In South Africa, the diagnosis of Theileria parva in cattle and buffalo has been complicated by the presence of mildly pathogenic and non-pathogenic Theileria spp. This can lead to inaccurate diagnostic results and confuse the epidemiology of theileriosis. The aims of this study were to identify and characterize the 18S rRNA genes of novel Theileria spp. of the African buffalo, as well as to test new gene targets that will allow for the development of more accurate diagnostic tests for the identification of T. parvainfections in cattle and buffalo. Buffalo blood samples originating from different geographical regions in South Africa and from Mozambique were screened for the presence of Theileria spp. by the reverse line blot (RLB) hybridization assay. A total of six Theileria spp., namely T. parva, Theileria sp. (buffalo), Theileria mutans, Theileria velifera and Theileria buffeli, were identified from the buffalo samples. These occurred mainly as mixed infections. Some of the samples hybridized only with the Theileria/Babesia genus specific probe that is used in the RLB assay, and not with any of the species-specific probes used, suggesting the presence of novel genotypes or species. The full-length 18S rRNA genes of parasites from selected samples were characterized by cloning and sequencing. In addition to the identification of 18S rRNA gene sequences that were similar to published Theileria spp. of cattle and buffalo, we identified Theileria sp. (bougasvlei), and novel 18S rRNA gene variants of T. mutans, T. velifera, T. bufJeli. This variation explained why the RLB hybridization assay failed to detect these species in some of the analysed samples. As extensive variation was observed within the T. mutan group, specific RLB oligonucleotide probes were designed from the V 4 hypervariable region of the T. mutans-like 1 and 2/3 18S rRNA gene sequences. Unfortunately these cross-hybridized with T. mutans target DNA and could not be used to screen buffalo samples to determine the occurrence of these genotypes in buffalo in South Africa. This problem could be solved by designing probes from a more variable area of the 18S rRNA gene of the T. mutans groups. Alternatively, a quantitative real-time PCR (qPCR) assay could be used for differentiation of these genotypes as it is more sensitive than the RLB assay. Despite the variation observed in the full-length T parva 18S rRNA gene sequences, the area in the V 4 hypervariable region where the T parva RLB and real-time PCR hybridization probes were developed was relatively conserved between sequences obtained in this study. The existing T parva-specific qPCR assay was able to successfully detect all T parva variants identified in this study and, although amplicons were obtained from Theileria sp. (buffalo) and Theileria sp. (bougasvlei) DNA, these species were not detected by the T parva-specific hybridization probes. The sequences of the other Theileria spp. and the novel genotypes identified in this study under the probes were also different from that of T parva and therefore these species do not compromise the specificity of the T parva 18S qPCR assay. In order to determine the sequence variation and phylogenetic positions of T buffeli spp. of the African buffalo, we cloned and sequenced their 18S rRNA gene and complete internal transcribed spacer (ITS). We identified novel T buffeli-like and T sinensis-like 18S rRNA and ITS genotypes from buffalo originating from two different geographical regions in South Africa. There was extensive sequence variation between these novel South African genotypes and known T buffeli-like and T sinensis-like genotypes. The presence of organisms with T buffeli-like and T. sinensis-like genotypes in the African buffalo is of significant importance, particularly to the cattle industry in South Africa as these animals might act as sources of infections to naIve cattle. Recently, a qPCR assay based on the cox III gene was developed for the diagnosis of Theileria spp. in cattle. This test detects and differentiates six Theileria spp. in cattle. We evaluated the use of this assay for the detection of Theileria spp. in buffalo. The results of the cox III qPCR were compared to those of the RLB and 18S qPCR for the simultaneous detection and differentiation of Theileria spp. of the African buffalo, and for the specific detection of T parva, respectively. The cox III genes from selected samples with non-specific melting peaks were characterized by cloning and sequencing. Extensive sequence variation in the cox III gene was observed between and within species. The T mutans group was the most variable. The qPCR assay could be further improved by designing new primers and probes using all known cox III gene sequences of Theileria spp. Of buffalo and cattle. This study highlights the complexity of the diagnosis of T parva in cattle and buffalo in South Africa. It provides invaluable information towards the development of an improved molecular diagnostic assay for T parva and co-infecting species in cattle and buffalo in South Africa which will assist the veterinary regulatory authorities in the control of Corridor disease in South Africa. / Thesis (PhD)--University of Pretoria, 2011. / Veterinary Tropical Diseases / Unrestricted

No description available.

Thesis (MSc (Veterinary Science))--University of Pretoria, 2005. / Includes bibliographical references.

Understanding what factors influence wildlife movement allows landscape planners to make informed decisions that benefit both animals and humans. New quantitative methods, such as step-selection functions, provide valuable objective analyses of wildlife connectivity. This paper provides a framework for creating a step-selection function and demonstrates its use in a case study. The first section provides a general introduction about wildlife connectivity research. The second section explains the math behind the step-selection function using a simple example. The last section gives the results of a step-selection model for African buffalo in the Kavango Zambezi Transfrontier Conservation Area. Buffalo were found to avoid fences, rivers, and anthropogenic land use; however, there was great variation in individual buffalo's preferences.

Lumpy skin disease (LSD) and Rift Valley fever (RVF) are transboundary viral diseases occurring in Africa and the Middle East (e.g. Israel, Saudi Arabia and Yemen) with increasing potential for global spread. Although the role of wildlife in the epidemiology of these diseases is still not clearly understood, the African buffalo (Syncerus caffer) is thought to play a role in the epidemiology of these diseases. This study sought to expand our understanding of the role of buffalo in the maintenance of RVF and LSD by determining seroprevalence to these viral diseases in buffalo during the inter-epidemic period. Lumpy skin disease is endemic in Africa, and has spread to the Middle East (e.g. Israel); consequently there is a high risk of lumpy skin disease virus (LSDV) expanding its geographical distribution to other areas and due to its economic importance it is included in the list of Notifiable Diseases of the World Organization of Animal Health (OIE). The African buffalo is also suspected to play a role in the epidemiology of RVF. Like LSD, RVF was, until recently, only endemic in Africa. However, it spread to the Arabian Peninsula (Saudi Arabia and Yemen) in 2000 exacerbating concerns that it will extend to other regions of the world. Studies have already established that competent mosquito vectors for RVFV exist in North America and other parts of the world. A total of 248 buffalo sera was tested for antibodies to capripoxviruses and neutralising antibodies against LSDV and RVFV using an indirect enzyme-linked immunosorbent assay (I-ELISA) as well as the serum neutralisation test (SNT). The samples were obtained from the Kruger National Park (KNP) and Hluhluwe-iMfolozi Park (HiP) in South Africa. The prevalence of antibodies to LSDV and RVFV in the sera tested was 70/248 (28.2%) and 15/248 (6.1%), respectively using an I-ELISA. The LSDV I-ELISA, using a sheeppox virus as antigen, has not been validated for use in African buffalo. The high percentage of LSDV positive antibody results obtained in this study is however a concern. Results obtained is in contrast with other published results as well as results obtained with the SNT for antibodies against LSDV. The SNT is currently the gold standard for LSDV antibody testing. Using this test for LSDV in this study, 5/66 (7.6 %) samples tested positive. The results of the RVF I-ELISA, which had previously been validated for use in the African buffalo, correlated with the SNT results. From 12 SNT RVFV-positive sera, 3 (25%) had very high SNT titres of 1:640. Neutralising antibody titres of more than 1:80 were found in 80% of the positive sera tested. Eleven buffaloes (4.4% of the total samples) also showed evidence of antibodies to both LSDV and RVFV. The results obtained in this study complement other reports indicating the role of African buffalo in the epidemiology of these diseases during inter-epidemic periods. / Dissertation (MSc)--University of Pretoria, 2012. / Veterinary Tropical Diseases / unrestricted

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

Vision studies and visual acuity investigations are an ongoing and progressive field in veterinary ophthalmology. These independent studies all help to contribute to a combined and collective knowledge in our understanding of this truly complex matter. Understanding retinal morphology and physiology is an integral factor in piecing together overall function of the eye. Many of these studies have been done in both medical and veterinary ophthalmology using behavioural factors, electrophysiology, special staining and scanning techniques on a histological level. In the veterinary field many species have been studied pointing out similarities or differences among them. This study hopes to contribute to the understanding of the retinal ultrastructure of the African buffalo (Syncerus caffer). Twenty-five pairs of African buffalo eyes were obtained, but only forty-eight eyes were included in this investigation. The globes of one donor appeared to have chronic intraocular disease and were phthisical. Since this is a descriptive study of normal anatomy and function, these eyes were excluded. Globe dimensions were recorded and statistically analysed, revealing an average horizontal diameter of 32.91mm and a vertical diameter of 33.04mm. The median age of the donor group was 4 years with Using scanning electron microscopy it was established that African buffalo retinas, like other domestic species, have a specialised region a few millimetres dorsolateral to the optic disc, synonymous to the well described area centralis. In this region a higher concentration of cones is found as opposed to other rod-rich regions. In a concurrent investigation, the contralateral globes were processed for immunohistochemical antibody staining. Colour specific anti-bodies were used to identify the cone population present in the African buffalo retina. The conclusion of this investigation reveals that this species like other domestic animals has dichromatic colour vision, recognising short and medium to long colour wavelengths. / Dissertation (MMedVet)--University of Pretoria, 2013. / gm2014 / Companion Animal Clinical 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 aim of this study was to investigate three key epidemiological aspects of Theileria parva infections in cattle and African buffalo (Syncerus caffer) in South Africa. The first of these was the possible behavioural change (i.e. transformation) of buffalo-derived T. parva (causing classical Corridor disease in cattle) to what might be considered cattle-derived T. parva (causing classical East Coast fever in cattle) after repeated tick-passage in cattle. For the first time a South African isolate of buffalo-derived T. parva was successfully transmitted using Rhipicephalus zambeziensis for eight passages in non-splenectomised cattle. This was achieved despite most animals developing fatal infections with extremely low piroplasm parasitaemias, and without chemotherapeutic intervention. This finding indicates that, contrary to earlier belief, Corridor disease is not a self-limiting disease in cattle, and given the opportunity, could well become established in a cattle population in the absence of buffalo. Despite repeated tick transmission in cattle of the South African buffalo isolate of T. parva used in this study, it did not exhibit the behavioural changes associated with “transformation” to typical cattle-derived T. parva. Secondly, the potential role of the common waterbuck (Kobus ellipsiprymnus) in the selection of cattle-adapted subpopulations of parasites from buffalo-derived T. parva was investigated. Waterbuck captured in Kruger National Park (KNP) were screened by conventional and molecular diagnostic techniques for Theileria spp. infections. Laboratory-reared R. zambeziensis were fed on captive buffalo confirmed to be naturally infected with T. parva. The ensuing adult ticks were fed on captive waterbuck and cattle. All the waterbuck were found to carry microscopically detectable Theileria sp. piroplasm infections, found by polymerase chain reaction (PCR) diagnosis to belong to a hitherto uncharacterised Theileria species. R. zambeziensis adults which fed as nymphs on the buffalo transmitted fatal T. parva infections to cattle. However, no transmission of T. parva to the waterbuck could be demonstrated clinically or by PCR diagnosis. Also, R. zambeziensis nymphs that were subsequently fed on the waterbuck failed to transmit T. parva to cattle in the ensuing adult stage, confirming the absence of T. parva-group infections in the waterbuck. The results suggest that buffalo in KNP probably do not carry T. parva-group parasites which are readily transmissible to common waterbuck and waterbuck are therefore unlikely to play an important role in the epidemiology of T. parva-group infections in cattle in South Africa. Thirdly, to investigate the carrier state of buffalo-derived T. parva infections in cattle, blood from infected non-splenectomised and splenectomised carrier cattle was subinoculated to splenectomised cattle. T. parva infections were successfully transmitted by subinoculation of 1000 ml of blood at various intervals after infection to splenectomised recipient cattle. Donor animals comprised of recovered intact cattle, reacting intact cattle or splenectomised recovered cattle. Microscopically detectable piroplasm parasitaemias were detected in all recipients after inoculation. One splenectomised recipient developed a moderate clinical reaction, accompanied by a moderate schizont parasitosis, but recovered spontaneously, confirming persistence of schizonts in some T. parva carrier animals. By contrast, a T. parva piroplasm infection, persisting in a treated recovered splenectomised bovine, in the apparent absence of circulating schizonts, was serially (consecutively) passaged in splenectomised cattle. Seroconversion occurred in all recipient cattle. With the exception of the recipient which developed a clinical reaction and circulating schizonts, none of the recipients showed any clinical signs of T. parva infection. Upon homologous sporozoite challenge with T. parva, two out of three recipient animals with only microscopically detectable piroplasm parasitaemias developed fatal T. parva infections and one recovered after exhibiting severe clinical signs. These findings confirm the stage-specific immunity in T. parva and, contrary to popular belief, the possibility of long-term maintenance of piroplasm parasitaemias in the absence of schizonts in carrier cattle. The technique of subinoculating and establishing virulent T. parva carrier infections in splenectomised cattle also provides a method whereby buffalo-derived parasite stocks may be isolated and maintained for characterisation and the preparation of sporozoite stabilates for inclusion in T. parva vaccines. Copyright / Dissertation (MSc)--University of Pretoria, 2011. / Veterinary Tropical Diseases / unrestricted

M.Sc. / Climate change, loss of habitat and over-exploitation of natural resources as well as the introduction of invasive alien species through human activities are resulting in an ever increasing risk of extinction of many plant and animal species. There are two major approaches to conserving threatened and endangered species. Firstly the large scale preservation of natural habitat and ecological processes, thereby protecting the species inhabiting the habitat. The second approach involves the ex-situ breeding of rare and endangered species. It is estimated that in the next 200 years approximately 800 mammalian species will require the assistance of breeding programs to ensure long term genetic viability. Biological Resource Banks (BRB) can potentially contribute to this challenge by providing a source of genes that can be used to counter the effects of external selection pressures, genetic drift and inbreeding depression in small or fragmented populations. These banks commonly contain biological materials such as cryopreserved sperm, embryos and cell cultures mainly as genetic and research resources. . Biological resource banks can potentially use these cryopreserved gametes together with assisted reproductive technologies (ART), such as artificial insemination (AI), in vitro fertilisation (IVF), embryo transfer (ET), intracytoplasmic sperm injection (ICSI) and nuclear transfer (NT) to maintain genetic heterogeneity in ex-situ and wild populations. Ascertaining the appropriate protocols for developing the ARTs necessary for non-domestic species is one of the major challenges faced by reproductive physiologists. Typically, there is very little available information about the processing of semen, the effects of diluents, concentration and type of cryoprotectants and freeze-thaw methods for sperm samples of non-domestic species. Procedures proven to be highly effective in humans and laboratory or domestic species, are frequently adopted and modified for use in related wildlife species. It is thus necessary to gain knowledge of the reproductive physiology of wildlife species in order to define effective protocols for the cryopreservation of biomaterials which assists in the conservation of South Africa‘s diverse wildlife species. Sperm quality assessment is a useful tool for assessing the reproductive health of free-ranging populations as well as for selecting individuals for future assisted reproduction programs.