Since October 2010, the USDA, in cooperation with State and industry partners, has conducted voluntary surveillance for Influenza A virus in swine (IAV-S) in the US. The program tests samples collected from diagnostic submissions to veterinary diagnostic laboratories. This surveillance is not conducted to define prevalence – the goal is to identify viruses that may be circulating in swine, and gain knowledge to contribute to improved animal health diagnostics and vaccines.
The IAV-S Surveillance report for FY 2017 2nd Quarter has been posted to the web and can be viewed at https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/swine-disease-information/ct_swine_health_monitoring_surveillance Some of the key points in the report include:
- In FY 2017 Q2, 1,931 samples were submitted for IAV-S surveillance from 888 accessions.
- H1N2 was the predominant subtype
- Over the past 8 quarters, H1N2 predominated in Regions 1, 2, 3, 4 and 5. When Regions are recorded as "unknown" H1N1 predominates (see map in regional section)
USDA has been able to extend the funding for this program through the use of both appropriated and emergency funding. Although producers will continue to bear the cost burden of the initial IAV-S screening test (Matrix PCR) USDA will continue to provide funding support to the National Animal Health Laboratory Network (NAHLN) for further testing of accessions that meet the Matrix PCR CT cutoff values (Oral fluids CT <20, and nasal swabs and lung CT <25). Further testing includes subtyping PCRs, virus isolation and sequencing of the HA and NA genes.
All IAV-S submissions are voluntary and based on clinical case submissions to veterinary diagnostic labs. Thus data are not a statistically representative sampling of the U.S. swine population. Likewise, the information in this report cannot be used to determine regional and/or national incidence, prevalence, or other epidemiological measures, but it may help identify IAV-S trends.
USDA, AASV and the swine industry encourage continued support for the program and the submission of samples from all geographic regions (some regions have been historically underrepresented in the report).