Public Health Implication of Drinking Water Sources Contaminated with Giardia and Cryptosporidium in South Ethiopia

Abstract Background: The concept of health is largely tied up with the quality of the ambient environment of human. There is a need to minimize the risks of environment to public health and comply with microbial contamination legislation stipulated by respective regulatory bodies. Though water borne protozoa are leading causes of diseases in socio-economically disadvantaged areas, less information is available about drinking water quality and its implication to the public. The present study aimed at characterizing the risks of Giardia and Cryptosporidium from water sources in southern Ethiopia.Methods: Twenty-one drinking water samples (10L per source) were collected from five different types of water sources. Sample analysis was performed using immunofluorescence assay (IFA) with fluorescein isothiocyanate–monoclonal antibodies and nested PCR with tpi, SSU-rRNA and gp60 loci of the parasites. Statistical analysis was performed using Spearman’s rho correlation and independent-samples nonparametric test.The risk was characterized using quantitative microbial risk assessment. Results: The IFA and genotyping assays overall showed that Giardia was detected in 81% (17/21) of the samples with a mean concentration of 64.6 cysts.10 L-1 and Cryptosporidium in 71% (15/21) with a mean concentration of 62.8 oocysts.10 L-1. Out of the 17 Giardia positive water sources, Giardia duodenalis (assemblage B) was detected in 29.4%, assemblage A in 17.6% and assemblages A+B in 52.9% of the sources. Likewise, Cryptosporidium genotype was detected in 57.1% (12/21) of the sources; C. parvum in 38.1% (8/21) and C. hominis in 14.3% (3/21) of the sources. The average probability of illness from the water sources was 0.06 for Giardia and 0.22 for Cryptosporidium.Conclusions: The present finding highlights the significance of water for transmission of Giardia and Cryptosporidium in southern Ethiopia. Genotypes detected in the water sources indicate that multiple sources likely contaminated the drinking water sources. The health risks that are inferred from the water sources to the public are significantly higher than most other reported findings. This study recommends the need of regular follow-up, improvement in water treatment facilities and setting appropriate legislation in areas where cycles of parasitic infection is linked to water sources.