A study was published on Nov. 15, 2016 by researchers from the Stanford University School of Medicine and other institutions that determined about 25% of individuals in a Sierra Leone village were infected with the Ebola virus but showed no symptoms. This finding supports previous suspicion that the virus does not cause severe disease to everyone it infects and suggests that the transmission of the virus may be greater than previously thought.
In the Sierra Leone village studied, there were 12 individuals who showed signs of being infected by the Ebola virus at some point, but had not shown any symptoms. This suggests that a significant number of people infected by this virus may have gone undetected and the virus spreads through more human-to-human transmission than we thought.
Gene Richardson, MD (lead author, former fellow in the Division of Infectious Diseases and Geographic Medicine at Stanford) and Paul Farmer, MD, PhD (Harvard professor and director of Partners in Health) conducted this research in a rural village of Sukudu, Sierra Leone. During the Ebola epidemic, more than 28,000 Ebola infection cases were reported in Africa, with an estimated 11,000 deaths due to the disease. Sukudu village was one of the three hot spots in the eastern part of the country during the outbreak in 2014-2015. Richardson and others returned to the village to see whether the Ebola infection could in fact be minimally symptomatic and gathered data with local physicians and community health workers.
The ELISA assay was used to detect the presence of an antibody and recruited 187 men, women, and children likely to have had been exposed to the virus. 14 people were found to carry antibodies to Ebola, and of those 14, 12 had no symptoms of the disease (usually fever, unexplained bleeding, headache, muscle pain, rash, vomiting, diarrhea, breathing problems, difficulty swallowing).
Richardson suggested that public health efforts could use improvement during virus epidemics when trying to prevent infection and contain the virus. He is now working with other villages in Sierra Leone that had poor public health surveillance with the hopes to improve efforts for future epidemics.
Read article here: http://med.stanford.edu/news/all-news/2016/11/study-finds-people-with-ebola-may-not-always-show-symptoms.html