This article is more than 5 years old. Information may no longer be current.
EVD cases from impoverished areas more likely to transmit infection
Individuals with Ebola virus disease residing in the most impoverished areas of Liberia were three times more likely to transmit infection compared with those from higher socioeconomic communities, according to recent data.
“In Liberia’s capital city Monrovia, approximately 68% of the population occupies slum neighborhoods characterized by overcrowding and lacking sanitation — conditions conductive to outbreaks of infectious disease,” Mosoka P. Fallah, PhD, MPH, researcher at Liberia’s Ministry of Health, and colleagues wrote. “Cases from low and middle [socioeconomic status (SES)] areas reported significantly more contacts during their symptomatic and therefore infectious periods than cases from high SES areas. Overcrowding and a lack of education on how the disease is transmitted could explain the observed differences in the number of secondary cases.”
The researchers examined data on 3,532 individuals with suspected, probable or confirmed EVD from low, middle and high SES areas of Montserrado County, Liberia, between Feb. 28, 2014 and Dec. 1, 2014. They used a model integrating Ebola disease progression and contact data to project transmission among the community types. Since contact behavior was expected to change during the epidemic, 2,500 confirmed and probable cases of EVD with symptom onset ranging from July to November — when Ebola transmission was at its peak — were further evaluated to estimate the likelihood of individual transmission over the course of an incubation period.
On average, the number of case patients from low SES areas had three additional contacts compared with cases residing in high SES areas (10.31 vs. 7.41; P < .001). Overall, EVD cases from middle and low SES communities were 1.5 (95% CI, 1.4-1.6) and 3.5 (95% CI, 3.1-3.9) times more likely to transmit infection vs. those from high SES communities.
While the majority of EVD cases from high SES communities transmitted the virus to residents from the same area, only one-third of individuals from low SES communities spread disease to those also from low SES areas.
“We found that infected individuals who were residents of low SES communities were more likely to export Ebola to other SES communities than infected individuals within higher SES communities,” Fallah and colleagues wrote. “Thus, not only were low SES communities disease hotspots, but they were also catalysts of spread throughout Monrovia.”
The researchers hypothesized that individuals from low SES communities may have spread infection to other areas while traveling for employment opportunities. However, they found no significant differences in the number of deaths reported, the amount of patients seeking care nor the time from symptom onset to hospitalization between the SES groups.
Fallah and colleagues concluded that the findings underscore the need to target impoverished areas through community-driven efforts.
“Despite the lack of infrastructure in Liberia’s urban slums, strong social networks exist,” they wrote. “These networks afford opportunities for grassroots efforts to effectively engage community members in combating infectious disease.” – by Stephanie Viguers
Disclosure: The researchers report no relevant financial disclosures.