Hospital based surveillance of Lassa fever, 2013 - 2015

Introduction: viral hemorrhagic fever is a generic term for a severe illness, often accompanied by bleeding and caused by viruses. Lassa fever is a viral hemorrhagic fever caused by Lassa Virus of the family Arenaviridae. Lassa fever is endemic in Nigeria especially Edo State with zero-prevalence of 21% and 28% mortality. The aim of this study was to evaluate the laboratory based surveillance system for Lassa fever to assess its key attributes and whether it meets its objectives. Methods: an evaluation of the Laboratory based Lassa fever surveillance system was carried out at the Institute of Lassa Fever Research and Control (ILFRC), Irrua Specialist Teaching Hospital, Irrua, Edo State from 2013 to 2015. The evaluation was conducted using the CDCs updated guidelines for evaluating public health surveillance system, 2001. The methods included interview of stakeholders and review of documents. Relevant stakeholders were identified and interviewed to obtain their input in describing the system and assessing key attributes of the system. Documents relevant to the surveillance of Lassa fever in Nigeria were also reviewed. Results: out of 3,268 suspected cases screened for Lassa fever from 2013 to 2015, 308 were laboratory confirmed as Lassa fever. The predictive value positive was 9.4%. The case definition for Lassa fever surveillance is simple and easy to apply. The system integrates well with the Integrated Disease Surveillance and Response (IDSR) system and is representative. The system is flexible as data is also being collected on malaria fever. Data incompleteness for all variables ranged from 7% to 11%. The system is also useful. Stakeholders interviewed agreed that effective Lassa fever surveillance ensured the control and elimination of Lassa fever. Conclusion: Lassa fever surveillance system in ILFRC is meeting its objectives of detecting and controlling the disease in Nigeria. However, the surveillance system has gaps in terms of data quality and completeness. Government should provide more funding and support to the system.