Background: Emerging infectious diseases in wildlife are major threats to both human health and biodiversity conservation. Infectious diseases can have serious consequences for the genetic diversity of populations, which could enhance the species’ extinction probability. The Ebola epizootic in western and central Africa induced more than 90% mortality in the Western lowland gorilla population. Although mortality rates are very high, the impacts of Ebola on the genetic diversity of Western lowland gorillas have never been assessed.
Methodology/Principal Findings: We carried out long-term studies of three populations of Western lowland gorillas in the Republic of the Congo (Odzala-Kokoua National Park, Lossi gorilla sanctuary both affected by Ebola and Lossi’s periphery not affected). Using 17 microsatellite loci, we compared the genetic diversity and structure of the populations and estimate their effective size before and after Ebola outbreaks. Despite the effective size decline in both populations, we did not detect loss in genetic diversity after the epizootic. We revealed temporal changes in allele frequencies in the smallest population.
Conclusions/Significance: Immigration and the short time elapsed since outbreaks could explain the conservation of genetic diversity after the demographic crash. Temporal changes in allele frequencies could not be explained by genetic drift or random sampling. Immigration from genetically differentiated populations and nonrandom mortality induced by Ebola, i.e., selective pressure and cost of sociality, are alternative hypotheses. Understanding the influence of Ebola on gorilla genetic dynamics is of paramount importance for human health, primate evolution, and conservation biology.
