Laboratory and clinical features of influenza A2 1971-72 in Montreal.

Virologic, serologic and clinical records at two Montreal hospitals revealed 19 adults and 27 children with influenza A2 (Hong Kong variant) .mfections 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. S i x (22 percent) children had pneumonia, nine (33 percent) gastrointestinal symptoms, two conjunctivitis, and two eports in recent years have emphasized the diverse manifestations and clinical presentations of influenza This review describes some of the serious influenza A2 infections seen during the 1971-72 outbreak in Montreal. Comparisons to previous epidemics and differences in clinical presentation between adults and children are featured. Included are virologic, serologic and clinical data of 19 adults and 27 children with influenza AzIHong Kong variant infections from the Montreal Children's Hospital and the Royal Victoria Hospital. Virus isohion techniques Specimens were diluted in 2 ml transport medium (50 percent tryptose phosphate broth in Hank's balanced salt solution with 1 percent inactivated fetal agamma calf serum) and treated with penicillin, streptomycin and amphotericin B (Fungizone). They were inoculated into two tubes each of primary rhesus monkey kidney, Hem (carcinoma of the 'nasopharynx) and Wistar 38 (human embryonic lung) cells. Specimens that were negative in tissue culture were tested in tenday-old chick embryos by the amniotic route. Cells were maintained in a medium consisting of 49 percent medium 199, 49 percent Eagle's minimum essential medium and 2 percent inactivated agamma calf serum. Rhesus monkey kidney cells were rotated on roller drums and the other cells maintained stationary at 3S°C for at least two weeks. Cells were checked daily for cytopathic effect and rhesus monkey kidney cells were tested for hemadsorption after three to five days of incubation.4 "De artments of Pediatrics meningitis. Of seven (37 percent) adult patients with complications , six (32 percent) had pneumonia, two pancrea-titis, and five (26 percent) underlying disease. Two adult patients with no previous history of illness had a ful-minant course and died within 48 hours of admission. Influenza continues to be associated with severe illness in a few patients especially, but not exchwively, in high risk individuals. Virus identification Virus identification was done by hemadsorption-inhibition and hemagglutination-inhibition tests using specific rabbit antiserum to influenza An/Hong Kong/68 (Flow Laboratories , lot No 825006) titered at 1:160, heat inactivated, treated with kaolin and absorbed with guinea pig red blood …