Removal of Escherichia coli in treated wastewater used for food production in Morogoro, Tanzania

Acadmic Journal Vol. 10(33), pp. 1344-1350The aim of this study was to assess the removal efficiency of Escherichia coli at Mafisa and Mzumbe domestic wastewater treatment ponds in Morogoro, Tanzania. The study was done from October, 2013 to April, 2014. A total of 125 water samples from inlets and subsequent anaerobic, facultative and maturation ponds as well as treated wastewater were collected and analysed for E. coli. The estimated retention times of the wastewater treatment units were 19 and 22 days in Mafisa and Mzumbe ponds, respectively. The concentration of E. coli ranged from 4.70 to 5.60 log cfu/mL in untreated wastewater and was reduced to <1.00 to 2.00 log cfu/mL in the treated wastewater. During rainy and cold seasons, the effluent discharged out at Mafisa during August 2013; and March and April, 2014 was about 2 log cfu/mL while at Mzumbe E. coli concentration in effluent discharged out was up to 1.23 log cfu/mL. The concentration of E. coli in untreated and treated wastewater from the two wastewater treatment ponds study sites were comparable (P<0.05). Reduction of E. coli concentration in wastewater treatment ponds study sites was significant with less reduction seen at Mafisa, during rainy and cold seasons in March, April and August. To conclude, the simple wastewater treatment ponds in the study sites were effective and demonstrated potential for reduction of public health risks associated with use of treated wastewater in agricultural irrigation and aquaculture

Investigation of bacterial hazards in low quality water used for food production in urban and peri-urban areas of Morogoro, Tanzania

PhD ThesisIn Sub Saharan African countries, there is no or limited information on use of low quality water (LQW), hazards in foodstuffs produced using LQW and their associated health risks to humans, animals and the environment. The objective of this study was to investigate faecal bacterial hazards on low quality water; and foodstuffs produced using LQW in Morogoro, Tanzania. This study assessed the extent of E. coli; antimicrobial resistance (AMR) and virulence genes in Extended Spectrum beta lactamase (ESBL) producing strains; and Salmonella spp. contamination in LQW, tilapia and Chinese cabbage (Brassica rapa L. chinensis) irrigated using LQW. The 3M Petrifilm Select E. coli plates were used for enumeration and isolation of E. coli and ESBL producing E. coli at 44.4oC. Isolation of Salmonella spp. was done as per ISO 6579:2002 (E) and its amendment of 2007, followed by; Pulsed Field Gel Electrophoresis (PFGE), genotyping, serotyping and antimicrobial susceptibility testing (AST). Levels of E. coli, ESBL producing E. coli and Salmonella spp. in wastewater were reduced from 5 - <1 log cfu/mL 4 - 0 log cfu/mL and 40 - <400 to <0.04 cfu/mL, respectively, following treatment in wastewater ponds. The ESBL producing E. coli isolates showed broad range of AMR genes in beta- and non-beta lactams antimicrobials including blaCTX-M1, blaCTX-M15, blaOXA-1; aac6, aadA4, aac6Ib, strA, strB; dfrA19, dfrA17, dfrA7; catA1, catB3; qnrA; sul1, sul2; tetA, tetB; and mphA, mrx; virulence genes (hemL, iss, tir, iha, sat, senB); 13 Salmonella serovars including S. Kentucky, S. Chandans, S. Durban and S. Kiambu from LQW and tilapia. Occurrence of E. coli in fish flesh from wastewater was 0.05% and in Mindu dam was 0%; while, in Chinese cabbage irrigated with river water was 86% and in treated wastewater was 10%. The concentration of E. coli in Morogoro river water was higher than the treated wastewater. Tilapia grown in wastewater treatment ponds and vegetables irrigated by treated wastewater were of good quality for human consumption. The quality of treated wastewater from the study sites complied with the WHO/FAO guidelines (1000 cfu/100 mL faecal coliforms) and can be recommended for use on food production.Danish International Development Assistance (DANIDA) Safe Water for Food (SaWaFo) project (Project Code: 11-058DHI

Investigation of bacterial hazards in low quality water used for food production in urban and peri-urban areas of Morogoro, Tanzania

PhD ThesisIn Sub Saharan African countries, there is no or limited information on use of low quality water (LQW), hazards in foodstuffs produced using LQW and their associated health risks to humans, animals and the environment. The objective of this study was to investigate faecal bacterial hazards on low quality water; and foodstuffs produced using LQW in Morogoro, Tanzania. This study assessed the extent of E. coli; antimicrobial resistance (AMR) and virulence genes in Extended Spectrum beta lactamase (ESBL) producing strains; and Salmonella spp. contamination in LQW, tilapia and Chinese cabbage (Brassica rapa L. chinensis) irrigated using LQW. The 3M Petrifilm Select E. coli plates were used for enumeration and isolation of E. coli and ESBL producing E. coli at 44.4oC. Isolation of Salmonella spp. was done as per ISO 6579:2002 (E) and its amendment of 2007, followed by; Pulsed Field Gel Electrophoresis (PFGE), genotyping, serotyping and antimicrobial susceptibility testing (AST). Levels of E. coli, ESBL producing E. coli and Salmonella spp. in wastewater were reduced from 5 - <1 log cfu/mL 4 - 0 log cfu/mL and 40 - <400 to <0.04 cfu/mL, respectively, following treatment in wastewater ponds. The ESBL producing E. coli isolates showed broad range of AMR genes in beta- and non-beta lactams antimicrobials including blaCTX-M1, blaCTX-M15, blaOXA-1; aac6, aadA4, aac6Ib, strA, strB; dfrA19, dfrA17, dfrA7; catA1, catB3; qnrA; sul1, sul2; tetA, tetB; and mphA, mrx; virulence genes (hemL, iss, tir, iha, sat, senB); 13 Salmonella serovars including S. Kentucky, S. Chandans, S. Durban and S. Kiambu from LQW and tilapia. Occurrence of E. coli in fish flesh from wastewater was 0.05% and in Mindu dam was 0%; while, in Chinese cabbage irrigated with river water was 86% and in treated wastewater was 10%. The concentration of E. coli in Morogoro river water was higher than the treated wastewater. Tilapia grown in wastewater treatment ponds and vegetables irrigated by treated wastewater were of good quality for human consumption. The quality of treated wastewater from the study sites complied with the WHO/FAO guidelines (1000 cfu/100 mL faecal coliforms) and can be recommended for use on food production.Danish International Development Assistance (DANIDA) Safe Water for Food (SaWaFo) project (Project Code: 11-058DHI

Tilapia lake virus threatens tilapines farming and food security: socio-economic challenges and preventive measures in Sub-Saharan Africa

Tanzania Veterinary Association Proceedings Vol. 35: 19-27Tilapiais a traditional and favorite dish in almost all countries of Sub-Saharan Africa (SSA) and the second most produced fish worldwide. A deadly viral disease caused by Tilapia Lake Virus (TiLV) currently threatens tilapia production. This study aimed to describe TiLV disease, discuss its related socio-economic impacts in SSA, and envisage preventive measures applicable in SSA countries. PubMed, Web of Science, Scopus, Google Scholar and Research Gate were searched. Results reveal that TiLV is an RNA virus causing the disease of over 90% mortalities in tilapia. It attacks early developmental stages of tilapia, transmitted horizontally between fish, and is a potential trade-influencing transboundary animal disease. It is currently confirmed in six countries: Ecuador, Israel, Colombia, Egypt, Thailand and Taiwan. 10 SSA countries have likely imported TiLV infected tilapia fingerlings from hatcheries in Thailand and Tanzania, Burundi, Congo, Mozambique, Nigeria, Rwanda, South Africa, Togo, Uganda, and Zambia are suspected infected with TiLV. Approximately 6 Million jobs with subsequent 18 million livelihoods are expected to be affected. Food insecurity is likely to hit over 400 Million lives in the course of TiLV disease. An estimate of US$ 3 billion per year could be lost in SSA countries due to TiLV. In SSA, technologies to achieve effective control of TiLV based on measures suggested by OIE, and FOA do not exist. There is a crucial need for capacity building among farmers and technical personnel on prompt diagnostic procedures and effective remedial action and establishment of outbreak response systems