CAGE HOUSING

37 LOHMANN TIERZUCHT › MANAGEMENT GUIDE 37 Avian Influenca Avian Influenza is since several years of major concern in many countries in the world, for the poultry industry but also for the potential of human infections. It is caused by an Avian In- fluenza A virus of the Family Orthomyxoviridae. These are Small-medium size, enveloped single stranded RNA virus, which have two major sur- face proteins, the Hemagglutinin (H1-H16) and the Neuraminidase (N1-N9), with 144 potential combinations. The H and the N gives these vi- ruses their Name, like H5N1, H5N8 or H7N7. The high variety of AI viruses is due to their potential to either mutate (antigenic drift) or to exchange genomic information if one host cell is infected with two different viruses (antigenic shift). Infections with Avian Influenza are notifiable to the World Organization for Animal Health (OIE) when they are caused by any Influen- za A virus of the H5 or H7 subtypes. Highly pathogenic notifiable avian influenza (HP- NAI) viruses are (until now) H5 and H7 viruses which have an IVPI in 6-week-old chickens greater than 1.2 or have multiple basic amino acids at the cleavage site of the hemaggluti- nin molecule (HA0). Table 10: Type A Influenza Surface Antigens Hemagglutinin (H) Subtypes 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Human ● ● ● ± ± ± Equine ● ● Swine ● ● ± ± ± Avian ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● Neuraminidase (N) Subtypes 1 2 3 4 5 6 7 8 9 Human ● ● ± Equine ● ● Swine ● ● ± Avian ● ● ● ● ● ● ● ● ● GENERAL RECOMMENDATIONS www.virologydownunder.blogspot.com

RkJQdWJsaXNoZXIy NTg2OTc2