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

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