Laboratory and Clinical Features of Influenza A₂ 1971-72 in Montreal

¹ Departments of Pediatrics (Infectious Disease) and Microbiology, McGill University-Montreal Children's Hospital Research Institute and McGill University, Montreal, Quebec
² Department of Microbiology, University of Toronto, Toronto, Ontario

Virologic, serologic and clinical records at two Montreal hospitals revealed 19 adults and 27 children with influenza A₂ (Hong Kong variant) infections during the winter months of 1971/72. Serious disease and two deaths were encountered in 14 (51 percent) children with underlying disease and 15 (55 percent) below three years of age. Six (22 percent) children had pneumonia, nine (33 percent) gastrointestinal symptoms, two conjunctivitis, and two meningitis. Of seven (37 percent) adult patients with complications, six (32 percent) had pneumonia, two pancreatitis, and five (26 percent) underlying disease. Two adult patients with no previous history of illness had a fulminant course and died within 48 hours of admission. Influenza continues to be associated with severe illness in a few patients especially, but not exclusively, in high risk individuals.