Rationale: Viral diseases are important in the African context as they cause significant clinical disease in both wild and domestic animals, as well as in humans. Viral diseases make up a large proportion of emerging infectious diseases. The management and prevention of these diseases have proven to be challenging due to the large population of reservoir hosts consisting of African wildlife. There is no comprehensive publication investigating viruses in African ungulates. Hence, this research study will provide comprehensive analyses to add to the current global knowledge base and provide guidance about areas where there is little information. Aim of the study: Provide a scoping review of viral diseases, which occur in free-ranging African ungulates and identify knowledge gaps with regards to these diseases. Objectives: 1. List and describe viruses diagnosed in free-ranging African ungulates 2. Identify ungulates affected by viruses 3. Describe the geographical distribution of viruses 4. Identify viruses which appear to be “under-studied” Study design: This is a scoping review of peer reviewed publications pertaining to viruses and viral diseases in African ungulates. The methodology for this scoping review was based on the guidelines set out in the PRISMA extension for scoping reviews. A search string was developed and run in three major databases, namely Scopus, Web of Science and Wildlife and Ecology Worldwide, to obtain publications relevant to the research topic. Publications were screened using predetermined inclusion and exclusion criteria to obtain a final set of publications to undergo data extraction and analysis. Results: The final set of publications consisted of 145 publications. A total of 32 viruses were identified in the publications. The range of the publication dates were from 1957 to 2018. Nine out of 32 viruses accounted for 74% of the total reports of viruses detected by antigen/antibody testing in African ungulates. African elephant polyomavirus 1 was the only virus that was solely detected in captive animals according to published literature using antigen/antibody detection. A total of 50 African ungulates were reported/diagnosed with viral infections. The four most frequently mentioned African ungulates in publications reporting on viruses or viral diseases, in descending order, were the African buffalo, blue wildebeest, impala and warthog (common and desert). Of the 52 countries on the African continent, only 18 countries (35%) had viruses diagnosed in wild ungulates reported in the literature. All the publications in this study reported on viruses or viral diseases in ungulates from only sub-Saharan Africa. Foot-and-mouth disease, African swine fever, Rift Valley fever, bluetongue and rabies were frequently reported in the literature. On the contrary, lumpy skin disease, peste des petits ruminants, African horse sickness, enzootic hemorrhagic disease, bovine viral diarrhoea, infectious bovine rhinotracheitis/infectious pustular vulvovaginitis, equine influenza, equine viral arteritis, equine viral rhinopneumonitis and classical swine fever were infrequently reported on. Conclusion: There are a variety of viruses which have been diagnosed in African ungulates and all African ungulates identified have had one or more viruses or viral diseases associated with them. The findings will be valuable to policymakers, funding bodies, researchers and other stakeholders who need an understanding of viral diseases in African ungulates. Research opportunities in this field will allow them to make informed decisions about investment in future research projects and animal health policies and protocols. It is recommended that governments and research institutions offer more funding to investigate and report viral diseases of greater clinical and zoonotic significance, such as rabies and Rift Valley fever. This is especially important in the current climate of emerging diseases and the related overflow of disease from wild to domestic animals and from animals, both wild and domestic, to humans. A further recommendation is for appropriate One Health approaches to be adopted for investigating, controlling, managing and preventing diseases (Cunningham et al., 2017). This is especially true for diseases such as African swine fever and Rift Valley fever where human actions, poor biosecurity and natural weather changes play a major role in the transmission of diseases (Cunningham et al., 2017, Penrith et al., 2019a, Swanepoel and Coetzer, 2004). Diseases which may threaten the conservation of certain wildlife species also require focused attention. In order to keep track of these diseases it may be necessary to consider adding a “wildlife” category to the OIE-listed diseases. Viral diseases, as a whole, are of great significance and require extra attention in the future as they make up a large proportion of emerging infectious diseases and can often infect multiple hosts (Bengis et al., 2004, Cleaveland et al., 2001). Hence, the viruses and viral diseases diagnosed in African ungulates are of significance, particularly at the wildlife/livestock interface and many of them have the potential of becoming emerging wildlife diseases. / Dissertation (MSc (Tropical Animal Health))--University of Pretoria, 2020. / Veterinary Tropical Diseases / MSc (Tropical Animal Health) / Restricted

The aim of this study was to investigate the prevalence and epidemiological significance of tuberculosis (TB) in bovine and humans living at a wildlife/livestock/human interface, as well as the risk factors associated with TB transmission at that interface. The Mnisi community was chosen as it is located at the western border of the Kruger National park (KNP) and enables research at the wildlife/livestock/human interface. The first objective of the study entailed investigating the presence of bovine tuberculosis (BTB) in 10% of Mnisi?s livestock, using the comparative intradermal skin test. A low individual prevalence of 0.33 % (95% CI.0.14 ? -0.79) was detected. Further investigations into the causative agent in livestock, using genotyping techniques identified the KNP parental strain, M. bovis KNP VNTR -1 strain.1 Supporting records from the provisional Mpumalanga Veterinary Services and the physical location of dip-tanks where BTB was detected, it was established the infection was a result of spillback infection from wildlife in the neighbouring KNP. The epidemiological significance of BTB in human TB was investigated through the isolation and genetic characterisation of the Mycobacterium tuberculosis complex (MTBC) strain population in the Mnisi community. Mycobacterium bovis was not detected in the human population. However, a high genetic diversity of M. tuberculosis was observed among the 13 isolates obtained.The M. tuberculosis isolates were identified as the following eight families: T; Beijing; LAM 11_ZWE; EAI5; MANU1; X1; X2; and S families. The predominant lineage was as T family, sub-lineage ST53. Based on the high diversity (8 clusters/13isolates) and the predominance of the T family, it was concluded that the TB population structure within the Mnisi community was largely impacted by human migration from urban towns and neighbouring Mozambique. A questionnaire was administered to investigate BTB transmission risk factors at the livestock/human interface. It was established that there were low risk levels of BTB transmission at the human/livestock interface mainly based on the fact that the majority of the households in the community obtained pasteurised milk commercially, and although undercooked/raw meat and organs were preferred, the majority of respondents reported that they discarded the meat if changes in meat quality were observed. / Thesis (PhD)--University of Pretoria, 2016. / tm2016 / Veterinary Tropical Diseases / PhD

Animal diseases have always been one of the main constraints on animal production, especially in Africa where there are a variety of tropical and subtropical diseases. Knowledge of these diseases and the development of approaches to combat them is highly relevant to the socio-economic development of Africa and its fight against poverty. Serological tests were performed to determine seroprevalence and important risk factors for occurrence of respiratory pathogens in cattle on 423 biobanked sera collected from cattle at 11 dip tanks in the Mnisi communal farming area which is on the edge of the Kruger National Park. These pathogens are known to cause significant production losses in livestock by predisposing animals to secondary infections including pneumonia. A pentavalent, indirect ELISA test was performed to estimate seroprevalence of bovine herpesvirus-1, bovine respiratory syncytial virus, bovine viral diarrhea virus, parainfluenza virus-3 and bovine adenovirus-3 infections in cattle at the wildlife-livestock interface in the Mnisi communal farming area. Previous exposure to the five pathogens was determined. Additionally, the data was analyzed using the statistical software R to determine important risk factors that predicted exposure to the pathogens in cattle, namely population factors (distance from interface and month of collection) and individual characteristics (age, sex, body condition and breed). Age and body condition of the animals were found to have an effect on seropositivity while breed, sex, spatial distribution of the animals and month of sample collection did not have an effect. Recommendations to reduce pathogen exposure and improve production are made to the livestock owners in the Mnisi community. / Dissertation (MSc)--University of Pretoria, 2016. / Veterinary Tropical Diseases / MSc / Unrestricted

Anaplasmosis, babesiosis, and heartwater are the three most important tick-borne diseases of cattle in South Africa and result in a large number of mortalities. Endemic stability contributes to disease control, but little is known about the conditions required for maintenance of endemic stability. Through the on-going Health and Demographic Surveillance System in Livestock in the study area of the Mnisi One Health Platform, Mpumalanga, a great deal of information is being collected about cattle in the area, with the eventual aim of developing mathematical models to describe and predict infections. More than 15000 cattle have been identified for tick burden assessment, serological analyses and parasite identification. However, little is known about the time-course of infection of cattle with various tick-borne haemoparasites. Therefore, this study aimed to investigate the time-course of infection in new-born calves (n=10) and the presence of haemoparasites in adult ticks over a one year period using reverse line blot (RLB) hybridization and quantitative polymerase chain reaction assays. Blood samples and adult ticks were collected monthly from new-born calves in two areas of the Mnisi communal area: five located in a peri-urban area and five at the wildlife/livestock interface. A total of 119 blood samples and 805 adult ticks were collected. The RLB results confirm the exposure of most new-born calves in the Mnisi communal area to non-pathogenic and pathogenic tick-borne haemoparasites in the genera Anaplasma, Babesia, Ehrlichia and Theileria in their first year of life. A total of 805 adult ticks were identified to species level using identification keys and molecular methods. Only two tick species, Amblyomma hebraeum and Rhipicephalus microplus, were found on the calves during the year. Non-pathogenic and pathogenic haemoparasites in the genera Anaplasma, Babesia, Ehrlichia and Theileria were detected in pooled DNA extracted from ticks that had digested their blood meal. Pathogen-specific qPCR results indicated that some of the pathogens could not be detected in the calves until six to seven months of age and A. marginale was not detected at all in three calves at the wildlife/livestock interface. These calves were either infected at levels below the detection limit of our assays, or they were not infected at all. If the latter, it is possible that exposure to related non-pathogenic haemoparasites might help to establish and maintain endemic stability. Factors such as cattle density and dipping methods within different areas in the Mnisi communal area may play a role in the number of infected tick vectors in an area, and thus in the time-course of infection in new-born calves. It is clear that detailed information for cattle in different localities in the Mnisi communal area will be required in order to build accurate mathematical models to describe and predict infections. / Dissertation (MSc)--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc / Unrestricted

Animal diseases impact on livestock production and threaten food security through loss of animal protein. Additionally, disease impacts may cause major production losses by adding to the cost of livestock production through the necessity to apply costly disease control measures. Taken together, farm animal diseases have been shown to increase poverty levels particularly in poor communities in Africa that have a high dependence on livestock farming for sustenance (Perry et al., 2009). Research to learn more about animal diseases is necessary for the development of appropriate policies and strategies to prevent, control and possibly eradicate costly animal diseases in order to increase socio-economic development and improve livelihood, especially in Africa (Perry et al., 2009). The purpose of this study was to investigate five viruses that cause upper respiratory tract infections in cattle: bovine alphaherpesvirus-1 (BoHV-1), bovine viral diarrhoea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine parainfluenza-3 virus (PI-3) and bovine mastadenovirus-3 (BAV-3), in the rural Mnisi farming community in the Mpumalanga Province, South Africa which is located adjacent to the Kruger National Park (KNP) and private game reserves (Figure 1). The Mnisi Community Project (MCP) is a University of Pretoria initiative that is based on an One Health approach at the human/livestock/wildlife/ecosystem interface. Within the Mnisi community there are a number of dip tanks to which cattle are obligated to attend weekly for FMD inspection. In return, cattle are plunge-dipped free of charge in acaricides, as an aid to control tick-borne diseases such a theileriosis, anaplasmosis, heartwater and redwater. These viruses are known to cause pathology of the respiratory tract and lead to morbidity and even mortality in some cases. In addition, two of the viruses studied here, BoHV-1 and BVDV, can suppress the immune system of the host and also increase the risk of secondary bacterial infections (Valarcher & Hägglund, 2006). This study used a cross sectional design to determine the spatially explicit herd-level antibody seroprevalence of five respiratory tract viruses. A total of 423 sera stored in the Hans Hoheisen Wildlife Centre biobank were collected at 11 dip tanks in the Mnisi communal farming area. A commercially available pentavalent, indirect enzyme linked immunosorbent assay (ELISA) was performed to estimate the seroprevalence of each. The overall proportion of sera that contained antibodies against each pathogen were as follows: 43.3% for BoHV-1; 30.5% for BVDV; 82.5% for BRSV; 44.4% for PI-3 and 83.2% for BAV-3. The prevalence of antibodies against the five respiratory viruses did not appear to be influenced by location, distance from the adjacent wildlife conservation area, time of the year, or sex. However, age was a risk factor as antibodies appeared less frequently in animals less than 12 months of age compared to animals between 12 and 24 months, or older than 24 months. Findings from this study should provide information for the cattle farmers and animal health sector that provide animal health and extension services about the risk of bovine respiratory disease in the Mnisi communal farming area. Appropriate measures to minimize exposure to viral respiratory tract infections are discussed. / Dissertation (MSc)--University of Pretoria, 2018. / Veterinary Tropical Diseases / MSc / Unrestricted

The global sustainable development has been marked by the United Nations plans for more than two decades. These plans have been adopted by most of the developed and developing countries to achieve the 2030 Agenda, currently formed by the 17 Sustainable Development Goals. Governments and policy-makers cannot make conscious decisions regarding sustainability progress without knowledge about how well the country is performing this path. This study assessed the evolution of each SDG in Spain through their indicators and whether correlation and dependency between the stated targets exist. Goals 1, 2, 6, 8 and 11 were the less evolved, those which were undergoing a slower process or a negative evolution over the years. The correlation analysis delivered a quick guide of relationships amidst targets to help the appropriate ministries to make prompt decisions knowing which fields will be affected largely. Goal 3 (Good health and well-being) was strongly linked with indicators from Goal 4 (Quality education) and also Goal 6 (Clean water and sanitation). Furthermore, indicators from Goal 7 (Affordable and clean energy) shared a high correlation with the ones from Goal 12 (Responsible consumption and production) and Goal 15 (Life on land). All together obtained 60% share of positive interactions and almost 80% of significant interplays between the targets. Correlation does not imply causality, so multiple linear regression analysis set true numerical relationships and revealed how to enhance certain targets by leveraging others. Less developed indicator was taken as dependent variables and the final independent ones were defined using shrinkage methods. The procedure to reach these expressions could be used to establish the dependency between other relevant indicators and getting the assessment of the performance of this country afterwards. / Den globala hållbara utvecklingen har präglats av FN:s planer i mer än två decennier. Dessa planer har antagits av de flesta av de utvecklade länderna och utvecklingsländerna för att uppnå agenda 2030, som för närvarande bildas av de 17 globala målen för hållbar utveckling (SDG). Regeringar och beslutsfattare kan inte fatta medvetna beslut om hållbarhetsframsteg utan kunskap om hur väl landet presterar denna väg. Denna studie undersökte utvecklingen av varje SDG i Spanien genom deras indikatorer och huruvida korrelation och beroende finns mellan de angivna målen. Mål 1, 2, 6, 8 och 11 var de mindre utvecklade. De genomgick en långsammare process eller hade negativ utveckling under åren. Korrelationsanalysen levererade en snabb guide över relationer förhållandet bland mål för att hjälpa de berörda ministerierna att fatta snabba beslut om att veta vilka områden som i hög grad kommer att påverkas. Mål 3 (God hälsa och välbefinnande) var starkt kopplat till indikatorer från mål 4 (Kvalitetsutbildning) och även mål 6 (Rent vatten och sanitet). Dessutom hade indikatorer från mål 7 (prisvärd och ren energi) en hög korrelation med indikatorer från mål 12 (Ansvarsfull konsumtion och produktion) och mål 15 (Liv på land). Tillsammans erhöll 60% positiva interaktioner och nästan 80% betydande samspel mellan målen. Korrelation innebär inte orsakssamband, så flera linjära regressionsanalyser satte riktiga numeriska förhållanden och avslöjade hur man kan förbättra vissa mål genom att utnyttja andra. Mindre utvecklade indikatorer togs som beroende variabler och de slutliga oberoende variablerna definierades med krympningsmetoder. Tillvägagångssättet för att nå dessa uttryck kan användas för att fastställa beroendet mellan andra relevanta indikatorer och få en utvärdering av landets resultat.

Zunehmend werden die Folgen des Klimawandels gravierender und die planetaren Grenzen spürbarer. Seit Beginn des Industriezeitalters kam es zu einem rasanten Anstieg der anthropogenen Treibhausgasemissionen, sodass die EU und die Mitgliedsstaaten sich auf das Klimaziel einigten, bis 2030 die Emissionen um 55 % zu senken. Mit der Agenda 2030 für nachhaltige Entwicklung und den darin enthaltenen 17 UN-Klimazielen werden alle Länder dazu aufgerufen, sich aktiv an deren Umsetzung und Erreichung zu beteiligen. Somit hat auch die Verlagsbranche als sehr energieintensiver Sektor einen Beitrag zu leisten. Durch eine nachhaltig gestaltete Produktion kann der Anteil am globalen CO2-Ausstoß minimiert werden. Dazu wird in der Arbeit folgende Forschungsfrage untersucht: »Welchen aktuellen Beitrag leistet die Verlagsbranche zur Erreichung der Agenda 2030 für nachhaltige Ziele?« Zur Beantwortung dieser werden theoretische Grundlagen analysiert und qualitativ Daten in Form von Leitfadeninterviews erhoben. Anhand dessen wurde deutlich, dass die größten Stellschrauben für eine nachhaltige Entwicklung in der Beschaffung, dem Transport und der Produktion des Papiers sowie im Druck liegen. Darüber hinaus beeinflussen auf unternehmenstechnischer Seite die Gebäudeversorgung, Dienstreisen und die Mitarbeitermobilität die Ökobilanz. Generell zeigten die Interviews, dass schon diverse kleine Initiativen ergriffen wurden, jedoch eine Einordnung in eine unternehmensweite Nachhaltigkeitsstrategie nur teilweise verfolgt wird. Als Ergebnis liefert die Arbeit Handlungsempfehlungen für Verlage durch das Aufzeigen von funktionalen Nachhaltigkeitsstrategien zur Erreichung einer klimaneutralen Produktion sowie umweltschonender Arbeitsabläufe und -bedingungen entlang der Wertschöpfungskette. Die Handlungsempfehlungen können dabei von Verlagen unabhängig ihrer Unternehmensgröße und Ausrichtung angewendet werden und unterstützen diese bei der Erreichung eigener Klimaziele.:Nachweis Abstract Inhaltsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Abkürzungsverzeichnis 1. Einführung 1.1 Ausgangslage und Problemstellung 1.2 Zielsetzung und Vorgehensweise 2. Theoretische Analyse 2.1 Internationale Abkommen 2.2 Theoretisches Vorgehen bei der Implementierung von Nachhaltigkeitsstrategien 2.2.1 Erstellung einer Klimabilanz 2.2.1.1 Relevanz und Quantifizierung von Treibhausgasen 2.2.1.2 Ökologieorientierte Bewertungsverfahren 2.2.1.3 Erfordernis von Reportingmaßnahmen durch EU-Richtlinien 2.2.1.4 Orientierungshilfen zur Nachhaltigkeitsberichterstattung 2.2.2 Identifizierung umweltschädlicher Treiber der Verlagsbranche 2.2.2.1 Produktionstechnische Perspektive 2.2.2.2 Unternehmenstechnische Perspektive 2.2.3 Ausgewählte Nachhaltigkeitsstrategien und ökologische Ziele 2.2.3.1 Strategien im Rahmen der Kreislaufwirtschaft 2.2.3.2 Möglichkeiten zur Kompensation der THG-Emissionen 2.2.3.3 Kommunikation mittels Umweltzeichen und Label 3. Qualitative Datenerhebung 3.1 Methodischer Ansatz 3.2 Ziel der Erhebung 4. Auswertung 4.1 Organisatorische Verankerung von Nachhaltigkeitsaspekten 4.2 Diskussion über die umweltschädlichen Treiber gegenüber bisherigen globalen Reduzierungsinitiativen 4.2.1 Dienstreisen und Mitarbeitermobilität 4.2.2 Ausstattung und Versorgung der Bürogebäude 4.2.3 Umgang mit Verbrauchsgütern und Finanzen 4.2.4 Produktionstechnische Perspektive 4.3 Nutzung der ökologieorientierten Bewertungsverfahren und Orientierungshilfen zur Nachhaltigkeitsberichterstattung 4.4 Ökologische Ziele und Nachhaltigkeitsstrategien 4.5 Kommunikation auf interner und externer Ebene 4.6 Notwendigkeit staatlicher Rahmenbedingungen 5. Abschlussbetrachtung 5.1 Übergreifendes Fazit zur Beantwortung der Fragestellung 5.2 Handlungsempfehlungen 5.3 Limitation und Ausblick Literaturverzeichnis Anhangsverzeichnis

Increased prevalence of antimicrobial resistance, treatment failure, and financial losses have been reported in dairy cattle with coagulase-negative Staphylococcus (CoNS) clinical mastitis. However, studies on CoNS are limited in South Africa. Therefore, the objectives of this study were to investigate the antimicrobial resistance patterns and biofilm formation in CoNS isolated from cow milk samples submitted to the Onderstepoort Milk Laboratory. A total of 142 confirmed CoNS isolates were used for this study. Isolates were subjected to the tissue culture plate method for biofilm formation testing and antimicrobial susceptibility testing against a panel of 11 antimicrobials using the disk diffusion method. Biofilm formation was identified in 18% of CoNS tested. Staphylococcus chromogenes (11%) had the highest proportion of biofilm formation followed by S. haemolyticus 4.0% and S. epidermidis, S. hominis, S. xylosus, and S. simulans with 1% respectively. Ninety percent (90%) of CoNS isolates were resistant to at least one antimicrobial (AMR) and 51% were multidrug-resistant (MDR). Resistance among CoNS was the highest to ampicillin (90%) and penicillin (89%), with few isolates resistant to cefoxitin and vancomycin, 9% respectively. The most common resistance patterns among the CoNS was penicillin-ampicillin (16%) and penicillin-ampicillin-erythromycin (10%). Forty-two percent (42%) of biofilm positive CoNS were MDR. At the species level, MDR was common among S. epidermis (65%), S. chromogenes (52%) and S. haemolyticus (44%). In conclusion, biofilm formation was uncommon among the MDR-CoNS isolates in this study suggesting that biofilm formation is not a major contributing factor to antimicrobial resistance in this study. In addition, most CoNS isolates in this study were _-lactams resistant. This is concerning as penicillins are used commonly by dairy farmers in treatment of mastitis in South Africa. Nonetheless, the role of antimicrobial use practice in the development of resistance in subclinical mastitis in the dairy industry should be investigated. / Dissertation (MSc)--University of Pretoria, 2019. / Paraclinical Sciences / MSc / Unrestricted

This study is a questionnaire-based, descriptive assessment of informal livestock slaughter practices by small scale farmers in Gauteng. This study aims to assess if the practice of informal slaughter poses a potential risk to public health specifically to brucellosis exposure, a disease of high seroprevalence in Gauteng and South Africa. Informal livestock slaughter from antemortem selection to carcass dressing, butchering and product preparation were descriptively assessed for potential disease exposure and resultant public health risk. This study assessed the frequency of brucellosis testing and the occurrence of livestock abortions as a possible disease indicator. Farmers were asked on the particulars of informal slaughter to ascertain if disease exposure could occur through this practice. The study made use of a questionnaire where 109 study participants were interviewed individually. Questionnaire results were compiled in Microsoft® Excel where data was analysed through descriptive statistics to identify trends and frequency data from the results. The study found that the majority of small-scale farmers participating in the study were older individuals, the majority of whom were not earning an income. It was found that study participants would slaughter livestock informally themselves or with a family member. This would occur only once or twice a year, usually for cultural or religious purposes or for a special occasion. Livestock most commonly owned and slaughtered by small-scale farmers were cattle, carriers of Brucella abortus. Participants rarely made use of adequate protective personal protective equipment (PPE) when slaughtering informally. The use of PPE and the adequacy thereof was however found to increase in frequency with participant age group. Older individuals, elders in their communities were often given the responsibility of livestock slaughter, thus providing some risk mitigation to disease exposure during the process. High risk structures such as lymph nodes and reproductive organs were handled during slaughter, the former frequently consumed with the tripe due to lack of recognition. While some organs previously found to harbour Brucella organisms were consumed raw or only exposed to short cooking times, the majority of slaughter products were exposed to prolonged cooking times, sufficient to reduce bacterial loads, reducing risk through consumption. While many participants recognised brucellosis as a zoonotic disease, the routes of transmission were poorly recognised. Exposure to Brucella spp. through informal slaughter is likely in the current environment of high brucellosis seroprevalence, poor disease control and the unreliable disease history of animals sourced for slaughter, posing a risk to public health. Should a brucella infected animal be slaughtered informally, exposure of those performing the slaughter, dressing the carcass and those involved in food preparation is likely and may lead to brucellosis. / Dissertation (MSc)--University of Pretoria, 2018. / Veterinary Tropical Diseases / MSc / Unrestricted

Rickettsia africae is a gram-negative bacterium which causes African tick bite fever (ATBF) in humans. ATBF is a febrile disease mainly affecting travellers to Southern Africa. This bacterium is known to be transmitted by Amblyomma hebraeum and Amblyomma variegatum ticks. In Southern Africa, the principal vector is A. hebraeum. This project was performed in a rural community in Mpumalanga province and aimed at addressing knowledge gaps of R. africae infection in A. hebraeum ticks. Infection rates in adult ticks and larvae as well as transovarial transmission efficiency of R. africae from the tick to its offspring were determined. To accomplish this, 106 adult A. hebraeum ticks were collected from cattle from Utah A and 106 from Welverdiend A. Larvae (n=1060) were collected by dragging at each of the two targeted dip tanks. Engorged female A. hebraeum ticks (n=53) were also collected from cattle from each of the two dip tanks and they were incubated in a humidity tank to oviposit and egg masses were collected from each tick. DNA was extracted from the engorged ticks and the egg masses as well as from the adult ticks and the larvae. After DNA quantification, a real-time quantitative PCR targeting Rickettsia gltA gene was performed to screen all samples for Rickettsia DNA. The gltA gene is common in all Rickettsia species. Samples positive for the gltA gene were subjected to conventional PCR targeting the ompA gene, which is specific for the Spotted Fever Group to which R. africae belongs. The samples positive for amplicons of ompA gene were sequenced and all the sequenced samples were found to be 99.98% identical to R. africae sequences from GenBank. From the sampled adult ticks, 13.43% tested positive for R. africae and 13.20% of the larvae also tested positive. The infection rate for larvae and adult ticks collected from Utah A was 15.09% and those from Welverdiend A was 11.79%. From these results, there were no notable differences in the infection rates of ticks at different stages of development. R. africae infection rates for the two study sites were found to be similar which can be an indication of even distribution of R. africae in this area. Transovarial transmission was found to be 100% in engorged female ticks collected from Utah and 71.43% in ticks from Welverdiend, which indicates a high transmission rate of the pathogen to the offspring of the vector. The presence of R. africae in A. hebraeum ticks from this area is a cause of concern since there are chances of people getting ATBF after bites by these ticks. / Dissertation (MSc)--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc / Unrestricted