Risk of influenza A (H5N1) infection among health care workers exposed to patients with influenza A (H5N1), Hong Kong.

The first outbreak of avian influenza A (H5N1) occurred among humans in Hong Kong in 1997. To estimate the risk of person-to-person transmission, a retrospective cohort study was conducted to compare the prevalence of H5N1 antibody among health care workers (HCWs) exposed to H5N1 case-patients with the prevalence among nonexposed HCWs. Information on H5N1 case-patient and poultry exposures and blood samples for H5N1-specific antibody testing were collected.

Antibody response in individuals infected with avian influenza A (H5N1) viruses and detection of anti-H5 antibody among household and social contacts.

The first documented outbreak of human respiratory disease caused by avian influenza A (H5N1) viruses occurred in Hong Kong in 1997. The kinetics of the antibody response to the avian virus in H5N1-infected persons was similar to that of a primary response to human influenza A viruses; serum neutralizing antibody was detected, in general, >/=14 days after symptom onset. Cohort studies were conducted to assess the risk of human-to-human transmission of the virus.

Detection of antibody to avian influenza A (H5N1) virus in human serum by using a combination of serologic assays.

From May to December 1997, 18 cases of mild to severe respiratory illness caused by avian influenza A (H5N1) viruses were identified in Hong Kong. The emergence of an avian virus in the human population prompted an epidemiological investigation to determine the extent of human-to-human transmission of the virus and risk factors associated with infection. The hemagglutination inhibition (HI) assay, the standard method for serologic detection of influenza virus infection in humans, has been shown to be less sensitive for the detection of antibodies induced by avian influenza viruses.

Evaluation of ureteral obstruction by early intravenous pyelography.

Acute ureteral obstruction was studied in dogs by intravenous pyelography at two, four, six, nine, 12, 24, 48 and 168 hours after total occlusion of the ureter. Ureteral obstruction was correctly diagnosed in all instances, if intravenous pyelography was performed within nine hours from the time of obstruction and if a two hour sequence roentgenogram was obtained. A variably diagnostic rate of 36 to 75 per cent occurred when intravenous pyelography was delayed until 12 hours or later.