Family members from patients with acute brucellosis were interviewed and serologically screened. All seropositive family members were clinically and serologically followed for six months.
Twenty-five acute brucellosis patients and their 178 family members were enrolled from January 2001 to February 2002. Of the 178 family members, 40 (23 % ) manifested various symptoms, 138 (77 % ) were asymptomatic, with an overall seroprevalence rate of 34 (19 % ). The rate of seropositivity among the symptomatic family members was 23 (58 % ) and for the asymptomatic was 11 (8 % ) (P < 0.001). The majority of the symptomatic family members (13 (57 % )) had a high Brucella titer in comparison to one (9 % ) of the asymptomatic group (P < 0.001). Acute brucellosis was diagnosed and treated in 18 (78 % ) of the symptomatic seropositive family members and in four (36 % ), of the asymptomatic seropositive family members with an acute brucellosis prevalence rate of 22 (12 % ). All family members with acute infection recovered without sequelae; one patient relapsed (5 % ).
Symptomatic family members are more likely to be seropositive with a high titer in comparison to the asymptomatic members.