An epidemic of meningococcal infection at Zaria, Northern Nigeria. 1. General epidemiological features

In 1977 Zaria, in Northern Nigeria, was affected by a severe epidemic of group A meningococcal infection, 1,257 patients being admitted to hospital with the disease during a three-month period. The epidemic started towards the end of the dry season when it was hot, dry and dusty and finished shortly after the onset of the rains. The over-all attack rate was 3.6 per 1,000 but this varied considerably from area to area within the town. Few cases occurred amongst those belonging to the upper social classes. The disease was seen most frequently amongst those from five to 14 years old and there was a strong male preponderance. The over-all mortality was 8.3% but mortality was much higher (40.6%) amongst 67 patients with acute meningococcaemia.