Browsing by Author "Magwedere, Kudakwashe"
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- ItemInvestigating the contributing factors to postmortem pH changes in springbok, eland, red hartebeest and kudu edible offal(AOSIS Publishing, 2013) Magwedere, Kudakwashe; Sithole, Fortune; Hoffman, Louw C.; Hemberger, Yvonne M.; Dziva, FrancisThe objective of the study was to assess pH measurements between offal organs of different species and the association between pH taken 4 h post-slaughter and different predictor variables in the liver and lungs. A linear regression analysis was conducted on selected variables to identify the main predictors and their interactions affecting the pH of meat 4 h post-slaughter. In an increasing order of magnitude during winter, the pH achieved at 16 h – 36 h post-slaughter in springbok heart, liver, spleen, kidney and lungs was significantly (p < 0.05) higher than pH 6.0. The pH attained in springbok carcasses was (p < 0.05) below 6.0, whilst no significant differences were observed from the regulatory reference (pH 6.0) in the heart. There was a positive association between the pH of game meat 4 h post-slaughter and liver congestion. The pH of game meat 4 h post-slaughter increased by 0.11 units (p < 0.05) per millilitre increase in liver congestion and decreased by 0.04 units (p < 0.05) per minute increase in the shooting-to-bleeding interval, irrespective of the species. The lack of a statistically significant association between some selected variables and pH changes in this study suggested that either the factors may have a small effect which is only detectable with large data-sets and/or the effect may be modified by other unidentified factors. As some of the offal organs had final pH readings above 6.0, alternative measures are required to inactivate certain endogenous pathogens in edible wild game offal sourced from endemic areas.
- ItemVeterinary public health aspects related with food-producing wildlife species in the domestic animal, human and environment interface(Stellenbosch : Stellenbosch University, 2013-03) Magwedere, Kudakwashe; Hoffman, Louwrens C.; Dviza, F.; Hemberger, Y. M.; Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Sciences.ENGLISH ABSTRACT: The wildlife industry in Namibia continues to grow as the production and consumption of game meat increases. However, the health risks posed by the trade in wildlife and related by-products to livestock and humans have not been fully assessed. The main objective of this study was to investigate the potential health risks related to the increased consumption of game meat and relevant by-products by assessing the quality of game meat, as well as determine the role of game meat species in the transmission of zoonoses. The microbiological quality and safety of export game meat was assessed. No differences in the aerobic plate count (APC) were observed between the years (2009 and 2010), but the mean Enterobacteriaceae count was 1.33±0.69log10 cfu/cm2 compared to 2.93±1.50log10 cfu/cm2 between the years. Insignificant heterotrophic plate count (HPC) levels were detected in 9/23 field water samples, while faecal bacteria (coliforms, Clostridium perfringens and enterococci) were not isolated in all samples. Seven serogroups, with the exception of O26, were detected in exotic species. A white tailed deer sample had a serotype belonging to O45 which confirmed positive for stx1 gene. In springbok, 5/15 pools of faecal samples tested positive for the intimin gene. No Salmonella spp were isolated, and all E. coli isolates from the meat samples were negative for STEC virulence genes (i.e. stx1, stx2, eae and hlyA). A linear regression analysis was conducted on selected variables to identify the main predictors and their interactions affecting pH of meat 4 hours post-slaughter. In an increasing order of magnitude during winter time, the pH reached at 16-36hr post slaughter in springbok heart, liver, spleen, kidney and lungs was significantly higher than pH 6.0, while no significant differences were observed from the regulatory reference (pH 6.0) in the heart. There was a positive association between the pH of game meat 4hr post-slaughter, and liver congestion. The pH of game meat 4hr post slaughter, increased by 0.11 units per mL increase in liver congestion, and decreased by 0.04 units per minute increase in the shooting to bleeding interval, irrespective of the species. Worm eggs of strongylids, Strongyloides papillosus, Toxocara spp, Trichuris spp and coccidia were found in variable numbers in both springbok and gemsbok faeces, indicating a potential risk of transmission to other species in the ecosystem. On examination of carcasses, a novel parasite, Skjabinodera kuelzii, was identified and noted to be associated with inguinal fascia and renal fat, but the public health significance remains unclear. Nevertheless, S. kuelzii should be considered as of potential significance during routine game meat inspection. A total of 12 310 springbok were harvested from 26 commercial farms over a period of two years. Tissue samples (i.e. 60 livers, 41 kidneys and 52 hindquarter muscles) were collected from randomly selected healthy animals. The mean values (i.e. above the detection limit) of cadmium (Cd) and lead (Pb) were 0.10±0.05mg/kg and 1.04±0.21mg/kg in the liver, respectively; and 0.33±0.22mg/kg and 0.905±0.51mg/kg in the kidney of springbok, respectively. The levels of cadmium and lead in the hindquarter muscles were below the detection limit. Serum samples (n=1692) collected from sheep, goats and cattle from four presumably at-risk farms, and 900 springbok (Antidorcas marsupialis) serum samples collected from 29 mixed farming units, were screened for Brucella antibodies by using the Rose-Bengal test (RBT). Positive cases were confirmed by complement fixation test (CFT). To assess the prevalence of human brucellosis, 137 abattoir employees were tested for Brucella antibodies using the standard tube agglutination test (STAT), and the enzyme linked immunosorbent assay (ELISA). Cattle and sheep from all four farms were negative by RBT and CFT, but two of the four farms carried 26/42 and 12/285 seropositive goats, respectively. Post mortem examination of seropositive goats revealed no gross pathological lesions. Culture for brucellae from organs of seropositive animals was negative. None of the wildlife sera tested positive by either RBT or CFT. Occurrence of confirmed brucellosis in humans was linked to the consumption of unpasteurized goat milk, home-made goat cheese and coffee with raw milk and prior contact with goats. All abattoir employees (n=137) tested negative by STAT, but 3 were positive by ELISA. The three abattoir workers were clinically normal, and lacked historical connections with clinical cases. This study illustrates the importance of microbiological, parasitic and residue monitoring as critical components of a hazard analysis and critical control point based system for game meat. The study also provides the basis for increased integrated health research, surveillance and meat safety risk analysis.
- ItemZoonoses : a potential obstacle to the growing wildlife industry in Namibia(Taylor & Francis, 2012) Magwedere, Kudakwashe; Hemberger, Maria Y.; Hoffman, Louw C.; Dziva, FrancisZoonoses, which account for approximately 75% of emerging human infectious diseases worldwide, pose a re-emerging threat to public health. With an ever-increasing interrelationship between humans, livestock and wildlife species, the threat to human health will rise to unprecedented levels. Wildlife species contribute to the majority of emerging diseases; therefore, there is an urgent need to define control systems of zoonoses of wildlife origin but very little information exists. In this review, we examine prevalent zoonotic infections reported in Namibia between 1990 and 2009 and assess their potential impact on the growing wildlife industry. A wide spectrum of zoonotic diseases was confirmed in both livestock and wildlife species, with rabies and anthrax cases being over-represented and also showing the widest species distribution. Whilst vaccination and ante-mortem inspection against these diseases may curb infected livestock species from entering the human food chain, such practices are difficult to implement in free-ranging wildlife species. In this context, there is a need to improve existing control measures and/or develop novel and better interventional strategies to reduce the threat of this re-emerging global problem. This review provides the basis for initiating a multidisciplinary evidence-based approach to control zoonoses in countries with thriving wildlife and game farming.