Community surveys of the prevalence, distribution, and coinfection of helminth and protozoan infections in semiurban and rural areas of Gabon, Central Africa

BACKGROUND: Protozoa and helminths cause significant morbidity and mortality, particularly in tropical and subtropical regions where an accurate understanding of their epidemiological profile is needed to improve their control. In Gabon, a country endemic for a diverse range of both helminths and protozoa, epidemiological data for protozoa are lacking, whereas updated data for helminths are needed. This study aimed to describe the distribution of helminth and protozoan infections in the Moyen-Ogooué province of Gabon. METHODS: This cross-sectional study included individuals aged one year and older living in the study areas for at least one year. The participants were selected via a stratified sampling procedure. Blood, urine, and stool samples, along with sociodemographic data, were collected. Soil-transmitted helminths (STHs) were diagnosed using the Kato-Katz, coproculture and Harada-Mori techniques. Urogenital schistosomiasis was diagnosed using the urine filtration technique. Intestinal protozoa were diagnosed using the mercurothiolate-iodine-formol technique. Plasmodium spp. and filarial infections were diagnosed by thick blood smear microscopy, and, in addition for filaria, by leucoconcentration technique. RESULTS: A total of 1,084 participants were included, with a mean age of 31.6 years (SD: 23.6) and a female-to-male sex ratio of 1.15. The overall prevalence of helminth infections was 36% (95%IC: 33-39), with STHs being most common (21%; 95%CI: 18-23), followed by schistosomiasis (11%; 95%CI: 8 - 13) and filariasis (9%; 95%CI: 7-10). The most prevalent STH species were Trichuris trichiura (11%; 95%CI: 10-14), followed by hookworm (9%; 95%CI: 8-11). The prevalence of Plasmodium spp. was 13% (95%CI: 11-15), and the overall prevalence of intestinal protozoa was 28% (95%CI: 25-31), with Blastocystis hominis (11%; 95%CI: 9-13) and Entamoeba coli (8%; 95%CI: 7-10) being the most common intestinal protozoan species. Coinfections with multiple parasite species were observed in 42% of the infected participants, predominantly involving T. trichiura, Schistosoma haematobium, and Plasmodium spp. infection prevalence varied with age, gender, location, and occupation. CONCLUSION: This study reveals a moderate prevalence of helminths and protozoa in our community, with age, gender, and location playing a significant role in their distribution, as do common coinfections between helminths and protozoa. These findings call for further research to provide valuable insights for controlling helminth transmission in the region.