Original Contribution PERIOD OF SHEDDING OF THE AVIAN INFLUENZA A H6N2 SUBTYPE VIRUS ISOLATE IN YOUNG DOMESTIC FOWL

The aim of the present study was to compare the susceptibility of 4 bird species (ducklings, goslings, turkeys and chickens) to a low pathogenic avian influenza A virus (H6N2 subtype) and to evaluate the corresponding virus shedding periods. For that purpose, 9 turkey poults, 9 chickens, 7 ducklings and 6 goslings, were experimentally infected by the H6N2 virus (105 ELD50) by intravenous route whereas another 16 birds (2 ducklings, 2 goslings, 6 turkey poults and 6 chickens) were not infected and served as negative controls. The virus re-isolation method was performed on cloacal and oropharyngeal samples collected before inoculation and 3, 5, 7, 10, 14, 21 and 28 days after inoculation. The virus was re-isolated from all ducklings (100%), 67 % of goslings, 56 % of turkey poults and from 33 % of chickens essentially during the first 10 days after virus inoculation. The proportion of positive cloacal samples was higher compared to that of oropharyngeal samples (positive cloacal samples were 72%, 83%, 80 % and 87 % from all positive samples in ducklings, turkey poults, chickens and goslings respectively). The mean virus shedding periods determined from cloacal samples were 10.6, 6.6, 5.4 and 4.3 days in ducklings, turkeys, goslings and chickens respectively. The longest periods observed in this study were 21 (ducklings), 10 (turkeys and goslings) and 5 days (chickens). The oropharyngeal virus shedding periods were shorter in the 4 species. Consequently, cloacal samples may be more relevant to exploring spontaneous avian influenza cases.