NEW YORK — As the global health community ramps up its efforts to treat Ebola patients and curb its spread in West Africa, a new analysis finds that the greatest impact would come from insuring safe burials for victims, scientists reported on Thursday.
The need for safe burials has been known from the beginning of the epidemic last spring, when people who attended the funeral of a faith healer in Guinea became infected.
U.S. guidelines call for workers wearing full protective gear to wrap the remains of Ebola victims, which have an extremely high concentration of the virus, in a plastic shroud and then place them in two body bags. The body should not be washed or handled in any way, something that has been a common practice in much of West Africa.
The new findings, published in the journal Science, are based on a mathematical model being developed by Ebola researchers at Yale School of Public Health.
It takes into account data from the current outbreak and previous ones, including how long people harbor the virus before becoming ill, how long they are infectious, and what percentage are isolated at home or in a treatment center.
Similar models have already informed public policy. A U.S. projection that there could be 1.4 million cases in Liberia and Sierra Leone by late January spurred Western nations to commit more funds and personnel to curb the worst Ebola outbreak since the disease was identified in 1976.
The Yale model calculates the spread of Ebola in the community, in hospitals and at funerals, including how many secondary cases are caused by the average case in each setting.
If transmission in the community or in hospitals could be eliminated through better isolation practices, Yale’s Alison Galvani and her colleagues found, each Ebola case would still cause 1.4 or 1.5 additional infections.
But if transmission via burial practices were eliminated, the secondary infection rate would drop below one per Ebola case, the sole way epidemics peter out.
“Reducing transmission in hospitals and the community is insufficient to stop the exponentially growing epidemic,” the scientists wrote. The most effective intervention is halting burial practices in which mourners handle bodies, which “are effectively serving as superspreader events.”
Because making all Ebola burials sanitary might not be feasible, Yale’s Martial Ndeffo-Mbah said, the Ebola response must also continue to isolate cases.
Other modelers predicted the study’s emphasis on funerals would be “quite controversial,” according to biostatistician Ira Longini of the University of Florida.
Longini and colleagues at Northeastern University created a mathematical model that shows that most Ebola transmission occurs in the community and within households, so isolating patients would have the most effect on the epidemic.
Still, “Liberia has concentrated hard on the funeral problems,” Longini said, and is now seeing fewer new cases than in recent weeks.