Surveillance of microbial pathogens in the Umgeni River, Durban South Africa.
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Date
2013
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Abstract
This study assessed the quality of the Umgeni River in Durban South Africa seasonally from March 2011
to January 2012, according to standard protocol. Water samples were collected from Inanda dam-U5,
KrantzKloof Nature Reserve-U4, New Germany-U3, Reservoir Hills –U2 and River mouth – U1 areas of
the Umgeni River. A two-step tangential flow filtration (TFF) process was setup for the concentration of
viruses from water samples. Virus like particles (VLPs) was detected using electron microscopy.
Canonical correspondence analysis (CCA) was used to statistically evaluate the data sets. All water
samples had turbidity values which exceeded the South African water quality guideline value of 0.1 NTU
for turbidity. Large seasonal variations in BOD5, COD and conductivity levels were observed. Chloride
concentrations were extremely high at point U1 (19234 mg/ℓ) Cl during summer. Total heterotrophic
bacterial (THB) population was highest at 13.67 x 106 cfu/100ml (U1 – summer). Enterococci (EC)
concentrations were detected at points U1, U2, U3, and U4 during the autumn and spring period. pH,
electrical conductivity, temperature, and turbidity positively correlated with the microbial communities,
and were the key parameters responsible for water pollution according to CCA. Most water samples
contained high populations of somatic (659 pfu/mℓ, U1 – summer) and F-RNA coliphages (550 pfu/mℓ,
U2 – summer). VLPs were detected throughout all seasons, with point U1 (summer) having the highest
population of 2086 VLP/mℓ. Several presumptive viruses including Adenoviridae, Picornaviridae,
Poxviridae, and Reoviridae were detected based on their morphologies. Six cell culture lines were used to
determine cytopathic effect (CPE) of the VLPs. VLP samples produced CPEs on the Vero, Hek 293,
Hela and A549 cell lines. Integrated cell culture (ICC) - PCR confirmed the presence of infectious VLPs
in the river water samples. Adenoviruses, Enteroviruses, rotaviruses and Hepatitis B viruses were
detected and quantified in all water samples by nested PCR/RT-PCR and Real-Time PCR respectively,
against positive control viruses. These results indicate the potential of viruses in the water samples
especially from the lower catchment areas to infect the human hosts throughout the year. These
observations have public health care implications and establish a need to monitor the viral population in
addition to traditional water quality indicators.
Description
Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2013.
Keywords
Water quality--KwaZulu-Natal--Umgeni River., Water quality biological assessment--KwaZulu-Natal--Umgeni River., Viruses--KwaZulu-Natal--Umgeni River--Etiology., Theses--Microbiology.