Severe sinusitis in ducklings caused by influenza A virus
Tanyi, J.; Romváry, J.; Derzsy, D.; Temesi, Z.; Sári, I.
Acta Veterinaria Academiae Scientiarum Hungaricae 25(2-3): 261-266
1975
ISSN/ISBN: 0001-7205 PMID: 1231558 Document Number: 88693
On a duck farm, 2 .times. 106 duck eggs from 20,000 ducks were incubated from April-Oct., 1974. The majority of the ducklings were sold when 1 day old, the minority when 3 wk old. In different groups of ducklings 15-50% were affected by an outbreak characterized by unilateral, occasionally bilateral, sinusitis. The ducklings became free of symptoms within 1-4 wk, except for complicated cases, when the sinusitis was still recognizable at 8 wk. In groups kept on the farm up to adult age, the loss ranged from 4.8-22.5% (mean, 10.6%). Hemagglutinating virus strain (42) were isolated from the respiratory tract of the diseased ducklings, most of them from the sinus secretion. In double agar-gel diffusion the isolates proved to be influenza A virus strains, but in the hemagglutination-inhibition (HI) test they did not react with antisera to the prototype strains of subtypes Hav1-Hav6. Chickens, day old ducklings and day old turkeys experimentally infected with an isolate developed fibrinous air sacculitis; adult cocks showed head edema lasting several days. The artificially infected birds gave a positive immune response, well-demonstrable 10-12 days after infection. The virus was isolated from all serous-mucous sinus secretion samples from several ducklings for 2-7 wk. Virus isolation was rarely successful from caseous-fibrinous masses. The HI titres reached relatively low levels in the sera of ducklings after natural infection. The virus could be isolated from carrier ducklings despite the presence of homologous antibodies demonstrable up to 1:20-1:40 serum dilutions. The serum antibodies disappeared by the 5th-12th wk after recovery.