Dynamics of conflict during the Ebola outbreak in the Democratic Republic of the Congo 2018-2019

Abstract

Background: The 2018-2019 Ebola virus disease (EVD) outbreak in North Kivu and Ituri provinces in the Democratic Republic of the Congo (DRC) is the largest ever recorded in the DRC. It has been declared a Public Health Emergency of International Concern. The outbreak emerged in a region of chronic conflict and insecurity, and directed attacks against health care workers may have interfered with disease response activities. Our study characterizes and quantifies the broader conflict dynamics over the course of the outbreak by pairing epidemiological and all available spatial conflict data.

Methods: We build a set of conflict variables by mapping the spatial locations of all conflict events and their associated deaths in each of the affected health zones in North Kivu and Ituri, eastern DRC, before and during the outbreak. Using these data, we compare patterns of conflict before and during the outbreak in affected health zones and those not affected. We then test whether conflict is correlated with increased EVD transmission at the health zone level.

Findings: The incidence of conflict events per capita is ~ 600 times more likely in Ituri and North Kivu than for the rest of the DRC. We identified 15 time periods of substantial uninterrupted transmission across 11 health zones and a total of 120 bi-weeks. We do not find significant short-term associations between the bi-week reproduction numbers and the number of conflicts. However, we do find that the incidence of conflict per capita was correlated with the incidence of EVD per capita at the health zone level for the entire outbreak (Pearson's r = 0.33, 95% CI 0.05-0.57). In the two provinces, the monthly number of conflict events also increased by a factor of 2.7 in Ebola-affected health zones (p value < 0.05) compared to 2.0 where no transmission was reported and 1.3 in the rest of the DRC, in the period between February 2019 and July 2019.

Conclusion: We characterized the association between variables documenting broad conflict levels and EVD transmission. Such assessment is important to understand if and how such conflict variables could be used to inform the outbreak response. We found that while these variables can help characterize long-term challenges and susceptibilities of the different regions they provide little insight on the short-term dynamics of EVD transmission.

Keywords: Conflict; Democratic Republic of the Congo; Ebola; Outbreak; Violence.

Fig. 1

a Map of the study areas of the Democratic Republic of the Congo (DRC) and health zones in the provinces of North Kivu and Ituri (box). Dots represent the precise location of conflicts in the DRC during the time of the ongoing outbreak (August 1, 2018, to July 26, 2019). The color of the dots represents the type of conflict, and the size represents the number of deaths. b Map of the North Kivu and Ituri provinces. Colors represent the number of EVD cases, and circles represent the number of conflicts during the outbreak (August 1, 2018, to July 26, 2019). c Epidemic curve of EVD during the 2018–2019 outbreak

Fig. 2

Trends in the bi-weekly reproduction number during time periods of substantial uninterrupted transmission (blue box plot indicating mean and 95% credible interval), the average weekly number of conflicts smoothed over a 1-month time period (colored lines), and the number of cases (gray bars, right hand side axis)

Fig. 3

Association between the reproduction number and the number of battles (a), deaths (b), violence towards civilians (c), and conflicts (d). The gray lines represent the fitted regression line between the reproduction number and the number of conflicts at a health zone level for periods of sustained, uninterrupted transmission. A full table of correlation coefficients is shown in Table S1

Fig. 4

a Change between the number of conflicts during the first half of the outbreak (August 1, 2018–January 31, 2019) vs. the second half of the outbreak (February 1, 2019–July 26, 2019) on a log scale (factor change). Blue dots show the areas that reported transmission. Red dots indicate the areas that are in North Kivu and Ituri but did not report transmission. Green is the rest of the Democratic Republic of the Congo. Black dots represent the population-weighted mean of conflicts per group which are 2.7 in health zones that reported transmission, 2.04 in health zones in North Kivu and Ituri that did not report transmission, and 1.32 in the rest of the Democratic Republic of the Congo. Between the initial phase of the outbreak (August 2018–January 2019) and the second phase of the outbreak (February 2019–July 2019), on average, the incidence of conflict events (by day) increased by a factor of 2.75 (Fig. 2a) in health zones that reported transmission (p value < 0.05). Health zones in Ituri and North Kivu that did not report transmission were not statistically significantly different (p value = 0.05017) but on average experienced a doubling in conflict events (factor 2.04). b The relationship between the number of conflicts per 10,000 individuals in the first half of the outbreak (August 2018–January 2019) vs. the second half of the outbreak (February 2019–July 2019). All points that fall above the gray line see an increase in conflict events in the second half of the outbreak. The correlation between the reported incidence of conflict during these two time periods is R² = 0.95 (p value < 0.01, regression line not shown)