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Ševčík R, Mahlerová K, Riera FA, Zárybnická M. Leucocytozoon Infection Does Not Influence the Survival of Boreal Owl Aegolius funereus Nestlings. Avian Dis 2024; 68:134-140. [PMID: 38885055 DOI: 10.1637/aviandiseases-d-23-00063] [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: 09/03/2023] [Accepted: 04/04/2024] [Indexed: 06/20/2024]
Abstract
Leucocytozoon infection has been observed to impact the reproductive ecology and physiology of avian hosts, but its influence on nestling survival remains unclear. We investigated the effect of Leucocytozoon infection intensity, determined through triplicate PCR sample analyses, on the survival of 256 boreal owl (Aegolius funereus) nestlings during an 8-yr study. Contrary to our expectations, the survival probability of boreal owl nestlings was not influenced by their Leucocytozoon infection intensity. Nestling age and Leucocytozoon infection intensity in male and female parents also did not impact nestling survival. Instead, food abundance and hatching order were the key factors influencing nestling survival. Additionally, we observed a significantly higher Leucocytozoon infection intensity in male parents compared to female parents and nestlings. We suggest a distinct division of parental roles may lead females and nestlings staying within the nest boxes (cavities) to experience lower exposure to potential vectors transmitting blood parasites than their male counterparts. Our study shows that Leucocytozoon disease may not be lethal for boreal owl chicks, exhibiting a below-average infection intensity compared to their male parents.
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Affiliation(s)
- Richard Ševčík
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, 165 00, Czech Republic
- Forestry and Game Management Research Institute, 252 02 Jíloviště, Czech Republic
| | - Karolina Mahlerová
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, 165 00, Czech Republic
| | - Fernando A Riera
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, 165 00, Czech Republic
| | - Markéta Zárybnická
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, 165 00, Czech Republic,
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Etterlin PE, Comin A, Eriksson H, Bagge E, Jinnerot T, Jonare L, Jansson DS. Questionnaire study suggests grave consequences of infectious laryngotracheitis, infectious coryza and mycoplasmosis in small chicken flocks. Acta Vet Scand 2023; 65:39. [PMID: 37710285 PMCID: PMC10500715 DOI: 10.1186/s13028-023-00703-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/30/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND A growing number of people in western countries keep small chicken flocks. In Sweden, respiratory disease is a common necropsy finding in chickens from such flocks. A respiratory real-time polymerase chain reaction (PCR) panel was applied to detect infectious laryngotracheitis virus (ILTV), Avibacterium paragallinarum (A. paragallinarum) and Mycoplasma gallisepticum (M. gallisepticum) in chickens from small flocks which underwent necropsy in 2017-2019 and had respiratory lesions. Owners (N = 100) of PCR-positive flocks were invited to reply to a web-based questionnaire about husbandry, outbreak characteristics and management. RESULTS Response rate was 61.0%. The flocks were from 18 out of Sweden's 21 counties indicating that respiratory infections in small chicken flocks are geographically widespread in Sweden. Among participating flocks, 77.0% were coinfected by 2-3 pathogens; 91.8% tested positive for A. paragallinarum, 57.4% for M. gallisepticum and 50.8% for ILTV. Larger flock size and mixed-species flock structure were associated with PCR detection of M. gallisepticum (P = 0.00 and P = 0.02, respectively). Up to 50% mortality was reported by 63.9% of respondents. Euthanasia of some chickens was carried out in 86.9% of the flocks as a result of the outbreaks. Full clinical recovery was reported by 39.3% of owners suggesting chronic infection is a major challenge in infected flocks. Live birds had been introduced in many flocks prior to outbreaks, which suggested these as an important source of infection. Following the outbreaks, 36.1% replaced their flocks with new birds and 9.8% ceased keeping chickens. CONCLUSIONS This study highlights the severity of respiratory outbreaks in small non-commercial chicken flocks and points to the need for more research and veterinary assistance to prevent and manage respiratory infections in small chicken flocks.
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Affiliation(s)
- Pernille Engelsen Etterlin
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, 751 89, Uppsala, Sweden
| | - Arianna Comin
- Department of Disease Control and Epidemiology, National Veterinary Institute, 751 89, Uppsala, Sweden
| | - Helena Eriksson
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, 751 89, Uppsala, Sweden
| | - Elisabeth Bagge
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, 751 89, Uppsala, Sweden
| | - Tomas Jinnerot
- Department of Microbiology, National Veterinary Institute, 751 89, Uppsala, Sweden
| | - Liv Jonare
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Box 7054, 750 07, Uppsala, Sweden
| | - Désirée S Jansson
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, 751 89, Uppsala, Sweden.
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Box 7054, 750 07, Uppsala, Sweden.
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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.
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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
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Valkiūnas G, Iezhova TA. Insights into the Biology of Leucocytozoon Species (Haemosporida, Leucocytozoidae): Why Is There Slow Research Progress on Agents of Leucocytozoonosis? Microorganisms 2023; 11:1251. [PMID: 37317225 DOI: 10.3390/microorganisms11051251] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 06/16/2023] Open
Abstract
Blood parasites of the genus Leucocytozoon (Leucocytozoidae) only inhabit birds and represent a readily distinct evolutionary branch of the haemosporidians (Haemosporida, Apicomplexa). Some species cause pathology and even severe leucocytozoonosis in avian hosts, including poultry. The diversity of Leucocytozoon pathogens is remarkable, with over 1400 genetic lineages detected, most of which, however, have not been identified to the species level. At most, approximately 45 morphologically distinct species of Leucocytozoon have been described, but only a few have associated molecular data. This is unfortunate because basic information about named and morphologically recognized Leucocytozoon species is essential for a better understanding of phylogenetically closely related leucocytozoids that are known only by DNA sequence. Despite much research on haemosporidian parasites during the past 30 years, there has not been much progress in taxonomy, vectors, patterns of transmission, pathogenicity, and other aspects of the biology of these cosmopolitan bird pathogens. This study reviewed the available basic information on avian Leucocytozoon species, with particular attention to some obstacles that prevent progress to better understanding the biology of leucocytozoids. Major gaps in current Leucocytozoon species research are discussed, and possible approaches are suggested to resolve some issues that have limited practical parasitological studies of these pathogens.
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Grant M, Bröjer C, Zohari S, Nöremark M, Uhlhorn H, Jansson DS. Highly Pathogenic Avian Influenza (HPAI H5Nx, Clade 2.3.4.4.b) in Poultry and Wild Birds in Sweden: Synopsis of the 2020-2021 Season. Vet Sci 2022; 9:344. [PMID: 35878361 PMCID: PMC9318561 DOI: 10.3390/vetsci9070344] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 11/16/2022] Open
Abstract
Highly pathogenic avian influenza (HPAI, Gs/Gd lineage) was introduced to Europe in 2005 and has since caused numerous outbreaks in birds. The 2020-2021 season was the hitherto most devastating when considering bird numbers and duration in Europe. Surveillance data, virologic results and epidemiologic investigations from the 2020-2021 outbreaks in Sweden were analysed. Subtypes H5N8 and H5N5 were detected on 24 farms with poultry or other captive birds. In wild birds, subtypes H5N8, H5N5, H5N1, H5N4, H5Nx were detected in 130 out of 811 sampled birds. There was a spatiotemporal association between cases in wild birds and poultry. Based on phylogeny and epidemiology, most of the introductions of HPAI to commercial poultry were likely a result of indirect contact with wild birds. A definite route of introduction to poultry could not be established although some biosecurity breaches were observed. No spread between farms was identified but airborne spread between flocks on the same farm was suspected. Our findings exemplify the challenges posed by the continuously changing influenza viruses that seem to adapt to a broader species spectrum. This points to the importance of wild bird surveillance, compliance to biosecurity, and identification of risk factors for introduction on poultry farms.
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Affiliation(s)
- Malin Grant
- Department of Disease Control and Epidemiology, National Veterinary Institute, 751 89 Uppsala, Sweden; (M.G.); (M.N.)
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
| | - Caroline Bröjer
- Department of Pathology and Wildlife Diseases, National Veterinary Institute, 751 89 Uppsala, Sweden; (C.B.); (H.U.)
| | - Siamak Zohari
- Department of Microbiology, National Veterinary Institute, 751 89 Uppsala, Sweden;
| | - Maria Nöremark
- Department of Disease Control and Epidemiology, National Veterinary Institute, 751 89 Uppsala, Sweden; (M.G.); (M.N.)
| | - Henrik Uhlhorn
- Department of Pathology and Wildlife Diseases, National Veterinary Institute, 751 89 Uppsala, Sweden; (C.B.); (H.U.)
| | - Désirée S. Jansson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
- Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, 751 89 Uppsala, Sweden
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