To assist in the evaluation of BCG vaccination in African buffaloes (Syncerus caffer), an infection model for Mycobacterium bovis was established, using an intratonsilar route of inoculation. Two groups of 11 buffaloes each, aged approximately 18 months, were infected with either 3,2 x 102 cfu (low dose) or 3 x 104 (high dose) of virulent buffalo strain M. bovis. A control group of six buffaloes received saline via the same route. The infection status was monitored using the intradermal tuberculin test, an ELISA and a modified interferon-gamma assay. All buffaloes were euthanased 22 weeks post infection and the development of lesions in the left retropharyngeal lymph node was evaluated by macroscopic examination, mycobacterial culture and histopathology. It was found that the high dose caused macroscopic lesions in 9 out of 11 buffaloes that were comparable to that observed in buffaloes with natural disease. Mycobacterium bovis was isolated from all animals in the high dose and from 6 out of 11 buffaloes in the low dose group. The efficacy of a live BCG-Pasteur vaccine was tested in a group of buffalo calves captured in the northern districts of the Kruger National Park from herds with known negative tuberculosis status. Primary and booster vaccinations with BCG (1173P2) were administered to 15 calves, while another 15 were left unvaccinated as control animals. All the buffalo calves were challenged with the high dose of live M. bovis (as determined in the Infection Model) via intratonsilar inoculation. Laboratory tests were able to distinguish between infected and non-infected animals from an early stage. All buffaloes were euthanased 34 weeks after infection and the development of lesions in the lymph nodes of the head, thorax, carcass and abdomen was evaluated by macroscopic examination, mycobacterial culture and histopathology. The lungs were carefully palpated to detect the presence of tuberculous granulomas. Macroscopic lesions in the lymph nodes were found in 10 out of 14 control buffaloes and 7 out of 15 vaccinated animals. The lesions were comparable to that observed in buffaloes with natural infection. The lesion scores of individual animals were generally much higher in the BCG vaccine study than what was experienced with the Infection Model. Mycobacterium bovis was isolated from 12 out of 14 control animals and from 12 out of 15 vaccinated buffaloes. Although fewer vaccinated animals developed tuberculous lesions, the differences between the two groups were not statistically significant and it can be concluded that under the prevailing conditions the BCG vaccine was unable to protect buffalo calves against the establishment of M. bovis infection. / Dissertation (MSc (Tropical Diseases))--University of Pretoria, 2004. / Veterinary Tropical Diseases / unrestricted

The objective of this project was to design tools for a diagnostic test that will prove valuable in the detection of tuberculosis in elephants and rhinoceros by using the cytokine IFNγ as an indicator of Mycobacterium bovis responsiveness. Interferon-gamma (IFNγ), a type II interferon, is a cytokine mainly produced by Th1 and cytotoxic T-cells expressing surface markers CD4 and CD8, respectively and natural killer cells (Ibelgaufts; 1999). In response to a mycobacterial infection antigen specific Th1- and cytotoxic T-cells are induced. When these cells encounter their specific mycobacterial antigen, they will respond by producing IFNγ. Based on this principle a diagnostic test was developed. In this test PBMCs will be stimulated with M.bovis specific antigen and the subsequent production of IFNγ by specific T-helper cells will be determined by IFNγ of elephants and rhinoceros. In order to develop such an assay recombinant elephant and rhinoceros IFNγ was cloned, sequenced, expressed, purified and subsequently a monoclonal antibody against IFNγ was produced. Monoclonal antibodies were selected by a number of ELISAs using recombinant IFNγ. Preliminary results are promising and further tests are underway regarding the specificity and sensitivity of the assay before field trials can be performed. The results of this study has significant implications in the design of an IFNγ diagnostic kit for the diagnosis of tuberculosis, as caused by M.bovis, in elephants and rhinoceros as well as other wildlife affected by this debilitating disease. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2003. / Veterinary Tropical Diseases / unrestricted

Bovine babesiosis occurs worldwide and is one of the most costly tick-borne cattle diseases in the tropics. The Soutpansberg region of the Northern Province in South Africa is endemic for Babesia bigemina, but Babesia bovis was only reported from this area in the 1980s when some farmers experienced heavy losses due to Asiatic redwater. The main objectives of the study were to confirm the presence of the tick vector Boophilus microplus in the Soutpansberg region where it had not been reported previously, and to determine the seroprevalence of Babesia bovis and Babesia bigemina in cattle in these areas. Other objectives were to assess the relative numbers of Boophilus microplus in relation to Boophilus decoloratus and to determine a possible displacement of Boophilus decoloratus by Boophilus microplus. It was also the intention to map the potential distribution of the Boophilus ticks in the area and to more accurately predict the further spread of Boophilus microplus. Tick collections and serological surveys were carried out during 1999 and 2000 on cattle at 30 communal dip tanks and on 5 commercial farms in the Soutpansberg, Dzanani, Mutale, Thohoyandou and Vuwani Districts. Of the 25,042 Boophilus ticks collected, 93.9 % were Boophilus microplus and 6.1 % were Boophilus decoloratus. At 8 of the dip tanks/farms both Boophilusspecies were found, and the displacement of Boophilus decoloratus by Boophilus microplus was monitored at 4 of these sites. There was a distinct displacement of Boophilus decoloratus at those dip tanks/farms where repeated tick collection was possible. Cattle at the communal dip tanks carried larger Boophilustick numbers than cattle on the commercial farms. Boophilus microplus was the most common Boophilustick collected at the dip tanks, and during the survey it also became the Boophilustick most commonly found on the commercial farms. CLIMEX was used to map the potential distribution of Boophilus microplus and Boophilus decoloratus in the survey area during years with average as well as double average rainfall. Ecoclimatic Indices were computed for each sampling location, using 30 years of climatic information. The displacement patterns of Boophilus species were also discussed. Blood samples (n = 2201) were collected for Indirect Fluorescent Antibody (IFA) testing. Serological evidence of Babesia bovis was detected in 97 % of the communal dip tank herds and in 100 % of the commercial farm herds. The overall seroprevalence of Babesia bovis in the dip tank herds during 1999 and 2000 was 63 %. The seroprevalence of Babesia bovis in the commercial herds increased significantly from 19 % in 1999 to 57.5 % in 2000. There was a slight increase in endemic stability in comparable herds from 1999 to 2000. The increase in seroprevalence and endemic stability probably came as a result of the influx of Boophilus microplus into the survey area. There was a significant correlation between the presence of Boophilus microplus in the survey area and the increasing seroprevalence of Babesia bovis, which confirms that Boophilus microplus is the main and probably the only vector of Babesia bovis in South Africa. Serological evidence of Babesia bigemina was detected in 100 % of communal dip tank and commercial farm herds. The overall seroprevalence of Babesia bigemina in the dip tank herds decreased significantly from 56.1 % in 1999 to 49.3 % in 2000. There was a marked decrease in endemic stability for Babesia bigemina in comparable dip tank herds from 1999 to 2000. The decrease in seroprevalence and endemic stability to Babesia bigemina in these herds was probably due to the substantial increase of Boophilus microplus in the survey area. This may indicate that Babesia bigeminaa was transmitted less effectively by Boophilus microplus than by Boophilus decoloratus. The seroprevalence of Babesia bovis was significantly higher than that of Babesia bigemina at those dip tanks/farms where only Boophilus microplus was present during 1999 and 2000. This may be explained by the possibility that Boophilus microplus transmits Babesia bigemina less effectively than it transmits Babesia bovis. This survey raises several questions on the ability of the African strain of Boophilus microplus to transmit African Babesiastrains. There are indications that the African Boophilus microplus is different to the Australian Boophilus microplus. More research needs to be done to investigate how the Babesia species are transmitted in Africa. / Dissertation (MSc (Veterinary Sciences))--University of Pretoria, 2002. / Veterinary Tropical Diseases / unrestricted

Ulcerative balanoposthitis and vulvovaginitis is a disease characterized by erosion and ulceration of the glans penis and muco-cutaneous junction of the vulval lips of sheep. The disease was first recognized in South Africa in 1979 in the Calvinia district, Northern Cape province, and its distribution has since extended to all major Dorper sheep farming areas of the country with serious economic consequences. It is now a major concern for Dorper sheep breeders and farmers due to the fact that the disease has a detrimental effect on conception and subsequent lambing percentages. The aetiology and epidemiology of the disease are not well established. During this study the microbial flora in the genital tract of both clinically healthy and infected sheep were compared. The aim was to isolate and identify the pathogenic microorganism/s that contribute to the disease in sheep and to determine the in vitro antimicrobial susceptibility of the isolates. Flocks of sheep in the Northern Cape province showing clinical signs of ulcerative balanoposthitis and vulvovaginitis were examined. The microbiological flora of 116 clinically unaffected sheep and 104 affected sheep from 15 different farms, and with characteristic ulcerative lesions were examined. Swabs from rams and ewes were collected aseptically, and put into cryovials consisting of transport medium for bacterial, mycoplasmal and viral maintenance. Swabs for Chlamydophila species antigen detection were placed into tubes without transport medium. All specimens were processed for virus isolation in cell culture, Chlamydophila antigen detection with ELISA, and bacteria and mycoplasmas were isolated on standard culture media. The latter were further identified with biochemical tests and indirect immunofluorescence antibody (IFA) test. The IFA test was found to be useful when contamination with other microorganisms was prevalent, especially in genital tract specimens. This procedure had reduced the necessity for sub-culturing and cloning. The IFAT was found to be effective for the identification of Mycoplasma spp. growing on primary growth media in mixed cultures. The technique also helped to confirm the presence of mycoplasmas that did not produce typical colonies, and it was possible to identify mycoplasma colonies overgrown by bacterial contaminants. Bacteriological examination of materials from affected and unaffected ewes and rams resulted in the isolation of a sizeable number of Arcanobacterium pyogenes. It was isolated from 44.2 % affected sheep and 17.2 % healthy ones. This isolation difference was statistically significant (p<0.01). Seventy four per cent of the isolates came from severe clinical cases. There were no significant differences in isolations of Corynebacterium species and streptococcus species between normal and clinically affected sheep. The mollicutes isolated from the genito-urinary tract of the sampled sheep included Mycoplasma mycoides mycoides large colony, Mycoplasma species Group 7, Mycoplasma capricolum, Mycoplasma capri, Mycoplasma bovigenitalium, Mycoplasma agalactiae, Mycoplasma arginini, and unidentified Mycoplasma spp. and Acholepalsma laidlawii and Ureaplasma species. Mycoplasma was isolated from 49.3 % of 116 clinically normal sheep and 78.2 % of 104 affected sheep. There were significant differences in rates of isolation among clinical groups (p<0.05). Of all the mycoplasma isolates, Mycoplasma mycoides mycoides LC was isolated from 61.5 % of clinically diseased sheep while 6.0 % of the isolates were from apparently healthy animals (p<0.05). There was a significant association between the degree of the severity of the lesion and the rate of isolation of M mm LC (p<0.05). The extent of the isolation of M mm LC suggests a causal relationship with ulcerative balanitis and vulvitis in sheep in South Africa. The present findings, together with those of Trichard et al, (1993), showed that M mm LC is the major pathogenic mycoplasma incriminated in ulcerative balanitis and vulvitis in sheep in South Africa. However, results also point towards other pathogens such as A. pyogenes playing a role in the pathogenesis of the disease and predisposing the genital tract to infection with mycoplasma. A number of other identified and unidentified strains of mycolasma were isolated from both clinically affected and healthy sheep. However, in genital tract infection is uncertain. Virus isolation efforts in cell culture and Chlamydophila antigen capture ELISA yielded negative results in affected rams and ewes, and healthy sheep. Current clinical observations during this project have shown that the typical ulceration appears to be confined to the glans penis and lips of the vulva and no ulceration has been observed on the shaft of the penis and vaginal vestibule. In uncomplicated cases inflammation of the prepuce and vaginal vestibule is not a regular feature of the disease. Therefore, the name ulcerative balanitis and vulvitis most accurately describe the clinical signs of the disease in South Africa. Age-related susceptibility to the disease was observed. Young sheep are 2.5 times more likely to have the lesion than adult sheep (p<0.05). It was also observed that male sheep acquire severe lesions more often than female sheep. Since, infection in both male and female sheep can spread by coitus, it may valuable to attempt detection of infected animals and follow a strict isolation policy. In addition, further studies to elucidate predisposing factors related to management and environment are required. The in vitro activities of enrofloxacin, florfenicol, oxytetracycline and spiramycin were determined against field isolates of MmmLC by means of the broth microdilution technique. The minimum inhibitory concentrations (MIC) of these antimicrobial drugs were determined for a representative number of 10 isolates and one type strain. The susceptibility of A. pyogenes to enrofloxacin, oxytetracycline and tilmicosin was determined by means of agar disk diffusion test. The MICs of enrofloxacin, florfenicol, oxytetracycline and spiramycin were within the ranges of 0.125-0.5, 1.0-2.0, 2.0-4.0 and 4.0-8.0 µg mℓ-1, respectively. This study has shown that resistance of MmmLC against enrofloxacin, florfenicol, oxytetracycline and spiramycin was negligible. All tested field strains of A. pyogenes were susceptible to enrofloxacin, oxytetracycline and tilmicosin with mean inhibition zones of 30.6, 42.3&35.8 mm, respectively. Although, there is a lack of data on in vivo efficacy and in vitro MIC breakpoints of these antimicrobial drugs for MmmLC, the MIC results indicate that these 4 classes of antimicrobial drugs should be effective in the treatment of ulcerative balanitis and vulvitis in sheep in South Africa. / Dissertation (MSc (Microbiology))--University of Pretoria, 2003. / Veterinary Tropical Diseases / unrestricted

A twelve-month study was conducted at four communal grazing areas namely, Oakley, Cunningmore, Mkhuhlu and Ronaldsy in the Bushbuckridge region, Limpopo Province, South Africa. The main objective of the study was to investigate the impact of reduced acaricide application on the endemic stability to bovine babesiosis (Babesia bigemina and Babesia bovis) and anaplasmosis in a sample of the local cattle population. The study should be of assistance to farmers who are attempting to move from intensive to strategic tick control strategies and reduce the frequency of dipping, whilst maintaining endemic stability. Sixty cattle per communal grazing area were bled at the beginning and the end of the experimental period and the sera were assayed for B. bovis, B. bigemina and Anaplasma antibodies. Cattle in the intensively dipped group were dipped 26 times and maintained on a fourteen-day dipping interval throughout the study, whereas, cattle in the strategic group had their acaricide application frequency reduced and were only dipped 13 times. Three cattle per village were selected from which adult ticks were collected and immature ticks were also collected by dragging the veld. A questionnaire to assess the prevalence of clinical cases of tick-borne diseases, abscessation and mortalities was completed by an Animal Health Technician at each diptank during dipping. This was done to determine the number of clinical cases of bovine babesiosis, anaplasmosis as well as abscessation. An increase in seroprevalence to B. bovis and B. bigemina and a decrease in seroprevalence to Anaplasma was detected in the strategically dipped group whilst in the intensively dipped group a decrease in seroprevalence to B. bovis and B. bigemina and an increase in seroprevalence to Anaplasma was detected. Amblyomma hebraeum was the most abundant tick species found on the cattle in this region, whilst Rhipicephalus (Boophilus) microplus and Rhipicephalus (Boophilus) decoloratus were also collected and R. (B.) microplus was the more abundant of the two species. Drag samples yielded more A. hebraeum immatures than Rhipicephalus (Boophilus) and a seasonal pattern was displayed. An increase in the number of clinical cases of tick-borne diseases and abscesses was recorded at the beginning of the survey in the strategically dipped group. / Dissertation (MSc (Veterinary Tropical Diseases))--University of Pretoria, 2005. / Veterinary Tropical Diseases / unrestricted

no abstract available / Dissertation (MA (Afrikaans))--University of Pretoria, 2005. / Afrikaans / unrestricted

No abstract available / Dissertation (MArch (Prof))--University of Pretoria, 2006. / Architecture / unrestricted

Malaria kills nearly 1.5 million and affects more than 500 million people annually, mostly in sub-Saharan Africa. The malaria parasite has developed resistance against almost all of the known drugs used for treatment. This fact has resulted in a constant battle between developing new anti-malarials and the parasite evolving resistance. One of the main drug combinations, pyrimethamine/sulfadoxine, targets the dihydrofolate reductase (DHFR) and dehydropteroate synthase (DHPS) proteins in the folate synthesis pathway of human malaria parasite, Plasmodium falciparum. The folate synthesis pathway is absent from the human host and thus presents itself as an ideal target for parasite-specific drugs. The three dimensional atomic coordinates of a target protein can help in designing new, more effective drugs. Malarial proteins are notoriously difficult to crystallize and thus homology modelling was chosen as an alternative method to obtain a protein structure. DHPS and PPPK occur as a bifunctional protein in the folate metabolism pathway. In this study, homology modelling was used to do in silico modelling of P. falciparum DHPS and hydroxymethyldihydropteridine pyrophosphokinase (PPPK). For the P. falciparum DHPS model the crystal structures of M. tuberculosis and B. anthracis DHPS were used as templates and for the P. falciparum PPPK model, the crystal structure ofE. coli PPPK. Molecular dynamics was used to investigate loop movement in DHPS and PPPK as well as to reveal the effect of resistance-causing mutations on sulfadoxine binding in P. falsiparum DHPS. This study revealed that four of the five known sulfadoxine resistance-causing mutations in DHPS disrupt the interaction between sulfadoxine and DHPS. This translates to a reduced capacity for sulfadoxine to inhibit DHPS, and results in resistance. The simulations also showed that both DHPS and PPPK have extensive loop movements during catalysis. The loop movements in DHPS and PPPK may also play a role in determining the catalytic rate of the enzymes. The work presented here provides researchers with models of P. falsiparum DHPS and PPPK. These models can be used to design experiments to investigate resistance, design new drugs and probe the structure of the PPPK-DHPS bifunctional enzyme. / Dissertation (MSc (Biochemistry))--University of Pretoria, 2005. / Biochemistry / unrestricted

I did my utmost best to present what I consider to be the essence of human rights from the perspective of the Bible. In my view human rights are a modern discovery and re-defining of what had long been implied, acknowledged and taught in the Bible. The implied form and acknowledgement of human rights in the Bible need not be overshadowed and hidden away by many of Bible characters’ sinful nature and acts (as all Bible characters except Christ were also born with a fallen and sinful nature, which needed God’s redemption by faith). Instead, they need to be perceived in God’s divine intention, which has progressively been revealed in God’s interaction with the Israelites and other nations and culminated in both the personhood and exemplary saving acts of Jesus Christ (Romans 3:23,24). My opinion is that in the Bible human rights have been expressed in the context of both the Israelite religion and culture, whereas currently there is a need and tendency to express them in an inter-cultural approach, which is driven by the trend of globalization. While in modern times context human rights have been expressed as human rights, in the Bible context they had long been implied in and acknowledged and expressed as an integral part of every person’s free will of choice imparted at man’s creation. In my view the Bible is authoritative because it is probably the only classic book that identifies every human being with our creator, God. It highlights the need for and possibility of a unique God-man relationship, which all people are worthy of to be identified with the only highest being such as God. The Bible serves as the source of information about the needed meaningful relationship that identifies people with their creator, God. It contains stories that inform us about various people’s counter-active relationship with God. Its authority, in my opinion is further demonstrated by the way it shows the necessity and possibility of developing the creator-creature (i.e.God-man) relationship, which lifts up human beings to the status above all other creatures. The authority of the message of the Bible from its various stories needs to be understood and accepted in the light of Christ’s exemplary constructive attitude towards the Scriptures of his time. His un-conniving but constructively critical attitude towards the unacceptable cultural aspects before and during his time show us the exemplary attitude people must adopt towards all cultures and the Bible. My opinion is that Christ needs to be seen as a corrective measure against both Bible and non-Bible characters before his time. He also needs to be seen as the role model to all people of our times, so that we can meaningfully implement and promote human rights. Christ-like love and attitude towards other people need to underscore everything we do or say in order that we may meaningfully implement and promote human rights. Human dignity, in my opinion, is one of the underlying factors, which has undisputedly long been acknowledged and promoted by the Bible. The identification of every person with the creator of the universe, God, implies the acknowledgement of human dignity in the highest dimension that cannot be surpassed by anything. Human dignity in the light of man’s identification with God puts God as the highest moral criterion worthy to be complied with by every person. Human dignity also implies that every person was created and is born with a free will of choice. With free will of choice goes the responsibility for every personal choice made by a human being at the age of accountability. In my opinion there is commonality between the need for every person to be accountable and God as every person’s highest moral criterion worthy to comply with. Current controversy on homosexuality is regarded by me as a situation that challenges us to agree to disagree as groups and individuals. None of us should judge another. None should compel the other to think and believe against personal choice. While there will always be disagreements, it is only practical outcomes of our choices and acts which help us have a much more objective judgement of them. The present general consensus on promiscuity as one of the contributing factors to the spread of HIV/AIDS is a good example. Here the ultimate concrete results serve to unite the previously divided opinions on the culpability of promiscuous life style, which according to human rights is blameless as a result of consensus of two individuals. In the words of Jesus (Matthew 13:24-30) undisputable judgement will finally be affirmed by God. My opinion is that God’s judgement will amaze all people. God’s ways and thoughts are higher than human beings’ ways and thoughts, (Isaiah 55:9). Therefore, his judgement will be unique. He will judge people’s acts and thoughts in the light of seen and unseen motives behind them. While every person has the freedom to choose what he or she wants to be, every person is accountable for the outcomes of his or her choice and actions. ‘Everything is uncovered and laid bare before the eyes of him to whom we must give account,’ (Hebrews 4:13). / Thesis (PhD (New Testament))--University of Pretoria, 2004. / New Testament Studies / unrestricted

An increasing number of ebusiness projects are undertaken as voluntary collaborations of independent organizations. These projects are known as ‘ebusiness collaborative projects’. Industry sources estimate only about 20% of these projects achieve their stated objectives due partly to inadequate project management. The volunteer and virtual nature of the collaboration and relationships among the participating organizations means existing project management frameworks and methods are not appropriate because they assume project management has authority, or that projects occur within a single organization. This thesis investigates the nature of ebusiness collaborative projects to provide insight into management approaches that increase the likelihood of success. The research questions are: What concepts need to be addressed in a framework capable of supporting effective management and providing an understanding of ebusiness collaborative project outcomes? Is there an existing framework with this capability? Are the concepts supported by empirical evidence and a sound theoretical base? Can these concepts be used to form an integrated framework suitable for use by practitioners? A qualitative meta analysis of 6 published case studies identified characteristics that explained challenges specific to ebusiness collaborative project management. Empirical research identified concepts that need to be addressed in a management framework, namely: 3 organizational levels – organizations, teams and representatives; 3 stages of the eBusiness Collaborative Project Lifecycle© and; 4 management meta factors - motivation, capability, communication and coordination These concepts were supported by theory. In the absence of an existing framework, the concepts were used to develop the Integrated Framework for Managing eBusiness Collaborative Projects. Five additional case studies were used to evaluate the Integrated Framework and its usefulness for practitioners. Findings indicate the Integrated Framework is capable of supporting effective management and providing an understanding of the outcomes of ebusiness collaborative projects within the Australian context. This thesis contributes to knowledge by integrating and building on theory and existing research about project management, collaborations and virtuality and applying these findings to a real world environment. The Integrated Framework enhances industry best practice and may apply to all collaborative projects in which participating organizations volunteer to work towards an agreed objective or outcome.