Epidemiology-driven approaches to surveillance in HPAI-vaccinated poultry flocks aiming to demonstrate freedom from circulating HPAIV

Harder, Timm C.; Wit, Sjaak de; Gonzáles, José L.; Ho, Jeremy H. P.; Mulatti, Paolo; Prajitno, Teguh Y.; Stegeman, Arjan

doi:10.1016/j.biologicals.2023.101694

Cited by 3 publications

(5 citation statements)

References 67 publications

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“…Biosecurity measures are important to limit the introduction of swIAV and should be strengthened on swine farms in areas with high densities of swine and poultry [60]. National and international regulatory agencies [61,62] and researchers worldwide [63] emphasize that improving biosecurity and surveillance practices and strategies is a priority in areas where AI vaccination is allowed under different circumstances [64].…”

Section: Discussionmentioning

confidence: 99%

Seroprevalence of Swine Influenza A Virus (swIAV) Infections in Commercial Farrow-to-Finish Pig Farms in Greece

Papatsiros,

Papakonstantinou,

Meletis

et al. 2023

Veterinary Sciences

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Swine influenza is a highly contagious respiratory disease caused by influenza A virus infection. Pigs play an important role in the overall epidemiology of influenza because of their ability to transmit influenza viruses of avian and human origin, which plays a potential role in the emergence of zoonotic strains with pandemic potential. The aim of our study was to assess the seroprevalence of Swine Influenza Viruses (swIAVs) in commercial pig farms in Greece. A total of 1416 blood samples were collected from breeding animals (gilts and sows) and pigs aged 3 weeks to market age from 40 different swIAV vaccinated and unvaccinated commercial farrow-to-finish pig farms. For the detection of anti-SIV antibodies, sera were analyzed using an indirect ELISA kit CIVTEST SUIS INFLUENZA®, Hipra (Amer, Spain). Of the total 1416 animals tested, 498 were seropositive, indicating that the virus circulates in both vaccinated (54% seroprevalence) and unvaccinated Greek pig farms (23% seroprevalence). In addition, maternally derived antibody (MDA) levels were lower in pigs at 4 and 7 weeks of age in unvaccinated farms than in vaccinated farms. In conclusion, our results underscore the importance of vaccination as an effective tool for the prevention of swIAV infections in commercial farrow-to-finish pig farms.

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Section: Discussionmentioning

confidence: 99%

Seroprevalence of Swine Influenza A Virus (swIAV) Infections in Commercial Farrow-to-Finish Pig Farms in Greece

Papatsiros,

Papakonstantinou,

Meletis

et al. 2023

Veterinary Sciences

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Section: Use Of Unvaccinated Sentinel Birdsmentioning

confidence: 99%

“…Sentinels can then be routinely tested for HPAIV infection with appropriate serological or virological methods (Suarez, 2005). However, several practical problems have been found to hamper the use of sentinels in the surveillance strategy in HPAI‐vaccinated flocks and areas, and therefore, the sentinel bird approach has been abandoned in countries with long‐standing vaccination experience such as Indonesia and Hongkong (Harder et al., 2023): Without good compliance of farmers and a proper management system, the presence of unvaccinated sentinel birds in the flock may in fact function as the ‘gap in the door of protection’ since if exposed to the virus they can get infected and spread HPAIV in the flock and to other farms. It is logistically challenging to identify sentinel animals in large flocks if sentinels are of the same species (conspecific) as the vaccinated part of the flock. Conspecific sentinels would enable an appropriate diffusion in the vaccinated flock.…”

Section: Assessmentmentioning

confidence: 99%

Vaccination of poultry against highly pathogenic avian influenza – Part 2. Surveillance and mitigation measures

Nielsen,

Alvarez,

Bicout

et al. 2024

EFS2

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Selecting appropriate diagnostic methods that take account of the type of vaccine used is important when implementing a vaccination programme against highly pathogenic avian influenza (HPAI). If vaccination is effective, a decreased viral load is expected in the samples used for diagnosis, making molecular methods with high sensitivity the best choice. Although serological methods can be reasonably sensitive, they may produce results that are difficult to interpret. In addition to routine molecular monitoring, it is recommended to conduct viral isolation, genetic sequencing and phenotypic characterisation of any HPAI virus detected in vaccinated flocks to detect escape mutants early. Following emergency vaccination, various surveillance options based on virological testing of dead birds ('bucket sampling') at defined intervals were assessed to be effective for early detection of HPAIV and prove disease freedom in vaccinated populations. For ducks, virological or serological testing of live birds was assessed as an effective strategy. This surveillance could be also applied in the peri-vaccination zone on vaccinated establishments, while maintaining passive surveillance in unvaccinated chicken layers and turkeys, and weekly bucket sampling in unvaccinated ducks. To demonstrate disease freedom with > 99% confidence and to detect HPAI virus sufficiently early following preventive vaccination, monthly virological testing of all dead birds up to 15 per flock, coupled with passive surveillance in both vaccinated and unvaccinated flocks, is recommended. Reducing the sampling intervals increases the sensitivity of early detection up to 100%. To enable the safe movement of vaccinated poultry during emergency vaccination, laboratory examinations in the 72 h prior to the movement can be considered as a risk mitigation measure, in addition to clinical inspection; sampling results from existing surveillance activities carried out in these 72 h could be used. In this Opinion, several schemes are recommended to enable the safe movement of vaccinated poultry following preventive vaccination.

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“…HPAIs were first identified in China and have been circulating in Asia since then. Globally, new contamination streams with this agent in African, European, and American countries have challenged the poultry industry (15). Currently, LPAIV H9N2 is the most common strain in poultry worldwide.…”

Section: Introductionmentioning

confidence: 99%

“…Vaccination is suggested to control Avian influenza disease as part of an integrated strategy along with biosecurity principles and surveillance programs, and its positive effect in reducing the risk of infection and its complications has been proven (1,4,5). Vaccination against HPAI is currently not allowed in some countries but may be used in emergencies or when there is a reasonable prospect of eradicating HPAI in that area shortly (15). Vaccination against LPAI, primarily H9N2, is commonly performed in countries where the virus is enzootic.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of inactivated vaccine's Antibody response to different H9N2 Vaccination programs with Hemagglutination Inhibition (HI) assay

Motamedi Nasab,

Pourbakhsh,

Haghbin Nazarpak

2023

J Poult Sci Avian Dis

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Influenza is a significant poultry disease that can also affect humans, making it a zoonosis. The World Health Organization (WHO) and Contagious Diseases Organization (CDO) have increasingly focused on this disease in recent years. The isolation of influenza, particularly H5N1 and H9N2 subtypes, has dramatically increased, posing a global epidemic threat and causing deaths in various communities, as well as substantial losses in poultry. In response, using inactivated avian influenza vaccines has become common in controlling the disease. A comprehensive study was conducted in broiler farms in Iran to address the importance of influenza control through vaccination. The study involved 50,000 broiler chicks divided into seven groups with different vaccination programs. The groups were vaccinated at different ages and received varying vaccine doses. Serum samples were collected weekly and analyzed for antibody titers using hemagglutination inhibition (HI). The results showed that the groups vaccinated after seven days of age had a more consistent immune response and higher antibody titers than those vaccinated at a younger age or with only one dose. Early vaccination before seven days of age did not effectively stimulate the desired antibody response or achieve expected titers for the H9N2 influenza virus. Therefore, vaccinating older chicks improved immunity and flock protection more effectively. This study highlights the importance of vaccination strategies in controlling influenza in broiler farms. It provides valuable insights into the optimal timing and dosage of vaccines to enhance the immune response and protect against the H9N2 subtype. Implementing appropriate vaccination programs can contribute to mitigating the impact of influenza on poultry and reducing the risk of transmission to humans, ultimately safeguarding both animal and public health.

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Epidemiology-driven approaches to surveillance in HPAI-vaccinated poultry flocks aiming to demonstrate freedom from circulating HPAIV

Cited by 3 publications

References 67 publications

Seroprevalence of Swine Influenza A Virus (swIAV) Infections in Commercial Farrow-to-Finish Pig Farms in Greece

Seroprevalence of Swine Influenza A Virus (swIAV) Infections in Commercial Farrow-to-Finish Pig Farms in Greece

Vaccination of poultry against highly pathogenic avian influenza – Part 2. Surveillance and mitigation measures

Evaluation of inactivated vaccine's Antibody response to different H9N2 Vaccination programs with Hemagglutination Inhibition (HI) assay

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