Screening of family members of patients with acute brucellosis in an endemic area of Iran

Brucellosis is a zoonotic disease and it’s still endemic in Iran. There are some reports regarding brucellosis infection in family members sharing same risk factors and remain unrecognized. However, few studies on the importance of family screening are available. We aimed to screen household members of index cases with acute brucellosis for detecting additional unrecognized cases in central province of Iran. 163 family members of 50 index cases were enrolled in the study. Standard Tube Agglutination Test (STA) and 2-mercaptoethanol (2ME) agglutination were checked in all samples. A case with STA titer ≥ 1:80, 2-mercaptoethanol (2ME) agglutination ≥ 40 and compatible signs and symptoms was considered positive for brucellosis. 15 (9.2%) of family members were seropositive for Brucella agglutinin and among them, 8 (53.3%) were asymptomatic and 7 (46.7%) were symptomatic. STA titer ranged from 1:80 to 1:640 in seropositive members. 4 of the 15 seropositive cases who identified by screening came from one index case with 6 family members. All symptomatic seropositive cases treated for Brucella infection and recovered without any complications in 6 months follow up. On the basis of our data, family members of brucellosis patients are at risk of disease acquisition, and screening of household members provides an effective way for early diagnosis and prompt treatment. However cost benefit of screening should be evaluated to reach definite decision for the implementation of the screening as a nationwide program.