A systematic review and meta-analysis of seroprevalence surveys of Ebola Virus infection
In the past, several cases of asymptomatic Ebola Virus Disease (EVD) were reported during or after outbreaks. It remains uncertain as to how critical asymptomatic EVD is to the general transmission of EVD and its prevalence.
A meta-analysis of fifty-one studies (84 population samples) was carried out to compile all cases under a standardized definition of ‘asymptomatic Ebola Virus Disease infection’ for better understanding of the Ebola virus transmission. To rule out test negative Ebola virus from asymptomatic EVD, diagnostic tests using IgG (antibody) measures (ex. IFA and ELISA) were carried out to determine seropositivity (presence in the blood serum). Limitations arose from the varying levels of threshold of the seropositivity reported, which ultimately affects the study results as diagnosis wouldn’t have been standardized throughout the compiled reports.
No categorization of the Ebola virus strains was reported and the study included reports from Ebola virus outbreaks between 1976 and 2015. It is a challenge to interpret this data due to the high degree of heterogeneity in the samples examined and unscripted exposure levels in the reports.