Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed Ducks
(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 suspic...
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| Format: | Article |
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MDPI AG
2021-11-01
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| Series: | Pathogens |
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| Online Access: | https://www.mdpi.com/2076-0817/10/11/1498 |
| _version_ | 1827675743843254272 |
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| author | Armin R. W. Elbers José L. Gonzales |
| author_facet | Armin R. W. Elbers José L. Gonzales |
| author_sort | Armin R. W. Elbers |
| collection | DOAJ |
| description | (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 (<i>n</i> = 56 and <i>n</i> = 11, respectively) and infected with HPAIV (<i>n</i> = 13, <i>n</i> = 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. |
| first_indexed | 2024-03-10T05:10:11Z |
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| language | English |
| last_indexed | 2024-03-10T05:10:11Z |
| publishDate | 2021-11-01 |
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| series | Pathogens |
| spelling | doaj.art-9bdaa16e30454a6c852064656333c55e2023-11-23T00:54:13ZengMDPI AGPathogens2076-08172021-11-011011149810.3390/pathogens10111498Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed DucksArmin R. W. Elbers0José L. Gonzales1Department of Epidemiology, Bioinformatics and Animal Models, Wageningen Bioveterinary Research, 8221 RA Lelystad, The NetherlandsDepartment of Epidemiology, Bioinformatics and Animal Models, Wageningen Bioveterinary Research, 8221 RA Lelystad, The Netherlands(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 (<i>n</i> = 56 and <i>n</i> = 11, respectively) and infected with HPAIV (<i>n</i> = 13, <i>n</i> = 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.https://www.mdpi.com/2076-0817/10/11/1498breeder and broiler ducksHPAIreporting thresholdsearly detection |
| spellingShingle | Armin R. W. Elbers José L. Gonzales Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed Ducks Pathogens breeder and broiler ducks HPAI reporting thresholds early detection |
| title | Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed Ducks |
| title_full | Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed Ducks |
| title_fullStr | Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed Ducks |
| title_full_unstemmed | Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed Ducks |
| title_short | Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed Ducks |
| title_sort | mortality levels and production indicators for suspicion of highly pathogenic avian influenza virus infection in commercially farmed ducks |
| topic | breeder and broiler ducks HPAI reporting thresholds early detection |
| url | https://www.mdpi.com/2076-0817/10/11/1498 |
| work_keys_str_mv | AT arminrwelbers mortalitylevelsandproductionindicatorsforsuspicionofhighlypathogenicavianinfluenzavirusinfectionincommerciallyfarmedducks AT joselgonzales mortalitylevelsandproductionindicatorsforsuspicionofhighlypathogenicavianinfluenzavirusinfectionincommerciallyfarmedducks |