Herausforderungen bei der Influenzadiagnostik in einem Schweinebetrieb – ein Fallbericht

Unterweger, Christine; Debeerst, Stephanie; Klingler, Eva; Auer, Angelika; Redlberger‐Fritz, Monika; Stadler, Julia; Pesch, S.; Lillie-Jaschniski, Kathrin; Ladinig, Andrea

doi:10.1055/a-1580-6938

Cited by 4 publications

(3 citation statements)

References 36 publications

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“…The use of serologic assays is hampered by the anti-genetic variability of swIAV, leading to cross-reactivity among subtypes. Additionally, antibodies after exposure cannot be discriminated from antibodies formed after vaccination [ 27 , 28 ]. Direct detection by the use of RT-PCR assays is limited by the short course of infection as the virus is mainly shed during days 1 and 5 after infection, and is eliminated from the lungs after 9 days [ 7 , 19 ].…”

Section: Discussionmentioning

confidence: 99%

A New Sampling Approach for the Detection of Swine Influenza a Virus on European Sow Farms

Lillie-Jaschniski¹,

Lisgara

Pileri³

et al. 2022

Veterinary Sciences

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Swine influenza A virus (swIAV), which plays a major role in the porcine respiratory disease complex (PRDC), is eliminated from the respiratory tract within 7–9 days after infection. Therefore, diagnosis is complicated in endemically infected swine herds presenting no obvious clinical signs. This study aimed to investigate the right time point for sampling to detect swIAV. A cross-sectional study was performed in 131 farms from 12 European countries. The sampling protocol included suckling piglets, weaners, and nursery pigs. In each age group, 10 nasal swabs were collected and further examined in pools of 5 for swIAV by Matrix rRT-PCR, followed by a multiplex RT-PCR to determine the influenza subtype. SwIAV was detected in 284 (37.9%) of the samples and on 103 (78.6%) farms. Despite the highest number of animals with clinical signs being found in the nursery, the weaners were significantly more often virus-positive compared to nursery pigs (p = 0.048). Overall, the swIAV detection rate did not significantly differ between diseased or non-diseased suckling and nursery piglets, respectively; however, diseased weaners had significantly more positive pools than the non-diseased animals. Interestingly, in 9 farms, different subtypes were detected in different age groups. Our findings indicate that to detect all circulating swIAV subtypes on a farm, different age groups should be sampled. Additionally, the sampling strategy should also aim to include non-diseased animals, especially in the suckling period.

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Section: Discussionmentioning

confidence: 99%

A New Sampling Approach for the Detection of Swine Influenza a Virus on European Sow Farms

Lillie-Jaschniski¹,

Lisgara

Pileri³

et al. 2022

Veterinary Sciences

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“…Here they suffer from low specificity as highly varying antigens of distinct lineages lead to cross reactions (false positives) or missing detection (false negatives). Vaccination-induced humoral responses further complicate the interpretation of the test outcome [16,[20][21][22]. Concerning the detection of acute swIAV infections by RT-qPCR in nasal swabs, the timeframe for the detection is limited to the acute phase which typically lasts between 1 and 7 days after infection [1,23,24].…”

Section: Introductionmentioning

confidence: 99%

Influenza surveillance in pigs: balancing act between broad diagnostic coverage and specific virus characterization

Stadler,

Zwickl,

Gumbert

et al. 2024

Porc Health Manag

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Background Monitoring of infectious diseases on swine farms requires a high diagnostic sensitivity and specificity of the test system. Moreover, particularly in cases of swine influenza A virus (swIAV) it is desirable to include characterization of the virus as precisely as possible. This is indispensable for strategies concerning prophylaxis of swIAV and furthermore, to meet the requirements of a purposeful monitoring of newly emerging swIAV strains in terms of vaccine design and public health. Within the present cross-sectional study, we compared the diagnostic value of group samples (wipes of surfaces with direct contact to mouth/nose, dust wipes, udder skin wipes, oral fluids) to individual samples (nasal swabs, tracheobronchial swabs) for both swIAV identification and characterization. Sampling included different stages of pig production on 25 sow farms with attached nursery considered as enzootically infected with swIAV. Firstly, samples were analyzed for IAV genome and subsequently samples with Ct-values < 32 were subtyped by multiplex RT-qPCR. Results Nasal swabs of suckling piglets and nursery pigs resulted in a higher odds to detect swIAV (p < 0.001) and to identify swIAV subtypes by RT-qPCR (p < 0.05) compared to nasal swabs of sows. In suckling piglets, significant higher rates of swIAV detection could be observed for nasal swabs (p = 0.007) and sow udder skin wipes (p = 0.036) compared to contact wipes. In the nursery, group sampling specimens were significantly more often swIAV positive compared to individual samples (p < 0.01), with exception of the comparison between contact wipes and nasal swabs (p = 0.181). However, in general nasal swabs were more likely to have Ct-value < 32 and thus, to be suitable for subtyping by RT-qPCR compared to dust wipes, contact wipes, udder skin wipes and tracheobronchial swabs (p < 0.05). Interestingly, different subtypes were found in different age groups as well as in different specimens in the same holding. Conclusion Although population-based specimens are highly effective for swIAV monitoring, nasal swabs are still the preferable sampling material for the surveillance of on-farm circulating strains due to significantly higher virus loads. Remarkably, sampling strategies should incorporate suckling piglets and different age groups within the nursery to cover as many as possible of the on-farm circulating strains.

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“…Here they suffer from low speci city as highly varying antigens of distinct lineages lead to cross reactions (false positives) or missing detection (false negatives). Vaccination-induced humoral responses further complicate the interpretation of the test outcome (16,(20)(21)(22). Concerning the detection of acute swIAV infections by PCR in nasal swabs, the timeframe for the detection is limited to the acute phase which typically lasts between 1 and…”

mentioning

confidence: 99%

Influenza surveillance in pigs: balancing act between broad diagnostic coverage and specific virus characterization

Stadler,

Zwickl,

Gumbert

et al. 2024

Preprint

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Background Monitoring of infectious diseases on swine farms requires a high diagnostic sensitivity and specificity of the test system. Moreover, particularly in cases of swine Influenza A virus (swIAV) it is desirable to include characterization of the virus as precisely as possible. This is indispensable for strategies concerning prophylaxis of swIAV and furthermore, to meet the requirements of a purposeful monitoring of newly emerging IAV strains in terms of vaccine design and public health. Within the present cross-sectional study, we compared the diagnostic value of group samples (wipes of surfaces with direct contact to mouth/nose, dust wipes, udder skin wipes, oral fluids) to individual samples (nasal swabs, tracheobronchial swabs) for both swIAV identification and characterization. Sampling included different stages of pig production on 25 sow farms with attached nursery considered as enzootically infected with swIAV. Firstly, samples were analyzed for IAV genome and subsequently samples with Ct-values < 32 were subtyped by multiplex RT-qPCR. Results Nasal swabs of suckling piglets and nursery pigs resulted in a higher odds to detect swIAV (p < 0.001) and to identify swIAV subtypes by RT-qPCR (p < 0.05) compared to nasal swabs of sows. In suckling piglets, nasal swabs and sow udder skin wipes were significantly more often swIAV positive compared to contact wipes from the farrowing unit (p = 0.007; p = 0.036). In the nursery, group sampling specimens yielded higher rates of swIAV detection compared to individual samples. However, in general nasal swabs were more likely to have Ct-value < 32 and thus, to be suitable for subtyping by RT-qPCR compared to dust wipes, contact wipes, udder skin wipes and tracheobronchial swabs (p < 0.05). Despite the high detection rate of swIAV in dust wipes, those specimens had the lowest odds of identifying subtypes by RT-qPCR (p < 0.05). Interestingly, different subtypes were found in different age groups as well as in different specimens in the same holding. Conclusion Although population-based specimens are highly effective for swIAV monitoring, nasal swabs are still the preferable sampling material for the surveillance of on-farm circulating strains due to significantly higher virus loads. Remarkably, sampling strategies should incorporate suckling piglets and different age groups within the nursery to cover all on-farm circulating strains.

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Herausforderungen bei der Influenzadiagnostik in einem Schweinebetrieb – ein Fallbericht

Cited by 4 publications

References 36 publications

A New Sampling Approach for the Detection of Swine Influenza a Virus on European Sow Farms

A New Sampling Approach for the Detection of Swine Influenza a Virus on European Sow Farms

Influenza surveillance in pigs: balancing act between broad diagnostic coverage and specific virus characterization

Influenza surveillance in pigs: balancing act between broad diagnostic coverage and specific virus characterization

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