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An Outbreak of Hepatitis A in Southwest Riyadh City, 1994-1995.


Confirmed cases of hepatitis A are reported to the primary health center (PHCC) nearest to the residence of the patient for institution of public health control measures. An unusual increase in the number of newly diagnosed cases of unspecified hepatitis and hepatitis A (HA), were reported from southwestern Riyadh in 1995. The objectives of the study were to identify the underlying causes that perpetuated this outbreak for more than ten months.


We recorded dates of onset of symptoms, bleeding, serological tests and reporting of the laboratory results of all cases of unspecified hepatitis and HA, and confirmed cases of HA. A 2:1 case-control study was conducted to assess potential risk factors for HA.


From October 94 and November 95, 154 (75%) out of 203 identified cases of unspecified hepatitis were reported through the Riyadh Health Surveillance System. Of those, 84 were submitted for, and received, the results of laboratory testing for hepatitis A (41.4%); 71 (84.5 %) were serologically confirmed as hepatitis A. All cases but two were Saudi children under 15 years of age (median 7 years). The sex ratio was 1:1. The secondary attack rate ranged from 10% to 75% within extended families. Cases of HA shared glasses for drinking water with a known case of HA (OR 14, 95% CI 1.6-337). Median interval between the onset of a primary case in a house and the onset of symptoms in the first subsequent co-primary or secondary cases is the same household was about 3 weeks, and the median duration between date of onset of symptoms and date of drawing for testing for HAV was 8 days. However, the median duration between the date of collecting a blood sample and date of running the HAV test was 18 days, and the median duration between the dates of onset of symptoms and the date of reporting the result to a selected PHCC was 51 days (range 18-374 days).


The delay in receiving laboratory results has resulted in delay in administration of human immunoglobulins that could have halted the spread of HA among close contacts of newly diagnosed cases of hepatitis A. Expediency in laboratory transactions is recommended.