Background: Two major public health issues facing Nigeria in 2017 and 2018 were terrorist activity by the Boko Haram Islamist group and an outbreak of Lassa fever. The objective of this study was to determine if Boko Haram activity was temporally or spatially related to the incidence of Lassa fever in Nigeria, and if so, to identify potential concurrent causes and mitigation measures.  

Methods: The study was a mixed-methods design. First, we conducted a secondary analysis of the Armed Conflict Location and Event Data (ACLED) Project for all known Boko Haram activity and of the weekly Nigeria Centre for Disease Control (NCDC) reports for suspected Lassa fever cases. Data were analyzed for January 2017 through June 2018. The ACLED data were spatially overlaid with suspected Lassa cases for each of Nigeria's 36 states. Second, we conducted interviews with six aid workers in Nigeria regarding Boko Haram activities and Lassa fever cases.

Results: From January 2017 to June 2018, 596 Boko Haram activities occurred in 13 (36.1%) states: 416 in 2017 and 180 in the first six months of 2018. During the same time period, 3,137 suspected Lassa cases were reported from 21 (58.3%) Nigerian states: 1,022 in 2017 and 2,115 in the first six months of 2018. Only one state, Sokoto, was unaffected by either issue. Aid workers reported a positive relationship between heavy Boko Haram activity and increased incidence of negative health outcomes.

Conclusions: We found little geographic overlap in Nigeria between Boko Haram activity and the unprecedented 2018 outbreak of Lassa fever, suggesting independence of these two issues. However, unmeasured factors, such as public fear and mistrust of governmental activities, may affect both issues. It is critical to also note that widespread co-occurrence (97.2% of 36 states) of these two issues presents a significant public health, medical and security challenge for Nigeria, calling for overarching solutions such as governmental stability and economic stimulus.

A Mixed-methods Analysis of the Spatial and Temporal Relationship Between Boko Haram Activity and Lassa Fever Incidence in Nigeria, 2017-2018