Types and seasonal diversity of helminth eggs in wastewater used for peri-urban vegetable crop production in tamale metropolis, Ghana

Thirteen (13) different types of helminths were identified for both the wet and dry seasons with the dry season recording eight (8) different helminths and the wet season recording nine (9) different helminths. The typical fertile Ascaris lumbricoides and Strongyloides stercoralis as well as Schistosoma mansoni were observed to be the most predominant types of helminths in both seasons and this may be due to their environmental tolerance and resistance. Ascaris lumbricoides was the most predominant species recorded with arithmetic mean population of 12 and 17 for wet and dry season respectively. Exceeded the recommended level of <1 egg/liter for unrestricted irrigation (WHO, 1989). Variable concentrations of helminth eggs were recorded for the dry season and wet season for the period of study. During the current study, all the recorded helminths were noted to have a population density ranging from 2 to 17 eggs with a coefficient of variation being between 0 and 85%. Commonly observed dominant species of Ascaris lumbricoides and Strongyloides stercoralis for both seasons, a higher dominance index of 0.58 for the wet season was recorded compared to 0.52 for the dry season. Also, environmental factors such as temperature, sunshine amount and duration, rainfall, etc have been noted to impact greatly on the occurrence and concentration of helminth eggs in wastewater of a particular locality. These were noted to have contributed largely to a high number of helminth eggs in the wet season as compared to the dry season.