Veterinary Medicine

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    Bacterial contamination determination and performance of a solar heater in the pasteurisation of cow milk in Western province, Zambia.
    (The University of Zambia., 2019) Chibwe, Mary
    Although milk contains many nutrients necessary for growth, raw milk may harbor numerous pathogens. The milk pathogens may be shed in harvested milk from an infected animal and may transmit zoonotic diseases. Consumption of raw milk is common in developing countries. However, milk needs to be pasteurised to render it safe for human consumption. In resource poor communities milk pasteurization is hindered due to lack of access to electricity and heat energy forcing people to consume raw milk. In this study, the presence of pathogens in raw milk was investigated and the identified pathogens were subjected to solar heating in order to determine the possible u province was collected. The collected milk was subjected to bacterial contamination determination and identification of selected bacterial species. Escherichia coli, Staphylococcus aureus and Bacillus species were identified as the major contaminants. Milk contaminated with these pathogens was subjected to heating using conventional methods and solar heating in the months of April, May, June and July 2017. Furthermore, other organisms that included Salmonella and Methicillin resistant Staphylococcus aureus were also subjected to solar heating. Further, 63 farmers who supplied milk to the milk collection centres in the study area were interviewed in order to capture bio-data, milk handling and consumption practices. The results indicated that solar heating is not effective in the cooler months of the year. It was also observed that sterilized milk allows rapid bacteria proliferation when contaminated compared to raw milk suggesting the presence of intrinsic antimicrobial factors in unsterilized milk. Pasteurization using electricity is expensive for rural communities and solar energy is a cheaper source of energy which can be used to inactivate pathogens in the months with no cloudy cover. This study also demonstrated that consumption of raw milk is a common traditional practice in western province where knowledge and application of good hygiene practice during milk collection, storage and transportation is inadequate. There is need to discourage consumption of raw milk and promote boiling of milk using affordable and environmentally friendly methods. More milk collection centres need be established and the traditional farmers should be trained in milk handling.
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    Social determinants of human anthrax transmission in Zambia.
    (The University of Zambia., 2019) Sitali, Doreen Chilolo
    Zambia has experienced an unprecedented increase in the number of human anthrax outbreaks in the Western Province where cycles of epidemic outbreaks commonly occur at the onset of rains after prolonged dry periods and frequent outbreaks occur in Chama District of Muchinga Province. Epidemics are triggered by an interplay of environmental and human activity factors. Notwithstanding that ecological and epidemiological factors have been researched to some extent, there is insufficient information concerning the social factors that influence human behavior associated with anthrax transmission in Zambia. The study was set to explore the socio-economic, cultural and political determinants associated with human anthrax transmission in Zambia. The study was conducted in the Western and Muchinga Provinces of Zambia. A convergent parallel mixed methods design was used to collect both quantitative and qualitative data. A questionnaire survey involving 1,127 respondents, six focus group discussions, and eight key informant interviews were conducted to collect data. The respondents included cattle farmers as well as those who are in contact with animals. Descriptive statistics of quantitative data and thematic analysis of qualitative data were run concurrently but separately. The use of matrices facilitated interpretation of both quantitative and qualitative results. Many of the socio-demographic and socio-economic characteristics of respondents suggested that the majority were living below the poverty datum line. A larger proportion (85%) of respondents never attended school. The study also found that most of the respondents in both regions (76%) in Western and (51%) in Muchinga respectively, had no access to safe drinking water and sanitation facilities. The study further established that, though the majority (88%) of respondents were knowledgeable about anthrax and knew that vaccination was a useful preventive measure, they had negative attitudes towards most control measures due to low perceived efficacy of the vaccine and lack of trust of professional staff. Also, 78.1% of those interviewed ate, sold or shared meat from dead animals suspected to have died of anthrax. A large proportion (68%) of respondents participated in slaughtering moribund animals, and only 13% had their cattle incinerated or buried when they died of disease. Based on the study findings, it can be argued that poverty; cultural practices such as mafisa (a traditional practice common in the Western Province where a cattle owner entrusts his cattle to another herder to reduce risk of losing all the animals), gender roles and responsibilities, and socio-economic factors are fundamental drivers influencing human anthrax transmission. Also, lack of community involvement, inadequate collaboration among veterinarians, ecologists, medical professionals, and social scientists, and inadequate logistical support adversely affects the control of anthrax in the communities affected. Lastly, geographical remoteness of the two regions compromised the effective monitoring and control of the disease by veterinary staff. Based on the study’s findings, government needs to provide funding for anthrax control and tackle poverty. Collaboration with ecologists, medical professionals, and social scientists within the One Health framework is essential to effectively tackle the socio-cultural issues surrounding cattle rearing and meat consumption beliefs. There is need to conduct a comparative random sampling based study that will allow for generalization of findings and provide a comprehensive understanding of how different factors shape anthrax transmission.
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    Zoonotic bacteria and their exposure factors in aquaculture in Chirundu and Siavonga districts of Zambia.
    (The University of Zambia., 2021) Chitambo, Bertha
    This study aimed to identify bacterial pathogens with zoonotic potential found in fish in Chirundu and Siavonga districts of Zambia. Accordingly, a total of 63 fish and 59 water samples from three fish farms (ponds and cages) were aseptically collected and bacteria isolated from the skin, gills, liver, spleen and intestines of fish and from the water samples. Isolates were identified through standard bacteriological methods through culturing, morphological characteristics, Gram staining characteristics and a series of biochemical tests. The following well-known fish pathogens were identified with attendant prevalence of, Aeromonas 13.2%, Lactococcus/Streptococcus 4.2% and Staphylococcus 18.1%. Other bacteria with varying significance as fish pathogens were also identified including Acinetobacter 2.1%, Aequorivita 1.4%, Aerococcus 1.4%, Bacillus 2.1%, Bordetella 2.1%, Carnobacterium 10.4%, Citrobacter 3.5%, Clostridium 2.1%, Corynebacterium 1.4%, Dermatophilus 1.4%, Enterococcus 2.1%, Escherichia coli 0.7%, Flavobacterium 4.2%, Klebsiella 6.9%, Lactococcus 2.1%, Listeria 0.7%, Micrococcus 6.9%, Planococcus 1.4%, Proteus 1.4%, Pseudomonas 6.3%, Rhodococcus 1.4%, Shewanella 1.4%, Streptococcus 0.7% and Vagococcus 0.7%. Aeromonas, Bacillus, Clostridium, Escherichia coli, Klebsiella, Lactococcus, Listeria, Staphylococcus and Streptococcus were of zoonotic importance. The three farms had various production types from which the general exposure factors were identified following visual determination. All key determinants in the exposure pathway were categorized under demographical, biological, environmental and/or management factors. These were then processed individually before being combined into a final framework to inform the impact pathway using the spider web analysis to aggregate exposure factors. The current study provides baseline information for future reference and implementation of public health guidelines regarding fish disease and the health of consumers in the country.
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    Milk hygiene assessment and characterization of staphylococcus aureus associated with the dairy value of chain in Western, Lusaka and Southern provinces of Zambia.
    (The University of Zambia, 2021) Phiri, Bruno Stephen July
    Raw milk provides a good environment for the growth of a wide variety of microorganisms including Staphylococcus aureus (S. aureus) and can be a vehicle to transmit such pathogens to humans. The study aimed to investigate milk hygiene practices and characterize S. aureus/MRSA associated with the Zambian dairy chain in the selected Provinces and reduce the risk to consumers. A total of 1939 samples (of different matrices) were collected from 288 facilities (farms, milk collection centres (MCCs), traders, processing plants, traditional markets, and supermarkets/shops). Microbiological methods were used to analyse the samples with regard to S. aureus, including methicillin-resistant S. aureus (MRSA). A total of 348 presumptive S. aureus isolates (including one presumptive MRSA) were isolated. Molecular characterisation was used to type and characterise isolates of which 295 were confirmed by MALDI-TOF MS and PCR. No MRSA was detected. Raw milk from farms was widely contaminated with S. aureus in all the three provinces (Western: 46 percent, Lusaka: 43 percent and Southern: 33 percent) including that from MCCs and traders in Western and Southern provinces. Raw milk and/or sour milk samples from traditional markets and raw milk samples from milk processing plants were contaminated with S. aureus in all three provinces. S. aureus was less frequently detected from hands and nasal swabs from milkers, milk buckets and mastitis cows. No S. aureus was detected from water and commercially processed (heat-treated) dairy products from supermarkets/shops. A total of 36 known spa types were detected including seven novel types: t18396, t18397, t18398, t18399, t18400, t18402 and t18416. Spa type t355, t267 and t084 were common in all the three provinces. Many isolates from Lusaka province belonged to t189 and t267, while in Southern province t521 was dominant. Diversity and differences in the distribution and pattern of virulence, enterotoxin and antibiotic resistance genes were detected. A total of 29 S. aureus strains (10 percent) carried genes that codes for the virulence factor Panton-Valentine leucocidin (PVL). In addition, many of the 77 isolates selected for detailed characterisation by microarray or whole genome sequencing carried the virulence genes hlgA, hlgB, hlgC, lukD, lukE, lukY, lukX, and/or hlb; some isolates carried at least SplA, SplB, sak, chp and/or scn while other strains harboured eta and tst1. Genes for staphylococcal enterotoxins (SEs) were found in only 16 out of 77 isolates. Of the classical SE genes, sea was found in two isolates, seb and sec in three each, and sed in one. The predominant antimicrobial resistance in isolates included penicillin (41.7 percent), tetracycline (33.3 percent) and trimethoprim (27.8 percent) and 19.4 percent were multi drug resistant (MDR). Enterotoxigenic, virulent and antibiotic resistant S. aureus strains are circulating in the Zambian dairy value chain and represent a public health threat. The possible transmission of S. aureus to humans through cow milk is indicated. Therefore, there is a need for improved milk handling and hygienic practices at different stages/levels along the entire Zambian dairy value chain.
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    Antibiotic susceptibility of E. coli isolated from dry fish sold in local markets in Lusaka, Zambia.
    (The University of Zambia, 2018) Nyimbili, Lillian
    Escherichia coli has been known as one of the most common bacteria found in the intestinal tract of human and warm blooded animals. It is the major causative agent of serious infections and a mediator of drug resistance through the production of Extended Spectrum Beta-Lactamase enzymes(ESBL) that hydrolyse the beta-lactam ring on most of the beta lactam antibiotics including of penicillins, cephalosporins, and the monobactam aztreonam. These antimicrobial resistant strains have become a global public health challenge affecting both humans and domestic livestock. In Lusaka and worldwide Fish is considered as a universal protein source consumed by a larger population of people. Some people also favour consuming raw dry fish. The objective of this study was to determine the antibiotic susceptibility and presence of resistant genes of E. coli isolated from dry fish sold in open markets of Lusaka district. A total of 120 fish samples were collected between July 2018 and August 2018. The fish samples were subjected to bacteriological analysis. Of the 120 samples of fish analysed for E. Coli 69 percent were positive for E. coli and 31 percent were negative. The determination of E. coli as an ESBL producing organism was determined by growing the bacteria on MacConkey agar containing 2 mg/L of cefotaxime. Following culturing of E. coli on MacConkey agar containing 2 mg/L of cefotaxime 46 isolates 55.4 percent were detected as ESBL-producing. The E. coli isolates presumably identified to be ESBL producing following culture on MacCkonkey agar supplemented with cefotaxime were subjected to PCR. A total of 35 out of 46 isolates were tested for the presence of the blaCTXM gene and out of these 21 were positive for the blaCTXM gene. Of the samples subjected to antimicrobial sensitivity test suggested that ESBL producing E. coli isolates had conferred resistance to beta-lactum antibiotics and other common antimicrobial agents. The results obtained indicate the need for surveillance on the emergence of antimicrobial resistance in fish sold in open markets and improve the food safety and hygiene of this important source of protein.