Excerpt from PubMed Abstract: "...Seroepidemiological surveys were conducted to determine the frequency and distribution of filovirus activity among selected ethnic groups inhabiting the tropical forests of the Central African Republic. 427 serum specimens were collected from hunter-gatherers and subsistence farmers living in forest environs in the Lobaye District south of the river Lobaye and west of the river Oubangui. Striking serological evidence for filovirus activity was found in both populations. Ebola virus appears to be the most active filovirus; 17.6% (75/427) of the Lobaye survey population were seropositive for Ebola virus reactive antibody while 1.2% (5/427) were seroreactive with Marburg viral antigens. Ethnic background appeared to be an important risk factor influencing filovirus exposure in the forest communities. The filovirus antibody prevalence among 21-40 years old male Aka Pygmy hunter-gatherers was significantly (P = 0.03) 3 times higher (37.5%) than that in similarly aged male Monzombo and Mbati subsistence farmers (13.2%). Continued epidemiological investigations are needed to define ethnic-related events influencing human filovirus activity in the Congo basin of equatorial Africa..."