Veterinary Medicine

Permanent URI for this collection

http://41.63.25.24:4000/handle/123456789/86

Browse

Now showing 1 - 5 of 122

Diversity of salmonella isolates from wildlife and domestic animals in selected areas of Zambia.
(The University of Zambia, 2020) Mubita, Charles Miyanda
Domestic animals and wildlife are considered important reservoirs from which Non-Typhoid Salmonella serotypes have emerged to cause public health concerns worldwide. Identification of the zoonotic origin of such organisms is important to understand the risk factors associated with a diversity of host types. In this study, phenotypic and genetic properties of Salmonella strains isolated from domestic animals and wildlife sources were characterized to determine their potential for causing invasive salmonellosis. The isolates were characterized into serogroups, serotypes, fermentative groups, resistotypes, and beta-lactamase activity types. Further, Salmonella plasmid virulence genes responsible for extraintestinal manifestations were determined among Salmonella serotypes from domestic animals (bovine, horse, dogs, and chickens) and wildlife (Leopard, Sable and Impala). Sequencing of the invA gene of Salmonella strains from different hosts and locations was performed and compared with reference sequences on the Gene-Bank. Thirty-four Salmonella strains belonging to four sero-groups; B, C1, D1, and a non- reactive group, were isolated and identified from the various animal hosts studied. The most prevalent sero-group was D1 (50.0%; 17/34) Salmonella strains, all from domestic animals followed by a non-reactive group (29.4%; 10/34) strains. Further, 12 serotypes, were detected among the strains. The most predominant serotype was Salmonella enterica serotype Enteritidis (47.1%; 16/34) isolated from horse and chicken, followed by S. Mbandaka (8.8%; 3/34) from dog and chicken. All Salmonella isolates were resistant to at-least four antimicrobial agents. Ampicillin, erythromycin, gentamicin, nitrofurantoin and penicillin G were observed as the most frequently resisted antimicrobial agents. Salmonella Enteritidis and S. Mbandaka isolated from the horse and dog respectively, each displayed multidrug resistance to 6 antimicrobial agents. All strains harboured Salmonella invasion A gene unique to the genus, while some strains possessed Salmonella plasmid virulence locus gene. The horse, leopard and chickens were found to be reservoirs of Salmonella isolates carrying spvA virulence genes and by consequence; these animals could serve as a reservoir for transmission of extra intestinal salmonellosis to humans and other animals through contamination of the environment. The homology percentage of nucleotide sequence (74.0 ~ 100.0) and amino acid sequence (60.0 ~ 100.0), showed genotypic differences between the strains isolated from domestic animals and wildlife, and the published sequences on the Gene-Bank. In conclusion, the present study isolated and identified multi-drug resistant Salmonella serotype strains that possess virulence genes which are of potential public health concern.
Prevalence and genotypic characterization of giardia duodenalis isolates and associated risk factors of infection from asymptomatic school-going children in Chawama, Lusaka district, Zambia.
(The University of Zambia, 2020) Tembo, Shadreck
Giardia duodenalis (synonyms: G. lamblia, G. intestinalis) is a mammalian infective protozoan flagellate which infects humans. The genus Giardia consists of six species, namely G. agilis, G. ardeae, G. psittaci, G. microti, G. muris and G. duodenalis. Among these species, only G. duodenalis is known to infect several hosts, including humans. G. duodenalis is said to be a species complex comprising of eight genetic assemblages (A to H) and infection in humans being mainly caused by assemblages A and B. The purpose of this study was to determine prevalence and genotypic characterization of Giardia duodenalis isolates and associated risk factors of infection from asymptomatic school-going children in Chawama, Lusaka, Zambia. A cross-sectional study was conducted between May and September 2017. A total of 329 faecal samples were collected from school-going children in Chawama within Lusaka City. G. duodenalis isolates were detected in asymptomatic school-going children aged three to sixteen years. All microscopically positive faecal samples were analyzed by semi-nested polymerase chain reaction (PCR) targeting the glutamate dehydrogenase (gdh) gene. Genotyping of amplified PCR products were further analyzed by restriction fragment length polymorphism (RFLP) and DNA sequence analysis. The microscopic examination of faecal samples showed 10% (33/329; 95% CI = [0.07 – 0.13]) prevalence of G. duodenalis infection. The infection amongst girls was 12% (22/183; 95% CI = 5 – 61) and 7.5% (11/146; 95% CI = [0.39 – 0.49]) amongst boys. Giardia infections were more observed in children enrolled in public schools (15.4%, 19/123; 95% CI = [0.32 – 0.43]) than those in community schools (6.8%, 14/206; 95% CI = [0.57 – 0.68]) and infection was significantly (p = 0.011) associated with the type of school. The PCR-RFLP analysis revealed assemblages A and B in 27.3% (9/33; 95% CI = [0.14 – 0.46]) and 72.7% (24/33; 95% CI = [0.54 – 0.86), respectively. Furthermore, analysis with restriction enzymes identified sub-assemblages AII (27.3%, 9/33; 95% CI = [0.14 – 0.46]), BIII (12.1%, 4/33; 95% CI = [0.04 – 0.29), BIV (51.5%, 17/33; 95% CI= [0.34 – 0.69) and mixed BIII/BIV (9.1%, 3/33; 95% CI = [0.03 – 0.26]) infections. Assemblage B and sub-assemblage BIV infection was predominant in this study. However, no statistical significance (p > 0.05) was found between G.duodenalis assemblages/sub-assemblages and sex or age. The phylogenetic analysis showed the clustering of 27.6% (8/29; CI = [0.14 – 0.48]) and 72.4% (21/29; CI = [0.52 – 0.86]) of Zambian Giardia gdh gene sequences into assemblages A and B, respectively. This study provides the first report on genotypic characterization of G. duodenalis infection in children in Chawama, Lusaka District, Zambia. The study revealed the circulation of assemblages A and B infection, which were further split into sub-assemblages AII, BIII and BIV. Mixed infections were observed between BIII/BIV. The assemblages detected could suggest anthroponotic transmission. The prevalence of Giardia infection was lower compared to previous surveys done in Zambia. Giardia infection was significantly associated with the type of school that children attended. Therefore, control measures aimed at improving hygiene in schools and the communities, along with education campaigns could help in curbing giardiasis.
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.
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.
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.

Browse

Recent Submissions