Theses and Dissertations Collection

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Aflatoxin contamination of marketed spices in Tanzania: a case study of Dar es salaam
(Sokoine University of Agriculture, 2018) Fundikira, S. S.
Aflatoxin contamination of spices, namely ginger, cinnamon, cardamom and cloves marketed in three districts of Ilala, Temeke and Kinondoni in Dar es Salaam region, Tanzania was investigated in the year 2017/18. Aflatoxin B1, B2, G1 and G2 and total aflatoxins were determined in 120 spice samples using immuno-affinity high performance liquid chromatography and post column derivatization. Fifty eight percent of the spice samples were contaminated and the mean total aflatoxins level in ginger, cinnamon, cloves and cardamom was 2.67, 2.88, 2.79 and 2.26 (μg/kg), respectively. Aflatoxin B1 level in ginger, cinnamon, cloves and cardamom was 0.65, 0.41, 0.40 and 1.09 (μg/kg), respectively. About 10% of the contaminated spices had total aflatoxins above the acceptable EU regulatory level of 10μg/kg and the highest level was 11.9μg/kg, whereas 20.4% of contaminated spices contained aflatoxin B1 above the acceptable EU regulatory level of 5μg/kg, of which the highest level was 11.23μg/kg. Thirty respondents, from whom the spice samples were collected, were interviewed through a structured questionnaire to assess their awareness on aflatoxins, handling and storage practices of spices. The majority (96.7%) of the participants had neither heard of aflatoxins nor attended any training related to food handling and storage. None of the participants were aware of the ill-health effects of aflatoxins on humans and animals. The odds of respondents with age between 36 and 44 years (OR = 0.326, 95%CI = 0.113 - 0.940, p = 0.038) was significantly associated with aflatoxin contamination of spices collected compared to other age groups. The odds of spices that were purchased from farmers (OR = 0.178, 95% CI = 0.061 - 0.525, p = 0.002) was also significantly associated with aflatoxin contamination of spices compared to other sources. The odds of storing spices for length of more than 14 days (OR = 3.608, 95%CI = 1.099 - 11.845, p = 0.034) was significantly associated with aflatoxin contamination of spices as compared to storing for shorter periods of time. It was concluded that the prevalence of aflatoxin contamination of the spices was high and the level of awareness on aflatoxins was very low in the study population. Hence, there was need for raising awareness and sensitization of stakeholders involved in spices and spice value chain.
Aflatoxins contamination in spices and associated predisposing factors in Morogoro region, Tanzania
(Sokoine University of Agriculture, 2021) Peter, Lilian G.
Aflatoxins contamination in spices can result to serious health impact to consumers. Little information is available about levels of aflatoxins in spices traded in Tanzania. This study investigated awareness on aflatoxins and handling, storage and packaging practices of spices in relation to aflatoxins contamination as well as levels in black pepper, cinnamon, cloves and turmeric in Morogoro, Tanzania. A total of 120 spices samples were collected from 52 spice dealers among spice traders and analyzed for aflatoxins B 1 , B 2 , G 1 , G 2 , total aflatoxins and moisture content. Aflatoxins were analyzed using HPLC with fluorescence detector. The association of aflatoxins contamination in spices with traders’ demographic and sociological characteristics, awareness and handling practices were determined using a questionnaire. Results showed that 24.2% of the spice samples were contaminated with aflatoxins; whereby 11.7% was with aflatoxin B 1 (AFB 1) . Spices from Morogoro rural had high rate of aflatoxin contamination (33.3%) compared to those from Morogoro municipality (15.0%). Turmeric had the lowest contamination rate of AFB 1 (0.0%) and total aflatoxins (3.3%) while cloves had highest contamination with 20% and 50.0% for AFB 1 and total aflatoxins, respectively. Lowest aflatoxins contamination was 0.2 μg/kg in cloves while the highest was 164.9 μg/kg in black pepper. Percentage of spice samples exceeded European Union regulatory limit was nine point two percent for AFB 1 and 13.3% for total aflatoxins. Majority (96.2%) of spice traders store their spices and storage time varied from 0 to 100 weeks. Among spice dealers who were doing storage, 34.9% of their samples had aflatoxin contaminations. Half of the respondents who were doing sorting, 65.4% of them discarded the rejected spices. Aflatoxin contaminations for the samples from respondent who were not doing sorting was 61.5%. Occurrence of aflatoxins in spices was associated (p>0.05) with sorting, criteria for sorting, handling of rejected spices, storage practices, awareness on causes of spoilage and awareness on aflatoxins in food. It is concluded that spices in the study area were highly contaminated with aflatoxins some of them beyond the maximum limit set by EU. The study revealed limited awareness and knowledge on aflatoxins contamination in spices among spice traders. Awareness creation on aflatoxins contamination in spices and preventive strategies need to be considered to reduce aflatoxins contamination to safeguard health of spices consumers in Morogoro, Tanzania.
Analysis of mutation rate of 17 y-chromosome short tandem repeats loci using Tanzanian father-son paired samples
(Sokoine University of Agriculture, 2015) Charles, Fidelis
In the present study, 100 unrelated father-son buccal swab sample pairs from consented Tanzanian population were examined to establish mutation rates using 17 Y-STRs loci DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385a, DYS385b, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, and Y- GATA-H4 of the AmpFlSTRYfiler kit used in forensics and paternity testing. Prior to 17 Y-STRs analysis, father-son pair biological relationships were confirmed using 15 autosomal STRs markers and found to be paternally related. A total of four single repeat mutational events were observed between father and sons. Two mutations resulted in the gain of a repeat and the other two resulted in a loss of a repeat in the son. All observed mutations occurred at tetranucleotide loci DYS389II, DYS385a and DYS385b. The locus specific mutation rate varied between 0 and 1.176 x10 -3 and the average mutation rate of 17 Y-STRs loci in the present study was 2.353x10 -3 (6.41x10 -4 - 6.013x10 -3 ) at 95% CI. Furthermore the mean fathers’ age with at least one mutation at son’s birth was 32 years with standard error 2.387 while the average age of all fathers without mutation in a sampled population at son’s birth was 26.781 years with standard error 0.609. The results shows that fathers’ age at son’s birth may have confounding effect on Y-STRs mutation rate analysis though this age difference is statistically not significant using un paired samples t-test (p = 0.05). As a consequence of observed mutation rates in this study, the precise and reliable understanding of mutation rate at Y chromosome short tandem repeats loci is necessary for a correct evaluation and interpretation of DNA typing results in forensics and paternity testing involving males. The criterion for exclusion in paternity testing should be defined, so that an exclusion from paternity has to be based on exclusion constellations at the minimum of two 17 Y-STRs loci.
Anti-trypanosomal and cytotoxic effects of extracts from commiphora swynnertonii burtt 1935
(Sokoine University of Agriculture, 2018) Nagagi, Yakob Petro
Application of trypanocides both curatively and prophylactically is a key component of beset with many problems including drug toxicity and treatment failure due to widespread resistance ofthe parasites. Given little progress in vaccine development, there is a pressing need for discovery of new alternative trypanocidal molecules that can further be developed into trypanocidal drugs. Plants are one such source from which alternative trypanocidal molecules could be obtained. Commiphora swynnertonii is a member of the family Burseraceae which is reported to possess a number of compounds active against protozoa. This thesis provides Commiphora swynnertonii extracts, and its potential as a source of lead molecules for development of alternative trypanocidal drug for trypanosomosis control. The main results are presented in two published papers and one submitted manuscript. The first paper presents the in vitro trypanocidal activity of Commiphora swynnertonii extracts on Trypanosoma congolense in which, the motility of T. congolense was evaluated after incubation for 20 minutes with ethanolic stem-bark and resin extracts at concentration of2 mg/ml and 4 mg/ml. In the second study, T. congolense was incubated with the extracts at concentrations of 0.4 mg/ml and 2 mg/ml for 36 - 56 min after which 0.08 ml of the aliquots were inoculated intraperitoneally into mice to assess infectivity. In both studies, negative (phosphate buffered saline with glucose without the extract) and positive (diminazene diaceturate) controls were used. The findings showed that C. swynnertonii ethanolic stem bark extract caused complete cessation of T. congolense motility in 30 minutes at the concentration of 4 mg/ml. Resin extract had a delayed effect on the cessation of T. congolense motility observed after 90 and 100 minutes of incubation at concentrations of 4 mg/ml and 2 mg/ml respectively. The drug incubation showed that ethanolic stem bark extract reduced significantly (P=0.000) the infectivity of T. congolense at concentration of 2 mg/ml compared to negative control and was not significantly (P=0.S97) different from the positive control. It was concluded that, C. swynnertonii ethanolic stem bark extract possesses in vitro trypanocidal activity. The second paper presents the results ofin vivo activity of C. swynnertonii ethanolic stem bark extract on T. congolense parasitaemia and its effect on immunological components in mice. Groups of mice infected with T. congolense were treated with the stem bark extracts at 1000 mg/kg, 1500 mg/kg and 2000 mg/kg, twice a day in one set and thrice a day in another setting for three days consecutively, and parasitaemia monitored. In the other setting, uninfected mice randomized in five groups were treated with the extract that was categorized as thorough mixed extract (TME) and supernatant extract (SE)) each at 500 mg/kg and 1500 mg/kg, in 8 hourly intervals respectively for three days consecutively. The groups that received the extracts (1000 mg/kg and 2000 mg/kg) at eight hourly intervals had drastically reduced parasitaemia (P<0.05). It was concluded that C. swynnertonii ethanolic stem bark extract possesses in vivo trypanocidal activity. On the other hand, SE at the dose of 1500 mg/kg significantly (P<0.05) reduced the percentage of peripheral lymphocytes. Both doses (500 mg/kg and 1500 mg/kg) of TME significantly (P<0.05) reduced lymphocytes percent while neutrophils and monocytes percent increased significantly (P<0.05). Histopathology of the spleen in the mice treated with 1500 mg/kg of SE and TME showed apoptosis of lymphocytes around the marginal zone and lymphoid follicles. Hence, it was concluded that C. swynnertonii ethanolic stem bark extract within anti-trypanosomal therapeutic dose range possesses cytotoxic effect on lymphocytes. The submitted manuscript provides the results on anti-trypanosomal activities of fractions and sub-fractions of C. swynnertonii ethanolic stem bark extract against T. congolense. Negative (phosphate buffered saline with glucose without the extract) and positive (diminazene diaceturate) controls were used. In addition, chromatographic techniques were employed to determine bioactive molecules in the sub-fractions. The findings indicated that anti-trypanosomal activity in the fractions of aqueous, dichloromethane and petroleum ether were decreasing in that order. In this study, four terpenoids (bomeol, geranylgeraniol, coronopilin and 4,8,13-duvatriene-l,3-diol) were detected and were considered to be likely responsible for trypanocidal activity of Commiphora swynnertonii ethanolic stem bark extract. Further studies to evaluate the in vivo trypanocidal potential are recommended. As a general conclusion, this study has shown that C. swynnertonii stem bark extract possesses in vitro and in vivo trypanocidal activity. The in vivo trypanocidal activity is probably affected by cytotoxic effect on lymphocytes at the therapeutic dosage. It was further found that bomeol, geranylgeraniol, coronopilin and 4,8,13-duvatriene-l,3-diol could be responsible for observed trypanocidal efficacy of C. swynnertonii stem bark extract. Further studies to determine their therapeutic trypanocidal potentials are recommended
Antibiotic resistance and virulence profiles of staphylococcus aureus and escherichia coli from rodents, humans and chicken coexisting in Karatu, Tanzania.
(Sokoine University of Agriculture, 2022) Sonola, V. S.
Antimicrobial resistance (AMR) is a rapidly growing multifaceted problem which threatens global security, public health and the economy. Currently, about 700 000 humans worldwide lose lives annually due to AMR infections that are difficult to treat which are also associated with higher health care costs, elongated time spent in hospitals and increased animal production costs. This study was conducted in Karatu district, northern Tanzania, to investigate antibiotic resistance and virulence profiles of Staphylococcus aureus and Escherichia coli isolated from humans, rodents, chicken and soil in households. Interaction of rodents with humans and livestock in households’ environment has frequently been reported in Karatu, facilitating wide spread of resistant bacterial infections among different hosts in the community. The main objective of this study was to determine the antibiotic resistance and virulence profiles of Staphylococcus aureus and Escherichia coli isolated from rodents, chicken, humans and their surrounding environment in Karatu District. S. aureus were isolated from 284 human nasal swabs, 101 rodents’ deep pharyngeal swabs, 286 chicken cloaca swabs and 285 household soil samples. Specimens were plated into Mannitol Salt Agar (Oxoid, Basingstoke, UK) and incubated aerobically at 37 °C for 24 h. Presumptive colonies of S. aureus were subjected to Gram staining, catalase, deoxyribonuclease (DNAse) and coagulase tests for identification. Antibiotic susceptibility testing (AST) was performed by using Kirby-Bauer disc diffusion method on Mueller-Hinton Agar (Oxoid, Basingstoke, UK). The antibiotics tested were tetracycline (30 μg), erythromycin (15 μg), gentamicin (10 μg), ciprofloxacin (5 μg), iii clindamycin (2 μg) and amoxicillin-clavulanate (20 μg/10 μg). S. aureus strain American Type Culture Collection (ATCC) 25923 was used as a standard organism. Results were interpreted according to Clinical and Laboratory Standard Institute (CLSI) guideline of 2020. The samples used for E. coli isolation included 288 chicken cloaca swabs, 281 human stool, 101 rodents’ intestinal contents and 290 household soils. The specimens were plated onto MacConkey agar (Oxoid Ltd., Detroid, Michigan, USA) and incubated aerobically at 37 ºC for 24 h. Presumptive E. coli colonies were subjected to motility test and later indole, methyl red, Voges-Proskauer and citrate utilization (IMViC) tests for identification. E. coli strain ATCC 29522 was used as a reference organism. AST was performed by using Kirby-Bauer disc diffusion method on Mueller-Hinton Agar plates (Oxoid, Basingstoke, UK). The antibiotics tested were; tetracycline (30 μg), imipenem (10 μg), gentamicin (10 μg), ciprofloxacin (5 μg) cefotaxime (30 μg) and amoxicillin clavulanate (20 μg/10 μg). The results were interpreted by using CLSI (2020) guideline. Results of this investigation revealed high frequencies of isolation for S. aureus and E. coli in rodents, humans, and chicken and soil samples. For S. aureus, the isolation frequencies were 52.1%, 66.5%, 74.3% and 24.5% in samples from chicken, human, rodent and soil, respectively. The isolation frequencies of E. coli from chicken, humans, rodents and soil were 81.6 %, 86.5 %, 80.2 % and 31.0 %, respectively. Based on AST phenotypic results, S. aureus isolates displayed resistance to clindamycin (51%), erythromycin (50.9%) and tetracycline (62.5%) while E. coli isolates showed high resistance against tetracycline (73.7%), imipenem (79.8%) and cefotaxime (79.7%). MDR E. coli (n=50) and S. aureus (n=57) isolates that exhibited high levels of phenotypic resistance to various classes of antibiotics were subjected to molecular analysis using iv multiplex polymerase chain reaction (PCR) technique to detect presence of antibiotic resistance (ARGs) and virulence genes (VGs). ARGs detected in MDR E. coli were; blaTEM (46%), blaCTX-M (26%), blaSHV (22%), tetA (46%), tetB (14%), qnrA (24%), qnrB (8%), blaOXA-48 (12%) and blaKPC (6%) while VGs detected included; ompA (72%), traT (26%), east (18%), bfp (10%), eae (2%) and stx-1 (4%). For MDR S. aureus, ARGs were; tetK (31.6%), tetL (8.9%), ermC (1.8%) and mecA (28.1%) while VGs detected were; clfB (10.5%), coa (14.0%), clfA (1.8%), hlg (1.8%), ebpS (3.5%), fnbB (3.5%), luk-PV (10.5%) and tst (1.8%). Positive and negative correlations between resistance and virulence genes were observed. For MDR E. coli, positive correlations were found between blaTEM and traT genes (r=0.51) and qnrB and bfp genes (r=0.63), while negative correlations were found between blaOXA-48 and ompA (r= -0.05), blaSHV and traT (r=-0.44) and tetA and east (r=-0.10). For S. aureus, positive correlations were found between resistance (ermC) and clfA (r=0.57), hlg (r=1.00) and clfB (r=0.43), tetK and clfB (r=0.39); tetK and coa (r=0.36). The principal component analysis (PCA) results for S. aureus showed that, resistance genes (tetK and mecA) and virulence determinants (clfB, coa and luk-PV) were common in all sample sources. The PCA also revealed that, MDR E. coli and S. aureus isolates from rodents and chicken had more ARGs and VGs compared to isolates from soil and humans. Besides, MDR E. coli isolates harboured traT, east, eae, stx-1, bfp and ompA genes indicating ability of isolates to cause various infections. Based on findings, this study documents high levels of antimicrobial resistance including MDR in E. coli and S. aureus isolated from chicken, humans, rodents and soil samples in Karatu, northern Tanzania. According to PCA results, E. coli isolates from rodents had more ARGs and VGs while for S. aureus these genes were found more in rodents and soil v environment implying that both subjects are potential reservoirs and can be sources of transmission. The increased prevalence of both resistance and virulence genes in the isolates suggests the ability of the pathogens to cause infections that are difficult to treat. Comprehensive one health interventions, are urgently needed and should include improving; i) improving hygiene and control of rodents in household environments. ii) Future studies should base on adequate understanding of the human-livestock environment interphase using well-designed genomic studies such as whole genomic sequencing (WGS) which provides a comprehensive picture on the pattern and magnitude of AMR and virulence genes spread. The advances and accessibility of genomic sequencing and analytical methods are essential in improving our understanding of AMR transmission dynamics at the human-livestock/animal-environment interface. Genomic studies should be coupled with behavioural, epidemiological, clinical and modelling using One Health approaches. This will ensure that the key drivers of resistance and virulence transmission between human-livestock-environment are accurately identified and the most appropriate interventions adopted. It is important to understand the importance of each component of the human-livestock/animal-environment. A One Health approach should be deployed to ensure involvement of relevant multisectoral and multidisciplinary to attain an optimal public health and ensure a safe environment.
Antimicrobial activity study and chemical characterization of pure compounds from synadenium glaucescens pax
(Sokoine University of Agriculture, 2017) Rwegoshora, F.
The modern medicine particularly drugs’ discovery and their development is a result of improvement of the local knowledge of the health practitioners on the medicinal plants and animal products. This study aimed at isolating and testing the bioactive compounds from Synadenium glaucescens collected from Njombe Region; Tanzania. Extraction was done using Soxhlet method while the isolation involved a series of chromatographic techniques. Nuclear magnetic resonance (NMR) technique was used for compound identification. Colour reaction was done using Vanillin reagent. Microdilution and agar well diffusion methods were used to test for antimicrobial activity of the isolates and/or compounds. The crude extracts obtained were 1.99 % and 6.25 % by weight of the pulverized stem wood and the stem bark respectively. The percentage composition of the pure compounds from crude extracts ranged between 0.5 % – 8.25 %. Out of nine isolates (5 from stem bark and 4 from stem wood (coded C1 – C9), two compounds C6 and C9 were identified. All compound isolates were conjugated except C2. The majority of fractional extracts reacted bluish purple with vanillin reagent which implies the characteristics of terpenoids. The NMR data were compared to literature, and indicated compound C6 to be a fatty acid and compound C9 showed to have lupeol acetate backbone based on the 1H and 13C NMR spectroscopic data. All tested isolates were bioactive against the tested standard bacterial and fungal strains at different efficacies. Isolate C7 demonstrated the highest activity of MIC (0.01 mg/ml) against A. baumannii and S. enterica, and the largest zone of inhibition (27 mm) against C. tropicalis. These results are recorded for the first time for this plant and present a good direction towards drugs discovery. Further studies on identification and bioassays of the compounds from stem of S. glaucescens are recommended.
Antimicrobial and phytochemical properties of plant extracts from Sterculia Africana, Acacia Sieberiana and Cassia abbreviata ssp. abbreviata
(Sokoine University of Agriculture, 2017) Kirabo, I.
The study of self-medication in non-human primates sheds new light on the complex interaction of animal, plant and parasite. The main objective of this study was to evaluate the antimicrobial properties and phytochemical profile of crude extracts from Sterculia Africana, Acacia sieberiana and Cassia abbreviata ssp. abbreviata, plants present in the yellow baboon diet in Mikumi National Park, Tanzania. Specifically aimed at assessing antibacterial activity of the crude extracts through in vitro studies using standard strains and to establish the phytochemical profile of the crude extracts using chromatography methods. Minimum Inhibitory Concentration (MIC) technique was employed to assess antibacterial activity whereas Thin layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC) techniques were used to assess the plants’ chemical profile. Acacia sieberiana and Cassia abbreviata ssp. abbreviata showed the lowest MIC values of 0.31mg/ml against the Gram negative strains whereas 0.63 mg/ml was the lowest value against the Gram positive strains used in this study. Total extraction was done by maceration and the highest extraction yields of 9.66% and 6.22% were obtained from the root bark of Cassia abbreviata ssp. abbreviata and the leaves of Acacia sieberiana respectively. Findings from Thin Layer Chromatography (TLC) indicated presence of saturated and unsaturated compounds while colour reactions with Vanillin reagent inferred presence of triterpene group of compounds in the ethanolic crude plant extracts. The chemical profile obtained from the HPLC for the plant extracts was comparable to the one from the TLC profile. Antibacterial studies revealed presence of pharmacological activity in the crude plant extracts suggesting that non–human primates feed on the nutrient poor parts of these plants for self-medication. Chromatography analysis offers a starting point in isolation of pure compounds for the purpose of drug development since these plant extracts exhibit activity against bacteria of medical and veterinary importance.
Antimicrobial use, prevalence of extended spectrum beta-lactamase producing escherichia coli and economic effects on cattle and poultry in Dar es salaam Tanzania
(SOKOINE UNIVERSITY OF AGRICULTURE, 2023) Azabo R.R
Antimicrobial usage (AMU) in livestock production provides a basis for improving animal health and productivity. However, it is evident that the over-dependence of animal production on antimicrobial agents is one of the major factors driving the emergence of antimicrobial resistance (AMR) in bacteria that can be transmitted via the food chain or environment to humans. This thesis aims to assess antimicrobial use in cattle and poultry production in relation to resistance in Extended Spectrum Beta-Lactamase (ESBL) producing Escherichia coli (E. coli) and also gain insight into economic effects (cost and benefit) of antimicrobial use reduction in animal production inIlala, Kinondoni and Ubungo districts which form part of the Dar es Salaam region, Tanzania with the following objectives.(i) To conduct a systematic review on the methods and metrics used to quantify and assess MU in cattle and poultry production in Sub-Saharan Africa, (ii) To determine the quantity, quality and pattern of antimicrobial use in cattle and poultry production in Dar es Salaam, Tanzania, (iii) To assess antimicrobial consumption in food-producing animals in Dar es Salaam, Tanzania, (iv) To determine the prevalence and antimicrobial resistance pattern of ESBL producing E.coli isolates from cattle and poultry production, and (v) To estimate the economic effects (costs and benefits) of antimicrobial use reduction in cattle and poultry production. In view of these objectives, the findings of this thesis are presented in five scientific papers. Paper 1: A systematic literature review was conducted to provide an overview of methods of measuring AMU and metrics used, reviewing existing data on AMU in cattle and poultry production in order to identify gaps in Sub-Saharan Africa. The study revealed a deficit of studies on estimate of quantity and quality of antimicrobials used in food-producing animals in Sub-Saharan Africa. Paper 2: A cross-sectional study was conducted on 116 farms (51 poultry and 65 small-scale dairy cattle) in Ilala, Kinondoni and Ubungo Districts of Dar-es-Salaam region, Eastern Tanzania from 15th August to 30th September 2019 to investigate the level of antimicrobial use practice, type and quantity (amount) of antimicrobials consumed. The study revealed that 23 (19.8%) of the farms visited had records while 93 (80.2%) relied on recall, 58.6% of the livestock farmers had adequate level of practices (favorable) in accordance to antimicrobial use based on their responses, the most commonly used class of antimicrobials in poultry production were: Fluoroquinolones (25.5%), sulphonamides (21.6%), tetracycline (11.8%) while in the small-scale dairy farms, tetracycline (20.0%), beta-lactams (18.5%), sulphonamides (12.3%) were most commonly used. Quantitatively, in the poultry farms, the frequently used antimicrobial class sulphonamides (46.1%), tetracycline (19%) and Macrolides (14.2%). In the small-scale dairy farms, the use beta-lactams (36.4%), sulphonamides (22.3%), tetracycline (14.3%) were predominant. For Paper 3: a cross-sectional study, using data extraction form to collate antimicrobial use data from sales records (three consecutive years) of five established licensed veterinary pharmaceutical wholesales/outlets which were purposively selected in Ilala, Kinondoni and Ubungo. The study revealed that 178.4 tonnes of antimicrobials (by weight of active ingredients) were consumed during the 3 year study period (2016-2018), with an average of 59.5 ± 3.8 tonnes/year. The commonly sold antimicrobials were tetracycline (44.4%), sulphonamides (20.3%) and aminoglycosides (10.3%). Regarding veterinary antimicrobial use importance to human medicine, 34.4% were critically important antimicrobials; 4.1% were reserve and 51% were watch groups according to AWaRe categorization of WHO. Overall, a mean of 7.44 ± 0.81 mg/PCU (population correction unit) was consumed by food-producing animals during the three-year study period. Paper 4: A cross-sectional study was conducted in 54 of the previously visited farms where a pre-tested questionnaire on antimicrobial (antibiotics) usage was completed. A total of 121 E. coli isolates were obtained from 201 sampled small-scale dairy cattle rectal swabs. Looped rectal swab specimens from Stuart transport medium, were streaked directly onto plain MacConkey agar (Oxoid, Basingstoke, UK) and aerobically incubated at 370C for 24 hours. Presumptive E. coli colonies were Gram stained and then subjected to biochemical tests (Indole test, Methyl red test, Voges-Proskauer test and Citrate Utilisation test; IMViC test) for identification. E. coli strain ATCC 29522 was used as a reference organism. Antimicrobial susceptibility testing (AST) was performed against eight types of antimicrobials: (Tetracycline, (TE) (30 μg), Ampicillin, (AMP) (10 μg), Gentamicin, (CN) (10 μg), Ciprofloxacin,(CIP) (5 μg), Cefotaxime,(CTX) (30 μg), Nalidixic Acid, (NA) (30 μg), Trimethoprim/Sulfamethoxazole, (SXT) (1.25/23.75μg) and Chloramphenicol,(C) (30 μg)). The highest prevalence of AMR was against AMP (96.7%), CTX (95.0%), TE (50.4%) and SXT (42.1%). The 121 isolates of E. coli belong to 41 different phenotypes showing a variation of resistance. The most frequently observed phenotypes were AMP-SXT-CTX with a prevalence of 12.4%, followed by the combination AMP-CTX with 10.7% and TE-AMP-CTX and NA+TE+AMP+CTX with 8.3% each. Fifteen different phenotypes that produce Extended Spectrum Beta-Lactamases (ESBLs) were detected with a prevalence of 42.9% and 74.4% of E.coli isolates exhibited multidrug resistance (MDR). This probably confirms that antimicrobial use is unregulated and thus inappropriate use which led to the emergence and development of resistance. Paper 5: A cross-sectional study was conducted on randomly sampled broiler farms which were in production for one year in Kinondoni and Ubungo Districts in Dar es Salaam region of Tanzania from February to March 2021. A pre-tested questionnaire was used to capture data required to complete the model for the estimation of the economic effects (costs and benefits) on reduction of antimicrobial use. Data collected included: number of chicks bought and dead on the farm (mortality), observed clinical signs; signs of respiratory infections (coughing, wheezing, sneezing and nasal discharge), enteric infection (diarrhea) and lameness (locomotive signs) (morbidity). A Mclnerney model built on biological and economic parameters of disease effects on livestock production was used to analyze the data. The net costs and benefits were estimated within a partial budgeting framework in the model. The results of this study showed that antimicrobial use reduction will have an effect on mortality and morbidity and thus increase the cost of production due to changes in additional management changes (animal health management and technical management). Findings from this thesis recommend that rational AMU should be emphasized by targeting cattle and poultry production in Tanzania in general and Dar es Salaam in particular.
Application of real-time RT-PCR assay for detection and typing of foot-and-mouth disease virus in Tanzania
(Sokoine University of Agriculture, 2015) Mero, Herieth R.
Speed is paramount in the diagnosis of highly infectious Foot-and-mouth disease (FMD). Recent developments in molecular biology have enabled specific detection of FMD virus by real-time RT-qPCR and sequencing in endemic settings in Africa. In this study, a laboratory-based experimental design was used to standardize real-time RT-qPCR assay for detection and typing of FMDV in selected regions of Tanzania. The optimized conditions for both pan-serotypic and serotype-specific real-time RT-qPCR assays were: reverse transcription (at 60°C for 30minutes), denaturation of reverse transcriptase and activation of DNA polymerase (at 95°C for 10minutes followed by 95°C for 15 seconds), annealing and elongation temperature (at 60°C for 1 minute) for 52 cycles. FMD virus were detected in 100% (n = 14) archived samples that were collected between 2010 and 2013 from confirmed FMD-cases. The standardized real-time RT-qPCR assays revealed 100% sensitivity and 100% specificity for detection and typing of FMDV, respectively.The frequency of FMDV detection among FMD-suspected cases of cattle collected from 2008 to 2014 in selected regions of Tanzania was 92% (n = 23). Of the 23 positive samples, 56.5% (n = 13), 8.7% (n = 2), 21.7% (n = 5), and 8.7% (n = 2) were typed into serotypes O, A, SAT 1 and SAT 2 respectively. One sample (4.3%) was positive for both serotype A and SAT 1. These findings indicate that the standardized pan-serotypic and serotype-specific real-time RT-qPCR assays have a potential use in detection and typing of FMDV field strains in endemic settings of Tanzania and Africa at large. Application of standardized real-time RT-qPCR assays could hasten diagnosis of FMDV that guide selection of effective FMD-control measures in the region. In-depth studies, including sequencing of one sample that revealed positive for two serotypes, are required to elucidate the possibility of mixed infection among FMD cases.
Assessing the molecular epidemiology and antimicrobial Susceptibility profiles of thermophilic campylobacter Species from human and animal feces in South Korea and Tanzania
(2021) Gahamanyi, Noel
Campylobacter species cause human gastroenteritis and have developed resistance to existing antimicrobials. The epidemiology of Campylobacter infections is not fully understood due to a complex genome and the existence of various reservoirs. Poultry is the primary reservoir of Campylobacter but other domestic and wild animals have also been reported as contributing sources. Natural products are regarded as alternative treatments in the post-antibiotic era while the whole-genome sequencing (WGS) is seen as a promising technology towards deciphering the epidemiology and evolution of Campylobacter. The main objective of this research was to assess the molecular epidemiology and antimicrobial susceptibility profiles of thermophilic Campylobacter species from human and animal feces in South Korea and Tanzania. Specifically, this study aimed at 1) determining the antimicrobial resistance (AMR) profiles, virulence genes, and genetic diversity of thermophilic Campylobacter species isolated from a layer poultry farm in Korea; 2) determining the susceptibility of layer chicken-derived and reference Campylobacter strains to selected natural products and frontline antibiotics; and 3) carrying out genomic characterization of fluoroquinolone (FQ)-resistant thermophilic Campylobacter strains isolated from layer chicken faeces in Gangneung, Korea by whole-genome sequencing; and 4) carrying out molecular techniques for the detection of Campylobacter species from human stool and cattle faecal samples in Kilosa district, Tanzania. In the first study, 153 faecal samples were obtained from two layer chicken farms in Gangneung, South Korea. Isolation of Campylobacter was carried out by culture, followed by species confirmation with PCR and sequencing. Antimicrobial susceptibility tesing for six antimicrobials (sitafloxacin, ciprofloxacin, nalidixic acid, gentamicin, erythromycin, and tetracycline) was performed by broth microdilution. Three antimicrobial resistance (AMR) and nine virulence genes were screened by PCR. Genotyping was performed by flagellin A-restriction fragment length polymorphism (flaA-RFLP) and multilocus sequence typing (MLST). Of the 153 samples, Campylobacter spp. were detected in 55 (35.9%) with 49 (89.1%) and 6 (10.9%) being C. jejuni and C. coli, respectively. High- level resistance (MIC ≥ 32 μg/mL) was observed for ciprofloxacin (100%), nalidixic acid (100%), and tetracycline (C. jejuni: 93.9%; C. coli: 83.3%) but no resistance was observed for sitafloxacin. Sequencing confirmed mutations associated with quinolones (C257T in gyrA gene) and tetracycline [tet(O) gene] resistance. Multidrug resistance at a rate of 8.2% was exclusively recorded in C. jejuni. cstII, flaA, dnaJ, cadF, and cdtB were found in alliii Campylobacter isolates while the proportions for other genes (ciaB, pldA, and csrA) varied from 33.3 to 98 %. The flaA-RFLP typing resulted in 21 types for C. jejuni and five for C. coli: 5 while MLST showed 10 sequence types (STs) for C. jejuni and three STs for C. coli with CC-607 (ST 3611) and CC-460 (ST-460) being predominant. Among the 10 STs of C. jejuni, three were newly assigned. The second work determined the susceptibility of layer chicken-derived and reference Campylobacter strains to selected natural products and frontline antibiotics. The efficacy of selected natural products was assessed by broth microdilution and the optical density recorded by a microplate reader. Antibiotic resistance genes (tet(O) and gyrA) were characterized at the molecular level. The minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) ranged from 25 to 1600 μg/mL. Cinnamon extract, cinnamon oil, (E)-Cinnamaldehyde, clove oil, eugenol, and baicalein had the lowest MIC and MBC values (25–200 μg/mL). Chicken-derived isolates were resistant to quinolones and tetracycline but sensitive to erythromycin and gentamicin. NPs were effective against both AMR and sensitive Campylobacter strains. The third study characterized FQ-resistant C. jejuni (200605) and C. coli (200605) strains of layer chicken origin by whole-genome sequencing using Illumina sequencing technology. A phylogenetic relationship to existing strains was also established. WGS confirmed C257T mutation in the gyrA gene and the presence of cmeABC complex conferring resistance to FQs in both strains. Both strains also exhibited tet(O) genes associated with tetracycline resistance. No resistance to macrolides and aminoglycosides was found. Putative genes conferring resistance to doxycycline, minocycline; bla OXA-452 , cephalosporin, and penam were also recorded in both strains. Virulence genes associated with motility, chemotaxis, and capsule formation were found in both strains. However, the analysis of virulence genes showed that C. jejuni strain 200605 is more virulent than C. coli strain 200606. The MLST showed that C. jejuni strain 200605 belongs to sequence type (ST)-5229 while C. coli strain 200606 belongs to ST-5935, and both STs are less common. The phylogenetic analysis clustered C. jejuni strain 200605 along with other strains reported in Korea (CP028933 from chicken and CP014344 from human) while C. coli strain 200606 formed a separate cluster with C. coli (CP007181) from turkey. The WGS confirmed FQ-iv resistance in both strains and showed potential virulence of both strains. Further studies are recommended to understand the reasons behind the regional distribution of such rare STs. Lastly, 70 human stool and 30 cattle faecal samples were collected in Kilosa district, Tanzania. Species confirmation was conducted by polymerase chain reaction (PCR) and 16S rRNA sequencing while the phylogenetic analysis was done with 16S rRNA sequences. Campylobacter species detection rates were 65.7% (46/70) and 20.0% (6/30) in humans and cattle, respectively. In humans, C. concisus was the predominant species 37.8% (14/37), followed by uncultured Campylobacter spp. 24.3% (9/37) and C. hominis 21.6% (8/37). The least represented species were C. jejuni and C. lanienae all occurring at 2.7% (1/37). Molecular detection methods need to be adopted in routine Campylobacter testing and surveillance studies because they provide results in short period of time. The findings of this study highlight (i) the usefulness of molecular techniques in emerging Campylobacter detection, (ii) the molecular epidemiology and antimicrobial resistance of Campylobacter from layers; (iii) the importance of some natural products as alternative to conventional antimicrobials in the control of Campylobacter infections; and (iv) WGS data of Campylobacter from layer chicken for better understanding the Campylobacter epidemiology and serve as a baseline for future studies. This study also identified new sequence types (STs) including ST-10645, ST-10647, ST-10648 that were isolated from layer chicken in Korea. I recommend further studies on (i) the synergism of natural products and existing antimicrobials; and (ii) chemical profiling of used plant extracts and their anti- adhesion effects to both biotic and abiotic surfaces.
Assessing the molecular epidemiology and antimicrobial susceptibility profiles of thermophilic campylobacter species from human and animal feces in South Korea and Tanzania
(Sokoine University of Agriculture, 2021) Gahamanyi, Noel
Campylobacter species cause human gastroenteritis and have developed resistance to existing antimicrobials. The epidemiology of Campylobacter infections is not fully understood due to a complex genome and the existence of various reservoirs. Poultry is the primary reservoir of Campylobacter but other domestic and wild animals have also been reported as contributing sources. Natural products are regarded as alternative treatments in the post-antibiotic era while the whole-genome sequencing (WGS) is seen as a promising technology towards deciphering the epidemiology and evolution of Campylobacter. The main objective of this research was to assess the molecular epidemiology and antimicrobial susceptibility profiles of thermophilic Campylobacter species from human and animal feces in South Korea and Tanzania. Specifically, this study aimed at 1) determining the antimicrobial resistance (AMR) profiles, virulence genes, and genetic diversity of thermophilic Campylobacter species isolated from a layer poultry farm in Korea; 2) determining the susceptibility of layer chicken-derived and reference Campylobacter strains to selected natural products and frontline antibiotics; and 3) carrying out genomic characterization of fluoroquinolone (FQ)-resistant thermophilic Campylobacter strains isolated from layer chicken faeces in Gangneung, Korea by whole-genome sequencing; and 4) carrying out molecular techniques for the detection of Campylobacter species from human stool and cattle faecal samples in Kilosa district, Tanzania. In the first study, 153 faecal samples were obtained from two layer chicken farms in Gangneung, South Korea. Isolation of Campylobacter was carried out by culture, followed by species confirmation with PCR and sequencing. Antimicrobial susceptibility tesing for six antimicrobials (sitafloxacin, ciprofloxacin, nalidixic acid, gentamicin, erythromycin, and tetracycline) was performed by broth microdilution. Three antimicrobial resistance (AMR) and nine virulence genes were screened by PCR. Genotyping was performed by flagellin A-restriction fragment length polymorphism (flaA-RFLP) and multilocus sequence typing (MLST). Of the 153 samples, Campylobacter spp. were detected in 55 (35.9%) with 49 (89.1%) and 6 (10.9%) being C. jejuni and C. coli, respectively. High-level resistance (MIC ≥ 32 μg/mL) was observed for ciprofloxacin (100%), nalidixic acid (100%), and tetracycline (C. jejuni: 93.9%; C. coli: 83.3%) but no resistance was observed for sitafloxacin. Sequencing confirmed mutations associated with quinolones (C257T in gyrA gene) and tetracycline [tet(O) gene] resistance. Multidrug resistance at a rate of 8.2% was exclusively recorded in C. jejuni. cstII, flaA, dnaJ, cadF, and cdtB were found in all Campylobacter isolates while the proportions for other genes (ciaB, pldA, and csrA) varied from 33.3 to 98 %. The flaA-RFLP typing resulted in 21 types for C. jejuni and five for C. coli: 5 while MLST showed 10 sequence types (STs) for C. jejuni and three STs for C. coli with CC-607 (ST 3611) and CC-460 (ST-460) being predominant. Among the 10 STs of C. jejuni, three were newly assigned. The second work determined the susceptibility of layer chicken-derived and reference Campylobacter strains to selected natural products and frontline antibiotics. The efficacy of selected natural products was assessed by broth microdilution and the optical density recorded by a microplate reader. Antibiotic resistance genes (tet(O) and gyrA) were characterized at the molecular level. The minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) ranged from 25 to 1600 μg/mL. Cinnamon extract, cinnamon oil, (E)-Cinnamaldehyde, clove oil, eugenol, and baicalein had the lowest MIC and MBC values (25–200 μg/mL). Chicken-derived isolates were resistant to quinolones and tetracycline but sensitive to erythromycin and gentamicin. NPs were effective against both AMR and sensitive Campylobacter strains. The third study characterized FQ-resistant C. jejuni (200605) and C. coli (200605) strains of layer chicken origin by whole-genome sequencing using Illumina sequencing technology. A phylogenetic relationship to existing strains was also established. WGS confirmed C257T mutation in the gyrA gene and the presence of cmeABC complex conferring resistance to FQs in both strains. Both strains also exhibited tet(O) genes associated with tetracycline resistance. No resistance to macrolides and aminoglycosides was found. Putative genes conferring resistance to doxycycline, minocycline; blaOXA-452, cephalosporin, and penam were also recorded in both strains. Virulence genes associated with motility, chemotaxis, and capsule formation were found in both strains. However, the analysis of virulence genes showed that C. jejuni strain 200605 is more virulent than C. coli strain 200606. The MLST showed that C. jejuni strain 200605 belongs to sequence type (ST)-5229 while C. coli strain 200606 belongs to ST-5935, and both STs are less common. The phylogenetic analysis clustered C. jejuni strain 200605 along with other strains reported in Korea (CP028933 from chicken and CP014344 from human) while C. coli strain 200606 formed a separate cluster with C. coli (CP007181) from turkey. The WGS confirmed FQ-resistance in both strains and showed potential virulence of both strains. Further studies are recommended to understand the reasons behind the regional distribution of such rare STs. Lastly, 70 human stool and 30 cattle faecal samples were collected in Kilosa district, Tanzania. Species confirmation was conducted by polymerase chain reaction (PCR) and 16S rRNA sequencing while the phylogenetic analysis was done with 16S rRNA sequences. Campylobacter species detection rates were 65.7% (46/70) and 20.0% (6/30) in humans and cattle, respectively. In humans, C. concisus was the predominant species 37.8% (14/37), followed by uncultured Campylobacter spp. 24.3% (9/37) and C. hominis 21.6% (8/37). The least represented species were C. jejuni and C. lanienae all occurring at 2.7% (1/37). Molecular detection methods need to be adopted in routine Campylobacter testing and surveillance studies because they provide results in short period of time. The findings of this study highlight (i) the usefulness of molecular techniques in emerging Campylobacter detection, (ii) the molecular epidemiology and antimicrobial resistance of Campylobacter from layers; (iii) the importance of some natural products as alternative to conventional antimicrobials in the control of Campylobacter infections; and (iv) WGS data of Campylobacter from layer chicken for better understanding the Campylobacter epidemiology and serve as a baseline for future studies. This study also identified new sequence types (STs) including ST-10645, ST-10647, ST-10648 that were isolated from layer chicken in Korea. I recommend further studies on (i) the synergism of natural products and existing antimicrobials; and (ii) chemical profiling of used plant extracts and their anti- adhesion effects to both biotic and abiotic surfaces.
Assessment of antibiotic residues in raw cows’ milk produced by small scale dairy farms in Bagamoyo district, Tanzania
(Sokoine University of Agriculture, 2015) Ramadhani, R.
A cross-sectional study was conducted in Bagamoyo District, Tanzania between October, 2013 and March, 2014 to assess the antibiotic residues in raw cows’ milk produced by small-scale dairy farms. One hundred and ten small-scale dairy farmers were interviewed at household level on the handling and use of veterinary drugs, access to and availability of veterinary services, livestock diseases frequency and means of treatment, most commonly used antibiotic, awareness of drug residues in raw milk and health risks associated with consumption of raw milk containing antibiotic residues. In addition 110raw milk samples were collected from three available milk collection centers for laboratory analysis of antibiotic residues. Laboratory assessment included, screening qualitative test using microbial inhibition test, followed by quantification of oxytetracycline (OTC) residues levels for positively detected samples by using HPLC Technique. Prevalence of OTC residues was 10% and all positive detected samples had OTC residues above MRL levels by FAO/WHO-CAC 2-2012. The mean value levelof OTC was766.3± μg/l. About 83.6% of respondents call livestock officers in the event of a sick cow and 56.4% of cases OTC were prescribed.On health risks associated with consumption of raw milk with antibiotics, 91.8% of respondents were aware. Screening for residues at the milk collection centers is recommended and further investigation of the milk production practices among small-scale dairy farmers is required. This will provide a basisfor designing appropriate and effective small scale milk production practices which will reduce milk contamination and help to protect the health of consumers in Tanzania.
Assessment of bacterial quality and associated handling practices of unpasteurised fruit juices vended in Dar es salaam city, Tanzania
(Sokoine University of Agriculture, 2013) Simforian, Edeltruds
Fresh fruit juices are essential components of and there is considerable evidence of health and nutritional benefits associated with their consumption. However, during processing contamination from raw materials, equipment or food handlers could be easily transferred to the final product of the juices resulting to food-borne illness. A cross-sectional study was conducted to assess bacterial quality and associated handling practices of unpasteurised fruit juices vended in Dar es Salaam city, Tanzania. A total of 90 juice vendors were interviewed followed by collection of 90 juice samples for laboratory analysis. Physicochemical and bacterial qualities of the juices were analysed. The results showed that the pH of the juices ranged between 2.7 to 6.4 while the acidity ranged from 0.01% to 1.3%. The total soluble solids ranged between -1.5 to 18.04⁰Brix. Most juices had ⁰Brix levels below Codex recommended minimum values and 67.8% were classified as weak and watery. The total plate counts (TPC) of the juices ranged between 2.32 to 8.54 (Log cfu/ml). About 72.2% juice samples had TPC above Codex recommended maximum levels (5x10³ - 10⁴cfu/ml). The prevalence of Escherichia coli in the juices was 80% with a range between -1.13 to 4.97 (Log MPN/ml). All samples were negative for Salmonella species. Risk factors for higher TPC and E. coli counts which were statistically significant (P < 0.05) included pH, type of juice, extraction methods, vending sites, storage containers and sex of the vendor. Generally, 78.9%; of preparation and vending premises were unhygienic and encouraged contamination of the juices. It is concluded that, the overall handling, preparation practices and bacterial quality of unpasteurised fruit juices vended in Dar es Salaam city are poor. The government should educate the vendors on food safety and hygiene as well as enforcing regular monitoring of the quality of street fruit juices.
Assessment of bacteriological quality of Rastrineobola Argentea along its value chain in lake Victoria, Mwanza, Tanzania
(Sokoine University of Agriculture., 2015) Baniga, Z.
A cross-sectional study design was used to assess bacteriological contamination in Rastrineobola argentea along its value chain in Lake Victoria, Mwanza. Rastrineobola argentea were collected from different points along the chain. Fresh, dried on raised racks and on ground samples of R. argentea were purposively collected from landing sites, drying areas and retail markets. Bacterial counts were performed and Escherichia coli and Salmonella spp were identified using bacteriological standard procedures. Antibiotic susceptibility testing was performed on Muller Hinton Agar. The findings showed a significant difference (p<0.05) in bacterial counts between ground and raised racks dried R. argentea. Results for E. coli quantification showed that fresh R. argentea had significant difference (p<0.05) in mean counts to those dried on raised racks and ground at processing and market levels. Overall prevalence of Salmonella spp along the chain was 15.8% (n=120). The prevalence of Salmonella typhimurium and unidentified Salmonella spp in fresh R. argentea were 20% and 5% (n=40) respectively. Prevalence of S. typhimurium in R. argentea dried on ground at processing and markets were 20% and 15% (n=20) respectively. Salmonella spp were not detected in R. argentea dried on racks. The overall prevalence of E. coli was 43.3% (n=120). Prevalence of 62.5% (n=40) was found in fresh R. argentea and 70% (n=20) in those dried on ground at market while none of R. argentea dried on racks were contaminated. Salmonella spp and E. coli were resistant to ampicillin, tetracycline and co-trimoxazole, however were sensitive to norfloxacin and ciprofloxacin. Escherichia coli showed sensitivity to chloramphenicol too. Therefore, sundried R. argentea using raised racks is recommended as it is more hygienic than drying on ground to provide quality products for consumptions. Antibiotics susceptibility revealed that R. argentea contains antibiotic resistant Salmonella spp and E. coli of public health implications.
Assessment of brucella abortus and antimicrobial residues in raw Cattle Milk In Bukombe District, Tanzania
(Sokoine University of Agriculture, 2017) Mhozya, M.
A cross sectional study was carried out in January 2017 with the aim of estimating the seroprevalence of Brucella circulating antibodies, detection of Brucella abortus in raw cattle milk, assess the risk factors for infection and establish the presence and levels of antimicrobial residues in raw milk in Bukombe district, Tanzania. A total of 221 blood samples from purposively selected lactating cows in 17 villages were collected and analysed for Brucella circulating antibodies using Rose Bengal Plate Test and c-ELISA. Also 221 raw milk samples were collected from the same cows and analysed for antimicrobial residues using Delvo SP® test and subsequently, Tetracyclines (Chlortetracycline, Tetracycline and Oxytetracycline) were analysed and quantified in 10 Delvo test positive milk samples using HPLC. Milk samples of seropositive animals (n=3) were analyzed by PCR to detect bcsp31gene of B. abortus using B4/B5 primer sets. The overall animal seroprevalence of brucellosis was 1.4% (n=219) and herd seroprevalence was 3.8% (n=52). One milk sample was confirmed to contain bcsp31gene of B. abortus. The proportion of antimicrobial residue contaminations in milk was 11.6%. Tetracyclines were confirmed and quantified in 9/10 of selected Delvo positive raw milk samples. Tetracyclines concentration was 6.1±5.8 ug/l with the mean concentrations of oxytetracycline and tetracycline being 7.7±5.3 ug/l and 9.6 ±16.9 ug/l respectively which were all below the recommended MRL of 100 µg/l. Interestingly, 70% of the quantified samples had oxytetracycline and only 40% had tetracycline. It is concluded that Bovine brucellosis is present in Bukombe district albeit at low prevalence (1.4%). Also detection of antimicrobial residues in raw milk samples (11%) may pose risk to consumers especially children who frequently drink milk. It is recommended that veterinarians in cooperation with other stakeholders and farmers to observe good livestock practices.
Assessment of dichapetalum plants infestation and its susceptibility to three herbicides in Mkuranga district Tanzania.
(Sokoine University of Agriculture, 2007) Mopei, Nassoro Athumani
A study was conducted in Mkuranga District between October, 2005 and February, 2006 to investigate Dichapetalum plants infestation and effectiveness of selected herbicides on these plants. Specifically, this study intended to identify species prevalence and their coverage in this District. The study further aimed at determining effectiveness of herbicides on the control of Dichapetalum plants. The Purposive sampling was used to select farms for the study. The actual areas of infestation for surveys in these farms were chosen on random basis so as to get representative picture for whole area infested with these plants in the District. The survey conducted using Scientific Quadrant Method, established presence of four Dichapetalum species; Dichapetalum stuhlmanii, Dichapetalum mossambicence, Dichapetalum ruhlandii and Dichapetalum arenarium, with percentage cover of 76%, 42%, 37% and 27% respectively. The plants that were commonly in close association with Dichapetalum plants were Deinbollia borbonica, Annona senegalensis, Xylotheca tetensis and Milletia spp. Dichapetalum plant sprouts were individually sprayed with 2,4-dichlorophenoxy acetic acid (2,4-D), glyphosate (Round up®) and paraquat in the field, followed by observation for responses to herbicides for 60 days. A number of phytotoxic effects were recorded. The efficacies of selected herbicides were assessed in terms of killing percentages. Killing percentages recorded at the end of study (Day 60) were analyzed by MSTAT-C. Overall killing percentage was 16.2 %. On individual herbicide, paraquat recorded the highest killing percentages (17.8 %) among the three tested herbicides. This was followed by 2,4-D (16.3 %). Glyphosate recorded killing percent of 14.6 % which was the lowest in the study. Analysis of variance (ANOVA) has shown that the degree of control on Dichapetalum plants is influenced by herbicide type, dosage rate, and interaction between herbicide and dose. It was concluded that Mkuranga District is heavily infested with Dichapetalum plants and application of 2,4-D, Glyphosate and Paraquat in dry conditions gave poor herbicide performance.
Assessment of insecticidal effectiveness of selected crude plant extracts on the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)
(Sokoine University of Agriculture, 2017) Matendo, R. E.
Effects of Commiphora swynnertonii, Synadenium glaucescens and Allium sativum ethanolic extracts on the tomato leaf miner, Tuta absoluta Meyrick were evaluated under laboratory and screen house conditions. The threes life stages (eggs, second instar larvae and adults) of the tomato leaf miner were involved in the experiment. All the life stages of tomato leaf miner were treated topically with the plants extracts at (2%, 4% and 8%). The mean percentage mortality of eggs, second instar larvae and adults were recorded daily for 5 days. Results indicated that, each plant extract caused significant mortality to larvae and adults of T. absoluta after 5 days in comparison to the control. In laboratory, using the leaf dipping technique, Commiphora showed the highest effects on T. absoluta second instar larvae while Synadenium extract exhibited the least effect. The Commiphora ethanolic extract was the only one that showed potential to be used as a control agent against eggs as it led to 0% egg hatchability. Synadenium resulted in no mortality of T. absoluta eggs in this trial as there was 96.6% hatchability. Leaf dipping against second instar and adult of T. absoluta proved to be the most effective for all plants extracts at 30-100%. Commiphora resulted in the highest second instar larval and adults’ mortality of 100%. In the screen house Commiphora showed the high reduction of infestation for Tanya and Cal J varieties. Treatment with this plants extracts resulted in the highest fruit yield and the lowest yield loss compared to all the plant extracts. Commiphora swynnertonii extract is recommended into integrated pest management strategies for the control of T. absoluta.
Assessment of microbial contamination of raw cow milk and antimicrobial resistance of salmonella spp isolated in Ilala district, Dar es salaam, Tanzania
(Sokoine University of Agriculture, 2022) Jonathan, Agnes
The current cross sectional study was conducted to determine factors influencing microbial contamination, proportion and antimicrobial susceptibility profiles of Salmonella spp isolated from raw cow milk in Ilala district, Dar Es Salaam, Tanzania. A total of 138 smallholder dairy farmers were randomly selected and interviewed, and subsequently, milk samples were aseptically collected from Kivule, Kitunda, Magole and Ukonga between July and October 2020. Identification was done by conventional culture method, biochemical tests and serotyping. Disc diffusion method was used for antimicrobial sensitivity testing. Reference organisms used in the study included; Salmonella typhimurium (ATCC 14028) and E. coli (ATCC 25922). Results showed that, majority of smallholder dairy farmers were males with primary education, 8% of respondents consume milk from animals under medication and 23.9% did not adhere to withdrawal periods. Furthermore, results indicated that, 34.8% and 57.1% reported not to wash hands before milking and between milking different cows and 30.4% reported to milk sick cows practices which were found to significantly predispose milk to microbial contamination (p=0.000; p=0.001 and p=0.042) respectively. Out of 138 samples, 8 (5.8%) samples confirmed to be Salmonella whereby 3 were S. typhimurium, 3 were S. enteriditis and 2 were S. typhi. Kivule ward showed high prevalence (14.6%) of Salmonella than the other wards with no statistical difference (P>0.05) between them. Antimicrobial susceptibility results showed all isolates were resistant to ampicillin, amoxicillin/clavulanic acid and penicillin but susceptible to gentamycin, tetracycline, chloramphenicol, ciprofloxacin and trimethoprim-sulfamethoxazole and 100% of isolates showed multi-drug resistant against three antibiotics. This study revealed the presence of Salmonella in apparently healthy dairy cows in Ilala district with antimicrobial resistances. Improvement in animal husbandry practices and public education on general milk hygiene are recommended. Additionally, extension officers, veterinarians and all other stakeholders should play a part in ensuring that consumers receive safe, high-quality milk.
Assessment of microbiological hazards along the milk value chain in Kilosa and Mvomero districts, Tanzania
(Sokoine University of Agriculture, 2015) Joseph, Ernesta
The consumption of raw milk is a common practice among pastoral and agro-pastoral communities of Tanzania. This behaviour predisposes consumers to the risk of contracting milk-borne and zoonotic diseases. This study was carried out to assess milk quality based on identification of bacterial contaminants indicated by total viable count (TVC), total coliform count (TCC) and contamination with Brucella and E .coli 0157: H7 microorganisms. The study was carried out along the milk value chain (MVC) in Kilosa and Mvomero Districts of Morogoro Region in Tanzania. A total of 109 milk samples were collected along the MVC from farmers (54), milk vendors (31), milk collection centres (6) and milk selling points (18). Collected milk samples were subjected to TVC, TCC and polymerase chain reaction (PCR) to identify the presence of microorganisms in the milk. Laboratory findings indicate that milk from Kilosa district had significantly (p=0.015) higher TVC than milk from Mvomero district. The TVC varied significantly (p=0.00) along the MVC in the two districts. Using PCR, the overall prevalence of Brucella was 17.1% (n=82 out of 109), with the prevalence of 25.8% and 11.8% recorded in Kilosa and Mvomero districts, respectively. The E. coli 0157:H7 was neither isolated nor detected in all 109 milk samples processed. Such findings suggest that milk marketed along the MVC is contaminated with Brucella organisms, thus posing public health risks to consumers. It is recommended that concerted efforts should be made to safeguard health of consumers through adopting various interventions that would reduce risks at each node along the MVC in the study area.
Assessment of milk handling practices and bacterial contaminations along the dairy value chain in Lushoto and Handeni districts, Tanzania
(Sokoine University of Agriculture, 2013) Shija, Fortunate
Contaminated milk is responsible for up to 90% of all dairy-related diseases of humans. A cross sectional study was carried out in Lushoto and Handeni districts of Tanga, Tanzania to determine the milk handling practices, bacterial contamination and selected milk-borne zoonotic pathogens along the dairy value chain. A total of 93 respondents were interviewed and 184 milk and milk product samples were collected. Laboratory analysis of total and coliform plate counts, detection of Escherichia coli O157:H7 and Brucella abortus using polymerase chain reaction (PCR) were done. Results showed that, most farmers (57 %) milked their cows under unhygienic conditions. More than 60% of farmers did not clean their hands, wash cow teats and clean animal houses before milking. The majority (92.1%) of farmers were not trained on livestock keeping and milk handling. Although the mean TPC was within the East African Community (EAC) standards, general counts ranged between 3.3 to 5.8 log10. Eighty seven and 93% of milk from farmers and vendors, respectively, did not meet the TPC EAC standards. All the collected milk did not meet the CPC EAC standards, indicating contamination of milk with coliforms. PCR analyses did not detect E. coli O157:H7 in all the tested samples while B. abortus was detected in 37 out of 87 samples tested. It was concluded that unhygienic practices of milking and post-harvest handling along the dairy value chain possibly contributed to microbial contamination of milk. Detection of B. abortus in milk is of public health significance due to its zoonotic potential. It is recommended that veterinary/extension services be provided to livestock farmers on proper animal husbandry and control of zoonotic animal diseases. Public education should be given to all stakeholders in dairy industry on milking and post harvest handling of milk to curtail the likely losses due to rejection of spoiled milk and milk-borne pathogens resulting from contamination of milk.