Influenza types Hav6 N1, Hav4 Neq2, Hav9 N2 and Hsw1 N1 were isolated from turkeys in Minnesota in 1978. Pathology from sub-clinical to acute cases were observed and one chicken flock was also infected. Over the course of ten years, increased virulence was observed and younger birds were affected. Transmission to new flocks was accomplished by commercial poultry handling practices. Spread within flocks was by direct contact but was supplemented with routine husbandry practices. Control was based on sanitation and isolation. A killed vaccine was considered in an attempt to eliminate the possibility of vertical transmission. © 1980.
Moulthrop, J. I., & Langston, A. (1980). Report on avian influenza outbreak in Minnesota Turkeys-1978. Comparative Immunology, Microbiology and Infectious Diseases, 3(1–2), 193–196. https://doi.org/10.1016/0147-9571(80)90056-9