Chiemela Chidozie OKORO

Acanthamoeba species are free-living protozoa commonly found in water sources and are recognized causes of Acanthamoeba keratitis, particularly among contact lens wearers. Reticulated bore-hole water is widely used in many communities, yet data on its contamination with Acanthamoeba and the effectiveness of multipurpose contact lens solutions against these organisms remain limited. This study investigated the prevalence and species distribution of Acanthamoeba in reticulated bore-hole water and evaluated the efficacy of selected multipurpose contact lens solutions in reducing Acanthamoeba counts. A total of 36 reticulated bore-hole water samples were collected and cultured for Acanthamoeba species using standard parasitological techniques. For Acanthamoeba detection, 500ml of water was passed through a 0.45µm cellulose nitrate membrane filter. Prepared non-nutrient agar plates were seeded with heat-killed Escherichia coli. Cultures were incubated at 32ºC for Amoebic growth and examined microscopically. Isolates were identified based on morphological characteristics of trophozoite and cyst stages. The effects of three multipurpose contact lens solutions—FreesolTM, RefreshTM, and FreshlookTM—on Acanthamoeba counts were assessed. Data were analyzed using one-way analysis of variance (ANOVA) followed by Duncan’s multiple range test, with statistical significance set at p < 0.05. Acanthamoeba species were detected in 32 (88.9%) of the water samples, yielding a total of 209 isolates and a mean intensity of 6.53 detections per positive sample. Ten species were identified, with Acanthamoeba royreba showing the highest prevalence (17.7%), followed by A. polyphaga (11.96%), A. lenticulata and A. mauritaniensis (11.0% each). All contact lens solutions significantly reduced Acanthamoeba counts compared with pre-treatment levels (p < 0.05). Freesol achieved the greatest reduction (98 ± 9.5), followed by Refresh (101 ± 12.5), while Freshlook showed the least reduction (170 ± 22.0). None of the solutions completely eliminated Acanthamoeba. This study showed that reticulated bore-hole water harbored a high prevalence of potentially pathogenic Acanthamoeba species. Although multipurpose contact lens solutions significantly reduce Acanthamoeba burden, complete elimination was not achieved, highlighting the organism’s resistance and the continued risk of exposure. Strict adherence to proper contact lens hygiene and avoidance of bore-hole water use are essential to reduce the risk of Acanthamoeba infection.

Acanthamoeba, a free-living Amoeba commonly found in water, a category of protozoans which are pervasive and can be found in diverse environments, including, sewage water, air, soil, dust, and sediments. One of the vital issues in water pollution is the occurrence of pathogenic amoebae in tap or drinking water. The aim of the study was to compare the detection of canthamoeba from borehole water source and tap water in Egor Local Government within Benin metropolis using two methods. This observational, prospective cross-sectional study collected 52 water samples from various locations within the Egor Local Government Area (26 samples each from bore-hole water source and tap water). Samples were processed on the same day of collection. For Acanthamoeba detection, 500 mL of water sample was passed through a 0.45 μm cellulose nitrate membrane filter. Prepared nonnutrient agar plates were seeded with heat-killed Escherichia coli. Cultures were incubated at 30℃ for amoebic growth and examined microsopically. The study also employed centrifugation, and sediments were microscopically viewed under iodine-stained slides. Results showed a significant difference in the occurrence of Acanthamoeba species (p = 0.007) in bore-hole water and tap water when using the culturing method. However, there was no significant difference (p = 0.277) between samples of bore-hole water and tap water obtained through centrifugation. This suggests that an isolation method can influence the detection of Acanthamoeba species. This research highlights the substantial prevalence of Acanthamoeba species in bore-hole water sources within Benin City, with potential implications for water quality and safety. The discrepancy in results between culture and centrifugation methods underscores the need for careful consideration when choosing a detection method. The high prevalence of Acanthamoeba in bore-hole water may have a link to the nature of the water facility. Further studies are necessary to investigate the reasons behind the methodological differences and their implications for water quality and safety in Benin City.