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Background: Ebola virus has been detected in the semen of men after their recovery from Ebola virus disease (EVD). We report the presence of Ebola virus RNA in semen in a cohort of survivors of EVD in Sierra Leone., Methods: We enrolled a convenience sample of 220 adult male survivors of EVD in Sierra Leone, at various times after discharge from an Ebola treatment unit (ETU), in two phases (100 participants were in phase 1, and 120 in phase 2). Semen specimens obtained at baseline were tested by means of a quantitative reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay with the use of the target sequences of NP and VP40 (in phase 1) or NP and GP (in phase 2). This study did not evaluate directly the risk of sexual transmission of EVD., Results: Of 210 participants who provided an initial semen specimen for analysis, 57 (27%) had positive results on quantitative RT-PCR. Ebola virus RNA was detected in the semen of all 7 men with a specimen obtained within 3 months after ETU discharge, in 26 of 42 (62%) with a specimen obtained at 4 to 6 months, in 15 of 60 (25%) with a specimen obtained at 7 to 9 months, in 4 of 26 (15%) with a specimen obtained at 10 to 12 months, in 4 of 38 (11%) with a specimen obtained at 13 to 15 months, in 1 of 25 (4%) with a specimen obtained at 16 to 18 months, and in no men with a specimen obtained at 19 months or later. Among the 46 participants with a positive result in phase 1, the median baseline cycle-threshold values (higher values indicate lower RNA values) for the NP and VP40 targets were lower within 3 months after ETU discharge (32.4 and 31.3, respectively; in 7 men) than at 4 to 6 months (34.3 and 33.1; in 25), at 7 to 9 months (37.4 and 36.6; in 13), and at 10 to 12 months (37.7 and 36.9; in 1). In phase 2, a total of 11 participants had positive results for NP and GP targets (samples obtained at 4.1 to 15.7 months after ETU discharge); cycle-threshold values ranged from 32.7 to 38.0 for NP and from 31.1 to 37.7 for GP., Conclusions: These data showed the long-term presence of Ebola virus RNA in semen and declining persistence with increasing time after ETU discharge. (Funded by the World Health Organization and others.).

The prevalence of Plasmodium falciparum in a cohort of over 900 nought to seven-year-old children living in a rural area of Sierra Leone was found to be approximately 61%, both before and after the rainy season. Plasmodium malariae rates measured in the same children were approximately 12%, and P. ovale rates averaged about 1%. Spleen rates averaged 44% for the two surveys; the age prevalence spleen profiles closely matched those for P. falciparum. The overall gametocyte rates for both P. falciparum and P. malariae were roughly one fifth of the prevalence rates for the asexual parasites. However, whilst there was no difference between the P. falciparum gametocyte rates at the two surveys, the P. malariae rate was significantly higher post-rains when compared with the pre-rains result. Spleen size did not increase with increased parasite density. There was a statistically significant difference between the geometric mean P. falciparum trophozoite densities of febrile and afebrile children both before and after the rainy season, but there was little seasonal difference in the means for the febrile children or in those for the afebrile children. Antimalaria antibody levels, measured by ELISA and IFAT, showed no significant differences at either survey. The levels found were high for all age groups, indicating that exposure to malaria begins at birth. Our results indicate that, in the area studied, malaria is hyperendemic and is probably transmitted perennially.