Risk Factors for Human Brucellosis in Northern Tanzania.

Shama Cash-Goldwasser,Michael C Shand,Venance P Maro,Katrina J Sharples,Blandina T Mmbaga,Robyn A Stoddard,Charles Muiruri,Sarah Cleaveland,Jo E B Halliday,Michael J Maze,Matthew P Rubach,John A Crump,Wilbrod Saganda,Holly M Biggs,Rudovick R Kazwala,Bingileki F Lwezaula

doi:10.4269/ajtmh.17-0125

Abstract

.Little is known about the epidemiology of human brucellosis in sub-Saharan Africa. This hampers prevention and control efforts at the individual and population levels. To evaluate risk factors for brucellosis in northern Tanzania, we conducted a study of patients presenting with fever to two hospitals in Moshi, Tanzania. Serum taken at enrollment and at 4–6 week follow-up was tested by Brucella microagglutination test. Among participants with a clinically compatible illness, confirmed brucellosis cases were defined as having a ≥ 4-fold rise in agglutination titer between paired sera or a blood culture positive for Brucella spp., and probable brucellosis cases were defined as having a single reciprocal titer ≥ 160. Controls had reciprocal titers < 20 in paired sera. We collected demographic and clinical information and administered a risk factor questionnaire. Of 562 participants in the analysis, 50 (8.9%) had confirmed or probable brucellosis. Multivariable analysis showed that risk factors for brucellosis included assisting goat or sheep births (Odds ratio [OR] 5.9, 95% confidence interval [CI] 1.4, 24.6) and having contact with cattle (OR 1.2, 95% CI 1.0, 1.4). Consuming boiled or pasteurized dairy products was protective against brucellosis (OR 0.12, 95% CI 0.02, 0.93). No participants received a clinical diagnosis of brucellosis from their healthcare providers. The under-recognition of brucellosis by healthcare workers could be addressed with clinician education and better access to brucellosis diagnostic tests. Interventions focused on protecting livestock keepers, especially those who assist goat or sheep births, are needed.

Highlights

Human brucellosis is a major zoonosis worldwide.[1,2] It presents as an acute febrile illness[3,4] and sometimes progresses to chronic debilitating disease.[5]
Our results point to multiple potential transmission pathways involving several livestock species in the epidemiology of human brucellosis in northern Tanzania
We showed that assisting goat or sheep births and contact with cattle were risk factors for brucellosis

Summary

Introduction

Human brucellosis is a major zoonosis worldwide.[1,2] It presents as an acute febrile illness[3,4] and sometimes progresses to chronic debilitating disease.[5]. Prevention of human brucellosis hinges on disease control in the livestock reservoir.[1] Livestock vaccination and test and slaughter programs have been used in some countries to achieve elimination of both livestock and human brucellosis.[1,8,9]. Such approaches have rarely been used in sub-

Methods

Results

Conclusion