Bovine anaplasmosis is a tick-borne disease caused by the intra-erythrocytic rickettsia Anaplasma... more Bovine anaplasmosis is a tick-borne disease caused by the intra-erythrocytic rickettsia Anaplasma marginale. A blood-based vaccine is used for control of anaplasmosis though it does not offer protection against heterologous challenge by all A. marginale field strains, and has potential to transmit emerging diseases. Outer membrane protein (OMP) preparations of A. marginale have been shown to induce immune protection in nearly all animals tested, thus demonstrating the potential efficacy of a subunit vaccine. Eight OMP vaccine candidates have been identified from North American A. marginale strains, but it is not known if they are sufficiently conserved to be broadly useful worldwide or if vaccine development based on regional pathogen strains is necessary. Primers were designed and used to amplify DNA sequences for two of these OMP genes, Am779 and Am854. Genomic DNA was extracted from A. marginale positive samples obtained from Gauteng, Mpumalanga and KwaZulu-Natal provinces, which...
Journal of the South African Veterinary Association
Theileria parva causes widespread morbidity and mortality in cattle in endemic regions. An outbre... more Theileria parva causes widespread morbidity and mortality in cattle in endemic regions. An outbreak of theileriosis occurred on a farm near Ladysmith in KwaZulu-Natal, South Africa, which is not a declared Corridor disease-infected area. A survey of Red Brangus cattle from all age groups and areas of the farm was performed. Transmission of the parasite from infected animals on the farm to susceptible animals by tick transmission and tick-stabilate injection, was attempted. The survey indicated high numbers of animals with antibody titres to T. parva but only 6 infected animals, based on real-time PCR and RLB analysis. The transmission experiments failed to transmit the parasite. The study shows the difficulty in elucidating a source of infection and determining the dynamics of new infections in a herd where multiple possible sources are present and treatment with tetracyclines has taken place.
Babesiosis in a sable antelope (Hippotragus niger Harris, 1838) was first reported in 1930; the p... more Babesiosis in a sable antelope (Hippotragus niger Harris, 1838) was first reported in 1930; the parasite was named Babesia irvinesmithi. Recently, specimens from an adult sable that presented with a sudden onset of disease and that subsequently died during immobilization were submitted for molecular characterization. Microscopic examination of thin blood smears revealed the presence of small piroplasms. DNA was extracted from blood samples; the V4 variable region of the 18S rRNA gene was amplified and analyzed using the reverse line blot (RLB) assay. Amplicons did not hybridize with any of the Babesia or Theileria species-specific probes present on the blot and hybridized only with a Babesia or Theileria genus-specific probe, suggesting the presence of a novel species. The full-length 18S rRNA gene sequence was obtained and aligned with published sequences of related genera, and phylogenetic trees were constructed. Sequence similarity analyses indicated that a Babesia species, desig...
Theileria buffeli/orientalis is a group of benign and mildly pathogenic species of cattle and buf... more Theileria buffeli/orientalis is a group of benign and mildly pathogenic species of cattle and buffalo in various parts of the world. In a previous study, we identified T. buffeli in blood samples originating from the African buffalo (Syncerus caffer) in the Hluhluwe-iMfolozi Game Park (HIP) and the Addo Elephant Game Park (AEGP) in South Africa. The aim of this study was to characterise the 18S rRNA gene and complete internal transcribed spacer (ITS1-5.8S-ITS2) region of T. buffeli samples, and to establish the phylogenetic position of this species based on these loci. The 18S rRNA gene and the complete ITS region were amplified from DNA extracted from blood samples originating from buffalo in HIP and AEGP. The PCR products were cloned and the resulting recombinants sequenced. We identified novel T. buffeli-like 18S rRNA and ITS genotypes from buffalo in the AEGP, and novel Theileria sinensis-like 18S rRNA genotypes from buffalo in the HIP. Phylogenetic analyses indicated that the T. buffeli-like sequences were similar to T. buffeli sequences from cattle and buffalo in China and India, and the T. sinensis-like sequences were similar to T. sinensis 18S rRNA sequences of cattle and yak in China. There was extensive sequence variation between the novel T. buffeli genotypes of the African buffalo and previously described T. buffeli and T. sinensis genotypes. The presence of organisms with T. buffeli-like and T. sinensis-like genotypes in the African buffalo could be of significant importance, particularly to the cattle industry in South Africa as these animals might act as sources of infections to naĂŻve cattle. This is the first report on the characterisation of the full-length 18S rRNA gene and ITS region of T. buffeli and T. sinensis genotypes in South Africa. Our study provides invaluable information towards the classification of this complex group of benign and mildly pathogenic species.
Bovine anaplasmosis is a tick-borne disease caused by the intra-erythrocytic rickettsia Anaplasma... more Bovine anaplasmosis is a tick-borne disease caused by the intra-erythrocytic rickettsia Anaplasma marginale. A blood-based vaccine is used for control of anaplasmosis though it does not offer protection against heterologous challenge by all A. marginale field strains, and has potential to transmit emerging diseases. Outer membrane protein (OMP) preparations of A. marginale have been shown to induce immune protection in nearly all animals tested, thus demonstrating the potential efficacy of a subunit vaccine. Eight OMP vaccine candidates have been identified from North American A. marginale strains, but it is not known if they are sufficiently conserved to be broadly useful worldwide or if vaccine development based on regional pathogen strains is necessary. Primers were designed and used to amplify DNA sequences for two of these OMP genes, Am779 and Am854. Genomic DNA was extracted from A. marginale positive samples obtained from Gauteng, Mpumalanga and KwaZulu-Natal provinces, which...
Journal of the South African Veterinary Association
Theileria parva causes widespread morbidity and mortality in cattle in endemic regions. An outbre... more Theileria parva causes widespread morbidity and mortality in cattle in endemic regions. An outbreak of theileriosis occurred on a farm near Ladysmith in KwaZulu-Natal, South Africa, which is not a declared Corridor disease-infected area. A survey of Red Brangus cattle from all age groups and areas of the farm was performed. Transmission of the parasite from infected animals on the farm to susceptible animals by tick transmission and tick-stabilate injection, was attempted. The survey indicated high numbers of animals with antibody titres to T. parva but only 6 infected animals, based on real-time PCR and RLB analysis. The transmission experiments failed to transmit the parasite. The study shows the difficulty in elucidating a source of infection and determining the dynamics of new infections in a herd where multiple possible sources are present and treatment with tetracyclines has taken place.
Babesiosis in a sable antelope (Hippotragus niger Harris, 1838) was first reported in 1930; the p... more Babesiosis in a sable antelope (Hippotragus niger Harris, 1838) was first reported in 1930; the parasite was named Babesia irvinesmithi. Recently, specimens from an adult sable that presented with a sudden onset of disease and that subsequently died during immobilization were submitted for molecular characterization. Microscopic examination of thin blood smears revealed the presence of small piroplasms. DNA was extracted from blood samples; the V4 variable region of the 18S rRNA gene was amplified and analyzed using the reverse line blot (RLB) assay. Amplicons did not hybridize with any of the Babesia or Theileria species-specific probes present on the blot and hybridized only with a Babesia or Theileria genus-specific probe, suggesting the presence of a novel species. The full-length 18S rRNA gene sequence was obtained and aligned with published sequences of related genera, and phylogenetic trees were constructed. Sequence similarity analyses indicated that a Babesia species, desig...
Theileria buffeli/orientalis is a group of benign and mildly pathogenic species of cattle and buf... more Theileria buffeli/orientalis is a group of benign and mildly pathogenic species of cattle and buffalo in various parts of the world. In a previous study, we identified T. buffeli in blood samples originating from the African buffalo (Syncerus caffer) in the Hluhluwe-iMfolozi Game Park (HIP) and the Addo Elephant Game Park (AEGP) in South Africa. The aim of this study was to characterise the 18S rRNA gene and complete internal transcribed spacer (ITS1-5.8S-ITS2) region of T. buffeli samples, and to establish the phylogenetic position of this species based on these loci. The 18S rRNA gene and the complete ITS region were amplified from DNA extracted from blood samples originating from buffalo in HIP and AEGP. The PCR products were cloned and the resulting recombinants sequenced. We identified novel T. buffeli-like 18S rRNA and ITS genotypes from buffalo in the AEGP, and novel Theileria sinensis-like 18S rRNA genotypes from buffalo in the HIP. Phylogenetic analyses indicated that the T. buffeli-like sequences were similar to T. buffeli sequences from cattle and buffalo in China and India, and the T. sinensis-like sequences were similar to T. sinensis 18S rRNA sequences of cattle and yak in China. There was extensive sequence variation between the novel T. buffeli genotypes of the African buffalo and previously described T. buffeli and T. sinensis genotypes. The presence of organisms with T. buffeli-like and T. sinensis-like genotypes in the African buffalo could be of significant importance, particularly to the cattle industry in South Africa as these animals might act as sources of infections to naĂŻve cattle. This is the first report on the characterisation of the full-length 18S rRNA gene and ITS region of T. buffeli and T. sinensis genotypes in South Africa. Our study provides invaluable information towards the classification of this complex group of benign and mildly pathogenic species.
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Papers by Marinda Oosthuizen