Reduction of testosterone levels in Schistosoma haematobium- or Schistosoma mansoni-infected men: a cross-sectional study in two schistosomiasis-endemic areas of the Adamawa region of Cameroon.

Background: The incidence of schistosomiasis-induced male reproductive dysfunction and infertility is probably underestimated compared to female genital schistosomiasis. This study aimed to investigate the impact of Schistosoma haematobium or S. mansoni infection on the reproductive function of men of reproductive age in Tibati and Wouldé, two endemic schistosomiasis areas in the Adamawa region of Cameroon.

Methods: A total of 89 men of reproductive age (range 14-56 years) from two localities were enrolled in the study, with 51 in Tibati and 38 in Wouldé. Each participant was submitted to a questionnaire to document data on sociodemographic and stream contact behaviors. A medical examination was performed to measure the testes' circumference and evaluate genital tract pathologies. Stool and urine samples were collected and screened for the presence of S. haematobium or S. mansoni ova. Blood serum was used to assess the levels of transaminases and testosterone.

Results: Schistosoma haematobium was present only in Tibati, with a prevalence of 31.37%. The S. mansoni prevalence was 3.92% at Tibati and 44.71% at Wouldé. The intensity of infection was 22.12 ± 9.57 eggs/10 mL for S. haematobium and 128.10 ± 3.76 epg for S. mansoni. Serum transaminase activity and the mean testicular circumference of Schistosoma-positive individuals were close to Schistosoma-negative individuals. However, the testes size was more prominent in S. mansoni-positive individuals than in S. haematobium-positive individuals (P < 0.05). The serum testosterone levels of S. haematobium- and S. mansoni-positive men were significantly reduced by 56.07% (P < 0.001) and 51.94% (P < 0.01), respectively, in comparison to those of Schistosoma-negative men. A significant and negative correlation was established between schistosomiasis and the low serum testosterone level. Male genital tract pathologies such as scrotal abnormalities, varicocele, nodular epididymis, inguinal hernia, and hydrocele were recorded in both Schistosoma-positive and Schistosoma-negative men. However, no significant link was established between schistosomiasis infection and these pathologies.

Conclusion: These results demonstrated that infection with S. haematobium or S. mansoni is associated with low production of the reproductive hormone testosterone and may be a significant cause of male infertility.