Ebola-targeted, untargeted violence increases disease transmission in DRC outbreak
A time-series study of the ongoing Ebola virus disease outbreak in the Democratic Republic of the Congo showed that both Ebola-targeted and untargeted violence increased transmission of the disease, especially when civilians were involved, according to findings in The Journal of Infectious Diseases.
“Of the more than 36 recorded Ebola virus disease (EVD) outbreaks globally, the current 2018-2020 outbreak in eastern Democratic Republic of the Congo (DRC) is the first to occur in an active conflict zone, where responders have faced both widespread violence and active community resistance targeting their efforts,” John Daniel Kelly, MD, MPH, assistant professor of epidemiology and biostatistics at University of California, San Francisco’s School of Medicine, and colleagues wrote. “The current DRC outbreak, as WHO Director-General Tedros Adhanom Ghebreyesus, PhD, MSc, describes, is different: ‘We’re not just fighting Ebola virus; we’re fighting insecurity, violence, misinformation, mistrust and the politicization of an outbreak.’”
To determine the role of violence in EVD transmission, researchers used time-series data of case counts to compare individuals who lived in Ebola-affected health zones in the DRC from April 2018 to August 2019. According to the study, exposure was defined as the number of violent events per health zone. Health zones were categorized as "Ebola targeted" or "Ebola untargeted" and further as "civilian involvement," "militia/political” or “protests." Researchers then estimated the daily reproduction number (Rt) by health zone and fit a linear time-series regression to model the relationship.
Overall, the average Rt was 1.06 (95% CI, 1.02-1.11). According to the study, a mean of 2.92 violent events resulted in a cumulative absolute increase in Rt of 0.1 (95% CI, 0.05-0.15), therefore showing that more violent events increased EVD transmission (P = .03). Additionally, when the researchers considered violent events in the 95th percentile over a 21-day period, and its relative impact on Rt Ebola-targeted events, the study showed that Ebola-targeted events corresponded to an Rt of 1.52 (95% CI, 1.30-1.74), whereas civilian-involved events corresponded to an Rt of 1.43 (95% CI, 1.21-1.35). Untargeted events corresponded to an Rt of 1.18 (95% CI, 1.02-1.35); of these, militia/political, or “ville morte,” events increased transmission.
“The types of violence that we identified may have a role in subsequent outbreaks because this is not likely to be the last time that a disease outbreak occurs in a high-conflict setting where there are challenges to providing timely and effective care to afflicted communities,” the authors wrote. “Under these circumstances, EVD has the potential to become an endemic disease, and until appropriate strategies are developed and implemented to protect health workers, allay conflict and insecurity, protect civilians, and rebuild trust, many scholars predict this outbreak may continue for the foreseeable future while Ebola responders struggle to contain it.”