The Cape Mountain Zebra (CMZ) has been described as one of the most vulnerable mammals in the Republic of South Africa with current populations existing in isolated units. In recent years, South African conservation officials have noted the appearance of tumour like growths, similar to equine sarcoids, in some of these populations. The possibility that the existing populations, numbering around 1 500 animals in total, arose from a very small gene pool is very real, considering that in the early 1970’s there were only 35 breeding animals in the Mountain Zebra National Park. A genetic component to the susceptibility to sarcoid tumour development has been identified in horses. Researchers have found an association between susceptibility to sarcoid and certain heritable cell-surface proteins called major histocompatibility antigens. Studies have reported the possibility of high levels of inbreeding in CMZ in the Bontebok National Park (BNP). The non-territorial social organisation of mountain zebras allows the population to increase to a high density within a relatively short period of time. These observations, coupled with the fact that there are no confirmed reports of sarcoids in the relatively outbred Burchell’s zebra population in the Kruger National Park and the Hartmann’s mountain zebra populations in Namibia, strongly support the hypothesis that a correlation exists between inbreeding in zebra populations and expression of sarcoids. The small number of CMZ in BNP with an apparent high prevalence of suspected sarcoid tumours made this an ideal population to capture, identify and to study the skin tumour. The entire population of CMZ in the BNP was observed and sampled. A total of 15 CMZ was present in the Park at the time of the study. The individual animals were darted from a helicopter using M99, Azaperone and Hyalase after which a ground team moved in and covered their eyes and ears. Each animal was thoroughly examined for the presence of any tumours; the distribution was recorded on a body chart and sizes and appearance were recorded. Anatomical location on the body was divided into head and neck, ventral abdomen and limbs. Biopsies were taken from all of the zebras with sarcoid-like growths. The sarcoids were either surgically excised or a representative biopsy was taken by means of 6mm biopsy punches. The samples were collected in 10% buffered formalin for histological examination. The prevalence of sarcoid in CMZ in BNP was 53%. Of the affected animals, 50% had multiple tumours. The main predilection sites were on the trunk, followed by the limbs and then the head and neck. The severity of the lesions in one stallion was so extreme that it warranted euthanasia. The verrucous type, followed by much lower percentages of the fibroblastic and nodular types, dominated the clinical appearance. Lastly, the sarcoids examined showed either all or some of the typical epidermal and dermal histological features of equine sarcoid. A total of 7 of the affected CMZ were treated using four different methods. The sarcoids were surgically excised (n = 2), treated with intra-lesional 5-fluorouracil (n = 2), autogenous vaccine (n = 2) or autogenous vaccine combined with 5-fluorouracil (n =1). The zebras were immobilised for examination 18 months later. One animal that had been treated with intralesional 5-fluorouracil only had large numbers of verrucous and fibroblastic sarcoids. Her condition was so severe that she had to be euthanased. No signs of sarcoids could be found anywhere on the remaining 6 treated CMZ. This study confirmed that the growths in the CMZ in BNP population are indeed sarcoids and that many of them exhibit an aggressive nature. Sarcoid tumours is a disease that is considered multifactorial in aetiology and therefore other parameters such as immune status of tumour-affected populations and associated environmental variables warrant further investigation. / Dissertation (MSc (CACS))--University of Pretoria, 2006. / Companion Animal Clinical Studies / unrestricted

Equine sarcoid was diagnosed in the Cape mountain zebra (CMZ) population at the Gariep Nature Reserve (GNR) located in the southern Free State Province of South Africa in 1996. The course of the disease outbreak over the period from 1996 to 2003 is retrospectively described from data gathered during that time. In total, data from 39 affected animals was gathered during the study period. The average population size during the outbreak was 69 individuals. The initial prevalence was 9.4% in 1996. When ompared to the neighbouring domestic horse population, where no cases of equine sarcoid had been noted, the CMZ population showed a high prevalence of sarcoid for reasons unknown at the time. To mimic dynamics in a natural ecosystem with predators, it was decided to remove sarcoid-affected zebra from the population during 1996 and 1997. No sarcoid cases were seen in 1998 and 1999. After thoroughly examining the population in 2000, seven new sarcoid cases were found. Given the endangered status of the CMZ, no further affected animals were culled and a decision was made to study the disease more intensively, with emphasis on epidemiology, aetiology, clinical appearance and pathology, and treatment options as well as to investigate the genetic status of the population and the possibility of a genetic predisposition to the development of equine sarcoid. Prevalence of sarcoid cases in the Gariep CMZ population increased to 24.7% in 2002. Incidence varied between 4.65-17.6% during the study period with higher incidence rates recorded towards the second half of the study period. No sexual predilection was established. Sarcoids were not seen in animals younger than three years of age. Of the affected individuals, 64.1% had a single lesion and no animal had more than four lesions. Sarcoids were mostly of the fibroblastic (57%), verrucose (16%), and nodular (10%) types or a combination of these. The majority of lesions in males occurred in the inguinal area (55.17%), whereas the majority of lesions in females occurred on the head and neck (41.38%). Because treatment trials were conducted in a number of affected individuals, there were not many untreated control animals in which to study the rate of growth of the tumours, but the average annual increase in lesion size in untreated animals was found to be as much as 260%, becoming so large as to mechanically impede movement. During the study period, known sarcoid-related mortalities numbered four, while nine animals were euthanased for humane reasons, and ten other animals having been identified once with sarcoid were not seen again and presumed dead. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2007. / Paraclinical Sciences / MSc / unrestricted

Sarcoid-like tumours have been reported in Cape mountain zebra (Equus zebra zebra) in two South African game parks recently. These tumours caused severe distress to the animals and also made them unsightly for tourists visiting the parks. The aim of this investigation was to identify and characterize the infectious agent considered to be involved in the aetiology of sarcoid in the Cape mountain zebra. Bovine papillomaviruses (BPV) -1 and -2 deoxyribonucleic acid (DNA) were detected by the polymerase chain reaction (PCR) in sarcoid tumour tissue, but not from blood specimens or unaffected skin. Differentiation between BPV-1 and -2 was made by using the restriction endonuclease BstXI on PCR products of the E5 open reading frame (ORF). A hybridization probe real-time assay was developed for the specific and sensitive detection and differentiation of BPV-1 and -2 DNA in blood, skin and sarcoid tumour samples. For the specific detection of BPV-1, an increase in fluorescence was detected at 640 nm and of BPV-2 at 705 nm. The test is extremely sensitive and able to detect 1.5 genome copies/reaction. The presence of BPV-1 and -2 DNA could be demonstrated in the blood of sarcoid-affected and -unaffected zebras even in the blood of zebras from parks where sarcoids have never been observed. The phylogenetic relationships of the papillomaviruses detected in tumours in the Cape mountain zebra in comparison with a broad selection of papillomavirus sequences available in GenBank were compiled. The papillomavirus sequences retrieved from the zebras were identified as variants of either BPV-1 or BPV-2. The age of the most recent common ancestor for BPV-1 variants is estimated to be 1.40 million years (Mya) and for BPV-2 variants, 0.55 Mya. The age of the most recent common ancestor of BPV-1 and BPV-2 is estimated to be 5.34 Mya. Certain major histocompatibility (MHC) haplotypes are associated with increased risk of sarcoid tumours in horses. The zebras in these parks may have become inbred for the MHC region with increased prevalence for a haplotype, conferring increased risk for sarcoid tumours. Therefore typing system was developed to determine whether or not a high prevalence of sarcoids among zebras is associated with a MHC haplotype. Single strand conformational polymorphism was used to assess the genetic variation in MHC class II genes. The use of DQB and DRB genes demonstrated that genetic variation and sarcoids in the zebras could not be attributed to a specific haplotype. The developed real-time PCR technique was also applied in the detection of cutaneous papillomavirus in two giraffes (Giraffa camelopardalis) which were manifesting cutaneous papillomatosis, in the Kruger National Park and in a fibropapilloma in a sable antelope (Hippotragus niger), on a game farm in the Kimberley district, South Africa. In conclusion, this was the first study to confirm the presence of BPV-1 and -2 DNA in the sarcoid tumours, healthy skin and blood of sarcoid-affected and healthy free-roaming zebras from sarcoidaffected parks. The presence of BPV-1 and -2 DNA in the blood of zebras from parks where sarcoids have not been previously observed was a significant finding. / Thesis (PhD)--University of Pretoria, 2010. / Veterinary Tropical Diseases / unrestricted