Apart from its slender appearance, four main factors lead to questions regarding the bone density, mineral content and morphology of the giraffe skeleton: X A rapid vertical growth rate ¡V especially in the neck and metapodials X Biomechanical considerations pertaining to the tall and slender shape of the skeleton X A proportionally larger skeleton in relation to body mass X A seemingly abnormal mineral balance in their diet with possible signs of mineral deficiency (i.e. osteophagia) In this study the skeleton of the giraffe was compared with that of the African buffalo with regards to bone density, skeletal calcium (Ca) and phosphorus (P) content and certain femoral and metacarpal morphological characteristics. The aim was to establish if, compared to buffalo, the features of the giraffe skeleton differed in any unique way. Fourteen similar bones or parts of bones were collected from carcasses of six adult giraffe bulls and nine adult buffalo bulls. These bones were cleaned, weighed and their volume determined through water displacement, from which their density could be calculated. Hereafter, Ca and P content were analysed in 10 bones from each carcass. Morphological characteristics of cross-sections from femoral and metacarpal shafts were also measured. No significant differences between the density or mineral content of bones in the two species could be found. In both species 19,5% Ca and 9,5% P were measured in defatted bone. Although similar in mineral concentration, the giraffe skeleton contains three times more absolute Ca and P, which translates into a 1,5-2-fold higher dietary requirement for these minerals compared to buffaloes. A gradation in the volume and weight of cervical vertebrae was also seen in giraffes. This could hold biomechanical advantage for the carriage and manoeuvrability of the long neck. Bone wall thickness of the giraffe femur and metacarpus is increased compared to buffaloes. This could hold biomechanical advantage for the slender legs that are subjected to increased vertical forces. Adequate Ca seems to be acquired through very specific browse selection, which seems to be of evolutionary origin, while the acquisition of adequate P seems to be critical and a possible cause for osteophagia. This study is the first of its kind in these species and therefore also provide valuable baseline data for future work in this field. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2004. / Production Animal Studies / unrestricted

Theileriosis, babesiosis, heartwater and anaplasmosis are considered to be amongst the most important tick-borne diseases of livestock in sub-Saharan Africa‟s tropical and subtropical regions resulting in extensive economic losses to farmers in endemic areas. It is well-known that the African buffalo (Syncerus caffer) is the natural reservoir host of various tick-borne haemoparasites of veterinary importance. In this study, the occurrence of tick-borne haemoprotozoan parasites (Theileria, Babesia, Anaplasma and Ehrlichia species) in buffalo from two geographically isolated national parks in South Africa (Kruger National Park and Hluhluwe-iMfolozi Park) was determined using the reverse line blot (RLB) hybridization assay. The RLB results revealed the presence of Theileria, Babesia and Anaplasma species either as single or as mixed infections. Although not detected with the RLB assay, 5% of the buffalo blood samples from the KNP tested positive for the presence of Ehrlichia ruminantium using the pCS20 real-time PCR assay. Previous studies on the occurrence of haemoparasites in the South African buffalo population have mainly focussed on the prevalence of Theileria species only. The finding on the presence of Anaplasma, Ehrlichia and Babesia species is therefore a novel contribution. This study has confirmed the findings of previous studies that buffalo is the natural reservoir host of both pathogenic and non-pathogenic Theileria species namely, T. parva, Theileria sp. (buffalo), T. mutans, T. velifera and T. buffe1i.In this study, the most frequently occurring Theileria species detected in the KNP were T. mutans (81%), Theileria sp. (sable) (61%), T. parva (40%), Theileria sp. (buffalo) (13%) and T. velifera (11%). Theileria buffeli was not detected in the KNP. In the Hluhluwe-iMfolozi Park, the most occurring Theileria species were T. mutans (55%), T. velifera (54%), T. parva (53%), Theileria sp. (sable) (53%), Theileria sp. (buffalo) (49%) and T. buffeli, (49%). Theileria sp. (sable) causes fatal clinical disease in roan and sable antelope in South Africa and we can only speculate whether the presence of Theileria sp. (sable) DNA in the buffalo population was a true and/or incidental finding. An interesting finding was the presence of Babesia occultans DNA in 50% of the buffalo from the Hluhluwe-iMfolozi Park. Babesia occultans is the causative agent of a benign form of cattle babesiosis in South Africa and, to date; this organism has not been identified in wildlife in South Africa. The significance of this finding warrents further investigation and confirmation using gene cloning, sequencing and phylogenetic analysis. Ehrlichia ruminantium has been reported to infect not only domesticated ruminants but also wild ruminants, however most wildlife species appear to carry the organism asymptomatically. In this study, we were not able to detect E. ruminantium DNA in any of the buffalo samples tested using the RLB hybridization assay. However, using the quantitative pCS20 real-time PCR assay we detected E. ruminantium DNA in 5% of the KNP samples. None of the Hluhluwe-iMfolozi Park samples tested positive for E. ruminantium using the real-time PCR assay. These results suggest that buffalo is not the natural reservoir host of E. ruminantium. However, a subclinical carrier state in buffalo has been experimentally shown to occur after tick transmission from carrier animals and further studies will have to be conducted to confirm whether this finding holds any potential risk to domestic animals. In Southern Africa, two Anaplasma species are known to infect cattle, A. marginale and A. centrale. Clinical bovine anaplasmosis is usually caused by A. marginale; whilst A. centrale generally results in mild disease. Because there is partial cross immunity between the two species, A. centrale is used as a live vaccine for cattle in Israel, South Africa, South America and Australia. Apart from cattle, Anaplasma marginale has been described in wild ruminants which can become persistently infected serving as reservoirs for infection of susceptible hosts; it has been recovered from 10 wild ruminants. Subclinical occurrence of A. marginale, either natural or after artificial infection has been confirmed in the African buffalo and various other wildlife species. In this study, the Anaplasma species detected from HluhluweiMfolozi Park buffalo samples were A. centrale (75%), A. marginale (42%) and Anaplasma (formerly Ehrlichia) sp. Omatjenne (28%). DNA of these species was also detected in buffalo from KNP; A. centrale (49%), A. marginale (24%) and Anaplasma (Ehrlichia) sp. Omatjenne (5%). The presence of A. marginale in the buffalo population suggests that buffalo may be a factor in the epidemiology and spread of bovine anaplasmosis because, as reservoir hosts of A. marginale, they could serve as a source of infective blood for mechanical spread by various routes and biological transmission by ticks. Factors such as climate, host abundance, tick host diversity, and topography have, however, all been shown to also impact on the epidemiology of A. marginale. Subsequently 64 samples were selected that either tested (i) positive for a specific Anaplasma spp. (A. centrale, A. marginale and/or Anaplasma (Ehrlichia) sp. Omatjenne) using the RLB assay, or (ii) in which the PCR products hybridized only with the Anaplasma/Ehrlichia genus-specific probes for molecular characterization by cloning and sequencing of the 16S rRNA gene. Aplification of the full-length and/or partial parasite 16S rRNA gene of any of the selected samples that previously tested positive for the presence of Anaplasma (Ehrlichia)sp. Omatjenne (using the RLB assay) or E. ruminantium (using the pCS20 real-time PCR assay) was unsuccessful. This was most probably due to low rickettsaemia. However, amplification of either the near full-length parasite 16S rRNA gene or a partial 16S rRNA gene from seven samples from the KNP and three from Hluhluwe-iMfolozi Park was successful. Results indicated that the obtained sequences of 12 of the 18 clones were highly similar to published A. centrale 16S rRNA gene sequences, four of the clones were highly similar to the published A. marginale sequences and the sequences of the remaining two clones were closely similar to Anaplasma (Ehrlichia) sp. strain Omatjenne. The observed sequence similarities were confirmed by phylogenetic analyses. An interesting finding was the presence of one full-length parasite 16S rDNA sequence that was 100% identical to that of the published A. centrale vaccine strain sequences. It is well known that A. centrale is widely used as live vaccine for the control of bovine anaplasmosis. The occurrence of A. centrale vaccine strain DNA in the South African buffalo population is therefore of great interest. It can only be speculated whether A. centrale has evolved in the African buffalo, and/or if buffalo act as natural reservoir hosts, or if is it merely being maintained in the buffalo population by in utero transmission. This also serves as the first report of Anaplasma (Ehrlichia) sp. Omatjenne DNA in the African buffalo which warrents further investigation. In conclusion, the findings suggest that buffalo is a natural reservoir of Anaplasma spp. infection and could play an important role in the epidemiology and spread of anaplasmosis and may represent a serious threat to the livestock industry. / Dissertation (MSc)--University of Pretoria, 2012. / Veterinary Tropical Diseases / unrestricted

Genetic variation, structure and dispersal among Cape buffalo populations from the Hluhluwe-Imfolozi and Kruger National Parks of South Africa Barend Jacobus (Ben) Greyling Doctor of Philosophy (Zoology) Department of Zoology and Entomology Supervisor: Prof. Armanda Slager-Bastos Co-supervisor: Dr. Pim van Hooft 2007 The research reported on in this thesis is aimed at quantifying and qualifying, using a molecular genetics approach, some of the factors that influence the population dynamics of Cape buffalo (Syncerus caffer caffer) from the Kruger National Park (KNP) and Hluhluwe-imFolozi park (HiP) in South Africa. Prior to large-scale genotyping of animals sampled from these parks, a high-throughput, cost- and time-effective profiling system was developed. The system, based on a panel of 17 microsatellites (Msats), was found to be quite suitable for the intended application, since it uncovered substantial genetic variation, while exclusion probabilities were in excess of 0.999 and a random match probability of 6.5 x 10-17 was obtained. Inter-population level analyses revealed that the two populations were significantly differentiated (Msat data: FST = 0.159; mtDNA data: FST = 0.275), while little or no differentiation could be demonstrated among most herds and subpopulations. It seems that while drift has played a major role in divergence of the two populations, gene flow is the primary driving force behind the maintenance of genetic variation among herds and subpopulations. A striking feature was that HiP exhibited significant lower levels of genetic variation than KNP, which is reflected by the fact that a mere 4 haplotypes could be found in HiP compared to 34 identified in KNP. The absence of geographic partitioning and small genetic distances separating the haplotypes may be attributed to genetic contact between the respective populations in the distant past. The reduced levels of genetic variation in HiP may be the remnants of the rinderpest bottleneck. HiP also displayed signals of a population contraction, while KNP is in equilibrium and seems to have retained substantial levels of genetic variation. HiP also experienced a steady decline in genetic variation from 1986 to 2004, while sex-biased dispersal was less pronounced in HiP than in KNP, possibly due to the lack of mtDNA diversity and the small size of the park. The results presented here provide valuable baseline information for making conservation management decisions from a genetic point of view. / Thesis (PhD (Zoology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

L’augmentation depuis une trentaine d’années des maladies infectieuses dites émergentes ou ré-émergentes chez l’homme, causées à plus de 70% par des pathogènes issus d’espèces hôtes animales (i.e. Ebola, SIDA), stimule l’étude de systèmes éco-épidémiologiques à l’interface entres populations humaines et animales (i.e. sauvages et/ou domestiques).Le contact entre hôtes est un phénomène important dans l’étude de ces systèmes car il permet la transmission des pathogènes entre individus et la diffusion de maladie au sein et entre populations. Nous avons choisi la maladie de la fièvre aphteuse comme modèle d’étude de la transmission de pathogènes des populations sauvages vers les populations domestiques. Le buffle africain (Syncerus caffer) étant le réservoir présumé de cette maladie fortement contagieuse, nous nous sommes interrogés sur les conditions de transfert au bétail (Bos taurus et Bos indicus) du virus aphteux aux frontières de trois parcs nationaux africains qui constituent des interfaces entre espaces anthropiques et protégés perméables aux mouvements d’animaux. Dans le cadre de ce doctorat 4 protocoles ont été mis en place entre 2010 et 2011 au Zimbabwe. Premièrement, des colliers GPS (Global Positionning System) ont été déployés sur des bovins sauvages/domestiques pour décrire leurs déplacements dans le paysage et quantifier les contacts interspécifiques. Des colliers furent également posés sur l’une des espèces prédatrices de ces ongulés: le lion (Panthera leo). L’intégration de la guilde des prédateurs nous a permis d’estimer les modifications de l’utilisation de l’espace par les herbivores en réponse à la présence de carnivores et les conséquences en termes de contacts et de transmission interspécifique de pathogènes. Deuxièmement, un suivi longitudinal sérologique sur le bétail a complété le protocole télémétrique avec des prélèvements répétés sur des individus marqués selon le cycle saisonnier. Troisièmement, les contacts au sein des populations de bovins domestiques ont été caractérisés par des enquêtes auprès des éleveurs. Quatrièmement, le rôle potentiel de la diversité des hôtes sur le risque infectieux d’un écosystème a été exploré par l’estimation de densité de macro-parasites dans le paysage selon une variation de la gamme d’hôtes potentiels (i.e. (i) sauvages, (ii) sauvages et domestiques et (iii) uniquement domestiques).Nos résultats montrent que (1) les taux d’interaction interspécifiques, estimés par télémétrie, varient entre sites et présentent une saisonnalité prononcée (i.e. pic saison sèche chaude). (2) La distribution des ressources conditionne la périodicité et la distribution de ces contacts dans les différents compartiments du paysage. (3) La fréquence des incursions du bétail dans un espace protégé ainsi que les taux de contacts avec les buffles influencent positivement la probabilité d’acquisition d’anticorps anti-aphteux chez le bétail. La probabilité de perte d’anticorps est également fonction du niveau d’interaction avec les buffles mais selon une relation négative. (4) La densité du réseau d’interaction intra-spécifique domestique influence positivement l’incidence sérologique de la fièvre aphteuse. (5) La présence de prédateurs supérieurs dans le paysage permettrait de limiter les incursions du bétail dans les espaces protégés et diminuerait la probabilité d’infection par les populations d’hôtes sauvages. (6) Enfin les densités de macro-parasites dans la végétation sont supérieures dans des espaces communaux sans interaction avec les populations sauvages et où la richesse spécifique des hôtes est plus faible. Les résultats de cette étude sur la transmission interspécifique de pathogènes entre populations sauvages et domestiques dans les écosystèmes tropicaux ouvrent des champs de réflexion encore largement inexplorés, notamment sur l’évolution de la virulence et des modes de transmission des pathogènes ayant comme hôtes des populations sympatriques sauvages et domestiques. / Emerging or re-emerging diseases in human populations have increased over the last thirty years. Since 70% of such diseases are caused by pathogens originating from animal hosts (i.e. Ebola, AIDS, and avian influenza), this increase has prompted the study of eco-epidemiological systems that occur at the interface between human and animal populations (i.e. wild and/or domestic). Contacts between hosts are particularly important factors in these systems since they result in pathogen transmission among individuals and, therefore, disease diffusion within and among populations. We used foot-and-mouth disease (FMD) as a model to study pathogen transmission from wild to domestic populations. As the African buffalo (Syncerus caffer) is the presumed reservoir of this highly contagious disease, we examined the conditions in which the virus was transmitted to cattle sensitive to the disease (Bos taurus and Bos indicus) at the borders of African national parks; these areas are interfaces between anthropogenic and protected areas in which animals can move freely.In the context, 4 protocols were implemented between 2010 and 2011 in Zimbabwe. First, GPS (Global Positioning System) collars were placed on cattle and buffalo in order to describe and analyze their movements across the landscape as well as to quantify interspecific contacts. In one of the study sites, collars were attached to one of the predators of these ungulates: the lion (Panthera leo). By integrating the predator guild into our telemetry protocols, we could examine the potential changes in spatial use by cattle and buffalo in response to predator presence and their consequences for contact dynamics and interspecific pathogen transmission. Second, a longitudinal serological survey was conducted in which tagged individuals were sampled repeatedly over the course of different seasons. Third, to characterize contacts within the domestic host population, interviews were conducted with cattle owners regarding their husbandry practices across seasons. Fourth, to describe the potential role of host diversity in ecosystem infection risks, macroparasite density (i.e. ticks) was estimated for landscape compartments that contrasted in terms of potential hosts present (i.e. (i) wild, (ii) domestic and wild, and (iii) domestic only).Our study primarily shows the following results. (1) Interspecific interaction rates, as estimated by telemetry, vary between sites and have a pronounced seasonality (peak occurs during the hot dry season). (2) Resource distribution (i.e. water and grazing areas) seems to condition the frequency and distribution of these contacts in the different landscape compartments. (3) Cattle incursion frequencies into protected areas and the frequency and intensity of contact with buffalo significantly positively affect the probability of foot-and-mouth antibody acquisition in cattle. The probability of antibody loss in cattle is also a function of diminished rates of interaction with buffalo. (4) Intraspecific interaction densities positively influence FMD serological incidence in cattle. (5) Top predator presence in the landscape could limit cattle incursion into protected areas and reduce the likelihood of their being infected by wild host populations. (6) Finally, the estimated densities of macroparasites in the vegetation were higher in communal spaces where there was no interaction with wild hosts and where host species richness was weak.The results of this study on the interspecific transmission of pathogens between wild and domestic populations in tropical ecosystems encourage the exploration of research topics that are still largely unexplored, including the evolution of virulence transmission modes of pathogens hosted by sympatric wild and domestic populations.

The African buffalo (Syncerus caffer) is a member of one of Africa’s most well known tourist attractions and unique grouping of mammals – the ‘big five’. Historical records indicate that during the 19th century approximately 3 million African buffaloes inhabited almost the whole of sub-Saharan Africa. Several factors such as disease, habitat fragmentation, over-hunting and drought reduced the buffalo population to approximately 400 000 by 1990. The African buffalo is host to a variety of sub-acute diseases, such as bovine tuberculosis (BTB), foot-and-mouth disease (FMD) and corridor disease (CD). Disease is an important factor which influenced African buffalo populations throughout the continent and more specifically the Kruger National Park (KNP) and is largely responsible for the fact that buffaloes are restricted to enclosed areas with strict regulations imposed on their movement. The social organization of animals influences the distribution and spread of a disease - especially in the case of the African buffalo in the KNP. The emergence of BTB in the largest conservation area in South Africa (the KNP), threatens wild and domestic animals and humans who are in close proximity to the Park. The potential economic losses associated with this disease are excessive. The results presented in this thesis provide baseline information into the genetic status of sampled African buffaloes in the KNP, genetic relatedness between sampled individuals as well as BTB associations between sampled African buffaloes in the KNP, based on a limited dataset of 181 animals. Twelve microsatellite markers were used to evaluate 181 samples which were collected from 39 locations dispersed throughout the KNP. Specific population genetic parameters revealed information based on the intra and inter - relationships at the ‘per population’ level as well as at the ‘per prevalence group’ level. Evidence indicates a medium to high level of genetic diversity, a low to medium level of inbreeding (inbreeding coefficient (Fis) for each group ranges between 0.143 and 0.147) and a relatively high level of migration for buffaloes associated with each prevalence group. Pairwise relatedness estimates were determined between individuals, to reveal their level of relatedness (unrelated, full siblings, parent-offspring or half siblings), based on Queller and Goodnight’s (1989) coefficient of relatedness. Relatedness was determined on different levels, intra and interpopulation level, BTB infected and BTB uninfected group level as well as prevalence group levels. Evaluation of data based on these different levels and between different groups, painted an overall picture of the disease condition and genetic relatedness within and between sampled BTB infected and BTB uninfected buffaloes. Evidence indicated that the greater majority of our sampled African buffaloes (BTB infected or uninfected), were genetically unrelated (in terms of sibling and parent-offspring relationships), irrespective of their disease status. M. bovis infected buffaloes sampled and used in our study are not more closely related to each other than to uninfected buffaloes in the same population or prevalence group. / Dissertation (MSc)--University of Pretoria, 2010. / Production Animal Studies / unrestricted