelium of both naturally and experimentally-infected waterfowl, without inducing significant changes 35,36 . However, renal lesions with concurrent positive immunolabelling were reported in wild Baikal teals (Anas Formosa), bean geese (Anser fabalis), and whooper swans (Cygnus Cygnus) and backyard chickens naturally-infected with H5N8 HPAI 37,38 . The involvement of the reproductive tract was mentioned in different avian species exposed to several HPAI subtypes. ...
At the end of 2020, an outbreak of HPAI H5N8 was registered in captive African houbara bustards (Chlamydotis undulata) in the United Arab Emirates. In order to better understand the pathobiology of this viral infection in bustards, a comprehensive pathological characterization was performed. A total of six birds were selected for necropsy, histopathology, immunohistochemistry, RNAscope in situ hybridization and RT-qPCR and nanopore sequencing on formalin-fixed and paraffin-embedded (FFPE) tissue blocks. Gross lesions included mottled and/or hemorrhagic pancreas, spleen and liver and fibrinous deposits on air sacs and intestine. Necrotizing pancreatitis, splenitis and concurrent vasculitis, hepatitis and fibrino-heterophilic peritonitis were identified, microscopically. Viral antigens (nucleoprotein) and RNAs (matrix gene) were both detected within necro-inflammatory foci, parenchymal cells, stromal cells and endothelial cells of affected organs, including the myenteric plexus. Molecular analysis of FFPE blocks successfully detected HPAI H5N8, further confirming its involvement in the lesions observed. In conclusion, HPAI H5N8 in African houbara bustards results in hyperacute/acute forms exhibiting marked pantropism, endotheliotropism and neurotropism. In addition, our findings support the use of FFPE tissues for molecular studies of poorly characterized pathogens in exotic and endangered species, when availability of samples is limited.
... Similar histological abnormalities, including pancreatic lesions, have been documented (NOORUZZAMAN et al., 2019;NÚÑEZ et al., 2016). Similar findings were reported in backyard chickens in Serbia infected with HPAI H5N8 (DJURDJEVIĆ et al., 2023). ...
In Egypt, poultry farms are still experiencing pressure from the avian influenza viruses H5N1, H5N8, and H9N2, as well as economic losses from direct viral infection or sharing other diseases that increase respiratory complications. Despite the administration of multiple vaccines against these viruses, protective immunity cannot develop due to frequent virus mutation and changes due to immunological pressure or genetic mixing. In this study, a six-weeks-old flock of Pekin ducks showed sudden mortality without any symptoms, while the still survived birds showed depression, mild to severe respiratory and/or nervous symptoms and greenish diarrhea. The mortality rate reached 25.4% in two weeks. Postmortem lesion included severely congested organs, tracheitis, pneumonia, massive hemorrhages on coronary fat and heart muscles, thymic hyperplasia, necrosis, and hemorrhages on pancreas. Liver samples were H5 positive by PCR, and sequences identified two isolates with the accession numbers MW917155 and MW917160. The phylogenetic analysis and identity table of the obtained two isolates demonstrated their relationship to the clade 2.3.4.4.1, which includes Egyptian isolates from ducks, goose, and chickens from 2017 to 2019. Our results showed clinical manifestation as well as molecular techniques to support the diagnosis of ducks infected with the highly pathogenic avian influenza (HPAI) virus. Furthermore, our findings revealed a link between our isolates and earlier local and worldwide isolates, as well as a match with the vaccines used in Egypt. Further coordinated national investigations on the prevalence and variations of HPAI virus infection in Egyptian poultry farms as well as the efficacy of used vaccinations are advised. Zusammenfassung Geflügelfarmen leiden in Ägypten immer noch unter dem Druck der Vogelgrippeviren H5N1, H5N8 und H9N2, sowie unter wirtschaftlichen Verlusten durch direkte Infektionen oder die Übertragung anderer Krankheiten, die Atemwegskomplikationen verstärken. Trotz der Verabreichung mehrerer Impfstoffe gegen diese Viren kann sich aufgrund häufiger Virusmutationen und Veränderungen, die durch immunologischen Druck oder genetische Vermischung hervorgerufen werden, keine schützende Immunität entwickeln. In dieser Studie zeigte eine sechs Wochen alte Herde von Pekin-Enten eine plötzliche Sterblichkeit ohne Symptome, während andere Depressionen, leichte bis schwere Atemwegs-und Nervensymptome, sowie grünlichen Durchfall zeigten. Die Sterblichkeitsrate erreichte 25,4% in zwei Wochen. Die postmortalen Läsionen umfassten stark verstopfte Organe, Tracheitis, Lungenentzündung, massive Blutungen an Koronarfett und Herzmuskeln, vergrößerte Thymusschlaufen, Nekrose und Blutungen an der Bauchspeicheldrüse. Die Proben waren mittels PCR H5-positiv, und die Sequenzen identifizierten zwei Isolate mit den Zugangsnummern MW917155 und MW917160. Die phylogenetische Analyse und Identifizierungstabelle der erhaltenen Isolate ergaben eine Verwandtschaft mit der Klade 2.3.4.4.1, die Europ.Poult.Sci., 87. 2023, ISSN 1612-9199, © Verlag Eugen Ulmer, Stuttgart.
... In the wave of influenza outbreaks across Europe in recent years, Serbia experienced specific incidences of the disease within backyard poultry populations. During the 2016/2017 period, a total of four outbreaks were officially recorded, followed by a subsequent occurrence of three outbreaks in the 2021/2022 period [20]. Despite the common practice of keeping pigs and poultry together in backyards, no spillover and seroconversion in backyard pigs in this study were detected, which might be due to the short life of backyard pigs and fast actions to limit the infection in poultry [20]. ...
... During the 2016/2017 period, a total of four outbreaks were officially recorded, followed by a subsequent occurrence of three outbreaks in the 2021/2022 period [20]. Despite the common practice of keeping pigs and poultry together in backyards, no spillover and seroconversion in backyard pigs in this study were detected, which might be due to the short life of backyard pigs and fast actions to limit the infection in poultry [20]. A similar situation with sporadic spillovers from poultry to pigs is seen in Europe [21]. ...
Contrary to pig farming in developed Western countries, in a large part of the world, pigs are still traditionally kept in small backyard farms, usually for family needs. Their main characteristics are low biosecurity, swill feeding, natural breeding and uncontrolled trade. Given the high number of backyard farms in Serbia and the risk they are thought to pose to intensive pig farming, the main aim of this study was to evaluate the prevalence of major viral diseases of swine among traditionally kept pigs in small holdings with low biosecurity. For this investigation, 222 serum samples from 69 backyard holdings were randomly selected and tested for antibodies to Porcine Reproductive and Respiratory Syndrome virus (PRRSV), Aujeszky’s disease virus (ADV), Porcine Parvovirus (PPV) and Swine influenza Virus (SIV) by enzyme-linked immunosorbent assay (ELISA). The herd-level seroprevalence of PRRS, Aujeszky’s disease and PPV was 2.9%, 27.5% and 37.7%, respectively. Swine influenza seroconversion was not confirmed in any of the tested holdings. Despite widely distributed PPV and AD in backyard farms in Serbia, almost 50% of them are still negative for all the tested diseases. The backyard farms must be monitored, and owners must be educated as their role in eradication programs and obtaining country-free status may be crucial.
... In the wave of influenza outbreaks across Europe in recent years, Serbia experienced specific incidences of the disease within backyard poultry populations. During the 2016/2017 period, a total of four outbreaks were officially recorded, followed by a subsequent occurrence of three outbreaks in the 2021/2022 period [16]. Despite the common practice of keeping pigs and poultry together in backyards, no spillover and seroconversion in backyard pigs in this study were detected, which might be due to the short life of backyard pigs, as well as fast actions to limit the infection in poultry [16]. ...
... During the 2016/2017 period, a total of four outbreaks were officially recorded, followed by a subsequent occurrence of three outbreaks in the 2021/2022 period [16]. Despite the common practice of keeping pigs and poultry together in backyards, no spillover and seroconversion in backyard pigs in this study were detected, which might be due to the short life of backyard pigs, as well as fast actions to limit the infection in poultry [16]. A similar situation with sporadic spillovers from poultry to pigs is seen in Europe [17]. ...
Contrary to pig farming in developed western countries, in a large part of the world, pigs are still traditionally kept, in small backyard farms, usually for family needs. Their main characteristics are low biosecurity, swill feeding, natural breeding and uncontrolled trade. Given the high number of backyard farms in Serbia and the risk they are thought to pose to intensive pig farming, the main aim of this study was to evaluate the prevalence of major viral diseases of swine among traditionally kept pigs in small holdings with low biosecurity. For this investigation, 222 serum samples from 69 backyard holdings were randomly selected and tested for PRRS, Aujeszky`s disease, PPV infection and Swine influenza by ELISA. The herd-level seroprevalence of PRRS, Aujeszky`s disease and PPV infection was 2.9%, 27.5% and 37.7%, respectively. Swine influenza seroconversion was not confirmed in any of the tested holdings. Despite widely distributed PPV and AD in backyard farms in Serbia, almost 50% of them are still negative for the all-tested disease. The backyard farms must be monitored, and owners educated as their role in eradication programs and obtaining country-free status may be crucial.
... In the last few years, in Serbia, it was recorded that avian influenza virus HPAI subtype H5N8 has emerged in wild birds (Božić et al., 2016;Djurdjević et al. 2023). H5N8 avian influenza virus was detected within the mute swan population in the Belgrade city area indicating a deteriorating epidemiological situation (Maletić et al., 2022). ...
The implementation of biosecurity measures as the first line of defense is an essential prerequisite for preventing the occurrence and spread of infectious agents in flocks. Assessment of biosecurity measures on the farms was carried out during farm visits based on the application of an appropriate questionnaire whereby the farmer answered a number of questions regarding the implemented biosecurity measures. The study was performed via Biocheck.UGent online survey on 16 broiler farms in the region of the city of Belgrade. The capacity of farms was 25,000-100,000 broilers, placed in 2-4 houses, depending on the farm. Farm visits were made by the authors to confirm the correct answers to the online survey. Results showed that external biosecurity scores ranged from 57% to 93%, averaging 83.6%. Internal biosecurity score ranged from 48% to 98%, with an average score of 85.7%. The total score for the biosecurity assessment ranged from 56% to 93%, with an average score of 84.3%. The scores for subcategories varied between the farms. Removing manure and carcasses, a subcategory within the category of external biosecurity, had the lowest mean score (farms 9 and 10 had a score of 12%). Relatively low scores were also obtained for the number of steps of broilers depopulation (farm 9 had a score of 44%) and for the location of the farm (farms 2 and 3 had a score of 44%). Concerning internal biosecurity, the lowest score was obtained for the subcategory material and measures that they apply between compartments (farm 10 had a score of 29%). These findings should be useful for decision-makers and flock veterinarians and farmers to set feasible targets and sustainable biosecurity programs to improve biosecurity, the health status of the flock, and farm profitability.
Circulation of highly pathogenic avian influenza (HPAI) H5Nx viruses of the A/Goose/Guangdong/1/96 lineage in birds regularly causes infections of mammals, including humans. In many mammalian species, infections are associated with severe neurological disease, a unique feature of HPAI H5Nx viruses compared with other influenza A viruses. Here, we provide an overview of the neuropathogenesis of HPAI H5Nx virus infection in mammals, centered on three aspects: neuroinvasion, neurotropism, and neurovirulence. We focus on in vitro studies, as well as studies on naturally or experimentally infected mammals. Additionally, we discuss the contribution of viral factors to the neuropathogenesis of HPAI H5Nx virus infections and the efficacy of intervention strategies to prevent neuroinvasion or the development of neurological disease.
The recently detected clade 2.3.4.4 of the highly pathogenic avian influenza (HPAI) H5N8 virus in poultry encouraged us to study the efficacy of the 6 most extensively used saleable H5 poultry vaccinations (bivalent [AI + ND], Re-5 H5N1, H5N1, H5N3, monovalent AI, monovalent ND) with or without aqueous 8% neem (Azadirachta indica) leaf extract as an immunostimulant. One hundred thirty birds were randomly divided into 7 groups. Groups 1, 2, 3, 4, 5, and 6 were divided into 2 subgroups (G1a, G2a, G3a, G4a, G5a, G6a) and (G1b, G2b, G3b, G4b, G5b, G6b) with 10 birds each. Subgroups (G1a, G2a, G3a, G4a, G5a, G6a) received the (bivalent [AI + ND], Re-H5N1, H5N1, H5N3, monovalent AI, monovalent ND) vaccines, while subgroups (G1b, G2b, G3b, G4b, G5b, G6b) received the same previous vaccination but treated with neem leaf extract administrated 2 d before and after vaccination, and G7 with 10 birds was kept unvaccinated as positive control group. Clinical signs of the challenged group showed conjunctivitis, closed eyes, cyanosis in comb and wattle, ocular discharge, and greenish diarrhea, while postmortem lesions showed congested trachea and lung, hemorrhage on the shank, proventriculus, and pancreas; gelatinous fluid submandibular, congestion of all organs (septicemia), mottled spleen. The clinical signs and lesions were mild in neem leaf extract treated with bivalent vaccine and Re-H5N1 while moderate in monovalent vaccine and H5N3 with or without neem leaf extract treated and reached severe in the group immunized with H5N1 with or without neem leaf extract treatment. The protection levels in the bivalent vaccine (AI + ND), Re-5 H5N1, and H5N3 treated with neem leaf extract, were 80%, 80%, and 60%, respectively, while bivalent vaccine (AI + ND), Re-5 H5N1 and H5N3 without treatment were 60%, 60%, and 40%, respectively. The virus shedding was prevented in groups vaccinated with bivalent vaccine and Re-H5N1 vaccine treated with neem leaf extract, while decreased in the group vaccinated with H5N3 with neem leaf extract and Re-H5N1 without neem leaf extract compared with H5N3, H5N1, and monovalent vaccine. The immunological response after vaccination was stronger in the bivalent vaccine group than in the other commercial vaccine groups treated with neem leaf extract, with geometric mean titer (GMTs) of 315.2 and 207.9 at the third and fourth weeks, respectively. The use of immunostimulant antiviral medicinal plants, such as neem, completely protected chicken flocks against HPAI (H5N8) and prevented AI virus shedding, leading us to the conclusion that the use of bivalent vaccines induces a higher immune response than other different commercial vaccines.
