Nearly a year after the Ebola epidemic infected more than 28,000 people and killed more than 10,000, researchers identified 14 new cases of Ebola in an outbreak hotspot in Sierra Leone in individuals previously not known to have the virus. Twelve of these individuals reported experiencing no symptoms associated with Ebola when active transmission was ongoing in the village, according to a new study published in PLOS Neglected Tropical Diseases.
To determine whether an Ebola infection could be minimally symptomatic, researchers tested the blood of 187 villagers for antibodies created by the virus. Tested individuals had either lived in the same home or shared a toilet with someone with a confirmed Ebola infection. Of the 14 new cases identified out of the 187 tested, two reported having a fever during the time of the outbreak. Other symptoms associated with Ebola but not reported by the two newly identified symptomatic individuals include unexplained bleeding, headache, muscle pain, rash, vomiting, diarrhea, breathing problems and difficulty swallowing.
When combining these newly identified infections with the 34 previously confirmed cases, researchers established the possible rate of prevalence of minimally symptomatic infections in the village to be 25 percent. It's unclear if or how these individuals may have facilitated the transmission of the virus during the outbreak. However, some evidence suggests Ebola can be transmitted sexually as it can survive in semen for months after initial infection.
The evidence suggests public health efforts made to contain the virus and limit infections during the outbreak may not have been as effective as they could have been.
"It reminds us that we need to do a much, much better job in future epidemics," said Gene Richardson, MD, a former fellow in the division of infectious diseases and geographic medicine at Stanford (Calif.) University School of Medicine. "We expect to find a lot more undocumented survivors, so we can begin to answer the question of what was the true burden of disease.
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