RESUMO
BACKGROUND: An outbreak of a chronic liver disease of unidentified cause, known as "Unidentified Liver Disease (ULD)" by local communities was first observed in a rural village in Tigray, northern-Ethiopia in 2001. Little was known about the geographical extent, trend, and epidemiology of the disease. METHODS: The Ethiopian Public Health Institute (EPHI) by then Ethiopian Health and Nutrition Research Institute (EHNRI), Centers for Disease Control and Prevention, World Health Organization, and Tigray Regional Health Bureaue established the ULD surveillance system in 2009 to characterize and monitor trends for this emerging disease and to identify cases for treatment and follow up. A large-scale official training was provided to the surveillance staff on case identification, management and reporting. In absence of a confirmatory test, the system used simple case definitions that could be applied by frontline staff with varying clinical training. To maximize resources, health extension workers already conducting household visits in affected communities identified cases and increased community awareness about the disease. A team was placed in Shire, in close proximity to the outbreak region, to provide support and collect reports from health facilities and district health offices. RESULTS: As of September 2011, a total of 1,033 cases, including 314 deaths were identified. Contamination of locally produced grains with several pyrrolizidine alkaloid producing plants was identified cause of the disease. Staff interviews identified that shortage and turnover of trained staff were major challenges. LESSONS LEARNED: Long term dedication by frontline staff, using simple case definitions to identify cases, and active collection of missing reports were critical for surveillance of this chronic non-infectious disease of unknown cause in a rural, resource-limited setting.