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Obara I, Makori P, Sibeko KP, Bishop RP, Nijhof AM, Mwamuye M. Conservation and variation in the region of the Theileria parva p104 antigen coding gene used for PCR surveillance of the parasite. Parasitol Res 2023; 122:1381-1390. [PMID: 37081209 PMCID: PMC10172223 DOI: 10.1007/s00436-023-07838-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/04/2023] [Indexed: 04/22/2023]
Abstract
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 South Africa. These frequent p104 variants were also present in the three component stocks of the Muguga cocktail used for the infection and treatment live immunisation procedure to control T. parva in the field. Other isolates exhibited unique alleles. This includes some of the p104 sequences from Cameroon, which is outside the known range of the Rhipicephalus tick vector and whose origin is therefore unclear. The nested primer oligonucleotides used to generate the amplicons were universally conserved in cattle-derived parasites and a majority of buffalo-derived isolates across the geographical range of the parasite. However, some rare South African buffalo-derived isolates exhibited one or two mismatches with the primer sequences. It therefore remains possible that some p104 alleles may be so divergent that they do not amplify with the current diagnostic primers and are not detectable in surveys, hence the need for increasing knowledge of genetic heterogeneity of diagnostic targets. There was no evidence for positive selection among those p104 mutations that resulted in residue changes. Importantly, the data indicate that the p104-based PCR detection assay should be effective across the majority of the range of T. parva, and if the one or two mismatches are shown in future to result in the primers annealing less efficiently, then the assay can be further improved by introduction of degenerate bases to enable amplification of the less frequent South African buffalo-derived variant p104 genes.
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Affiliation(s)
- Isaiah Obara
- Department of Veterinary Medicine, Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
- Department of Veterinary Medicine, Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany.
| | | | - Kgomotso P Sibeko
- Vector and Vector-Borne Disease Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Richard P Bishop
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Ard M Nijhof
- Department of Veterinary Medicine, Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
- Department of Veterinary Medicine, Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany
| | - Micky Mwamuye
- Department of Veterinary Medicine, Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
- Department of Environment and Natural Resource Management, Africa Nazarene University, Kajiado, Kenya
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Amzati GS, Djikeng A, Odongo DO, Nimpaye H, Sibeko KP, Muhigwa JBB, Madder M, Kirschvink N, Marcotty T. Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa. Parasit Vectors 2019; 12:588. [PMID: 31842995 PMCID: PMC6915983 DOI: 10.1186/s13071-019-3848-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 12/10/2019] [Indexed: 02/07/2023] Open
Abstract
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 nucleotide and amino acid polymorphisms in both antigens, resulting in 11 and 10 distinct nucleotide alleles, that predicted 6 and 9 protein variants in Tp1 and Tp2, respectively. Theileria parva samples showed high variation within populations and a moderate biogeographical sub-structuring due to the widespread major genotypes. The diversity was greater in samples from lowlands and midlands areas compared to those from highlands and other African countries. The evolutionary dynamics modelling revealed a signal of selective evolution which was not preferentially detected within the epitope-coding regions, suggesting that the observed polymorphism could be more related to gene flow rather than recent host immune-based selection. Most alleles isolated in the Great Lakes region were closely related to the components of the trivalent Muguga vaccine. Conclusions Our findings suggest that the extensive sequence diversity of T. parva and its biogeographical distribution mainly depend on host migration and agro-ecological conditions driving tick population dynamics. Such patterns are likely to contribute to the epidemic and unstable endemic situations of ECF in the region. However, the fact that ubiquitous alleles are genetically similar to the components of the Muguga vaccine together with the limited geographical clustering may justify testing the existing trivalent vaccine for cross-immunity in the region.
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Affiliation(s)
- Gaston S Amzati
- Research Unit of Veterinary Epidemiology and Biostatistics, Faculty of Agricultural and Environmental Sciences, Université Evangélique en Afrique, PO Box 3323, Bukavu, Democratic Republic of the Congo. .,Unit of Integrated Veterinary Research, Department of Veterinary Medicine, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Rue de Bruxelles 61, 5000, Namur, Belgium. .,Biosciences Eastern and Central Africa - International Livestock Research Institute (BecA-ILRI) Hub, PO Box 30709-00100, Nairobi, Kenya.
| | - Appolinaire Djikeng
- Biosciences Eastern and Central Africa - International Livestock Research Institute (BecA-ILRI) Hub, PO Box 30709-00100, Nairobi, Kenya.,Centre for Tropical Livestock Genetics and Health (CTLGH), The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - David O Odongo
- Biosciences Eastern and Central Africa - International Livestock Research Institute (BecA-ILRI) Hub, PO Box 30709-00100, Nairobi, Kenya.,School of Biological Sciences, University of Nairobi, PO Box 30197-00100, Nairobi, Kenya
| | - Herman Nimpaye
- Faculty of Medicine, University of Burundi, PO Box 1550, Bujumbura, Burundi
| | - Kgomotso P Sibeko
- Vector and Vector-Borne Disease Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, P/Bag X04, Onderstepoort, Gauteng, 0110, South Africa
| | - Jean-Berckmans B Muhigwa
- Research Unit of Veterinary Epidemiology and Biostatistics, Faculty of Agricultural and Environmental Sciences, Université Evangélique en Afrique, PO Box 3323, Bukavu, Democratic Republic of the Congo
| | - Maxime Madder
- Vector and Vector-Borne Disease Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, P/Bag X04, Onderstepoort, Gauteng, 0110, South Africa
| | - Nathalie Kirschvink
- Unit of Integrated Veterinary Research, Department of Veterinary Medicine, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Rue de Bruxelles 61, 5000, Namur, Belgium
| | - Tanguy Marcotty
- Unit of Integrated Veterinary Research, Department of Veterinary Medicine, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Rue de Bruxelles 61, 5000, Namur, Belgium
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Njiiri NE, Bronsvoort BMD, Collins NE, Steyn HC, Troskie M, Vorster I, Thumbi SM, Sibeko KP, Jennings A, van Wyk IC, Mbole-Kariuki M, Kiara H, Poole EJ, Hanotte O, Coetzer K, Oosthuizen MC, Woolhouse M, Toye P. The epidemiology of tick-borne haemoparasites as determined by the reverse line blot hybridization assay in an intensively studied cohort of calves in western Kenya. Vet Parasitol 2015; 210:69-76. [PMID: 25858115 PMCID: PMC4427107 DOI: 10.1016/j.vetpar.2015.02.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 02/13/2015] [Accepted: 02/16/2015] [Indexed: 10/25/2022]
Abstract
The development of sensitive surveillance technologies using PCR-based detection of microbial DNA, such as the reverse line blot assay, can facilitate the gathering of epidemiological information on tick-borne diseases, which continue to hamper the productivity of livestock in many parts of Africa and elsewhere. We have employed a reverse line blot assay to detect the prevalence of tick-borne parasites in an intensively studied cohort of indigenous calves in western Kenya. The calves were recruited close to birth and monitored for the presence of infectious disease for up to 51 weeks. The final visit samples from 453 calves which survived for the study period were analyzed by RLB. The results indicated high prevalences of Theileria mutans (71.6%), T. velifera (62.8%), Anaplasma sp. Omatjenne (42.7%), A. bovis (39.9%), Theileria sp. (sable) (32.7%), T. parva (12.9%) and T. taurotragi (8.5%), with minor occurrences of eight other haemoparasites. The unexpectedly low prevalence of the pathogenic species Ehrlichia ruminantium was confirmed by a species-specific PCR targeting the pCS20 gene region. Coinfection analyses of the seven most prevalent haemoparasites indicated that they were present as coinfections in over 90% of the cases. The analyses revealed significant associations between several of the Theileria parasites, in particular T. velifera with Theileria sp. sable and T. mutans, and T. parva with T. taurotragi. There was very little coinfection of the two most common Anaplasma species, although they were commonly detected as coinfections with the Theileria parasites. The comparison of reverse line blot and serological results for four haemoparasites (T. parva, T. mutans, A. marginale and B. bigemina) indicated that, except for the mostly benign T. mutans, indigenous cattle seem capable of clearing infections of the three other, pathogenic parasites to below detectable levels. Although the study site was located across four agroecological zones, there was little restriction of the parasites to particular zones.
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Affiliation(s)
- Nyawira E Njiiri
- The International Livestock Research Institute, PO Box, 30709, 00100 Nairobi, Kenya; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | | | - Nicola E Collins
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Helena C Steyn
- Agricultural Research Council-Onderstepoort Veterinary Institute, Private Bag X05, Onderstepoort 0110, South Africa
| | - Milana Troskie
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Ilse Vorster
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - S M Thumbi
- Centre for Immunity, Infection & Evolution, University of Edinburgh, Edinburgh EH9 3JT, UK; Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7090, USA
| | - Kgomotso P Sibeko
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Amy Jennings
- The Roslin Institute, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK; The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK
| | - Ilana Conradie van Wyk
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Mary Mbole-Kariuki
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK; African Union InterAfrican Bureau for Animal Resources (AU-IBAR), PO Box 30786, 00100 Nairobi, Kenya
| | - Henry Kiara
- The International Livestock Research Institute, PO Box, 30709, 00100 Nairobi, Kenya
| | - E Jane Poole
- The International Livestock Research Institute, PO Box, 30709, 00100 Nairobi, Kenya
| | - Olivier Hanotte
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Koos Coetzer
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Marinda C Oosthuizen
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Mark Woolhouse
- Centre for Immunity, Infection & Evolution, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Philip Toye
- The International Livestock Research Institute, PO Box, 30709, 00100 Nairobi, Kenya.
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Eygelaar D, Jori F, Mokopasetso M, Sibeko KP, Collins NE, Vorster I, Troskie M, Oosthuizen MC. Tick-borne haemoparasites in African buffalo (Syncerus caffer) from two wildlife areas in Northern Botswana. Parasit Vectors 2015; 8:26. [PMID: 25589064 PMCID: PMC4302575 DOI: 10.1186/s13071-014-0627-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 12/29/2014] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The African buffalo (Syncerus caffer) is a host for many pathogens known to cause economically important diseases and is often considered an important reservoir for livestock diseases. Theileriosis, heartwater, babesiosis and anaplasmosis are considered the most important tick-borne diseases of livestock in sub-Saharan Africa, resulting in extensive economic losses to livestock farmers in endemic areas. Information on the distribution of tick-borne diseases and ticks is scarce in Northern Botswana. Nevertheless, this data is necessary for targeting surveillance and control measures in livestock production at national level. METHODS In order to address this gap, we analyzed 120 blood samples from buffalo herds for the presence of common tick-borne haemoparasites causing disease in livestock, collected in two of the main wildlife areas of Northern Botswana: the Chobe National Park (CNP, n=64) and the Okavango Delta (OD, n=56). RESULTS Analysis of the reverse line blot (RLB) hybridization assay results revealed the presence of Theileria, Babesia, Anaplasma and Ehrlichia species, either as single or mixed infections. Among the Theileria spp. present, T. parva (60%) and T. mutans (37%) were the most prevalent. Other species of interest were Anaplasma marginale subsp. centrale (30%), A. marginale (20%), Babesia occultans (23%) and Ehrlichia ruminantium (6%). The indirect fluorescent antibody test (IFAT) indicated 74% of samples to be positive for the presence of T. parva antibodies. Quantitative real-time PCR (qPCR) detected the highest level of animals infected with T. parva (81% of the samples). The level of agreement between the tests for detection of T. parva positive animals was higher between qPCR and IFAT (kappa=0.56), than between qPCR and RLB (kappa=0.26) or the latter and IFAT (kappa=0.15). CONCLUSIONS This is the first report of tick-borne haemoparasites in African buffalo from northern Botswana, where animals from the CNP showed higher levels of infection than those from OD. Considering the absence of fences separating wildlife and livestock in the CNP and the higher levels of some parasite species in buffalo from that area, surveillance of tick-borne diseases in livestock at the interface in the CNP should be prioritized.
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Affiliation(s)
- Dewald Eygelaar
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
| | - Ferran Jori
- Department of Zoology and Entomology, University of Pretoria, Pretoria, 0002, South Africa.
- UPR AGIRs, CIRAD, Campus International de Baillarguet, Montpellier, 34398, France.
- Department of Animal Science and Production, Botswana College of Agriculture, Private Bag 0027, Gaborone, Botswana.
| | - Mokganedi Mokopasetso
- FAO-ECTAD Office for Southern Africa, Gaborone, Botswana.
- Botswana Vaccine Institute, Private Bag 0031, Gabarone, Botswana.
| | - Kgomotso P Sibeko
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
| | - Nicola E Collins
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
| | - Ilse Vorster
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
| | - Milana Troskie
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
| | - Marinda C Oosthuizen
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
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Dogonyaro BB, Bosman AM, Sibeko KP, Venter EH, van Vuuren M. Genetic analysis of the VP2-encoding gene of canine parvovirus strains from Africa. Vet Microbiol 2013; 165:460-5. [DOI: 10.1016/j.vetmic.2013.04.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 04/11/2013] [Accepted: 04/13/2013] [Indexed: 11/25/2022]
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Chaisi ME, Sibeko KP, Collins NE, Potgieter FT, Oosthuizen MC. Identification of Theileria parva and Theileria sp. (buffalo) 18S rRNA gene sequence variants in the African Buffalo (Syncerus caffer) in southern Africa. Vet Parasitol 2011; 182:150-62. [PMID: 21700394 DOI: 10.1016/j.vetpar.2011.05.041] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 05/10/2011] [Accepted: 05/20/2011] [Indexed: 10/18/2022]
Abstract
Theileria parva is the causative agent of Corridor disease in cattle in South Africa. The African buffalo (Syncerus caffer) is the reservoir host, and, as these animals are important for eco-tourism in South Africa, it is compulsory to test and certify them disease free prior to translocation. A T. parva-specific real-time polymerase chain reaction (PCR) test based on the small subunit ribosomal RNA (18S rRNA) gene is one of the tests used for the diagnosis of the parasite in buffalo and cattle in South Africa. However, because of the high similarity between the 18S rRNA gene sequences of T. parva and Theileria sp. (buffalo), the latter is also amplified by the real-time PCR primers, although it is not detected by the T. parva-specific hybridization probes. Preliminary sequencing studies have revealed a small number of sequence differences within the 18S rRNA gene in both species but the extent of this sequence variation is unknown. The aim of the current study was to sequence the 18S rRNA genes of T. parva and Theileria sp. (buffalo), and to determine whether all identified genotypes can be correctly detected by the real-time PCR assay. The reverse line blot (RLB) hybridization assay was used to identify T. parva and Theileria sp. (buffalo) positive samples from buffalo blood samples originating from the Kruger National Park, Hluhluwe-iMfolozi Park, the Greater Limpopo Transfrontier Park, and a private game ranch in the Hoedspruit area. T. parva and Theileria sp. (buffalo) were identified in 42% and 28%, respectively, of 252 samples, mainly as mixed infections. The full-length 18S rRNA gene of selected samples was amplified, cloned and sequenced. From a total of 20 sequences obtained, 10 grouped with previously published T. parva sequences from GenBank while 10 sequences grouped with a previously published Theileria sp. (buffalo) sequence. All these formed a monophyletic group with known pathogenic Theileria species. Our phylogenetic analyses confirm the distinction between Theileria sp. (buffalo) and T. parva and indicate the existence of a single group of T. parva and two Theileria sp. (buffalo) 18S rRNA gene variants in the African buffalo. Despite the observed variation in the full-length parasite 18S rRNA gene sequences, the area in the V4 hypervariable region where the RLB and real-time PCR hybridization probes were developed was relatively conserved. The T. parva specific real-time PCR assay was able to successfully detect all T. parva variants and, although amplicons were obtained from Theileria sp. (buffalo) DNA, none of the Theileria sp. (buffalo) 18S rRNA sequence variants were detected by the T. parva-specific hybridization probes.
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Affiliation(s)
- Mamohale E Chaisi
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
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Sibeko KP, Collins NE, Oosthuizen MC, Troskie M, Potgieter FT, Coetzer JAW, Geysen D. Analyses of genes encoding Theileria parva p104 and polymorphic immunodominant molecule (PIM) reveal evidence of the presence of cattle-type alleles in the South African T. parva population. Vet Parasitol 2011; 181:120-30. [PMID: 21621920 DOI: 10.1016/j.vetpar.2011.04.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 04/13/2011] [Accepted: 04/20/2011] [Indexed: 11/16/2022]
Abstract
Restriction fragment length polymorphism analysis of PCR products (PCR-RFLP) and sequencing of the variable region of the p104 and PIM genes was performed on samples obtained from South African T. parva parasites originating from cattle on farms with suspected theileriosis and from buffalo. p104 and PIM PCR-RFLP profiles similar to those of the T. parva Muguga stock, an isolate that causes ECF in Kenya, were obtained from three of seven cattle samples collected on a farm near Ladysmith in KwaZulu-Natal Province. Amino acid sequences of the p104 and PIM genes from two of these samples were almost identical to the T. parva Muguga p104 and PIM sequences. This result supports findings from a recent p67 study in which p67 alleles similar to those of the T. parva Muguga stock were identified from the same samples. While these results suggest the presence of a cattle-derived T. parva parasite, reports of cattle-to-cattle transmission could not be substantiated and ECF was not diagnosed on this farm. Although extensive diversity of p104 and PIM gene sequences from South African T. parva isolates was demonstrated, no sequences identical to known cattle-type p104 and PIM alleles were identified from any of the buffalo T. parva samples analyzed. 'Mixed' PIM alleles containing both cattle- and buffalo-type amino acid motifs were identified for the first time, and there appeared to be selection of cattle-type and 'mixed'-type PIM sequences in the cattle samples examined.
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Affiliation(s)
- Kgomotso P Sibeko
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
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Sibeko KP, Geysen D, Oosthuizen MC, Matthee CA, Troskie M, Potgieter FT, Coetzer JAW, Collins NE. Four p67 alleles identified in South African Theileria parva field samples. Vet Parasitol 2009; 167:244-54. [PMID: 19836893 DOI: 10.1016/j.vetpar.2009.09.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous studies characterizing the Theileria parva p67 gene in East Africa revealed two alleles. Cattle-derived isolates associated with East Coast fever (ECF) have a 129bp deletion in the central region of the p67 gene (allele 1), compared to buffalo-derived isolates with no deletion (allele 2). In South Africa, Corridor disease outbreaks occur if there is contact between infected buffalo and susceptible cattle in the presence of vector ticks. Although ECF was introduced into South Africa in the early 20th century, it has been eradicated and it is thought that there has been no cattle to cattle transmission of T. parva since. The variable region of the p67 gene was amplified and the gene sequences analyzed to characterize South African T. parva parasites that occur in buffalo, in cattle from farms where Corridor disease outbreaks were diagnosed and in experimentally infected cattle. Four p67 alleles were identified, including alleles 1 and 2 previously detected in East African cattle and buffalo, respectively, as well as two novel alleles, one with a different 174bp deletion (allele 3), the other with a similar sequence to allele 3 but with no deletion (allele 4). Sequence variants of allele 1 were obtained from field samples originating from both cattle and buffalo. Allele 1 was also obtained from a bovine that tested T. parva positive from a farm near Ladysmith in the KwaZulu-Natal Province. East Coast fever was not diagnosed on this farm, but the p67 sequence was identical to that of T. parva Muguga, an isolate that causes ECF in Kenya. Variants of allele 2 were obtained from all T. parva samples from both buffalo and cattle, except Lad 10 and Zam 5. Phylogenetic analysis revealed that alleles 3 and 4 are monophyletic and diverged early from the other alleles. These novel alleles were not identified from South African field samples collected from cattle; however allele 3, with a p67 sequence identical to those obtained in South African field samples from buffalo, was obtained from a Zambian field isolate of a naturally infected bovine diagnosed with ECF. The p67 genetic profiles appear to be more complex than previously thought and cannot be used to distinguish between cattle- and buffalo-derived T. parva isolates in South Africa. The significance of the different p67 alleles, particularly the novel variants, in the epidemiology of theileriosis in South Africa still needs to be determined.
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Affiliation(s)
- Kgomotso P Sibeko
- Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort 0110, South Africa.
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Sibeko KP, Oosthuizen MC, Collins NE, Geysen D, Rambritch NE, Latif AA, Groeneveld HT, Potgieter FT, Coetzer JA. Development and evaluation of a real-time polymerase chain reaction test for the detection of Theileria parva infections in Cape buffalo (Syncerus caffer) and cattle. Vet Parasitol 2008; 155:37-48. [DOI: 10.1016/j.vetpar.2008.03.033] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 03/13/2008] [Accepted: 03/27/2008] [Indexed: 10/22/2022]
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