Concurrent summer influenza and pertussis outbreaks in a nursing home in Sydney, Australia.
OBJECTIVE
To report on the investigation of a summer outbreak of acute respiratory illness among residents of a Sydney nursing home.


METHODS
An epidemiologic and microbiological investigation of the resident cohort at the time of the outbreak and medical record review 5 months later.


METHODS
A nursing home located in Sydney, Australia, during February to July 1999.


METHODS
The cohort of residents present in the nursing home at the time of the outbreak.


METHODS
Public health interventions included recommendations regarding hygiene, cohorting of residents and staff, closure to further admissions, and prompt reporting of illness; and virologic and serologic studies of residents.


RESULTS
Of the 69 residents (mean age, 85.1 years), 35 fulfilled the case definition of acute respiratory illness. Influenza A infection was confirmed in 19 residents, and phylogenetic analysis of the resulting isolate, designated H3N2 A/Sydney/203/99, showed that it differed from strains isolated in eastern Australia during the same period. Serologic evidence of Bordetella infection was also found in 10 residents; however, stratified epidemiologic analysis pointed to influenza A as the cause of illness.


CONCLUSIONS
The investigation revealed an unusual summer outbreak of influenza A concurrent with subclinical pertussis infection. Surveillance of acute respiratory illness in nursing homes throughout the year, rather than solely during epidemic periods, in combination with appropriate public health laboratory support, would allow initiation of a timely public health response to outbreaks of acute respiratory illness in this setting.
Ferson
Mark J
MJ
South Eastern Sydney Public Health Unit, Randwick, New South Wales, Australia.
Morgan
Keira
K
Robertson
Peter W
PW
Hampson
Alan W
AW
Carter
Ian
I
Rawlinson
William D
WD
D000368:Aged; D000369:Aged, 80 and over; D001884:Bordetella / Q000302:isolation & purification; D001885:Bordetella Infections / Q000453:epidemiology / Q000382:microbiology; D015897:Comorbidity; D004196:Disease Outbreaks / Q000517:prevention & control / Q000706:statistics & numerical data*; D005260:Female; D006282:Health Personnel / Q000706:statistics & numerical data; D006707:Homes for the Aged / Q000458:organization & administration / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D017053:Infection Control / Q000379:methods; D009980:Influenza A virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology* / Q000382:microbiology; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D009735:Nursing Homes / Q000458:organization & administration / Q000706:statistics & numerical data*; D012621:Seasons; D016019:Survival Analysis; D014917:Whooping Cough / Q000453:epidemiology*