RÉSUMÉ
To determine risk factors of relapse among outpatient treated brucellosis. It is a Cohort study carried out from 2004 to 2006, in an Infectious Diseases Clinic in Ahvaz, Iran. We studied 115 patients with brucellosis. The diagnostic criteria were the finding of > 1/80 [Wright] with a 2 mercaptoethanol [2 ME] >1/40, in association with compatible clinical findings [back pain, sweating and fever]. Treatment by standard drug regimen against brucellosis was established according to National Program against Brucellosis [NPB] in Iran. The patients were evaluated at the end of treatment and after two, four and six months by clinical and serological examinations. Patients with relapse and patients without relapse were placed separately in two groups. The data in the two groups were statistically compared with SPSS, 11.5 by chi square test. Of the 115 patients, 12 were excluded because of study's exclusion criteria. Of 93 studied patients 17 [18.3%] had relapse, results in whom are as fallow: 12 [70.6%] had Longer than three months duration of the symptoms prior to diagnosis [P=0.0001]. 100% of relapses were in male [P=0.003]. Aging was associated with increased risk of relapses [P=0.04]. Eleven patients [64.6%] had lymphopenia [P<0.0001]. Increased in ESR and CRP values were observed in 16[94.1%] and 17[100%], respectively [P