A village epidemic of brucellosis, due to Brucella melitensis, contracted from infected sheep and goats owned by the vifiagers is described. Of the 309 inhabitants eighty-four became infected and seventy-nine were clinically ill with brucellosis. The investigation covered 232 of the total population and nearly all those not examined belonged to the age group, 0–5 years, not directly exposed to infection by contact with diseased animals.
The population of the village was made up of forty-six families, only nine of which escaped infection. In the affected families, the incidence varied from one to seven in each case. The size of the family varied from three to eleven but there was no correlation between the size of the family and the number contracting brucellosis, neither did sex play any part in the incidence. All age groups were susceptible but the morbidity increased with age and this was correlated with increased risk of exposure to infection of the older age groups.
There was considerable variation in the severity of the clinical illness but there were no fatiities and all patients responded to antibiotic therapy.
Brucella melitensis was isolated from twenty-eight of the thirty-six patients subjected to blood culture and specific agglutinins at an acceptable level were demonstrated in all but three of those with a clinical illness.
The number of persons without evidence of clinical brucellosis who possessed significant brucella agglutinins was very small and the assumption that in an endemic area the number of infected persons is much greater than the number clinically ill was not borne out in the outbreak described here.
Persistence of specific agglutinins up to 2 years after recovery from the clinical illness is recorded.
We wish to pay tribute to the late Professor J. Gurevitch for his constant interest and helpful advice.
Thanks are due to Prof. M. Ruiz Castaneda for providing us with the Castaneda bottles for blood culture work, to Dr E. Neeman of the Government Brucella Reference Laboratory for supplying the Standard Brucella Antigen and for examining the strains of Brucella isolated, and to Colonel H. J. Bensted for his interest and help in preparing the paper. Finally, we are indebted to Mrs Aliza Abut Kayner, social worker in the village health centre, for her valuable help in gathering statistical data.