1
|
Graziosi G, Lupini C, Catelli E, Carnaccini S. Highly Pathogenic Avian Influenza (HPAI) H5 Clade 2.3.4.4b Virus Infection in Birds and Mammals. Animals (Basel) 2024; 14:1372. [PMID: 38731377 PMCID: PMC11083745 DOI: 10.3390/ani14091372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
Avian influenza viruses (AIVs) are highly contagious respiratory viruses of birds, leading to significant morbidity and mortality globally and causing substantial economic losses to the poultry industry and agriculture. Since their first isolation in 2013-2014, the Asian-origin H5 highly pathogenic avian influenza viruses (HPAI) of clade 2.3.4.4b have undergone unprecedented evolution and reassortment of internal gene segments. In just a few years, it supplanted other AIV clades, and now it is widespread in the wild migratory waterfowl, spreading to Asia, Europe, Africa, and the Americas. Wild waterfowl, the natural reservoir of LPAIVs and generally more resistant to the disease, also manifested high morbidity and mortality with HPAIV clade 2.3.4.4b. This clade also caused overt clinical signs and mass mortality in a variety of avian and mammalian species never reported before, such as raptors, seabirds, sealions, foxes, and others. Most notably, the recent outbreaks in dairy cattle were associated with the emergence of a few critical mutations related to mammalian adaptation, raising concerns about the possibility of jumping species and acquisition of sustained human-to-human transmission. The main clinical signs and anatomopathological findings associated with clade 2.3.4.4b virus infection in birds and non-human mammals are hereby summarized.
Collapse
Affiliation(s)
- Giulia Graziosi
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell’Emilia, 40064 Bologna, Italy; (G.G.); (C.L.); (E.C.)
| | - Caterina Lupini
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell’Emilia, 40064 Bologna, Italy; (G.G.); (C.L.); (E.C.)
| | - Elena Catelli
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell’Emilia, 40064 Bologna, Italy; (G.G.); (C.L.); (E.C.)
| | - Silvia Carnaccini
- Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| |
Collapse
|
2
|
Bauer L, Benavides FFW, Veldhuis Kroeze EJB, de Wit E, van Riel D. The neuropathogenesis of highly pathogenic avian influenza H5Nx viruses in mammalian species including humans. Trends Neurosci 2023; 46:953-970. [PMID: 37684136 PMCID: PMC10591965 DOI: 10.1016/j.tins.2023.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/04/2023] [Indexed: 09/10/2023]
Abstract
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.
Collapse
Affiliation(s)
- Lisa Bauer
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | | | | | - Emmie de Wit
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Debby van Riel
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands.
| |
Collapse
|
3
|
El-Shall NA, Abd El Naby WSH, Hussein EGS, Yonis AE, Sedeik ME. Pathogenicity of H5N8 avian influenza virus in chickens and in duck breeds and the role of MX1 and IFN-α in infection outcome and transmission to contact birds. Comp Immunol Microbiol Infect Dis 2023; 100:102039. [PMID: 37591150 DOI: 10.1016/j.cimid.2023.102039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 07/18/2023] [Accepted: 08/02/2023] [Indexed: 08/19/2023]
Abstract
This study examined the pathogenicity, immunogenicity, and transmission potential of the H5N8 HPAI clade 2.3.4.4b virus in three breeds of ducks and in broiler chickens. Chickens, Muscovy, Pekin, and Mallard ducks (n = 10) received a dose of 6 log10 EID50 of HPAIV H5N8 directly. Nine contact chickens were introduced to each group on the day of infection. All infected chickens died, with MDT of 7.6 days. Muscovy and Pekin ducks died by 11.1% and 10%, respectively, with MDTs of 7 and 6 days. No Mallards died but showed more severe clinical disease than Pekin ducks. Mallards had the highest MX1 gene expression in the lung and spleen and IFN-α in the spleen. MX1 expression levels were lower in the spleen and lung of Pekin ducks, in the spleen of chickens and in the lung of Muscovy ducks than in noninfected controls. However, viral shedding was higher in ducks than in chickens and was highest in Mallards. 66.7% of chickens placed in contact with infected chickens died and 77.8% of in-contact chickens to infected three duck breeds died. In conclusion, there was a diversity in sensitivity and immunogenicity for HPAIV H5N8 among duck breeds, resulting in diverse infection outcomes and transmissibility to contacts. This study provides duck/chicken interface models for HPAIV transmission to poultry.
Collapse
Affiliation(s)
- Nahed A El-Shall
- Department of Poultry and Fish Diseases, Faculty of Veterinary Medicine, Alexandria University, Edfina, 22758, Egypt.
| | - Walaa S H Abd El Naby
- Genetics and Genetic Engineering in the Department of Animal Husbandry and Animal Wealth Development, Faculty of Veterinary Medicine, Alexandria University, Edfina, 22758, Egypt
| | - Eid G S Hussein
- Reference Laboratory for Veterinary Quality Control on Poultry Production, Damanhour Branch, Animal Health Research Institute, Agriculture Research Center, Egypt
| | - Ahlam E Yonis
- Biotechnology Department, Reference Laboratory for Veterinary Quality Control on Poultry Production ( RLQP), Damanhour branch, Animal health research institute (AHRI), Agriculture Research Center (ARC), Damanhour, 22511, Egypt
| | - Mahmoud E Sedeik
- Department of Poultry and Fish Diseases, Faculty of Veterinary Medicine, Alexandria University, Edfina, 22758, Egypt
| |
Collapse
|
4
|
Djurdjević B, Polaček V, Pajić M, Petrović T, Vučićević I, Vidanović D, Aleksić-Kovačević S. Highly Pathogenic Avian Influenza H5N8 Outbreak in Backyard Chickens in Serbia. Animals (Basel) 2023; 13:ani13040700. [PMID: 36830487 PMCID: PMC9952722 DOI: 10.3390/ani13040700] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/16/2023] [Accepted: 02/13/2023] [Indexed: 02/19/2023] Open
Abstract
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 avian influenza in poultry in Serbia during the first and second introduction waves. In both cases, the diagnosis was based on real-time reverse transcriptase PCR. The most common observed lesions included subepicardial hemorrhages, congestion and hemorrhages in the lungs, and petechial hemorrhages in coelomic and epicardial adipose tissue. Histologically, the observed lesions were mostly nonpurulent encephalitis accompanied by encephalomalacia, multifocal necrosis in the spleen, pancreas, and kidneys, pulmonary congestion, and myocardial and pulmonary hemorrhages. In H5N8-infected chickens, immunohistochemical examination revealed strong positive IHC staining in the brain and lungs. Following these outbreaks, strict control measures were implemented on farms and backyard holdings to prevent the occurrence and spread of the disease. Extensive surveillance of birds for avian influenza virus did not detect any additional cases in poultry. These outbreaks highlight the importance of a rapid detection and response system in order to quickly suppress outbreaks.
Collapse
Affiliation(s)
- Biljana Djurdjević
- Department of Epizootiology, Clinical diagnostics and DDD, Scientific Veterinary Institute “Novi Sad”, 21000 Novi Sad, Serbia
- Correspondence:
| | - Vladimir Polaček
- Department of Epizootiology, Clinical diagnostics and DDD, Scientific Veterinary Institute “Novi Sad”, 21000 Novi Sad, Serbia
| | - Marko Pajić
- Department of Epizootiology, Clinical diagnostics and DDD, Scientific Veterinary Institute “Novi Sad”, 21000 Novi Sad, Serbia
| | - Tamaš Petrović
- Department of Virology, Scientific Veterinary Institute “Novi Sad”, 21000 Novi Sad, Serbia
| | - Ivana Vučićević
- Department of Pathology, Faculty of Veterinary Medicine, University of Belgrade, 11080 Belgrade, Serbia
| | - Dejan Vidanović
- Veterinary Specialized Institute Kraljevo, 36000 Kraljevo, Serbia
| | - Sanja Aleksić-Kovačević
- Department of Pathology, Faculty of Veterinary Medicine, University of Belgrade, 11080 Belgrade, Serbia
| |
Collapse
|
5
|
Foret-Lucas C, Figueroa T, Coggon A, Houffschmitt A, Dupré G, Fusade-Boyer M, Guérin JL, Delverdier M, Bessière P, Volmer R. In Vitro and In Vivo Characterization of H5N8 High-Pathogenicity Avian Influenza Virus Neurotropism in Ducks and Chickens. Microbiol Spectr 2023; 11:e0422922. [PMID: 36625654 PMCID: PMC9927090 DOI: 10.1128/spectrum.04229-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 12/01/2022] [Indexed: 01/11/2023] Open
Abstract
H5N8 high-pathogenicity avian influenza virus (HPAIV) of clade 2.3.4.4B, which circulated during the 2016 epizootics in Europe, was notable for causing different clinical signs in ducks and chickens. The clinical signs preceding death were predominantly neurological in ducks versus respiratory in chickens. To investigate the determinants for the predominant neurological signs observed in ducks, we infected duck and chicken primary cortical neurons. Viral replication was identical in neuronal cultures from both species. In addition, we did not detect any major difference in the immune and inflammatory responses. These results suggest that the predominant neurological involvement of H5N8 HPAIV infection in ducks could not be recapitulated in primary neuronal cultures. In vivo, H5N8 HPAIV replication in ducks peaked soon after infection and led to an early colonization of the central nervous system. In contrast, viral replication was delayed in chickens but ultimately burst in the lungs of chickens, and the chickens died of respiratory distress before brain damage became significant. Consequently, the immune and inflammatory responses in the brain were significantly higher in duck brains than those in chickens. Our study thus suggests that early colonization of the central nervous system associated with prolonged survival after the onset of virus replication is the likely primary cause of the sustained inflammatory response and subsequent neurological disorders observed in H5N8 HPAIV-infected ducks. IMPORTANCE The severity of high-pathogenicity avian influenza virus (HPAIV) infection has been linked to its ability to replicate systemically and cause lesions in a variety of tissues. However, the symptomatology depends on the host species. The H5N8 virus of clade 2.3.4.4B had a pronounced neurotropism in ducks, leading to severe neurological disorders. In contrast, neurological signs were rarely observed in chickens, which suffered mostly from respiratory distress. Here, we investigated the determinants of H5N8 HPAIV neurotropism. We provide evidence that the difference in clinical signs was not due to a difference in neurotropism. Our results rather indicate that chickens died of respiratory distress due to intense viral replication in the lungs before viral replication in the brain could produce significant lesions. In contrast, ducks better controlled virus replication in the lungs, thus allowing the virus to replicate for a sufficient duration in the brain, to reach high levels, and to cause significant lesions.
Collapse
Affiliation(s)
- Charlotte Foret-Lucas
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| | - Thomas Figueroa
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| | - Amelia Coggon
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| | - Alexandre Houffschmitt
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| | - Gabriel Dupré
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| | - Maxime Fusade-Boyer
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| | - Jean-Luc Guérin
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| | - Maxence Delverdier
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| | - Pierre Bessière
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| | - Romain Volmer
- Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, ENVT, INRAE, IHAP, UMR 1225, Toulouse, France
| |
Collapse
|
6
|
Abotaleb MM, Mourad A, Fouad E, Abdo W, Nassif SA. Pathogenicity and pathogenesis of a recent highly pathogenic avian influenza subtype H5N8 in mule ducklings in Egypt. Vet World 2023; 16:59-67. [PMID: 36855343 PMCID: PMC9967731 DOI: 10.14202/vetworld.2023.59-67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 11/14/2022] [Indexed: 01/11/2023] Open
Abstract
Background and Aim In late 2017, an H5N8 highly pathogenic avian influenza (HPAI) virus, clade 2.3.4.4, was isolated from domestic ducks in Egypt, which was associated with high morbidity and low mortality. The pathogenicity increased due to the continuous circulation of virus in ducks. Thus, this study aimed to monitor the pathogenesis and pathogenicity of new H5N8 Avian influenza (AI) virus in mule ducklings. Materials and Methods The lethal dose 50 (LD50) for this new local HPAI H5N8 isolate was calculated. Twenty ducklings were inoculated with 0.1 mL of dilution containing 10 LD50 HPAI per duck. The clinical signs and mortalities were recorded until 30 days post-infection (DPI) to confirm viral pathogenesis. Reverse transcription polymerase chain reaction was used to detect viral shedding from collected cloacal swabs after 3rd, 5th, 7th, 10th, 14th, 21st, and 30th DPI. The main histopathological lesions associated with the presence of HPAI virus were also recorded on the 3rd and 14th DPI. Results The result showed that the LD50 of the new HPAI H5N8 was 104 log10. Clinical signs were observed after 2nd DPI, but it was clinically severe on 3rd, 4th, and 5th DPI in the form of respiratory and gastric disorders, forming 90% of all diseased ducklings, whereas 30% of the infected ducks only showed nervous signs. The mortality rate peaked on 4th and 5th DPI with a cumulative mortality rate of 60% for the inoculated ducks, whereas no mortality was recorded after 6th DPI. Dead ducks showed typical postmortem lesions of AI disease. Necrosis and ecchymotic or petechial hemorrhages on the heart, pancreas, liver, and spleen were observed, whereas the lung showed pneumonia. With regard to viral shedding, infected ducklings shed the virus from its gut until 7th DPI, but the number of duck shedders gradually decreased until 14th DPI after viral shedding. The histopathological findings indicated that the spleen and thymus showed necrosis and hemorrhages, whereas the brain showed multifocal malacic foci and spread meningitis. Moreover, the lung had intrabronchial hyaline degeneration and fibrinous pneumonia on 3rd DPI. Furthermore, the liver showed multifocal necrotic foci and subcapsular hemorrhage, whereas the kidney showed remarkable tubular degeneration, mostly within the collecting tubules. Furthermore, the heart showed marked myocardiolysis of the cardiac muscle fibers. On 14th DPI, all histopathological lesions of the examined organs were restored to normal. Conclusion The currently circulating HPAI H5N8 virus strain has high virulence, particularly for imported mule ducks that originated from non-vaccinated breeder ducks. Therefore, vaccination and quarantine measures must be applied on imported 1-day-old mule ducklings. Moreover, the pathogenesis must be reviewed and monitored for updating circulating AI strains caused by the continuous and rapid evolution of AI viruses.
Collapse
Affiliation(s)
- Mahmoud M. Abotaleb
- Central Laboratory for Evaluation of Veterinary Biologics, Agriculture Research Center (ARC), Cairo, Egypt,Corresponding author: Mahmoud M. Abotaleb, e-mail: Co-authors: AM: , EF: , WS: , SAN:
| | - Ahlam Mourad
- Central Laboratory for Evaluation of Veterinary Biologics, Agriculture Research Center (ARC), Cairo, Egypt
| | - Esraa Fouad
- Central Laboratory for Evaluation of Veterinary Biologics, Agriculture Research Center (ARC), Cairo, Egypt
| | - Walied Abdo
- Department of Pathology, Faculty of Veterinary Medicine, Kafr-Elsheikh University, Egypt
| | - Samir A. Nassif
- Central Laboratory for Evaluation of Veterinary Biologics, Agriculture Research Center (ARC), Cairo, Egypt
| |
Collapse
|
7
|
Gaide N, Lucas MN, Delpont M, Croville G, Bouwman KM, Papanikolaou A, van der Woude R, Gagarinov IA, Boons GJ, De Vries RP, Volmer R, Teillaud A, Vergne T, Bleuart C, Le Loc’h G, Delverdier M, Guérin JL. Pathobiology of highly pathogenic H5 avian influenza viruses in naturally infected Galliformes and Anseriformes in France during winter 2015–2016. Vet Res 2022; 53:11. [PMID: 35164866 PMCID: PMC8842868 DOI: 10.1186/s13567-022-01028-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 12/10/2021] [Indexed: 12/22/2022] Open
Abstract
In late 2015, an epizootic of Highly Pathogenic Avian Influenza (H5Nx) was registered in Southwestern France, including more than 70 outbreaks in commercial poultry flocks. Phylogenetic analyses suggested local emergence of H5 viruses which differed from A/goose/Guangdong/1/1996 clade 2.3.4.4b lineage and shared a unique polybasic cleavage site in their hemagglutinin protein. The present work provides an overview of the pathobiological picture associated with this epizootic in naturally infected chickens, guinea fowls and ducks. Upon necropsy examination, selected tissues were sampled for histopathology, immunohistochemistry and quantitative Real Time Polymerase Chain Reaction. In Galliformes, HPAIVs infection manifested as severe acute systemic vasculitis and parenchymal necrosis and was associated with endothelial expression of viral antigen. In ducks, lesions were mild and infrequent, with sparse antigenic detection in respiratory and digestive mucosae and leukocytes. Tissue quantifications of viral antigen and RNA were higher in chickens and guinea fowls compared to duck. Subsequently, recombinant HA (rHA) was generated from a H5 HPAIV isolated from an infected duck to investigate its glycan-binding affinity for avian mucosae. Glycan-binding analysis revealed strong affinity of rHA for 3’Sialyl-LacNAc and low affinity for Sialyl-LewisX, consistent with a duck-adapted virus similar to A/Duck/Mongolia/54/2001 (H5N2). K222R and S227R mutations on rHA sequence shifted affinity towards Sialyl-LewisX and led to an increased affinity for chicken mucosa, confirming the involvement of these two mutations in the glycan-binding specificity of the HA. Interestingly, the rHA glycan binding pattern of guinea fowl appeared intermediate between duck and chicken. The present study presents a unique pathobiological description of the H5 HPAIVs outbreaks that occurred in 2015–2016 in Southwestern France.
Collapse
|
8
|
Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed Ducks. Pathogens 2021; 10:pathogens10111498. [PMID: 34832653 PMCID: PMC8620262 DOI: 10.3390/pathogens10111498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/10/2021] [Accepted: 11/15/2021] [Indexed: 11/17/2022] Open
Abstract
(1) Background: Highly pathogenic avian influenza (HPAI) is a viral infection characterized by inducing severe disease and high levels of mortality in gallinaceous poultry. Increased mortality, drop in egg production or decreased feed or water intake are used as indicators for notification of suspicions of HPAI outbreaks. However, infections in commercial duck flocks may result in mild disease with low mortality levels, thereby compromising notifications. (2) Methods: Data on daily mortality, egg production, feed intake and water intake from broiler and breeder duck flocks not infected (n = 56 and n = 11, respectively) and infected with HPAIV (n = 13, n = 4) were used for analyses. Data from negative flocks were used to assess the baseline (daily) levels of mortality and production parameters and to identify potential threshold values for triggering suspicions of HPAI infections and assess the specificity (Sp) of these thresholds. Data from infected flocks were used to assess the effect of infection on daily mortality and production and to evaluate the sensitivity (Se) of the thresholds for early detection of outbreaks. (3) Results: For broiler flocks, daily mortality > 0.3% (after the first week of production) or using a regression model for aberration detection would indicate infection with Se and Sp higher than 80%. Drops in mean daily feed or water intake larger than 7 g or 14 mL (after the first week of production), respectively, are sensitive indicators of infection but have poor Sp. For breeders, mortality thresholds are poor indicators of infection (low Se and Sp). However, a consecutive drop in egg production larger than 9% is an effective indicator of a HPAI outbreak. For both broiler and breeder duck flocks, cumulative average methods were also assessed, which had high Se but generated many false alarms (poor Sp). (4) Conclusions: The identified reporting thresholds can be used to update legislation and provide guidelines to farmers and veterinarians to notify suspicions of HPAI outbreaks in commercial duck flocks.
Collapse
|
9
|
Schreuder J, Manders TTM, Elbers ARW, van der Spek AN, Bouwstra RJ, Stegeman JA, Velkers FC. Highly pathogenic avian influenza subtype H5Nx clade 2.3.4.4 outbreaks in Dutch poultry farms, 2014-2018: Clinical signs and mortality. Transbound Emerg Dis 2021; 68:88-97. [PMID: 32418364 PMCID: PMC8048556 DOI: 10.1111/tbed.13597] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 03/03/2020] [Accepted: 04/17/2020] [Indexed: 12/18/2022]
Abstract
In recent years, different subtypes of highly pathogenic avian influenza (HPAI) viruses caused outbreaks in several poultry types worldwide. Early detection of HPAI virus infection is crucial to reduce virus spread. Previously, the use of a mortality ratio threshold to expedite notification of suspicion in layer farms was proposed. The purpose of this study was to describe the clinical signs reported in the early stages of HPAI H5N8 and H5N6 outbreaks on chicken and Pekin duck farms between 2014 and 2018 in the Netherlands and compare them with the onset of an increased mortality ratio (MR). Data on daily mortality and clinical signs from nine egg-producing chicken farms and seven Pekin duck farms infected with HPAI H5N8 (2014 and 2016) and H5N6 (2017-2018) in the Netherlands were analysed. In 12 out of 15 outbreaks for which a MR was available, MR increase preceded or coincided with the first observation of clinical signs by the farmer. In one chicken and two Pekin duck outbreaks, clinical signs were observed prior to MR increase. On all farms, veterinarians observed clinical signs of general disease. Nervous or locomotor signs were reported in all Pekin duck outbreaks, but only in two chicken outbreaks. Other clinical signs were observed less frequently in both chickens and Pekin ducks. Compared to veterinarians, farmers observed and reported clinical signs, especially respiratory and gastrointestinal signs, less frequently. This case series suggests that a MR with a set threshold could be an objective parameter to detect HPAI infection on chicken and Pekin duck farms at an early stage. Observation of clinical signs may provide additional indication for farmers and veterinarians for notifying a clinical suspicion of HPAI infection. Further assessment and validation of a MR threshold in Pekin ducks are important as it could serve as an important tool in HPAI surveillance programs.
Collapse
Affiliation(s)
- Janneke Schreuder
- Department of Farm Animal HealthFaculty of Veterinary MedicineUtrecht UniversityUtrechtthe Netherlands
| | - Thijs T. M. Manders
- Department of Farm Animal HealthFaculty of Veterinary MedicineUtrecht UniversityUtrechtthe Netherlands
| | - Armin R. W. Elbers
- Department of Bacteriology and EpidemiologyWageningen Bioveterinary ResearchLelystadthe Netherlands
| | - Arco N. van der Spek
- Netherlands Food and Consumer Product Safety Authority (NVWA)Utrechtthe Netherlands
| | | | - J. Arjan Stegeman
- Department of Farm Animal HealthFaculty of Veterinary MedicineUtrecht UniversityUtrechtthe Netherlands
| | - Francisca C. Velkers
- Department of Farm Animal HealthFaculty of Veterinary MedicineUtrecht UniversityUtrechtthe Netherlands
| |
Collapse
|
10
|
Dinev I, Zarkov I, Goujgoulova GV, Stoimenov GM, Georgiev G, Kanakov D. Pathologic Evaluation of Influenza A H5N8 Infection Outbreaks in Mule Ducks in Bulgaria. Avian Dis 2020; 64:203-209. [PMID: 32550621 DOI: 10.1637/0005-2086-64.2.203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/19/2020] [Indexed: 11/05/2022]
Abstract
This article outlines pathomorphologic findings of a study involving commercial mule ducks with confirmed influenza A H5N8 infections after a series of outbreaks in Bulgaria. Examinations were carried out after performing necropsy on dead birds from three different age groups (up to 15, 20 to 30, and 40+ days of age) fattened on different farms. Among birds of all ages, gross lesions were present as lesions affecting the heart. Histologically, the myocardium exhibited severe intermyofibrillar edema, moderate to massive hemorrhages, and degenerative changes. All lesions resulted in single or multiple and small to massive myocardial infarctions. Other affected organs included the brain, lungs, liver, spleen, and pancreas. Nonpurulent lymphocytic encephalitis was found postmortem in ducks that had shown prior clinical nervous signs. Among ducks of all ages, a viral antigen in the cardiomyocytes and the epithelium of air capillaries was found through immunohistochemical detection methods. The results of the present study allowed us to conclude that the highly pathogenic avian influenza A H5N8 viral infection may manifest itself as a systemic illness in commercial mule ducks with septicemic lesions, resulting in high morbidity and mortality rates of up to 100%. Pathomorphologic lesions were somewhat different from those previously reported in wild waterfowl.
Collapse
Affiliation(s)
- Ivan Dinev
- Department of General and Clinical Pathology, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria,
| | - Ivan Zarkov
- Department of Microbiology, Infection and Parasite Diseases, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria
| | | | - Georgi M Stoimenov
- Department of Infectious Pathology and Food Hygiene, Faculty of Veterinary Medicine, University of Forestry, 1000 Sofia, Bulgaria
| | - Georgi Georgiev
- Risk Assessment Center on Food Chain, Ministry of Agriculture, Food and Forestry, 1000 Sofia, Bulgaria
| | - Dian Kanakov
- Department of Internal Noninfectious Diseases, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria
| |
Collapse
|
11
|
Muzyka D, Rula O, Tkachenko S, Muzyka N, Köthe S, Pishchanskyi O, Stegniy B, Pantin-Jackwood M, Beer M. Highly Pathogenic and Low Pathogenic Avian Influenza H5 Subtype Viruses in Wild Birds in Ukraine. Avian Dis 2020; 63:235-245. [PMID: 31713401 DOI: 10.1637/11880-042718.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 12/09/2018] [Indexed: 11/05/2022]
Abstract
There have been three waves of highly pathogenic avian influenza (HPAI) outbreaks in commercial, backyard poultry, and wild birds in Ukraine. The first (2005-2006) and second (2008) waves were caused by H5N1 HPAI virus, with 45 outbreaks among commercial poultry (chickens) and backyard fowl (chickens, ducks, and geese) in four regions of Ukraine (AR Crimea, Kherson, Odesa, and Sumy Oblast). H5N1 HPAI viruses were isolated from dead wild birds: cormorants (Phalacrocorax carbo) and great crested grebes (Podiceps cristatus) in 2006 and 2008. The third HPAI wave consisted of nine outbreaks of H5N8 HPAI in wild and domestic birds, beginning in November 2016 in the central and south regions (Kherson, Odesa, Chernivtsi, Ternopil, and Mykolaiv Oblast). H5N8 HPAI virus was detected in dead mute swans (Cygnus olor), peacocks (Pavo cristatus) (in zoo), ruddy shelducks (Tadorna ferruginea), white-fronted geese (Anser albifrons), and from environmental samples in 2016 and 2017. Wide wild bird surveillance for avian influenza (AI) virus was conducted from 2006 to 2016 in Ukraine regions suspected of being intercontinental (north-south and east-west) flyways. A total of 21 511 samples were collected from 105 species of wild birds representing 27 families and 11 orders. Ninety-five avian influenza (AI) viruses were isolated (including one H5N2 LPAI virus in 2010) from wild birds with a total of 26 antigenic hemagglutinin (HA) and neuraminidase (NA) combinations. Fifteen of 16 known avian HA subtypes were isolated. Two H5N8 HPAI viruses (2016-2017) and two H5N2 LPAI viruses (2016) were isolated from wild birds and environmental samples (fresh bird feces) during surveillance before the outbreak in poultry in 2016-2017. The Ukrainian H5N1, H5N8 HPAI, and H5N2 LPAI viruses belong to different H5 phylogenetic groups. Our results demonstrate the great diversity of AI viruses in wild birds in Ukraine, as well as the importance of this region for studying the ecology of avian influenza.
Collapse
Affiliation(s)
- Denys Muzyka
- National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine", Kharkiv, 61023, Ukraine,
| | - Oleksandr Rula
- National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine", Kharkiv, 61023, Ukraine
| | - Semen Tkachenko
- National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine", Kharkiv, 61023, Ukraine
| | - Nataliia Muzyka
- State Poultry Research Station, v. Birky, Kharkiv Region, 63422, Ukraine
| | - Susanne Köthe
- Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany
| | - Oleksandr Pishchanskyi
- National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine", Kharkiv, 61023, Ukraine
| | - Borys Stegniy
- National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine", Kharkiv, 61023, Ukraine
| | - Mary Pantin-Jackwood
- Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, GA 30677
| | - Martin Beer
- Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany
| |
Collapse
|
12
|
Sultan HA, Arafa AE, Talaat S, Gaballa AA, Kilany WH, Elfeil WK, Shehata AA, Amarin N. Efficacy of Clade 2.3.2 H5-Recombinant Baculovirus Vaccine in Protecting Muscovy and Pekin Ducks from Clade 2.3.4.4 H5N8 Highly Pathogenic Avian Influenza Infection. Avian Dis 2020; 63:219-229. [PMID: 31713400 DOI: 10.1637/0005-2086-63.1.219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 01/03/2019] [Indexed: 11/05/2022]
Abstract
In late 2016, a highly pathogenic avian influenza (HPAI) virus subtype H5N8 clade 2.3.4.4 was reported in Egypt in migratory birds; subsequently, the virus spread to backyard and commercial poultry in several Egyptian governorates, causing severe economic losses to the poultry industry. Here, a recombinant subunit commercial H5 vaccine prepared from the clade 2.3.2 H5 segment on baculovirus was evaluated in Pekin ducks (Anasplatyrhynchos domesticus) and Muscovy ducks (Cairina moschata) in Biosafety Level 3 isolators by using two vaccination regimes: either a single dose on day 10 and a challenge on day 31 or a double dose on days 10 and 28 and a challenge on day 49. The protection parameters were evaluated after experimental infection with the Egyptian HPAI H5N8 isolate clade 2.3.4.4b (A/common-coot/Egypt/CA285/2016) based on mortality rate, clinical signs, gross lesions, seroconversion, virus shedding, and histopathologic changes. In the single-dose vaccination regime, the mortality rate in Muscovy and Pekin ducks was 10% and 0% vs. 40% and 0% in nonvaccinated challenged ducks, respectively. In the double-dose vaccination regime, the mortality rates in Muscovy and Pekin ducks were 0% and 0% vs. 60% and 40% in nonvaccinated challenged ducks, respectively. Muscovy ducks developed more severe clinical signs and gross lesions than Pekin ducks. In addition, tracheal viral shedding in challenged Muscovy ducks, in the single-dose vaccination regime, was 50%, 22%, and 0% at 3, 5, and 7 days postchallenge (DPC), respectively, and was 0% in all Pekin ducks vs. 100% in all challenged nonvaccinated Muscovy and Pekin ducks at 3, 5, and 7 DPC. The viral shedding in challenged Muscovy and Pekin ducks, in the double-dose vaccination regime, was 0% at 3, 5, and 7 DPC vs. 100% in nonvaccinated challenged Muscovy and Pekin ducks, respectively. The results of this study indicate that the H5 baculovirus-based vaccine can be used in ducks with better vaccination regime based on double-dose vaccination at 10 and 28 days of age. In addition, they highlight the need to evaluate the efficacy of currently used commercial vaccines against challenge with the newly emerged HPAI H5N8 clade 2.3.4.4 in the field in Egypt to ensure proper control strategy in ducks.
Collapse
Affiliation(s)
- Hesham A Sultan
- Department of Bird and Rabbit Medicine, Faculty of Veterinary Medicine, University of Sadat City, Menoufiya, Egypt, 32958.,Corresponding author. E-mail:
| | - Abd-Elsatar Arafa
- Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, P.O. Box 264-Dokki, Giza, Egypt, 12618
| | - Shaimaa Talaat
- Department of Bird and Rabbit Medicine, Faculty of Veterinary Medicine, University of Sadat City, Menoufiya, Egypt, 32958
| | - Alaa A Gaballa
- Department of Bird and Rabbit Medicine, Faculty of Veterinary Medicine, University of Sadat City, Menoufiya, Egypt, 32958
| | - Walid H Kilany
- Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, P.O. Box 264-Dokki, Giza, Egypt, 12618
| | - Wael K Elfeil
- Department of Avian and Rabbit Medicine, Faculty of Veterinary Medicine, University of Suez Canal, Ismailia, Egypt, 41522
| | - Awad A Shehata
- Department of Bird and Rabbit Medicine, Faculty of Veterinary Medicine, University of Sadat City, Menoufiya, Egypt, 32958
| | - N Amarin
- Boehringer Ingelheim, Middle East and North Africa, Dubai, United Arab Emirates
| |
Collapse
|
13
|
Guinat C, Artois J, Bronner A, Guérin JL, Gilbert M, Paul MC. Duck production systems and highly pathogenic avian influenza H5N8 in France, 2016-2017. Sci Rep 2019; 9:6177. [PMID: 30992486 PMCID: PMC6467959 DOI: 10.1038/s41598-019-42607-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 04/02/2019] [Indexed: 11/20/2022] Open
Abstract
In winter 2016-2017, Highly Pathogenic Avian Influenza (HPAI) H5N8 virus spread across Europe, causing unprecedented epizootics. France was massively affected, resulting in the culling of over 6 million poultry. Boosted regression tree (BRT) models were used to quantify the association between spatial risk factors and HPAI H5N8 infection in poultry holdings and to generate predictive maps for HPAI infection. Three datasets were combined to build the model: a dataset of the reported outbreaks in poultry, a dataset of the poultry holdings where the virus has not been reported and a set of relevant spatial risk factors, including poultry production and trade, and water bird habitat. Results identified key associations between the 'foie gras' production systems and HPAI H5N8 risk of occurrence and indicate that strengthening surveillance of fattening duck production systems and making the transportation of fattening ducks more secure would be key priority options for HPAI prevention and control.
Collapse
Affiliation(s)
- C Guinat
- IHAP, Université de Toulouse, INRA, ENVT, Toulouse, France.
| | - J Artois
- Université Libre de Bruxelles, Brussels, Belgium
| | - A Bronner
- Direction Générale de l'Alimentation, Paris, France
| | - J L Guérin
- IHAP, Université de Toulouse, INRA, ENVT, Toulouse, France
| | - M Gilbert
- Université Libre de Bruxelles, Brussels, Belgium
- Fonds National de la Recherche Scientifique, Brussels, Belgium
| | - M C Paul
- IHAP, Université de Toulouse, INRA, ENVT, Toulouse, France
| |
Collapse
|
14
|
Anis A, AboElkhair M, Ibrahim M. Characterization of highly pathogenic avian influenza H5N8 virus from Egyptian domestic waterfowl in 2017. Avian Pathol 2018; 47:400-409. [PMID: 29701481 DOI: 10.1080/03079457.2018.1470606] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In 2016, the highly pathogenic avian influenza (HPAI) H5N8 virus was detected in wild birds for the first time in Egypt. In the present study, we identified the HPAI virus H5N8 of clade 2.3.4.4 from domestic waterfowl in Egypt, suggesting its transmission to the domestic poultry from the migratory birds. Based on partial haemagglutinin gene sequence, this virus has a close genetic relationship with subtype H5N8 viruses circulating in Asia and Europe. Pathologically, H5N8 virus in hybrid duck induced nervous signs accompanied by encephalomalacia, haemorrhages, nonsuppurative encephalitis and nonsuppurative vasculitis. The granular layer of cerebellum showed multifocal areas of hydropic degeneration and the Purkinje cell neurons were necrotized or lost. Additionally, the lung, kidney and spleen were congested, and necrotizing pancreatitis was also observed. The co-circulation of both HPAI H5N1 and H5N8 subtypes with the low pathogenic avian influenza H9N2 subtype complicate the control of avian influenza in Egypt with the possibility of emergence of new reassortant viruses. Therefore, continuous monitoring with implementation of strict control measures is required. Research highlights HPAI H5N8 virus clade 2.3.4.4 was detected in domestic ducks and geese in Egypt in 2017. Phylogenetically, the virus was closely related to HPAI H5N8 viruses identified in Asia and Europe Nonsuppurative encephalitis was widely observed in HPAI H5N8 virus-infected ducks. Degeneration of the cerebellar granular layer was found in most of the brain tissues examined.
Collapse
Affiliation(s)
- Anis Anis
- a Department of Pathology, Faculty of Veterinary Medicine , University of Sadat City , Menoufiya , Egypt
| | - Mohammed AboElkhair
- b Department of Virology, Faculty of Veterinary Medicine , University of Sadat City , Menoufiya , Egypt
| | - Mahmoud Ibrahim
- c Department of Birds and Rabbit Medicine, Faculty of Veterinary Medicine , University of Sadat City , Menoufiya , Egypt
| |
Collapse
|
15
|
Pantin-Jackwood MJ, Costa-Hurtado M, Bertran K, DeJesus E, Smith D, Swayne DE. Infectivity, transmission and pathogenicity of H5 highly pathogenic avian influenza clade 2.3.4.4 (H5N8 and H5N2) United States index viruses in Pekin ducks and Chinese geese. Vet Res 2017; 48:33. [PMID: 28592320 PMCID: PMC5463389 DOI: 10.1186/s13567-017-0435-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/11/2017] [Indexed: 11/13/2022] Open
Abstract
In late 2014, a H5N8 highly pathogenic avian influenza (HPAI) virus, clade 2.3.4.4, spread by migratory waterfowl into North America reassorting with low pathogenicity AI viruses to produce a H5N2 HPAI virus. Since domestic waterfowl are common backyard poultry frequently in contact with wild waterfowl, the infectivity, transmissibility, and pathogenicity of the United States H5 HPAI index viruses (H5N8 and H5N2) was investigated in domestic ducks and geese. Ducks infected with the viruses had an increase in body temperature but no or mild clinical signs. Infected geese did not show increase in body temperature and most only had mild clinical signs; however, some geese presented severe neurological signs. Ducks became infected and transmitted the viruses to contacts when inoculated with high virus doses [(104 and 106 50% embryo infective dose (EID50)], but not with a lower dose (102 EID50). Geese inoculated with the H5N8 virus became infected regardless of the virus dose given, and transmitted the virus to direct contacts. Only geese inoculated with the higher doses of the H5N2 and their contacts became infected, indicating differences in infectivity between the two viruses and the two waterfowl species. Geese shed higher titers of virus and for a longer period of time than ducks. In conclusion, the H5 HPAI viruses can infect domestic waterfowl and easily transmit to contact birds, with geese being more susceptible to infection and disease than ducks. The disease is mostly asymptomatic, but infected birds shed virus for several days representing a risk to other poultry species.
Collapse
Affiliation(s)
- Mary J. Pantin-Jackwood
- Exotic and Emerging Avian Viral Diseases Research Unit, Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Rd, Athens, GA 30605 USA
| | - Mar Costa-Hurtado
- Exotic and Emerging Avian Viral Diseases Research Unit, Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Rd, Athens, GA 30605 USA
| | - Kateri Bertran
- Exotic and Emerging Avian Viral Diseases Research Unit, Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Rd, Athens, GA 30605 USA
| | - Eric DeJesus
- Exotic and Emerging Avian Viral Diseases Research Unit, Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Rd, Athens, GA 30605 USA
| | - Diane Smith
- Exotic and Emerging Avian Viral Diseases Research Unit, Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Rd, Athens, GA 30605 USA
| | - David E. Swayne
- Exotic and Emerging Avian Viral Diseases Research Unit, Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Rd, Athens, GA 30605 USA
| |
Collapse
|
16
|
Adlhoch C, Brown IH, Angelova SG, Bálint Á, Bouwstra R, Buda S, Castrucci MR, Dabrera G, Dán Á, Grund C, Harder T, van der Hoek W, Krisztalovics K, Parry-Ford F, Popescu R, Wallensten A, Zdravkova A, Zohari S, Tsolova S, Penttinen P. Highly pathogenic avian influenza A(H5N8) outbreaks: protection and management of exposed people in Europe, 2014/15 and 2016. ACTA ACUST UNITED AC 2017; 21:30419. [PMID: 27983512 PMCID: PMC5291128 DOI: 10.2807/1560-7917.es.2016.21.49.30419] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 12/07/2016] [Indexed: 11/26/2022]
Abstract
Introduction of highly pathogenic avian influenza (HPAI) virus A(H5N8) into Europe prompted animal and human health experts to implement protective measures to prevent transmission to humans. We describe the situation in 2016 and list public health measures and recommendations in place. We summarise critical interfaces identified during the A(H5N1) and A(H5N8) outbreaks in 2014/15. Rapid exchange of information between the animal and human health sectors is critical for a timely, effective and efficient response.
Collapse
Affiliation(s)
- Cornelia Adlhoch
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Ian H Brown
- Animal and Plant Health Agency (APHA), Weybridge, United Kingdom
| | - Svetla G Angelova
- National Centre of Infectious and Parasitic Diseases, Sofia, Bulgaria
| | - Ádám Bálint
- National Food Chain Safety Office (NEBIH), Budapest, Hungary
| | | | - Silke Buda
- Robert Koch Institute (RKI), Berlin, Germany
| | | | | | - Ádám Dán
- National Food Chain Safety Office (NEBIH), Budapest, Hungary
| | - Christian Grund
- Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Timm Harder
- Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Wim van der Hoek
- National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | | | | | | | | | | | - Siamak Zohari
- National Veterinary Institute (SVA), Uppsala, Sweden
| | - Svetla Tsolova
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Pasi Penttinen
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| |
Collapse
|