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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/7954

Title: Cryptosporidium SPP contamination and risk associated with the irrigation of lettuce with contaminated water in the Kumasi Metropolis of Ghana
Authors: Sampson, Ewusiwaa Angelina
Issue Date: 2-Nov-2015
Abstract: Cryptosporidium is a protozoan parasite which can be transmitted via food and water. Some studies have shown irrigation water to be routes of transmission for Cryptosporidium into the food chain, however, little information is known about Cryptosporidium levels in water used for irrigation in the Kumasi Metropolis. The purpose of this study was to evaluate Cryptosporidium contamination and risk associated with the irrigation of lettuce with contaminated water in the Kumasi Metropolis of Ghana. The study considered Cryptosporidium detection and enumeration in water and on lettuce samples using light microscopy, fluorescent microscopy and molecular identification using nested polymerase chain reaction (PCR). A total of 54.10% of all water samples tested positive by using microscopy or nested PCR (HSP70) approach. A comparative assessment for microscopy and nested PCR (HSP70) showed that 37.5% of all water samples were positive for Cryptosporidium using microscopy whilst 41.67% showed positive presence using nested PCR approach. The study revealed that water samples from irrigation water contaminated with hospital waste upstream had the highest number of oocyst with a total of 263.15±0.92 oocysts /10 L on all rounds of sampling. Water contaminated with effluent from a waste stabilization pond had no detectable number of oocysts on all rounds of sampling. All irrigation water with the exception of water contaminated with effluent from a waste stabilization pond exceeded the recommendation of WHO/FAO for protozoan parasites (1 egg/L); however, there was no statistical difference between oocysts counts from the various water samples from the farms. Temperature had an inverse relationship with oocyst concentration from the farms whilst pH and turbidity had no significant relationship with oocyst concentration. Molecular detection of Cryptosporidium using nested PCR (HSP70) showed that 50.00% of all lettuce iv samples analysed were positive for Cryptosporidium. Risk analysis indicated that all water sources for irrigation posed risk as possible sources of human infection through direct contact with these water sources. The risk was higher than the WHO accepted threshold of threshold. However, risk analysed using the E. coli conversion for Cryptosporidium distribution resulted in an underestimation of risk. Based on the risk assessment, measures should be put in place to reduce pathogen concentration in water sources in order to reduce risk posed to farmers.
Description: A Thesis submitted to the Department of Biochemistry and Biotechnology, College of Science, in partial fulfilment of the requirements for Master of Philosophy degree in Biochemistry, 2015
URI: http://hdl.handle.net/123456789/7954
Appears in Collections:College of Science

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