rs79.vrx.palo-alto.ca.us

2000 Gonzales

2010-Becquart

2010-IRD

2014 NYTimes

2015 BBC

2016 Richardson

2018 US-Army

2000 Gonzales Ebola and Marburg virus antibody prevalence in selected populations of the Central African Republic "Our present study done in human populations living in forested areas of CAR has bought to the fore two main observations: 1/active circulation of filovirus without apparent clinical manifestations 2/ potential association of filovirus infection and a specific lifestyle" 2010-Becquart High Prevalence of Both Humoral and Cellular Immunity to Zaire ebolavirus among Rural Populations in Gabon PDF Abstract "To better understand Zaire ebolavirus (ZEBOV) circulation and transmission to humans, we conducted a large serological survey of rural populations in Gabon, a country characterized by both epidemic and non epidemic regions. The survey lasted three years and covered 4,349 individuals from 220 randomly selected villages, representing 10.7% of all villages in Gabon. Using a sensitive and specific ELISA method, we found a ZEBOV-specific IgG seroprevalence of 15.3% overall, the highest ever reported. The seroprevalence rate was significantly higher in forested areas (19.4%) than in other ecosystems, namely grassland (12.4%), savannah (10.5%), and lakeland (2.7%). No other risk factors for seropositivity were found. The specificity of anti-ZEBOV IgG was confirmed by Western blot in 138 individuals, and CD8 T cells from seven IgG+ individuals were shown to produce IFN-γ after ZEBOV stimulation. Together, these findings show that a large fraction of the human population living in forested areas of Gabon has both humoral and cellular immunity to ZEBOV. In the absence of identified risk factors, the high prevalence of “immune” persons suggests a common source of human exposure such as fruits contaminated by bat saliva. These findings provide significant new insights into ZEBOV circulation and human exposure, and raise important questions as to the human pathogenicity of ZEBOV and the existence of natural protective immunization." 2010-IRD A surprisingly high proportion of the Gabonese population could have immunity against Ebola. Antibodies to the virus were found in 15.3% of rural communities Covers the PLOS paper. "A surprisingly high proportion of the Gabonese population could have immunity against Ebola. Antibodies to the virus were found in 15.3% of rural communities, whereas these people had never had haemorrhagic fever or other specific symptoms of the disease (such as severe diarrhea or vomiting). IRD researchers and their partners 1 recently discovered this large number of healthy carriers among Gabonese people, even in areas where there has never been an Ebola outbreak. The scientists consider that these people have somehow come into contact with the virus, probably present in fruit contaminated by saliva from Chiroptera (fruit bats) " 2014 NYTimes Many in West Africa May Be Immune to Ebola Virus Covers the PLOS paper. "Although few medical experts realize it, part of the population in West Africa is immune to the Ebola virus, according to virologists who specialize in the disease. Assuming they are correct, and if those people can be identified, they could be a great help in fighting the outbreak. Immune persons could safely tend the sick and bury the dead just as smallpox survivors did in the centuries before smallpox vaccine. Also, antibodies could be harvested from their blood to treat new Ebola victims."

2015 BBC "We've now seen several cases that don't have any symptoms at all, asymptomatic cases," But Prof Jonathan Ball, a virologist at the University of Nottingham, says it's still unclear whether more people are actually not showing symptoms in this outbreak compared with previous ones. "We know asymptomatic infections occur… but whether we are seeing more of it in the current outbreak is difficult to ascertain," he said. 2016 Richardson "The phenomenon of previously undetected, minimally symptomatic EBOV infection was evident around the discovery of the virus in 1976." Minimally Symptomatic Infection in an Ebola ‘Hotspot’: A Cross-Sectional Serosurvey 'Some of the “true negatives” used for the validation of our ELISA assays could have been infected with EBOV' "The findings provide further evidence that Ebola, like many other viral infections, presents with a spectrum of clinical manifestations, including minimally symptomatic infection. These data also suggest that a significant portion of Ebola transmission events may have gone undetected during the outbreak." 2018 US-Army However, results of most of these surveys are puzzling. In some surveys, the seroprevalence of anti-EBOV antibodies is extremely high (>5%–20%) in humans indicating frequent exposure to EBOV or related agents in the absence of disease. Without convincing data for any of these possibilities, serosurvey data should not be ignored, but they should be used with caution for prediction of filovirus distribution or infection risk assessments.