Kgomotso Sibeko | University of Pretoria (original) (raw)

Papers by Kgomotso Sibeko

Research paper thumbnail of Selection and evaluation of housekeeping genes for haemocytes of soft-shell clams (Mya arenaria) challenged with Vibrio splendidus

Journal of Invertebrate Pathology, 2008

Gene expression studies have opened a tremendous field of investigation in biological research ov... more Gene expression studies have opened a tremendous field of investigation in biological research over the last decades. Expression of genes is most frequently quantified by real time PCR (RT-qPCR), as this method has proven to be highly sensitive. One of the critical steps, however, in comparing transcription profiles is the availability of selected housekeeping genes. Expression of these genes should be steadily stable across the conditions under study so that they provide a baseline for gene expression comparison. Such a baseline is best established using a set of few housekeeping genes. Usually, those genes are involved in maintaining homeostasis and cell viability. In our study, nine candidate genes were used, including some commonly used housekeeping genes, such as ribosomal RNA (18S, S-15, S-18 and L-37), beta actin, ubiquitin, receptor activated C kinase (RACK) and elongation factor 1 and 2, in order to determine the most stable housekeeping genes, after haemocytes of Mya arenaria were exposed to Vibrio splendidus for 2 h. Our results showed that EF-1, S-18 and ubiquitin appear to be the most stable genes for this experimental condition. On the other hand, both 18S and beta actin, the most widely used housekeeping genes, turned out to be the least stable. This demonstrates the absolute need for preliminary assessment of housekeeping genes in gene expression studies.

Research paper thumbnail of Optimization of oil production by lipomyces tetrasporus isolated from soil in the Northern Province

Research paper thumbnail of Conservation and variation in the region of the Theileria parva p104 antigen coding gene used for PCR surveillance of the parasite

Parasitology Research

The range of the protozoan parasite Theileria parva, which causes East Coast fever in cattle, has... more The range of the protozoan parasite Theileria parva, which causes East Coast fever in cattle, has been expanding to countries where it has not previously been detected, as a result of cross-border domestic cattle movement. Countries where T. parva has not previously been observed until recently include Cameroon and South Sudan. This raises the issue of the conservation of the p104 antigen gene, on which the nested PCR assay that is widely used for T. parva surveillance in the blood of infected cattle is based. We sampled 40 isolates from six countries widely distributed across the geographical range of the parasite, including eastern, central and southern Africa, for p104 sequence polymorphism. These included parasites from both domestic cattle and the Cape buffalo (Syncerus caffer) wildlife reservoir. The most frequent allelic variants were present in cattle transmissible isolates from multiple widely separated geographical regions in Zambia, Uganda, Kenya, Tanzania, Rwanda and Sou...

Research paper thumbnail of MOESM5 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 5: Table S4. Estimates of evolutionary divergence between gene alleles for Tp1 an... more Additional file 5: Table S4. Estimates of evolutionary divergence between gene alleles for Tp1 and Tp2, using proportion nucleotide distance.

Research paper thumbnail of MOESM1 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 1: Table S1. Cattle blood sample distribution across agro-ecological zones.

Research paper thumbnail of MOESM12 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 12: Figure S4. Phylogenetic tree showing the relationships among concatenated Tp1... more Additional file 12: Figure S4. Phylogenetic tree showing the relationships among concatenated Tp1 and Tp2 nucleotide sequences of 93 T. parva samples from cattle in DRC and Burundi.

Research paper thumbnail of MOESM7 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 7: Table S6. Amino acid variants of Tp1 and Tp2 CD8+ T cell target epitopes of T.... more Additional file 7: Table S6. Amino acid variants of Tp1 and Tp2 CD8+ T cell target epitopes of T. parva from DRC and Burundi.

Research paper thumbnail of MOESM6 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 6: Table S5. Tp1 and Tp2 genes alleles with their corresponding antigen variants.

Research paper thumbnail of MOESM9 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 9: Table S7. Distribution of Tp1 gene alleles of T. parva from cattle and buffalo... more Additional file 9: Table S7. Distribution of Tp1 gene alleles of T. parva from cattle and buffalo in the sub-Saharan region of Africa.

Research paper thumbnail of MOESM8 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 8: Figure S2. Multiple sequence alignment of the 10 Tp2 gene alleles obtained in ... more Additional file 8: Figure S2. Multiple sequence alignment of the 10 Tp2 gene alleles obtained in this study.

Research paper thumbnail of MOESM3 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 3: Table S3. Characteristics of 119 T. parva samples obtained from cattle in diff... more Additional file 3: Table S3. Characteristics of 119 T. parva samples obtained from cattle in different agro-ecological zones (AEZs) of The Democratic Republic of Congo and Burundi.

Research paper thumbnail of MOESM2 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 2: Table S2. Nucleotide and amino acid sequences of Tp1 and Tp2 antigen epitopes ... more Additional file 2: Table S2. Nucleotide and amino acid sequences of Tp1 and Tp2 antigen epitopes from T. parva Muguga reference sequence.

Research paper thumbnail of MOESM11 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 11: Figure S3. Neighbor-joining tree showing phylogenetic relationships among 48 ... more Additional file 11: Figure S3. Neighbor-joining tree showing phylogenetic relationships among 48 Tp1 gene alleles described in Africa.

Research paper thumbnail of MOESM10 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 10: Table S8. Distribution of Tp2 gene alleles of T. parva from cattle and buffal... more Additional file 10: Table S8. Distribution of Tp2 gene alleles of T. parva from cattle and buffalo in the sub-Saharan region of Africa.

Research paper thumbnail of MOESM4 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 4: Figure S1. Multiple sequence alignment of the 11 Tp1 gene alleles obtained in ... more Additional file 4: Figure S1. Multiple sequence alignment of the 11 Tp1 gene alleles obtained in this study.

Research paper thumbnail of Unraveling the Complexity of the Rhomboid Serine Protease 4 Family of Babesia bovis Using Bioinformatics and Experimental Studies

Pathogens, 2022

Babesia bovis, a tick-transmitted apicomplexan protozoon, infects cattle in tropical and subtropi... more Babesia bovis, a tick-transmitted apicomplexan protozoon, infects cattle in tropical and subtropical regions around the world. In the apicomplexans Toxoplasma gondii and Plasmodium falciparum, rhomboid serine protease 4 (ROM4) fulfills an essential role in host cell invasion. We thus investigated B. bovis ROM4 coding genes; their genomic organization; their expression in in vitro cultured asexual (AS) and sexual stages (SS); and strain polymorphisms. B. bovis contains five rom4 paralogous genes in chromosome 2, which we have named rom4.1, 4.2, 4.3, 4.4 and 4.5. There are moderate degrees of sequence identity between them, except for rom4.3 and 4.4, which are almost identical. RT-qPCR analysis showed that rom4.1 and rom4.3/4.4, respectively, display 18-fold and 218-fold significantly higher (p < 0.01) levels of transcription in SS than in AS, suggesting a role in gametogenesis-related processes. In contrast, transcription of rom4.4 and 4.5 differed non-significantly between the st...

Research paper thumbnail of International interlaboratory validation of a nested PCR for molecular detection of Babesia bovis and Babesia bigemina causative agents of bovine babesiosis

Veterinary Parasitology, 2022

Research paper thumbnail of Molecular characterisation of canine parvoviruses from clinical samples and vaccines in Nigeria

Infection, Genetics and Evolution, 2020

ABSTRACT Canine parvovirus type two (CPV-2), the aetiological agent of haemorrhagic enteritis in ... more ABSTRACT Canine parvovirus type two (CPV-2), the aetiological agent of haemorrhagic enteritis in dogs, emerged in 1978 and is a socio-economic problem worldwide. In the mid 1980s, the original CPV-2 had evolved and was completely replaced by two variants, CPV 2a/2b. In 2000, a new variant of CPV (CPV-2c) was detected in Italy and now circulates in other countries. The infection rate with CPV-2 and case fatality rate in young dogs is high. CPV-2 is a 22nm negative sense, single-stranded DNA virus and a member of the Parvoviridae family, which also includes feline panleukopenia virus (FPV) and mink enteritis virus (MEV). The CPV-2 genome is prone to mutations at the VP2 region and, as a result, in this study we investigated the composition of the VP2 region in the CPV-2 genome using real-time PCR assay and sequencing to provide information for comparison of field and vaccine strains ofthe virus. A total of 150 clinical samples of unvaccinated dogs less than 6 months old manifesting diarrhoea was collected from South Africa (n = 120) and Nigeria (n = 30) for characterisation of CPV-2 variants. Total DNA was extracted from faeces and subjected to a real-time PCR assay to screen for CPV-2 types positive samples. Positive samples were used for genotyping using two different real-time TaqMan assays employing minor groove binder (MGB) probes, one differentiating between types 2a and 2b whilst the other differentiates between types 2b and 2c. Purified amplicons were analysed on an ABI 3130 XL Automated DNA Sequencer and the DNA sequences confirmed using NCBI-BLAST. An alignment of all the sequences was performed using ClustalX and the phylogenetic trees were generated using bayesian and maximum parsimony analyses. The results of this finding will be fully discussed.

Research paper thumbnail of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Parasites & Vectors, 2019

Background Theileria parva causes East Coast fever (ECF), one of the most economically important ... more Background Theileria parva causes East Coast fever (ECF), one of the most economically important tick-borne diseases of cattle in sub-Saharan Africa. A live immunisation approach using the infection and treatment method (ITM) provides a strong long-term strain-restricted immunity. However, it typically induces a tick-transmissible carrier state in cattle and may lead to spread of antigenically distinct parasites. Thus, understanding the genetic composition of T. parva is needed prior to the use of the ITM vaccine in new areas. This study examined the sequence diversity and the evolutionary and biogeographical dynamics of T. parva within the African Great Lakes region to better understand the epidemiology of ECF and to assure vaccine safety. Genetic analyses were performed using sequences of two antigen-coding genes, Tp1 and Tp2, generated among 119 T. parva samples collected from cattle in four agro-ecological zones of DRC and Burundi. Results The results provided evidence of nucleo...

Research paper thumbnail of Molecular Detection of Zoonotic Rickettsiae andAnaplasmaspp. in Domestic Dogs and Their Ectoparasites in Bushbuckridge, South Africa

Vector-Borne and Zoonotic Diseases, 2016

Members of the order Rickettsiales are small, obligate intracellular bacteria that are vector-bor... more Members of the order Rickettsiales are small, obligate intracellular bacteria that are vector-borne and can cause mild to fatal diseases in humans worldwide. There is little information on the zoonotic rickettsial pathogens that may be harboured by dogs from rural localities in South Africa. To characterize rickettsial pathogens infecting dogs we screened 141 blood samples, 103 ticks and 43 fleas collected from domestic dogs in Bushbuckridge Municipality, Mpumalanga Province of South Africa between October 2011 and May 2012 using the reverse line blot (RLB) and Rickettsia genus and species-specific qPCR assays. Results from RLB showed that 49% of blood samples and 30% of tick pools were positive for the genus-specific probes for Ehrlichia/Anaplasma; 16% of the blood samples were positive for Ehrlichia canis. Haemoparasite DNA could not be detected in 36% of blood samples and 30% of tick pools screened. Seven (70%) of tick pools and both flea pools were positive for Rickettsia spp; three (30%) of tick pools were positive for R. africae and both flea pools (100%) were positive for R. felis. Sequencing confirmed infection with R. africae and Candidatus Rickettsia asemboensis; a Rickettsia felis-like organism from one of the R. felis-positive flea pools. Anaplasma sp. South Africa dog strain (closely related to Anaplasma phagocytophilum), A. phagocytophilum, and an Orientia tsutsugamushi-like sequence were identified from blood samples. The detection of emerging zoonotic agents from domestic dogs and their ectoparasites in a rural community in South Africa highlights the potential risk of human infection that may occur with these pathogens.

Research paper thumbnail of Selection and evaluation of housekeeping genes for haemocytes of soft-shell clams (Mya arenaria) challenged with Vibrio splendidus

Journal of Invertebrate Pathology, 2008

Gene expression studies have opened a tremendous field of investigation in biological research ov... more Gene expression studies have opened a tremendous field of investigation in biological research over the last decades. Expression of genes is most frequently quantified by real time PCR (RT-qPCR), as this method has proven to be highly sensitive. One of the critical steps, however, in comparing transcription profiles is the availability of selected housekeeping genes. Expression of these genes should be steadily stable across the conditions under study so that they provide a baseline for gene expression comparison. Such a baseline is best established using a set of few housekeeping genes. Usually, those genes are involved in maintaining homeostasis and cell viability. In our study, nine candidate genes were used, including some commonly used housekeeping genes, such as ribosomal RNA (18S, S-15, S-18 and L-37), beta actin, ubiquitin, receptor activated C kinase (RACK) and elongation factor 1 and 2, in order to determine the most stable housekeeping genes, after haemocytes of Mya arenaria were exposed to Vibrio splendidus for 2 h. Our results showed that EF-1, S-18 and ubiquitin appear to be the most stable genes for this experimental condition. On the other hand, both 18S and beta actin, the most widely used housekeeping genes, turned out to be the least stable. This demonstrates the absolute need for preliminary assessment of housekeeping genes in gene expression studies.

Research paper thumbnail of Optimization of oil production by lipomyces tetrasporus isolated from soil in the Northern Province

Research paper thumbnail of Conservation and variation in the region of the Theileria parva p104 antigen coding gene used for PCR surveillance of the parasite

Parasitology Research

The range of the protozoan parasite Theileria parva, which causes East Coast fever in cattle, has... more The range of the protozoan parasite Theileria parva, which causes East Coast fever in cattle, has been expanding to countries where it has not previously been detected, as a result of cross-border domestic cattle movement. Countries where T. parva has not previously been observed until recently include Cameroon and South Sudan. This raises the issue of the conservation of the p104 antigen gene, on which the nested PCR assay that is widely used for T. parva surveillance in the blood of infected cattle is based. We sampled 40 isolates from six countries widely distributed across the geographical range of the parasite, including eastern, central and southern Africa, for p104 sequence polymorphism. These included parasites from both domestic cattle and the Cape buffalo (Syncerus caffer) wildlife reservoir. The most frequent allelic variants were present in cattle transmissible isolates from multiple widely separated geographical regions in Zambia, Uganda, Kenya, Tanzania, Rwanda and Sou...

Research paper thumbnail of MOESM5 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 5: Table S4. Estimates of evolutionary divergence between gene alleles for Tp1 an... more Additional file 5: Table S4. Estimates of evolutionary divergence between gene alleles for Tp1 and Tp2, using proportion nucleotide distance.

Research paper thumbnail of MOESM1 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 1: Table S1. Cattle blood sample distribution across agro-ecological zones.

Research paper thumbnail of MOESM12 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 12: Figure S4. Phylogenetic tree showing the relationships among concatenated Tp1... more Additional file 12: Figure S4. Phylogenetic tree showing the relationships among concatenated Tp1 and Tp2 nucleotide sequences of 93 T. parva samples from cattle in DRC and Burundi.

Research paper thumbnail of MOESM7 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 7: Table S6. Amino acid variants of Tp1 and Tp2 CD8+ T cell target epitopes of T.... more Additional file 7: Table S6. Amino acid variants of Tp1 and Tp2 CD8+ T cell target epitopes of T. parva from DRC and Burundi.

Research paper thumbnail of MOESM6 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 6: Table S5. Tp1 and Tp2 genes alleles with their corresponding antigen variants.

Research paper thumbnail of MOESM9 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 9: Table S7. Distribution of Tp1 gene alleles of T. parva from cattle and buffalo... more Additional file 9: Table S7. Distribution of Tp1 gene alleles of T. parva from cattle and buffalo in the sub-Saharan region of Africa.

Research paper thumbnail of MOESM8 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 8: Figure S2. Multiple sequence alignment of the 10 Tp2 gene alleles obtained in ... more Additional file 8: Figure S2. Multiple sequence alignment of the 10 Tp2 gene alleles obtained in this study.

Research paper thumbnail of MOESM3 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 3: Table S3. Characteristics of 119 T. parva samples obtained from cattle in diff... more Additional file 3: Table S3. Characteristics of 119 T. parva samples obtained from cattle in different agro-ecological zones (AEZs) of The Democratic Republic of Congo and Burundi.

Research paper thumbnail of MOESM2 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 2: Table S2. Nucleotide and amino acid sequences of Tp1 and Tp2 antigen epitopes ... more Additional file 2: Table S2. Nucleotide and amino acid sequences of Tp1 and Tp2 antigen epitopes from T. parva Muguga reference sequence.

Research paper thumbnail of MOESM11 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 11: Figure S3. Neighbor-joining tree showing phylogenetic relationships among 48 ... more Additional file 11: Figure S3. Neighbor-joining tree showing phylogenetic relationships among 48 Tp1 gene alleles described in Africa.

Research paper thumbnail of MOESM10 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 10: Table S8. Distribution of Tp2 gene alleles of T. parva from cattle and buffal... more Additional file 10: Table S8. Distribution of Tp2 gene alleles of T. parva from cattle and buffalo in the sub-Saharan region of Africa.

Research paper thumbnail of MOESM4 of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Additional file 4: Figure S1. Multiple sequence alignment of the 11 Tp1 gene alleles obtained in ... more Additional file 4: Figure S1. Multiple sequence alignment of the 11 Tp1 gene alleles obtained in this study.

Research paper thumbnail of Unraveling the Complexity of the Rhomboid Serine Protease 4 Family of Babesia bovis Using Bioinformatics and Experimental Studies

Pathogens, 2022

Babesia bovis, a tick-transmitted apicomplexan protozoon, infects cattle in tropical and subtropi... more Babesia bovis, a tick-transmitted apicomplexan protozoon, infects cattle in tropical and subtropical regions around the world. In the apicomplexans Toxoplasma gondii and Plasmodium falciparum, rhomboid serine protease 4 (ROM4) fulfills an essential role in host cell invasion. We thus investigated B. bovis ROM4 coding genes; their genomic organization; their expression in in vitro cultured asexual (AS) and sexual stages (SS); and strain polymorphisms. B. bovis contains five rom4 paralogous genes in chromosome 2, which we have named rom4.1, 4.2, 4.3, 4.4 and 4.5. There are moderate degrees of sequence identity between them, except for rom4.3 and 4.4, which are almost identical. RT-qPCR analysis showed that rom4.1 and rom4.3/4.4, respectively, display 18-fold and 218-fold significantly higher (p < 0.01) levels of transcription in SS than in AS, suggesting a role in gametogenesis-related processes. In contrast, transcription of rom4.4 and 4.5 differed non-significantly between the st...

Research paper thumbnail of International interlaboratory validation of a nested PCR for molecular detection of Babesia bovis and Babesia bigemina causative agents of bovine babesiosis

Veterinary Parasitology, 2022

Research paper thumbnail of Molecular characterisation of canine parvoviruses from clinical samples and vaccines in Nigeria

Infection, Genetics and Evolution, 2020

ABSTRACT Canine parvovirus type two (CPV-2), the aetiological agent of haemorrhagic enteritis in ... more ABSTRACT Canine parvovirus type two (CPV-2), the aetiological agent of haemorrhagic enteritis in dogs, emerged in 1978 and is a socio-economic problem worldwide. In the mid 1980s, the original CPV-2 had evolved and was completely replaced by two variants, CPV 2a/2b. In 2000, a new variant of CPV (CPV-2c) was detected in Italy and now circulates in other countries. The infection rate with CPV-2 and case fatality rate in young dogs is high. CPV-2 is a 22nm negative sense, single-stranded DNA virus and a member of the Parvoviridae family, which also includes feline panleukopenia virus (FPV) and mink enteritis virus (MEV). The CPV-2 genome is prone to mutations at the VP2 region and, as a result, in this study we investigated the composition of the VP2 region in the CPV-2 genome using real-time PCR assay and sequencing to provide information for comparison of field and vaccine strains ofthe virus. A total of 150 clinical samples of unvaccinated dogs less than 6 months old manifesting diarrhoea was collected from South Africa (n = 120) and Nigeria (n = 30) for characterisation of CPV-2 variants. Total DNA was extracted from faeces and subjected to a real-time PCR assay to screen for CPV-2 types positive samples. Positive samples were used for genotyping using two different real-time TaqMan assays employing minor groove binder (MGB) probes, one differentiating between types 2a and 2b whilst the other differentiates between types 2b and 2c. Purified amplicons were analysed on an ABI 3130 XL Automated DNA Sequencer and the DNA sequences confirmed using NCBI-BLAST. An alignment of all the sequences was performed using ClustalX and the phylogenetic trees were generated using bayesian and maximum parsimony analyses. The results of this finding will be fully discussed.

Research paper thumbnail of Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

Parasites & Vectors, 2019

Background Theileria parva causes East Coast fever (ECF), one of the most economically important ... more Background Theileria parva causes East Coast fever (ECF), one of the most economically important tick-borne diseases of cattle in sub-Saharan Africa. A live immunisation approach using the infection and treatment method (ITM) provides a strong long-term strain-restricted immunity. However, it typically induces a tick-transmissible carrier state in cattle and may lead to spread of antigenically distinct parasites. Thus, understanding the genetic composition of T. parva is needed prior to the use of the ITM vaccine in new areas. This study examined the sequence diversity and the evolutionary and biogeographical dynamics of T. parva within the African Great Lakes region to better understand the epidemiology of ECF and to assure vaccine safety. Genetic analyses were performed using sequences of two antigen-coding genes, Tp1 and Tp2, generated among 119 T. parva samples collected from cattle in four agro-ecological zones of DRC and Burundi. Results The results provided evidence of nucleo...

Research paper thumbnail of Molecular Detection of Zoonotic Rickettsiae andAnaplasmaspp. in Domestic Dogs and Their Ectoparasites in Bushbuckridge, South Africa

Vector-Borne and Zoonotic Diseases, 2016

Members of the order Rickettsiales are small, obligate intracellular bacteria that are vector-bor... more Members of the order Rickettsiales are small, obligate intracellular bacteria that are vector-borne and can cause mild to fatal diseases in humans worldwide. There is little information on the zoonotic rickettsial pathogens that may be harboured by dogs from rural localities in South Africa. To characterize rickettsial pathogens infecting dogs we screened 141 blood samples, 103 ticks and 43 fleas collected from domestic dogs in Bushbuckridge Municipality, Mpumalanga Province of South Africa between October 2011 and May 2012 using the reverse line blot (RLB) and Rickettsia genus and species-specific qPCR assays. Results from RLB showed that 49% of blood samples and 30% of tick pools were positive for the genus-specific probes for Ehrlichia/Anaplasma; 16% of the blood samples were positive for Ehrlichia canis. Haemoparasite DNA could not be detected in 36% of blood samples and 30% of tick pools screened. Seven (70%) of tick pools and both flea pools were positive for Rickettsia spp; three (30%) of tick pools were positive for R. africae and both flea pools (100%) were positive for R. felis. Sequencing confirmed infection with R. africae and Candidatus Rickettsia asemboensis; a Rickettsia felis-like organism from one of the R. felis-positive flea pools. Anaplasma sp. South Africa dog strain (closely related to Anaplasma phagocytophilum), A. phagocytophilum, and an Orientia tsutsugamushi-like sequence were identified from blood samples. The detection of emerging zoonotic agents from domestic dogs and their ectoparasites in a rural community in South Africa highlights the potential risk of human infection that may occur with these pathogens.