Ticks and tick borne diseases remain a huge threat to livestock productivity the world over. While several efforts have been made to control ticks, current control measures are still not adequate. Conventionally, tick control programmes are heavily reliant on the use of synthetic chemical acaricides while the impact of other less frequently used control methods has not been fully established. Unfortunately, heavy chemical use has led to a number challenges that include: unsustainable high costs of acaricides, development of tick resistance, environmental pollution, contamination of animal products with chemical residues and many other topical issues. Ethnoveterinary plants are however an alternative but possibly effective, environmentally benign and safe option that can complement and in some cases substitute synthetic chemical acaricides. In this study, plant species identified in Zimbabwe and found elsewhere in southern Africa were characterised for anti-tick properties with the aim of developing an ethnobotanical product for use. The initial step involved the identification of plants through an ethnobotanical survey carried out in 4 arid and semi-arid districts of Zimbabwe, namely Muzarabani, Chiredzi, Matobo and Kadoma. These areas were purposively selected on the basis of high cattle production and high likelihood of use of traditional practices in primary animal health care. More than 51 plant species were recorded and a ranking according to frequency of mention showed that Cissus quadrangularis, Aloe sp., Lippia javanica and Psydrax livida were the most popular plants mentioned by farmers. The most common method for preparation was crushing and soaking in water before spraying the animals. Despite the farmers acknowledging that they had access challenges to the normal government-provided dipping services and having knowledge on traditional practices of tick control, the actual use of these practices was low. It was concluded that farmers and other knowledgeable people do have plants they know that have anti-tick properties, thus providing a good basis for the development of ethno-based tick control products. In order to confirm farmer claims of efficacy of the plant extracts and to find ways of increasing that efficacy, three in vitro screening experiments were done using the modified Shaw Larval Immersion Test on Rhipicephalus (Boophilus) decoloratus tick larvae. Different extraction methods were used in the screening: crude water extracts, acetone extracts and solvent – solvent fractions of acetone extracts of Maerua edulis. Results showed that contrary to the high activity reported by farmers in the surveys, water extracts were not toxic to the tick larvae. Perhaps the high activity reported by farmers, if confirmed may be associated with the repellence of volatile emissions from the plants. The addition of a liquid soap as a surfactant however increased the efficacy of the M. edulis tuber aqueous extract to activity levels comparable with those of an amitraz-based commercial acaricide, which was the positive control. The use of the organic solvent acetone as an extractant markedly increased the efficacy of 13 of the plant species under study, particularly M. edulis, Monadenium lugardae and Kleinia species. The chloroform and hexane fractions from M. edulis exhibited very high activity, possibly indicating that less-polar compounds are responsible for the observed activity. Thus, the use of water as a sole extractant is limited in terms of extracting compounds active against ticks, but organic solvents and acetone in particular increase the efficacy of the extracts. In the case of M. edulis less polar extracts and fractions were most active against the ticks. Because Maerua edulis consistently showed good activity in all prior testing, it was further tested using low-cost optimisation strategies like the use of hot water, a surfactant and a different organic solvent (methanol). Hot water extraction and use of a surfactant increased efficacy of the crude extracts of the M. edulis leaves against ticks to satisfactory levels compared to cold water extracts. There was no significant difference between the positive control and methanol-extracted M. edulis. It is, however, the use of ordinary soap that may bring relief to rural farmers who are generally unable to have access to organic solvents. From the observation that the hexane and chloroform extracts of the M. edulis leaf and roots were very active against the ticks, cytotoxicity of the extracts on African Green monkey kidney (Vero) cells and bovine dermal cells was determined to shed some preliminary insights on safety aspects of the plant. Neither extract had high toxicity against these cell lines. The LC50 was greater than 20 _g/ml which is considered as a maximum threshold for indicating toxicity of plant extracts. After confirmation that non-polar fractions of M. edulis were active against ticks and that cytotoxicity results showed that the extracts are relatively non-toxic to animal cell lines, attempts to isolate and identify the active compounds in the chloroform fractions of M. edulis were made without much success. Using column chromatography, an impure compound was isolated in the chloroform fraction but the amount was too low for characterisation by NMR. When the compound was analysed using Gas Chromatography-Mass Spectrometry, a number of chemicals in the isolate were avident but which did not have the pre requisite high similarities with the compound library to be considered. Because of the low quantities no further work was done to further purify and test the compounds against the ticks. For purposes of confirming laboratory activity under field conditions, M. edulis, C. quadrangularis and Aloe vera crude water extracts combined with a surfactant (liquid soap), were tested on Mashona cattle at Henderson Research Station (Zimbabwe) over 7 weeks during the period of peak tick infestation. Only M. edulis tuber extracts with a surfactant were as effective as the amitraz-based positive control. There was no significant difference in activity between the other plant extracts and the negative control. It can be concluded that there is scope to use M. edulis tubers extracted with locally available surfactant as a tick control product. This whole study therefore shows that ticks can be controlled using locally available plant materials provided they are prepared and applied properly. While the overall aim of the study of producing a working plant based tick control product was not met, there is sufficient data from the study to justify developing crude formulations from M. edulis that can be used to control ticks. / Thesis (PhD)--University of Pretoria, 2019. / Paraclinical Sciences / PhD / Unrestricted

Syftet med studien har varit att undersöka och analysera hållbarhetsredovisningens förändring samt incitamenten bakom åtagandet av frivillig hållbarhetsredovisning i svenska kommuner. Utgångsläget för studien har varit att förklara hur kommunernas hållbarhetsredovisning har utvecklats och harmoniserats under perioden 2015–2019 samt vilka incitament som ligger bakom kommunernas frivilliga hållbarhetsredovisning. För att besvara studiens syfte och problemformulering har empiri samlats in genom en innehållsanalys av kommunernas hållbarhets- och årsredovisningar samt intervjuer. Innehållsanalysen har utförts på fem svenska kommuner och intervjuer har utförts med tre respondenter från hållbarhetsavdelningar i tre av studiens fem granskade kommuner.   I analysen har insamlad empiri tolkats med hjälp av den teoretiska referensramen, vilken behandlar intressentteorin och legitimitetsteorin. Resultatet påvisar att kommunernas redovisningsform i de frivilliga hållbarhetsredovisningarna har utvecklats genom en övergång till separata hållbarhetsredovisningar. Resultatet konstaterar även att det sker ett skifte i kommunernas tillämpning av redovisningsstandard till att tillämpa SDG som redovisningsstandard i kommunernas hållbarhetsredovisningar. Till följd av övergången till tillämpningen av SDG som redovisningsstandard har antalet upplysta SDG:er ökat i majoriteten av kommunernas hållbarhetsredovisningar. Även upplysningsformen har förändrats genom en ökning av kvantifierade upplysningar, vilka redovisas verbalt i kombination med mätetal. Det framgår även en påtaglig ökning av harmonisering av hållbarhetsredovisning i kommunerna mellan åren 2015–2019. Både den formella och materiella harmoniseringen tilltar. Det primära incitamentet bakom kommunernas frivilliga hållbarhetsredovisning är uppdraget från politikerna som är kommunernas primära intressenter. De sekundära incitamenten framgick att vara påvisande av legitimitet och ansvarsskyldighet. / The purpose of this study was to examine and analyze the change in sustainability reporting as well as the incentives behind the commitment of voluntary sustainability reporting in municipalities. The initial point for the study was to explain how the municipalities' sustainability reports have developed and harmonized during the period 2015–2019 and what incentives are behind the municipalities' voluntary sustainability report. To answer the study's purpose and problem formulation, empirical data have been collected through content analysis of the municipalities' sustainability and annual reports and interviews. The content analysis was conducted in five Swedish municipalities and interviews were conducted with three respondents from sustainability departments in three of the study's five municipalities.   In the analysis, collected empirics have been interpreted with the help of the theoretical framework which deals with stakeholder theory and legitimacy theory. The result shows that the municipalities' form of accounting in the voluntary sustainability reports has been developed through a clear transition to separate sustainability reports. The result also clarifies that there is a shift in the municipalities' application of accounting standard to applying SDG as the accounting standard in the municipalities' sustainability reports. As a result of the transition to the application of SDG as the accounting standard, the number of informed SDGs has increased in the majority of the municipalities' sustainability reports. The form of information has also been changed through an increase in quantified information, which is reported verbally in combination with measurements. There is also a marked increase in the harmonization of sustainability reporting in the municipalities between the years 2015–2019. Both formal and material harmonization are increasing. The primary incentive behind the municipalities' voluntary sustainability report is the assignment from the politicians who are the municipalities' primary stakeholders. The secondary incentives proved to be legitimacy and accountability.

A risk assessment was conducted for Salmonella enteritidis (SE) in the broiler production chain of the Western Cape of South Africa, using a literature review, historical data analysis, microbiological sampling from abattoirs and questionnaire responses. A questionnaire to characterise the risk pathway in the broiler chain was developed based on a review of the literature. Spatio-temporal analysis was conducted using historical data of reported SE outbreaks. The data showed spatio-temporal clustering, however, the analysis was not correct for groups of farms that form part of the same organisation. Neck skin samples were collected from five abattoirs and tested for salmonella. In total, 499 samples were collected, representing 46 broiler farms of which nine (20%) were positive. Salmonella positive cultures (2.81%) were serotyped. No SE was identified during the study. The questionnaire was completed for all stages of the broiler production chain. Significant risk factors were found using univariate analysis (Odds Ratio,OR). The significant risk factors identified by OR were further analysed using principal component analysis (PCA). The factors moving with or opposing, farm positivity were analysed using logistic regression and one layer farm was found to be a significant factor. The farms receiving eggs or chicks from that layer farm had a number of factors that were found to be significant using OR and therefore the presence of this layer farm could be a representation of these factors at the broiler farm level. SE was not identified in the samples collected from abattoirs, a number of other non-typhoidal Salmonella subspecies enterica were isolated. Given the high rates of immunosuppressive diseases within the South African population, it is important for broiler producers to be aware of the zoonotic potential of non-typhoidal Salmonella and continually improve their control measures. / Dissertation (MSc)--University of Pretoria, 2018. / Veterinary Tropical Diseases / MSc / Unrestricted

Rift Valley fever virus (RVFV) is a mosquito-borne virus and a member of the family Phenuiviridae and genus Phlebovirus. The single stranded RNA genome consists of three segments, Large (L), Medium (M) and Small (S). Rift Valley fever (RVF) is a mosquito-borne zoonotic disease that may cause large epidemics in ruminants and humans. Infection in humans causes influenza-like symptoms but the disease can also be more severe and fatal. Outbreaks in livestock are classified by abortion storms and young and newborn animals are severely affected with a high mortality rate. Rift Valley fever causes severe health and economic consequences in the areas where it occurs. Since the first recorded incidence of RVF in Kenya in 1930, South Africa has had three major countrywide outbreaks: in 1950-1951, 1973-1975 and 2008-2011. The disease is characterized in southern Africa by large epidemics at long, irregular intervals. The epidemics are usually associated with conditions favourable for proliferation of mosquito populations, such as high rainfall and flooding. Rift Valley fever has previously been isolated from 12 different mosquito species in South Africa including 5 Aedes spp., 3 Culex spp., 3 Anopheles spp. and 1 Eretmapodites sp. The presence of the virus and patterns of occurrence of the disease in the eastern parts of South Africa are poorly understood. Multiple studies were conducted; the aim of the first study was to detect the presence of RVFV in far northern KwaZulu-Natal Province, South Africa and to estimate the incidence rate of seroconversion. Cross-sectional studies were performed in communally farmed cattle (n=423) and goats (n=104), followed by longitudinal follow-up of seronegative livestock (n=253) 14 times over 24 months, representing 160.3 animal-years at risk. Exposure to RVFV was assessed using an IgG sandwich ELISA and a serum neutralization test (SNT) and seroconversion was assessed using SNT. Initial overall seroprevalence was 34.0% (95%CI: 29.5-38.8%) in cattle and 31.7% (95%CI: 22.9-41.6%) in goats, varying by locality from 18-54%. Overall seroconversion rate in cattle was 0.59 per animal-year (95% CI: 0.46-0.75) and in goats 0.41 per animal-year (95% CI: 0.25-0.64), varying significantly over short distances. The high seroprevalence in all age groups and evidence of year-round viral circulation provide evidence for a hyperendemic situation in the study area. The second study investigated the seroprevalence and associated risk factors of RVFV in antelope in the Tembe Elephant Park (TEP) and the Ndumo Game Reserve (NGR), using 326 sera from nyala (Tragelaphus angasii) and impala (Aepyceros melampus) routinely culled over a two-year period. The overall seroprevalence of RVFV was 35.0% (114/326; 95% CI 29.8-40.4%); the presence of antibodies in juveniles (6/21; 28.6%; 95% CI 11.3-52.2%) and sub-adults (13/65; 20.0%; 95% CI 11.1-37.8%) confirmed that infections had occurred subsequent to the 2008-2011 RVF outbreaks in South Africa. Seroprevalence was highest in adults and inversely associated with distance from a swamp or floodplain. The third study aimed to investigate the diversity, abundance, and seasonal dynamics of mosquitoes in the study area, and to screen mosquitoes for RVFV. Monthly collections of adult mosquitoes were carried out from January 2017 to June 2018 at three sites using CO2-baited tent traps. Mosquitoes were identified, pooled and screened for RVFV by quantitative reverse transcriptase (RT)-polymerase chain reaction (PCR) directed toward amplification of a 217-bp fragment of the L segment. A total of 34,848 mosquitoes of 7 genera and 48 species, were captured; Culex (Cux.) tritaeniorhynchus (31%), Cx. (Cux.) antennatus (29%), Aedes (Adm.) durbanensis (12%) and Cx. (Cux.) neavei (10%) were the most abundant species collected. Genera differences were noted between the collection sites. Cumulative rainfall and average minimum temperatures 30 days prior to collection were positively associated with the number of mosquitoes collected while maximum temperatures were only associated with the number of Culex mosquitoes caught. A single pool of Ae. durbanensis was found to be positive for RVFV genomic RNA. The same pool was also positive for Chikungunya virus (Family Togaviridae, genus Alphavirus) (CHIKV) and Sindbis virus (Family Togaviridae, genus Alphavirus) (SINV). The RVFV isolate was closely related to one obtained from Ae. (Neo.) circumluteolus at Simbu pan in 1955, ±20 km from the collection sites for this study. Further investigation should be done on the human health implications of the presence of these three zoonotic arboviruses. It is possible that these viruses are causing disease among the communities in the area and that the diseases are under-reported. The results of this study show that RVFV is circulating in the area in domestic ruminants and wildlife, in the absence of apparent clinical disease, at a rate that varies by location, season and year. It appears that, under similar ecological conditions, domestic and wild ruminants may play a similar role in maintenance of viral circulation, and either or both may serve as the mammalian host in a vector-host maintenance system. The study also demonstrates the presence of a wide variety of mosquito species, several of which are known to be competent RVFV vectors. / Thesis (PhD)--University of Pretoria, 2019. / Veterinary Tropical Diseases / PhD / Unrestricted

In Mnisi, a rural community in South Africa, Rhipicephalus sanguineus is one of the most prevalent ticks found on dogs. The community lies at the wildlife/livestock/human interface where humans are at risk of tick-borne diseases. The aim of this study was to investigate the diversity of the bacterial microbiome in R. sanguineus that may impact human health. Over a 12-month period, R. sanguineus (n=1,788), Rhipicephalus simus (n=61), Rhipicephalus turanicus (n=73), Amblyomma hebraeum (n=68), Haemaphysalis leachi (n=219) and Hyalomma truncatum (n=1) ticks were collected from 64 dogs. Genomic DNA was extracted from salivary gland and midgut tissues of 62 R. sanguineus tick pools (1 pool = 10 ticks); identifications were confirmed using Cytochrome c oxidase I barcoding. The 16S rRNA gene was amplified using barcoded primers and sent for Pacific Bioscience’s circular consensus sequencing. Characterisation of the bacterial microbiome of midgut and salivary gland pools revealed a total of 260,312 sequences with Proteobacteria (85.44%) being the most prevalent phylum found; with Anaplasma (21.69%), Coxiella (12.12%) and Ehrlichia (19.94%) species dominating the microbiome. Further classification of Ehrlichia revealed 95.46% Ehrlichia canis and 4.54% Ehrlichia species Anaplasma consisted of 15.36% Anaplasma centrale, 75.82% Anaplasma platys and 8.82% Anaplasma species Phylogenetic analysis indicated that the A. centrale and A. platys clustered with various other published A. centrale and A. platys sequences, respectively. It also confirmed that all Ehrlichia species sequences detected in this study are E. canis sequences (94.46%). Furthermore, we determined that the Coxiella sequences detected in the study belong to the R. sanguineus Coxiella-like endosymbionts group. Assessment of risk factors for R. sanguineus infestation indicates that higher average monthly temperatures have a significant association with an increased risk of R. sanguineus tick infestations on dogs. Additionally, rearing chickens at the household was significantly associated with a decreased risk of R. sanguineus tick infestations on dogs. Our study indicated that R. sanguineus could be a potential reservoir for important bacterial pathogens of zoonotic importance. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc (Veterinary Science) / Unrestricted

Ticks and tick-borne diseases (TBDs) cause significant losses, through their effects on health, production of animals and humans worldwide. Notably, the countries located within the tropics and subtropics such as Uganda are the most affected due to abundance and distribution of the tick vector. Unfortunately, there is little data in Karamoja Region regarding tick species and the pathogens they transmit. Therefore, a cross-sectional study was undertaken to determine the various tick species, and to detect the tick-borne pathogens within the ticks collected from cattle in Karamoja Region, northeastern Uganda. Between June 2017 and early September 2017 (wet season), a total of 4,897 ixodid ticks were collected from 100 cattle in 20 purposively-selected herds. Three genera of ticks, namely Amblyomma (96.8%), Hyalomma (0.6%) and Rhipicephalus (2.6%) were identified. From the ticks collected, the most dominant species was A. lepidum (93.85%), followed by A. variegatum (2.0%), R. evertsi evertsi (1.0%) and A. gemma (0.98%). Tick species that have not been reported in recent studies in Uganda were found amongst cattle in Karamoja, and these were R. pravus, R. praetextatus and R. turanicus. A representative number of ticks, from each tick species identified in the present study were placed in pools of 1 to 10. Subsequently, a reverse line blot (RLB) hybridization assay was performed to screen for the presence of tick-borne pathogens. Out of the 40 tick pools, 30 (75%) were positive for tick-borne pathogens of the genera Ehrlichia, Anaplasma, Babesia and Theileria. The RLB assay results showed that 57% (n=17) of the tick pools were positive for single infections, while 43% (n=13) had mixed infections. The most frequently detected tick-borne pathogens were T. parva (10 pools), T. velifera (10 pools), T. mutans (9 pools) and Theileria sp. (sable) (5 pools). Other pathogens detected were E. ruminantium, B. microti, B. rossi, T. separata and B. bigemina. The tick-borne species B. microti, B. rossi, Theileria sp. (sable) and T. separata are not common in cattle, or not known to infect cattle, but were detected from the ticks collected. The detection of B. microti in this study may point to incidental infections with implications for human health. There could have also been a possibility of cross reactions during the RLB analysis leading to the detection of B. microti in this study. These findings provide knowledge of the distribution of ticks and epidemiology of tick-borne pathogens in cattle and may provide support for control of TBDs and improve cattle productivity. / Mini Dissertation (MSc (Tropical Animal Health))--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc (Tropical Animal Health) / Unrestricted

Rift Valley fever (RVF), is a mosquito-borne viral disease affecting humans and some species of ruminants including sheep, cattle, goats, buffalos and to a lesser extent wild animals. It is a re-emerging disease responsible for major losses in livestock production, with negative impacts on livelihoods of both commercial and resource- poor farmers in sub-Saharan African and some countries in the Middle East. It remains a threat to both endemic and non-endemic countries where competent mosquito vectors exist. The RVF virus (RVFV) causes the disease and though only a single serotype exists, differences in virulence and pathogenicity of the virus have been observed in a wide range of affected mammalian host species. This necessitates the need for a detailed genetic characterization of various isolates of the virus and whether the causal factors for host tissue tropism can be explained. Therefore, the aims of this study were to obtain comprehensive information on the genetic composition of the RVFVs circulating in South Africa between 2008 and 2010 and to differentiate these isolates based on cell infectivity and genomic parameters. In the first chapter the status of some published literature on the disease as well as the virus are reviewed. Viral characteristics, replication, assembly and release of the viral particle from the cell as well as virus-host receptors documented are also mentioned in this chapter. Chapter two focused on the genetic composition of RVFVs that caused outbreaks during 2008- 2010 in South Africa. Complete genome sequence analysis of isolates from different hosts and tissues collected at discrete foci of outbreaks were analysed and compared with virus sequences from earlier outbreaks in South Africa and from other countries. Phylogenetic analysis indicated that viruses that caused outbreaks during 2008-2010 were most probably reassortants, resulting from exchange of portions of the genome of different isolates, particularly of Segment M. In addition, the analysis indicated that the viruses were not introduced from outside the country but mutated in time and caused the outbreaks when the environmental conditions became favourable. Although no clear association between the virus genotype and phenotype has been established, various amino acid substitutions have been implicated for changes in the phenotype. The third chapter describes the characterization of isolates derived from different hosts (bovine and ovine), but from the same tissue (liver). The isolates from bovine liver presented a different growth phenotype in a cell culture-based system as well as some amino acid substitutions when compared with isolates from ovine livers. Although the codon usage patterns of the six isolates were the same, they differed with those of their hosts. Further investigation of the coding regions of the genome, molecular modelling of glycoproteins and codon usage bias failed to explain the phenotypic changes. The fourth chapter focused on an attempt to identify RVFV glycoprotein receptors using the yeast two-hybrid (Y2H) system. Baby hamster kidney cells were chosen as host cells in the laboratory because hamsters are known to be highly susceptible to RVFV. The complexity of the cDNA library constructed from BHK cells were assessed by random sequencing of 100 clones and revealed that 51 clones were genes from mRNA from the Syrian/Golden hamster using BLAST. The constructed library can also be used to study other animal pathogens such as bluetongue virus and African horse sickness virus. The constructed bait plasmids did not show any autoactivation or toxicity in yeast, thus making them suitable to be used in the Y2H system. Twelve unique clones (4 clones using transformants of the glycoprotein Gn and 8 clones using transformants of glycoprotein Gc) were screened from the cDNA library. Identification and further characterization of the clones is necessary. Sampling of the isolates that caused the 2008-2010 outbreaks in South Africa and full genome sequencing indicated that the isolates were genetically distinct, grouping in different clades, namely C and H. Reassortment have been identified in some of these isolates, particularly in their M segments. The majority of isolates that emerged in the outbreaks accumulated mutations over time while circulating in South Africa. The impact of these mutations on the pathogenicity of RVFV should be further investigated. Sequencing should be done on clinical samples directly to have a better idea of the phenotype and the effect of amino acid substitutions. Different phenotypes observed between cattle and sheep in tissue culture systems should be further investigated including investigation of different phenotypes in vivo using small experimental animals. The study has laid a foundation in understanding the pathogenicity of RVFV and necessitates the importance of understanding molecular mechanisms of the virus. / Thesis (PhD)--University of Pretoria, 2019. / Veterinary Tropical Diseases / PhD / Unrestricted

Foetal loss can be devastating to a cattle farmer. In the Free State province many commercial cattle farms contend with foetal loss due to abortion. The causes of most of these abortions are never diagnosed because of inappropriate samples submitted; diagnostics being too expensive or non-submission of samples due to ignorance. The aim of this study was to investigate the apparent seroprevalence of Brucella species and Coxiella burnetii in commercial cattle of five epidemiological units. The overall apparent seroprevalence in this study was 22% and 11% respectively for Brucella species and Coxiella burnetii antibodies. Although the presence of antibodies does not lead to a definitive diagnosis, it is now known that there are bacterial challenges in these commercial cattle, and this could form the basis of future studies. Improved education of the public as well as communication with the human health sector is necessary to effectively control brucellosis and Q-fever. / Dissertation (MSc)--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc / Unrestricted

African swine fever (ASF) has been reported and confirmed in South Africa since the early 20th century, which lead to the inception of the Swine Fever control zone in 1935. In the South African context, the sylvatic cycle is the main maintenance and transmission cycle that leads to sporadic outbreaks in the domestic pig population, particularly reported in the designated ASF control area. ASF is endemic in sub-Saharan Africa and maintains itself through three different epidemiological cycles in different regions of the continent. The current outbreaks in the Caucasus and Russia have shown the ability of African swine fever virus (ASFV) to establish itself where low biosecurity conditions exist. In South Africa, the spread of ASF has been successfully controlled in the domestic pig populations with control based on the Animal Disease Act 35 of 1984. The act prohibits the movement of all suid species and their products from the ASF control area in the north, except where special permission has been granted by the Provincial Veterinary Services. One of the key uncertainties related to climate change is potential variations in the weather patterns and fluctuations in climatic conditions that could lead to alterations in production systems and land use patterns. These in turn raise the possibility of redistribution of both the arthropod vectors and wild suids to environmentally suitable areas. It is therefore critical for the zoning of ASF that patterns of distribution of the reservoir hosts are monitored in line with the possible variations in the weather patterns around and along the ASF control line. Nonetheless, there are no known records of the reassessment of the swine fever control line, which was instituted based on the distribution of previous outbreaks and the presence of warthogs and tampans, since its inception in 1935. The objective of this study was to evaluate the distribution of the ASF disease determinants; warthogs and warthog burrows, Ornithodoros moubata and ASFV; along the ASF control line with the view of determining whether there was a need to re-align the trajectory of the line or not. A total of 304 farms were randomly selected 20 km north and 20 km south of the ASF control line from the North West, Gauteng, Limpopo and Mpumalanga Provinces through proportional weighting. A total of 73 farms from the initial sample, distributed along the ASF control line, were sampled for the presence of warthogs, warthog burrows and soft ticks of the Ornithodoros spp. (tampans). One hundred and fifty seven warthog burrows were found, of which 92% were recently used by warthogs. Tampans were recovered from 22.2% of the 63 farms where warthog burrows were found and 12.74% of the total (157) warthog burrows. Of the infested warthog burrows, only 5% (one of the twenty burrows) constituting 7.14% (one out of 14 farms) found south but in close proximity to the ASF control line, was positive for ASFV DNA. There were no warthog burrows found with PCR positive tampans north of the ASF control line. The spread of tampans beyond the ASF control line poses a question on whether the control line needs to be moved further south in the affected parts of the country. The study confirmed that the reservoirs are found beyond the current ASF control line. Although the causes for this apparent re-distribution are unclear, changes in land use and the increase in wildlife farming may contribute to this finding. Examination of weather data along the control line between 1993 and 2012 found the maximum temperatures was increasing and humidity is decreasing. In the absence of previous data on warthog and tampan distribution along the control line, the present study cannot evaluate if these changes have had an impact on the distribution of warthogs and tampans in the vicinity of the control line. This study provides baseline data for future monitoring of the control line and concluded that there was currently no need to realign the trajectory of the ASF disease control line but to conduct scheduled monitoring of the O. moubata status in the future. / Dissertation (MSc)--University of Pretoria, 2015. / tm2015 / Production Animal Studies / MSc / Unrestricted

Emerging small-scale pig farmers in Limpopo province perceive pig production and management as an important means of improving their livelihood and alternative investment option for the future. Their performance has not been optimal due to the lack of practical understanding of the basics of animal production, biosecurity and efficient production system. Thus, an attempt was made to evaluate the challenges and constrains of pig farm production systems identified and reported by emerging small scale pig farmers (ESSPF) in the province. In addition, the risk factors associated with pig movement by ESSPF by means of spatio-temporal analysis was evaluated. The study revealed that the average number of sows/farm was 7.4, while the number of boars/farm was 1.7. On average, the number of days that the sows take to return to oestrus from weaning was 42.9 days while the number of piglet s weaned/sow/year was 4.85 pigs. Also the study showed that 98.77% of ESSPF don t vaccinate their breeding stock against major pig diseases and only 2.47% ESSPF farmers had previously benefited from the infrastructure programme of the department referred to as Comprehensive Agricultural Support Programme (CASP). The majority of the respondents (82.61%) will prefer to sell their pigs at local points and within communities and only 9.32% and 14.09% will sell at the auctions or formal abattoir/supermarkets respectively. It is therefore recommended CASP be evaluated to reach and impact more pig farmers positively. Good animal husbandry and transfer of knowledge by the veterinary officials is central to the growth of farmers and their productivity. The provision of regional slaughter facilities will reduce the travelling costs to Bronkhorstspruit and Belfast, but also reduce the likelihood of the disease spread within or outside the province. The involvement of different stakeholders should be encouraged to ensure ESSPF are trained, mentored, coached, with the aim of improving their livelihood, food security and safety. / Limpopo provinsie is n belangrike vark produseerende gebied met n groot populasie van huishoudelike en wilde diere. Om die rede dien dit as n interfase tussen huishoudelike diere, mense en wilde diere.Alhoewel opkomende varkboere in die provinsie die produksie en bestuur as n belangrike verbetering in hul lewensbestaan asook alternatiewe finansiële beleggingsopsies vir die toekoms beskou, is hul prestasie nie optimaal nie as gevolg van die gebrek aan praktiese begrip van die basiese beginsels van diereproduksie, biosekuriteit en doeltreffende produksie stelsels. Dus, is 'n poging aangewend om die uitdagings en beperkings van varkplaas produksiestelsels te ïdentifiseer en die opkomende kleinskaalse varkboere (ESSPF) in die provinsie te evalueer. Bykomend is die risikofaktore wat verband hou met vark beweging deur ESSPF deur middel van tydruimtelike analise ontleed. Die studie het getoon dat die gemiddelde aantal sôe per plaas was 7,4 terwyl die aantal bere per plaas 1,7 was. Die sôe neem gemiddeld 42,9 dae om terug te keer na estrus vanaf speen, terwyl die aantal varkies gespeen / sog / jaar is 4,85 varkies. Die studie het ook getoon dat 98,77% van ESSPF nie hul teeldiere ent teen die hoof vark siektes en slegs 2,47% ESSPF boere het voorheen voordeel getrek uit die program infrastruktuur van die departement verwys na as omvattende landbou?ondersteuningsprogram (CASP). Die meerderheid van die respondente (82,61%) verkies om hul varke by plaaslike punte binne gemeenskappe te verkoop en slegs 9,32% en 14,09% onderskeidelik verkoop by veilings of formele slagpale/ supermarkte. Dit word dus aanbeveel dat CASP herevalueer om n positiewe impak te bereik by meer varkboere. Goeie veeteelt en die oordrag van kennis deur die veeartseny?amptenare is sentraal tot die groei van die boere en hul produktiwiteit. Die voorsiening van plaaslike slaggeriewe sal die reiskoste na Bronkhorstspruit en Belfast (beide buite die provinsie en tans gekiesde slagpale van die ESSPF) verminder, maar ook die waarskynlikheid van die verspreiding van siektes binne of buite die provinsie verminder. Die betrokkenheid van die verskillende belanghebbendes moet aangemoedig word om te verseker ESSPF opgelei word, gementor, afgerig, met die doel om van die verbetering van hul lewensbestaan, voedselsekuriteit en veiligheid. / Dissertation (MMedVet)--University of Pretoria, 2015. / tm2016 / Production Animal Studies / MMedVet