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East Coast Fever Carrier Status and Theileria parva Breakthrough Strains in Recently ITM Vaccinated and Non-Vaccinated Cattle in Iganga District, Eastern Uganda. Pathogens 2023; 12:pathogens12020295. [PMID: 36839567 PMCID: PMC9965312 DOI: 10.3390/pathogens12020295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/20/2023] [Accepted: 02/08/2023] [Indexed: 02/16/2023] Open
Abstract
East Coast fever (ECF) is a tick-borne disease of cattle that hinders the development of the livestock industry in eastern, central and southern Africa. The 'Muguga cocktail' live vaccine, delivered by an infection and treatment method (ITM), remains the only immunisation strategy of controlling ECF. However, there are challenges of the live vaccine inducing ECF carrier status in immunised animals and the possibility of lack of protection from parasite strains that are antigenically different from the vaccine strains. In Uganda, there are insufficient data regarding the ECF carrier status and T. parva genetic diversity in vaccinated and associated non-vaccinated cattle to assess the effectiveness of ITM vaccination. Blood was collected from recently ECF vaccinated (98) and non-vaccinated (73) cattle from Iganga district in Eastern Uganda at 120 days post-vaccination. The p104 gene nested PCR was used to screen for T. parva DNA, 11 minisatellite and 3 microsatellite markers (SSR) were used for genotyping. Two minisatellite markers (MS7 and MS19) were used to determine whether ECF carrier status was due to the T. parva vaccine or local strains. The prevalence of T. parva based on p104 nPCR was 61.2% (60/98) (RR 2.234, 95% CI 1.49-3.35, p-value < 0.001) among recently vaccinated cattle and 27.4% (20/73) (RR 1.00) among associated non-vaccinated cattle. The Muguga cocktail vaccine strains were responsible for carrier status in 10 (58.8%) by MS7 and 11 (64.7%) by MS19 in vaccinated cattle. Genotypes of T. parva with different-sized alleles to the vaccine strains that could be potential 'breakthroughs' were detected in 2 (11.8%)) and 4 (23.5%) isolates from vaccinated cattle based on MS7 and MS19 minisatellite markers, respectively. Using 14 SSR markers, T. parva diversity was higher in vaccinated (Na = 2.214, Ne = 1.978, He = 0.465) than associated non-vaccinated (Na = 1.071, Ne = 1.048, He = 0.259) cattle. The principal component analysis (PCA) showed isolates from vaccinated cattle were closely related to those from non-vaccinated cattle. The analysis of molecular variance (AMOVA) revealed high genetic variation (96%) within T. parva isolates from vaccinated and non-vaccinated cattle but low variation (4%) between vaccinated and non-vaccinated cattle. This study reveals the role of ITM in inducing the carrier status and higher T. parva genetic diversity in vaccinated cattle. The low genetic variation between T. parva isolates in both vaccinated and non-vaccinated cattle may be suggestive of the protective role of vaccine strains against genetically related local strains in the study area.
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Goh S, Kolakowski J, Holder A, Pfuhl M, Ngugi D, Ballingall K, Tombacz K, Werling D. Development of a Potential Yeast-Based Vaccine Platform for Theileria parva Infection in Cattle. Front Immunol 2021; 12:674484. [PMID: 34305904 PMCID: PMC8297500 DOI: 10.3389/fimmu.2021.674484] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/10/2021] [Indexed: 01/05/2023] Open
Abstract
East Coast Fever (ECF), caused by the tick-borne apicomplexan parasite Theileria parva, remains one of the most important livestock diseases in sub-Saharan Africa with more than 1 million cattle dying from infection every year. Disease prevention relies on the so-called "Infection and Treatment Method" (ITM), which is costly, complex, laborious, difficult to standardise on a commercial scale and results in a parasite strain-specific, MHC class I-restricted cytotoxic T cell response. We therefore attempted to develop a safe, affordable, stable, orally applicable and potent subunit vaccine for ECF using five different T. parva schizont antigens (Tp1, Tp2, Tp9, Tp10 and N36) and Saccharomyces cerevisiae as an expression platform. Full-length Tp2 and Tp9 as well as fragments of Tp1 were successfully expressed on the surface of S. cerevisiae. In vitro analyses highlighted that recombinant yeast expressing Tp2 can elicit IFNγ responses using PBMCs from ITM-immunized calves, while Tp2 and Tp9 induced IFNγ responses from enriched bovine CD8+ T cells. A subsequent in vivo study showed that oral administration of heat-inactivated, freeze-dried yeast stably expressing Tp2 increased total murine serum IgG over time, but more importantly, induced Tp2-specific serum IgG antibodies in individual mice compared to the control group. While these results will require subsequent experiments to verify induction of protection in neonatal calves, our data indicates that oral application of yeast expressing Theileria antigens could provide an affordable and easy vaccination platform for sub-Saharan Africa. Evaluation of antigen-specific cellular immune responses, especially cytotoxic CD8+ T cell immunity in cattle will further contribute to the development of a yeast-based vaccine for ECF.
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Affiliation(s)
- Shan Goh
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Jeannine Kolakowski
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Angela Holder
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Mark Pfuhl
- Faculty of Life Science and Medicine, King's College London, London, United Kingdom
| | - Daniel Ngugi
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | | | - Kata Tombacz
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Dirk Werling
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
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Atuhaire DK, Muleya W, Mbao V, Niyongabo J, Nyabongo L, Nsanganiyumwami D, Salt J, Namangala B, Musoke AJ. Molecular characterization and population genetics of Theileria parva in Burundi's unvaccinated cattle: Towards the introduction of East Coast fever vaccine. PLoS One 2021; 16:e0251500. [PMID: 33999934 PMCID: PMC8128232 DOI: 10.1371/journal.pone.0251500] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/27/2021] [Indexed: 11/18/2022] Open
Abstract
Theileria parva (T. parva) is a protozoan parasite that causes East Coast fever (ECF). The disease is endemic in Burundi and is a major constraint to livestock development. In this study, the parasite prevalence in cattle in six regions namely; Northern, Southern, Eastern, Western, Central and North Eastern was estimated. Furthermore, the sequence diversity of p67, Tp1 and Tp2 genes was assessed coupled with the population genetic structure of T. parva using five satellite markers. The prevalence of ECF was 30% (332/1109) on microscopy, 60% (860/1431) on ELISA and 79% (158/200) on p104 gene PCR. Phylogenetic analysis of p67 gene revealed that only allele 1 was present in the field samples. Furthermore, phylogenetic analysis of Tp1 and Tp2 showed that the majority of samples clustered with Muguga, Kiambu and Serengeti and shared similar epitopes. On the other hand, genetic analysis revealed that field samples shared only two alleles with Muguga Cocktail. The populations from the different regions indicated low genetic differentiation (FST = 0.047) coupled with linkage disequilibrium and non-panmixia. A low to moderate genetic differentiation (FST = 0.065) was also observed between samples and Muguga cocktail. In conclusion, the data presented revealed the presence of a parasite population that shared similar epitopes with Muguga Cocktail and was moderately genetically differentiated from it. Thus, use of Muguga Cocktail vaccine in Burundi is likely to confer protection against T. parva in field challenge trials.
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Affiliation(s)
| | - Walter Muleya
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
- * E-mail:
| | - Victor Mbao
- International Development Research Centre, Eastern and Southern Africa Regional Office, Nairobi, Kenya
| | - Joseph Niyongabo
- National Veterinary Research Laboratory, Directorate of Animal Health, Bujumbura, Burundi
| | - Lionel Nyabongo
- National Veterinary Research Laboratory, Directorate of Animal Health, Bujumbura, Burundi
| | | | - Jeremy Salt
- Global Alliance for Livestock Veterinary Medicines, Pentlands Science Park, Bush Loan, Penicuik Edinburgh, Scotland
| | - Boniface Namangala
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
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Atuhaire DK, Muleya W, Mbao V, Bazarusanga T, Gafarasi I, Salt J, Namangala B, Musoke AJ. Sequence diversity of cytotoxic T cell antigens and satellite marker analysis of Theileria parva informs the immunization against East Coast fever in Rwanda. Parasit Vectors 2020; 13:452. [PMID: 32894166 PMCID: PMC7487574 DOI: 10.1186/s13071-020-04322-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 08/30/2020] [Indexed: 11/21/2022] Open
Abstract
Background East Coast fever (ECF) caused by Theileria parva is endemic in Rwanda. In this study, the antigenic and genetic diversity of T. parva coupled with immunization and field challenge were undertaken to provide evidence for the introduction of ECF immunization in Rwanda. Methods Blood collected from cattle in the field was screened for T. parva using ELISA and PCR targeting the p104 gene. Tp1 and Tp2 gene sequences were generated from field samples and from Gikongoro and Nyakizu isolates. Furthermore, multilocus genotype data was generated using 5 satellite markers and an immunization challenge trial under field conditions using Muguga cocktail vaccine undertaken. Results Out of 120 samples, 44 and 20 were positive on ELISA and PCR, respectively. Antigenic diversity of the Tp1 and Tp2 gene sequences revealed an abundance of Muguga, Kiambu and Serengeti epitopes in the samples. A further three clusters were observed on both Tp1 and Tp2 phylogenetic trees; two clusters comprising of field samples and vaccine isolates and the third cluster comprising exclusively of Rwanda samples. Both antigens exhibited purifying selection with no positive selection sites. In addition, satellite marker analysis revealed that field samples possessed both shared alleles with Muguga cocktail on all loci and also a higher proportion of unique alleles. The Muguga cocktail (Muguga, Kiambu and Serengeti) genotype compared to other vaccine isolates, was the most represented in the field samples. Further low genetic sub-structuring (FST = 0.037) coupled with linkage disequilibrium between Muguga cocktail and the field samples was observed. Using the above data to guide a field immunization challenge trial comprising 41 immunized and 40 control animals resulted in 85% seroconversion in the immunized animals and an efficacy of vaccination of 81.7%, implying high protection against ECF. Conclusions Antigenic and genetic diversity analysis of T. parva facilitated the use of Muguga cocktail vaccine in field conditions. A protection level of 81.7% was achieved, demonstrating the importance of combining molecular tools with field trials to establish the suitability of implementation of immunization campaigns. Based on the information in this study, Muguga cocktail immunization in Rwanda has a potential to produce desirable results.![]()
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Affiliation(s)
| | - Walter Muleya
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, 10101, Zambia.
| | - Victor Mbao
- International Development Research Centre, Eastern and Southern Africa Regional Office, Nairobi, Kenya
| | | | | | - Jeremy Salt
- Global Alliance for Livestock Veterinary Medicines, Doherty Building, Pentlands Science Park, Bush Loan, Penicuik, Edinburgh, EH26 0PZ, Scotland, UK
| | - Boniface Namangala
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, 10101, Zambia
| | - Antony Jim Musoke
- LMK Medical laboratories and consultancies, P.O. Box 33686, Kampala, Uganda
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Lubembe DM, Odongo DO, Salih DA, Sibeko-Matjila KP. Microsatellite and minisatellite genotyping of Theileria parva population from southern Africa reveals possible discriminatory allele profiles with parasites from eastern Africa. Ticks Tick Borne Dis 2020; 11:101539. [PMID: 32993948 DOI: 10.1016/j.ttbdis.2020.101539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/20/2020] [Accepted: 07/30/2020] [Indexed: 10/23/2022]
Abstract
The control of Theileria parva, a protozoan parasite that threatens almost 50% of the cattle population in Africa, is still a challenge in many affected countries. Theileria parva field parasites from eastern Africa, and parasites comprising the current live T. parva vaccine widely deployed in the same region have been reported to be genotypically diverse. However, similar reports on T. parva parasites from southern Africa are limited, especially in Corridor disease designated areas. Establishing the extent of genetic exchange in T. parva populations is necessary for effective control of the parasite infection. Twelve polymorphic microsatellite and minisatellite loci were targeted for genotypic and population genetics analysis of T. parva parasites from South Africa, Mozambique, Kenya and Uganda using genomic DNA prepared from cattle and buffalo blood samples. The results revealed genotypic similarities among parasites from the two regions of Africa, with possible distinguishing allelic profiles on three loci (MS8, MS19 and MS33) for parasites associated with Corridor disease in South Africa, and East Coast fever in eastern Africa. Individual populations were in linkage equilibrium (VD<L), but when considered as one combined population, linkage disequilibrium (VD>L) was observed. Genetic divergence was observed to be more within (AMOVA = 74%) than between (AMOVA = 26%) populations. Principal coordinate analysis showed clustering that separated buffalo-derived from cattle-derived T. parva parasites, although parasites from cattle showed a close genetic relationship. The results also demonstrated geographic sub-structuring of T. parva parasites based on the disease syndromes caused in cattle in the two regions of Africa. These findings provide additional information on the genotypic diversity of T. parva parasites from South Africa, and reveal possible differences based on three loci (MS8, MS19 and MS33) and similarities between buffalo-derived T. parva parasites from southern and eastern Africa.
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Affiliation(s)
- Donald M Lubembe
- Vectors and Vector-borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
| | - David O Odongo
- School of Biological Sciences, University of Nairobi, P.O. Box 30197, Nairobi, 00100, Kenya
| | - Diaeldin A Salih
- Central Veterinary Research Laboratory, P.O. Box 8067, Khartoum, Sudan
| | - Kgomotso P Sibeko-Matjila
- Vectors and Vector-borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
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Magulu E, Kindoro F, Mwega E, Kimera S, Shirima G, Gwakisa P. Detection of carrier state and genetic diversity of Theileria parva in ECF-vaccinated and naturally exposed cattle in Tanzania. Vet Parasitol Reg Stud Reports 2019; 17:100312. [PMID: 31303233 DOI: 10.1016/j.vprsr.2019.100312] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 05/27/2019] [Accepted: 06/07/2019] [Indexed: 10/26/2022]
Abstract
Infection and Treatment Method (ITM) has been practiced in Tanzania for over 20 years as a prevention measure against East Coast Fever disease. It is known that ITM, like natural ECF infection, leads to a carrier state, whereby vaccinated cattle become asymptomatic carriers of the parasite. It is expected that ECF vaccination using ITM also leads to generation of combinations of vaccine specific Theileria parva and local strains that circulate in the field what contributes to an unknown level of parasite diversity. Moreover, the long term impact of ITM on carrier state and parasite diversity in cattle are largely unknown. To address this question blood was collected from ECF-vaccinated (n = 239) and unvaccinated (n = 97) cattle from Loiborsoit, Emboreet, Esilalei, Manyara ranch and Mswakini villages in the Maasai steppe of northern Tanzania, as well as Mruazi and Leila farms in Tanga in eastern Tanzania. Screening for T. parva using nested PCR revealed an overall prevalence of T. parva to be 34.5%, with a significant higher prevalence among ECF-vaccinated cattle. Using three VNTR markers (ms2, ms5 and MS7) higher parasite genetic diversity in terms of higher number of alleles and expected heterozygosity was shown in vaccinated than unvaccinated cattle. These parameters were highest in cattle from Manyara ranch. Nevertheless, the principle component analysis (PCoA) showed no distinct clustering patterns as most T. parva alleles clustered together throughout the four quadrants implying parasite homogeneity among the sampled populations. However, some of the parasite alleles closely clustered with Muguga vaccine alleles in two of the quadrants, consistent with closer genetic relatedness between the vaccine strains and the T. parva populations from the Maasai steppe. Likewise analysis of molecular variance (AMOVA) revealed most of the genetic variation (93%) being contained within populations with only 7% being among populations. This study therefore confirms the role of ECF vaccination in enhancing carrier state and T. parva diversity in vaccinated cattle populations. Higher T. parva diversity may play an important role in carrier cattle by way of restricting breakthrough infections from field parasite strains.
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Affiliation(s)
- Emelesiana Magulu
- School of Life Sciences and Bioengineering, Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania
| | - Fatuma Kindoro
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, P.O. Box 3019, Morogoro, Tanzania
| | - Elisa Mwega
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, P.O. Box 3019, Morogoro, Tanzania
| | - Sharadhuli Kimera
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, P.O. Box 3019, Morogoro, Tanzania
| | - Gabriel Shirima
- School of Life Sciences and Bioengineering, Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania
| | - Paul Gwakisa
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, P.O. Box 3019, Morogoro, Tanzania.
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Patel E, Mwaura S, Di Giulio G, Cook EAJ, Lynen G, Toye P. Infection and treatment method (ITM) vaccine against East Coast fever: reducing the number of doses per straw for use in smallholder dairy herds by thawing, diluting and refreezing already packaged vaccine. BMC Vet Res 2019; 15:46. [PMID: 30704455 PMCID: PMC6357393 DOI: 10.1186/s12917-019-1787-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 01/17/2019] [Indexed: 11/23/2022] Open
Abstract
Background The Infection and Treatment Method (ITM) of vaccination is the only immunization procedure currently available to protect cattle against East Coast fever (ECF), a tick-transmitted disease responsible for losses of several hundreds of millions of dollars per year in sub-Saharan Africa. The vaccine comprises a homogenized preparation of infected ticks packaged in straws and stored in liquid nitrogen. The current manufacturing protocol results in straws containing 30–40 doses (ILRI 0804), which is impractical for immunizing small herds as found in dairy and smallholder farming systems. The ILRI 0804 SD stabilate was prepared as a 1:5 dilution of the parent stabilate, with the aim of producing vaccine stabilate straws containing between four to eight doses and thus suitable for smallholder farming systems. Infectivity of the diluted stabilate was assessed and the protective efficacy of the diluted stabilate was determined by performing experimental and field immunizations. Results Two groups of six cattle were inoculated with 1 ml of the diluted stabilate at 1:20 (equivalent to the recommended field dose for ILRI 0804, assuming no loss of sporozoite viability during thawing and refreezing) and 1:14 (assuming 30–35% loss of sporozoite viability). Schizonts were detected in all 12 animals, showing viability of sporozoites. Ten animals from the infectivity study and two control animals not previously exposed to T. parva were challenged with the parental ILRI 0804 stabilate. The results show that the two control animals displayed severe ECF reactions and were treated 14 days after challenge. Of the previously infected animals, only one underwent a severe reaction following challenge, a result in accord with the challenge experiments performed previously with the parent stabilate [Ticks Tick-Borne Dis 7:306-314, 2016]. The animal that displayed a severe reaction had no detectable schizonts and did not seroconvert following the initial inoculation with ILRI 0804 SD. In addition, 62 animals immunized under field conditions showed a mean seroconversion rate of 82%. Conclusion The results presented in this article demonstrate that it is possible to prepare straws suitable for use in smallholder herds by thawing, diluting and refreezing already packaged vaccine.
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Affiliation(s)
- Ekta Patel
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya.
| | - Stephen Mwaura
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya
| | | | - Elizabeth A J Cook
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya
| | - Godelieve Lynen
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya
| | - Philip Toye
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya.
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Steinaa L, Svitek N, Awino E, Njoroge T, Saya R, Morrison I, Toye P. Immunization with one Theileria parva strain results in similar level of CTL strain-specificity and protection compared to immunization with the three-component Muguga cocktail in MHC-matched animals. BMC Vet Res 2018; 14:145. [PMID: 29716583 PMCID: PMC5930519 DOI: 10.1186/s12917-018-1460-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 04/16/2018] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND The tick-borne protozoan parasite Theileria parva causes a usually fatal cattle disease known as East Coast fever in sub-Saharan Africa, with devastating consequences for poor small-holder farmers. Immunity to T. parva, believed to be mediated by a cytotoxic T lymphocyte (CTL) response, is induced following natural infection and after vaccination with a live vaccine, known as the Infection and Treatment Method (ITM). The most commonly used version of ITM is a combination of parasites derived from three isolates (Muguga, Kiambu 5 and Serengeti-transformed), known as the "Muguga cocktail". The use of a vaccine comprising several strains is believed to be required to induce a broad immune response effective against field challenge. In this study we investigated whether immunization with the Muguga cocktail induces a broader CTL response than immunization with a single strain (Muguga). RESULTS Four MHC haplotype-matched pairs of cattle were immunized with either the trivalent Muguga cocktail or the single Muguga strain. CTL specificity was assessed on a panel of five different strains, and clonal responses to these strains were also assessed in one of the MHC-matched pairs. We did not find evidence for a broader CTL response in animals immunized with the Muguga cocktail compared to those immunized with the Muguga strain alone, in either the bulk or clonal CTL analyses. This was supported by an in vivo trial in which all vaccinated animals survived challenge with a lethal dose of the Muguga cocktail vaccine stabilate. CONCLUSION We did not observe any substantial differences in the immunity generated from animals immunized with either Muguga alone or the Muguga cocktail in the animals tested here, corroborating earlier results showing limited antigenic diversity in the Muguga cocktail. These results may warrant further field studies using single T. parva strains as future vaccine candidates.
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Affiliation(s)
- Lucilla Steinaa
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100 Kenya
| | - Nicholas Svitek
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100 Kenya
| | - Elias Awino
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100 Kenya
| | - Thomas Njoroge
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100 Kenya
| | - Rosemary Saya
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100 Kenya
| | - Ivan Morrison
- The Roslin Institute, The University of Edinburgh, Midlothian, EH25 9RG UK
| | - Philip Toye
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100 Kenya
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Steinaa L, Svitek N, Awino E, Saya R, Toye P. Cytotoxic T lymphocytes from cattle sharing the same MHC class I haplotype and immunized with live Theileria parva sporozoites differ in antigenic specificity. BMC Res Notes 2018; 11:44. [PMID: 29343295 PMCID: PMC5773172 DOI: 10.1186/s13104-018-3145-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 01/09/2018] [Indexed: 12/04/2022] Open
Abstract
Objectives The objective of this study was to assess whether cytotoxic T cells (CTL) generated by the live vaccine, known as “ITM Muguga cocktail”, which is used for the cattle disease East Cost fever (ECF) in Sub-Saharan Africa, showed a broad reactivity against many different strains of the causative parasite Theileria parva. We also assessed whether immune responses were similar in cattle expressing the same MHC class I haplotypes. Results The antigenic specificity of CTL from MHC class I-matched cattle vaccinated with the Muguga cocktail were different. Three cattle of MHC class I haplotype A18, one A18/A19 and two haploidentical (A18v/A12) animals, showed differential recognition of autologous cells infected with a panel of T. parva isolates. This could have implications in the field where certain strains could break through the vaccine. Furthermore, neither of the haploidentical cattle recognized the CTL epitope (Tp1214–224), presented by the A18 haplotype, in contrast to the third animal, showing differences in immunodominance in animals of the same haplotype A18. This suggests that the CTL specificities following immunization with the Muguga cocktail can vary even between haploidentical individuals and that some parasite strains may break through immunity generated by the Muguga cocktail. Electronic supplementary material The online version of this article (10.1186/s13104-018-3145-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lucilla Steinaa
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100, Kenya.
| | - Nicholas Svitek
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100, Kenya
| | - Elias Awino
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100, Kenya
| | - Rosemary Saya
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100, Kenya
| | - Philip Toye
- International Livestock Research Institute, P.O. Box 30709, Nairobi, 00100, Kenya
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Genes encoding two Theileria parva antigens recognized by CD8+ T-cells exhibit sequence diversity in South Sudanese cattle populations but the majority of alleles are similar to the Muguga component of the live vaccine cocktail. PLoS One 2017; 12:e0171426. [PMID: 28231338 PMCID: PMC5322890 DOI: 10.1371/journal.pone.0171426] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 01/20/2017] [Indexed: 11/19/2022] Open
Abstract
East Coast fever (ECF), caused by Theileria parva infection, is a frequently fatal disease of cattle in eastern, central and southern Africa, and an emerging disease in South Sudan. Immunization using the infection and treatment method (ITM) is increasingly being used for control in countries affected by ECF, but not yet in South Sudan. It has been reported that CD8+ T-cell lymphocytes specific for parasitized cells play a central role in the immunity induced by ITM and a number of T. parva antigens recognized by parasite-specific CD8+ T-cells have been identified. In this study we determined the sequence diversity among two of these antigens, Tp1 and Tp2, which are under evaluation as candidates for inclusion in a sub-unit vaccine. T. parva samples (n = 81) obtained from cattle in four geographical regions of South Sudan were studied for sequence polymorphism in partial sequences of the Tp1 and Tp2 genes. Eight positions (1.97%) in Tp1 and 78 positions (15.48%) in Tp2 were shown to be polymorphic, giving rise to four and 14 antigen variants in Tp1 and Tp2, respectively. The overall nucleotide diversity in the Tp1 and Tp2 genes was π = 1.65% and π = 4.76%, respectively. The parasites were sampled from regions approximately 300 km apart, but there was limited evidence for genetic differentiation between populations. Analyses of the sequences revealed limited numbers of amino acid polymorphisms both overall and in residues within the mapped CD8+ T-cell epitopes. Although novel epitopes were identified in the samples from South Sudan, a large number of the samples harboured several epitopes in both antigens that were similar to those in the T. parva Muguga reference stock, which is a key component in the widely used live vaccine cocktail.
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Perry BD. The control of East Coast fever of cattle by live parasite vaccination: A science-to-impact narrative. One Health 2016; 2:103-114. [PMID: 28616483 PMCID: PMC5441314 DOI: 10.1016/j.onehlt.2016.07.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
There is an increasing interest in determining the impact of vaccine technologies developed using public funding targeted at international development, and understanding the factors and ingredients which contribute to the success and impacts of such vaccines. This paper chronicles the development of a live vaccine against East Coast fever, a tick-borne disease of cattle caused by Theileria parva. The paper describes the technological innovation, commonly known as infection-and-treatment, which was developed some 40 years ago, explores the institutional settings in which the vaccine was developed and refined, and discusses the political dynamics of both during the decades from first development to field deployment and impacts. The paper also analyses the direct and indirect indicators of success of ITM and the many qualifiers of these, the impacts that the emerging technology has had, both in positive and negative terms, and maps the key contributors and milestones on the research-to-impact pathway.
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Affiliation(s)
- B D Perry
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, UK
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12
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The biology of Theileria parva and control of East Coast fever – Current status and future trends. Ticks Tick Borne Dis 2016; 7:549-64. [DOI: 10.1016/j.ttbdis.2016.02.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 01/02/2023]
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13
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Population genetic analysis of Theileria parva isolated in cattle and buffaloes in Tanzania using minisatellite and microsatellite markers. Vet Parasitol 2016; 224:20-26. [PMID: 27270385 DOI: 10.1016/j.vetpar.2016.04.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/22/2016] [Accepted: 04/24/2016] [Indexed: 11/23/2022]
Abstract
A population genetic study of Theileria parva was conducted on 103 cattle and 30 buffalo isolates from Kibaha, Lushoto, Njombe Districts and selected National parks in Tanzania. Bovine blood samples were collected from these study areas and categorized into 5 populations; Buffalo, Cattle which graze close to buffalo, Kibaha, Lushoto and Njombe. Samples were tested by nested PCR for T. parva DNA and positives were compared for genetic diversity to the T. parva Muguga vaccine reference strain, using 3micro and 11 minisatellite markers selected from all 4 chromosomes of the parasite genome. The diversity across populations was determined by the mean number of different alleles, mean number of effective alleles, mean number of private allele and expected heterozygosity. The mean number of allele unique to populations for Cattle close to buffalo, Muguga, Njombe, Kibaha, Lushoto and Buffalo populations were 0.18, 0.24, 0.63, 0.71, 1.63 and 3.37, respectively. The mean number of different alleles ranged from 6.97 (Buffalo) to 0.07 (Muguga). Mean number of effective alleles ranged from 4.49 (Buffalo) to 0.29 (Muguga). The mean expected heterozygosity were 0.07 0.29, 0.45, 0.48, 0.59 and 0.64 for Muguga, cattle close to buffalo, Kibaha, Njombe, Lushoto and Buffalo populations, respectively. The Buffalo and Lushoto isolates possessed a close degree of diversity in terms of mean number of different alleles, effective alleles, private alleles and expected heterozygosity. The study revealed more diversity in buffalo isolates and further studies are recommended to establish if there is sharing of parasites between cattle and buffaloes which may affect the effectiveness of the control methods currently in use.
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Hemmink JD, Weir W, MacHugh ND, Graham SP, Patel E, Paxton E, Shiels B, Toye PG, Morrison WI, Pelle R. Limited genetic and antigenic diversity within parasite isolates used in a live vaccine against Theileria parva. Int J Parasitol 2016; 46:495-506. [PMID: 27080723 PMCID: PMC4935670 DOI: 10.1016/j.ijpara.2016.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/17/2016] [Accepted: 02/29/2016] [Indexed: 11/02/2022]
Abstract
An infection and treatment protocol is used to vaccinate cattle against Theileria parva infection. Due to incomplete cross-protection between different parasite isolates, a mixture of three isolates, termed the Muguga cocktail, is used for vaccination. While vaccination of cattle in some regions provides high levels of protection, some animals are not protected against challenge with buffalo-derived T. parva. Knowledge of the genetic composition of the Muguga cocktail vaccine is required to understand how vaccination is able to protect against field challenge and to identify the potential limitations of the vaccine. The aim of the current study was to determine the extent of genetic and antigenic diversity within the parasite isolates that constitute the Muguga cocktail. High throughput multi-locus sequencing of antigen-encoding loci was performed in parallel with typing using a panel of micro- and mini-satellite loci. The former focused on genes encoding CD8(+) T cell antigens, believed to be relevant to protective immunity. The results demonstrate that each of the three component stocks of the cocktail contains limited parasite genotypic diversity, with single alleles detected at many gene/satellite loci and, moreover, that two of the components show a very high level of similarity. Thus, the vaccine incorporates very little of the genetic and antigenic diversity observed in field populations of T. parva. The presence of alleles at low frequency (<10%) within vaccine component populations also points to the possibility of variability in the content of vaccine doses and the potential for loss of allelic diversity during tick passage. The results demonstrate that there is scope to modify the content of the vaccine in order to enhance its diversity and thus its potential for providing broad protection. The ability to accurately quantify genetic diversity in vaccine component stocks will facilitate improved quality control procedures designed to ensure the long-term efficacy of the vaccine.
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Affiliation(s)
- Johanneke D Hemmink
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK
| | - William Weir
- College of Medical, Veterinary and Life Sciences, Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Henry Wellcome Building, Garscube Campus, Bearsden Road, Glasgow G61 1QH, UK
| | - Niall D MacHugh
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK
| | - Simon P Graham
- The International Livestock Research Institute, PO Box 30709, Nairobi, Kenya
| | - Ekta Patel
- The International Livestock Research Institute, PO Box 30709, Nairobi, Kenya
| | - Edith Paxton
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK
| | - Brian Shiels
- College of Medical, Veterinary and Life Sciences, Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Henry Wellcome Building, Garscube Campus, Bearsden Road, Glasgow G61 1QH, UK
| | - Philip G Toye
- The International Livestock Research Institute, PO Box 30709, Nairobi, Kenya
| | - W Ivan Morrison
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK.
| | - Roger Pelle
- The International Livestock Research Institute, PO Box 30709, Nairobi, Kenya
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Patel E, Mwaura S, Kiara H, Morzaria S, Peters A, Toye P. Production and dose determination of the Infection and Treatment Method (ITM) Muguga cocktail vaccine used to control East Coast fever in cattle. Ticks Tick Borne Dis 2015; 7:306-14. [PMID: 26698194 DOI: 10.1016/j.ttbdis.2015.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 11/07/2015] [Accepted: 11/24/2015] [Indexed: 11/28/2022]
Abstract
The Infection and Treatment Method (ITM) of vaccination against the apicomplexan parasite Theileria parva has been used since the early 1970s and is still the only commercially available vaccine to combat the fatal bovine disease, East Coast fever (ECF). The disease is tick-transmitted and results in annual economic losses of at least $300 million per year. While this vaccine technology has been available for over 40 years, few attempts have been made to standardize the production process and characterize the vaccine. The latest batch was produced in early 2008 at the International Livestock Research Institute (ILRI). The vaccine production involves the use of cattle free from parasites routinely monitored throughout the production process, and a pathogen-free tick colony. This paper describes the protocol used in the recent production, and the process improvements, including improved quality control tools, that had not been employed in previous ITM productions. The paper also describes the processes involved in determining the appropriate field dose, which involved a three-step in vivo study with various dilutions of the vaccine stabilate. The vaccine was shown to be safe and viable after production, and a suitable field dose was identified as 1 ml of a 1:100 dilution.
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Affiliation(s)
- Ekta Patel
- International Livestock Research Institute, P.O. Box 30709-00100, Old Naivasha Road, Nairobi, Kenya.
| | - Stephen Mwaura
- International Livestock Research Institute, P.O. Box 30709-00100, Old Naivasha Road, Nairobi, Kenya
| | - Henry Kiara
- International Livestock Research Institute, P.O. Box 30709-00100, Old Naivasha Road, Nairobi, Kenya
| | - Subhash Morzaria
- Senior Animal Health Adviser, Emergency Centre for Transboundary Animal Diseases, Food and Agriculture Organization of the United Nations, Viale Delle Terme di Caracalla, 00153 Rome, Italy
| | - Andrew Peters
- Scotland's Rural College, King's Buildings, Edinburgh EH9 3JG, UK
| | - Philip Toye
- International Livestock Research Institute, P.O. Box 30709-00100, Old Naivasha Road, Nairobi, Kenya
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Norling M, Bishop RP, Pelle R, Qi W, Henson S, Drábek EF, Tretina K, Odongo D, Mwaura S, Njoroge T, Bongcam-Rudloff E, Daubenberger CA, Silva JC. The genomes of three stocks comprising the most widely utilized live sporozoite Theileria parva vaccine exhibit very different degrees and patterns of sequence divergence. BMC Genomics 2015; 16:729. [PMID: 26403690 PMCID: PMC4583173 DOI: 10.1186/s12864-015-1910-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 09/09/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There are no commercially available vaccines against human protozoan parasitic diseases, despite the success of vaccination-induced long-term protection against infectious diseases. East Coast fever, caused by the protist Theileria parva, kills one million cattle each year in sub-Saharan Africa, and contributes significantly to hunger and poverty in the region. A highly effective, live, multi-isolate vaccine against T. parva exists, but its component isolates have not been characterized. Here we sequence and compare the three component T. parva stocks within this vaccine, the Muguga Cocktail, namely Muguga, Kiambu5 and Serengeti-transformed, aiming to identify genomic features that contribute to vaccine efficacy. RESULTS We find that Serengeti-transformed, originally isolated from the wildlife carrier, the African Cape buffalo, is remarkably and unexpectedly similar to the Muguga isolate. The 420 detectable non-synonymous SNPs were distributed among only 53 genes, primarily subtelomeric antigens and antigenic families. The Kiambu5 isolate is considerably more divergent, with close to 40,000 SNPs relative to Muguga, including >8,500 non-synonymous mutations distributed among >1,700 (42.5 %) of the predicted genes. These genetic markers of the component stocks can be used to characterize the composition of new batches of the Muguga Cocktail. CONCLUSIONS Differences among these three isolates, while extensive, represent only a small proportion of the genetic variation in the entire species. Given the efficacy of the Muguga Cocktail in inducing long-lasting protection against infections in the field, our results suggest that whole-organism vaccines against parasitic diseases can be highly efficacious despite considerable genome-wide differences relative to the isolates against which they protect.
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Affiliation(s)
- Martin Norling
- SLU Global Bioinformatics Centre, Department of Animal Breeding and Genetics (HGEN), Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
| | | | - Roger Pelle
- International Livestock Research Institute, Nairobi, Kenya.
| | - Weihong Qi
- Functional Genomics Centre, ETH/UZH, Zürich, Switzerland.
| | - Sonal Henson
- International Livestock Research Institute, Nairobi, Kenya.
| | - Elliott F Drábek
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, USA.
| | - Kyle Tretina
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, USA.
| | - David Odongo
- International Livestock Research Institute, Nairobi, Kenya. .,School of Biological Sciences, The University of Nairobi, Nairobi, Kenya.
| | - Stephen Mwaura
- International Livestock Research Institute, Nairobi, Kenya.
| | - Thomas Njoroge
- International Livestock Research Institute, Nairobi, Kenya.
| | - Erik Bongcam-Rudloff
- SLU Global Bioinformatics Centre, Department of Animal Breeding and Genetics (HGEN), Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
| | - Claudia A Daubenberger
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, USA. .,Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, USA.
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Sitt T, Poole EJ, Ndambuki G, Mwaura S, Njoroge T, Omondi GP, Mutinda M, Mathenge J, Prettejohn G, Morrison WI, Toye P. Exposure of vaccinated and naive cattle to natural challenge from buffalo-derived Theileria parva. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2015; 4:244-51. [PMID: 26005635 PMCID: PMC4437466 DOI: 10.1016/j.ijppaw.2015.04.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/29/2015] [Accepted: 04/30/2015] [Indexed: 12/02/2022]
Abstract
The Muguga cocktail was tested in cattle in a buffalo-only location. Infection with buffalo-derived T. parva caused Corridor disease in cattle. At the conservancy, the cocktail did not protect cattle against Corridor disease. Efficacious vaccines can support integrative livestock/wildlife management.
Integrative management of wildlife and livestock requires a clear understanding of the diseases transmitted between the two populations. The tick-borne protozoan parasite Theileria parva causes two distinct diseases in cattle, East Coast fever and Corridor disease, following infection with parasites derived from cattle or buffalo, respectively. In this study, cattle were immunized with a live sporozoite vaccine containing three T. parva isolates (the Muguga cocktail), which has been used extensively and successfully in the field to protect against cattle-derived T. parva infection. The cattle were exposed in a natural field challenge site containing buffalo but no other cattle. The vaccine had no effect on the survival outcome in vaccinated animals compared to unvaccinated controls: nine out of the 12 cattle in each group succumbed to T. parva infection. The vaccine also had no effect on the clinical course of the disease. A combination of clinical and post mortem observations and laboratory analyses confirmed that the animals died of Corridor disease. The results clearly indicate that the Muguga cocktail vaccine does not provide protection against buffalo-derived T. parva at this site and highlight the need to evaluate the impact of the composition of challenge T. parva populations on vaccine success in areas where buffalo and cattle are present.
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Affiliation(s)
- Tatjana Sitt
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - E Jane Poole
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Gideon Ndambuki
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Stephen Mwaura
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Thomas Njoroge
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | | | - Matthew Mutinda
- Veterinary Services Department, Kenya Wildlife Service, P.O. Box 40241-00100, Nairobi, Kenya
| | - Joseph Mathenge
- Veterinary Services Department, Kenya Wildlife Service, P.O. Box 40241-00100, Nairobi, Kenya
| | - Giles Prettejohn
- Veterinary Services Department, Kenya Wildlife Service, P.O. Box 40241-00100, Nairobi, Kenya
| | - W Ivan Morrison
- The Roslin Institute, The University of Edinburgh, Midlothian EH25 9RG, UK
| | - Philip Toye
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
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Successful vaccines for naturally occurring protozoal diseases of animals should guide human vaccine research. A review of protozoal vaccines and their designs. Parasitology 2014; 141:624-40. [PMID: 24476952 PMCID: PMC3961066 DOI: 10.1017/s0031182013002060] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Effective vaccines are available for many protozoal diseases of animals, including vaccines for zoonotic pathogens and for several species of vector-transmitted apicomplexan haemoparasites. In comparison with human diseases, vaccine development for animals has practical advantages such as the ability to perform experiments in the natural host, the option to manufacture some vaccines in vivo, and lower safety requirements. Although it is proper for human vaccines to be held to higher standards, the enduring lack of vaccines for human protozoal diseases is difficult to reconcile with the comparatively immense amount of research funding. Common tactical problems of human protozoal vaccine research include reliance upon adapted rather than natural animal disease models, and an overwhelming emphasis on novel approaches that are usually attempted in replacement of rather than for improvement upon the types of designs used in effective veterinary vaccines. Currently, all effective protozoal vaccines for animals are predicated upon the ability to grow protozoal organisms. Because human protozoal vaccines need to be as effective as animal vaccines, researchers should benefit from a comparison of existing veterinary products and leading experimental vaccine designs. With this in mind, protozoal vaccines are here reviewed.
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Hayashida K, Abe T, Weir W, Nakao R, Ito K, Kajino K, Suzuki Y, Jongejan F, Geysen D, Sugimoto C. Whole-genome sequencing of Theileria parva strains provides insight into parasite migration and diversification in the African continent. DNA Res 2013; 20:209-20. [PMID: 23404454 PMCID: PMC3686427 DOI: 10.1093/dnares/dst003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The disease caused by the apicomplexan protozoan parasite Theileria parva, known as East Coast fever or Corridor disease, is one of the most serious cattle diseases in Eastern, Central, and Southern Africa. We performed whole-genome sequencing of nine T. parva strains, including one of the vaccine strains (Kiambu 5), field isolates from Zambia, Uganda, Tanzania, or Rwanda, and two buffalo-derived strains. Comparison with the reference Muguga genome sequence revealed 34 814–121 545 single nucleotide polymorphisms (SNPs) that were more abundant in buffalo-derived strains. High-resolution phylogenetic trees were constructed with selected informative SNPs that allowed the investigation of possible complex recombination events among ancestors of the extant strains. We further analysed the dN/dS ratio (non-synonymous substitutions per non-synonymous site divided by synonymous substitutions per synonymous site) for 4011 coding genes to estimate potential selective pressure. Genes under possible positive selection were identified that may, in turn, assist in the identification of immunogenic proteins or vaccine candidates. This study elucidated the phylogeny of T. parva strains based on genome-wide SNPs analysis with prediction of possible past recombination events, providing insight into the migration, diversification, and evolution of this parasite species in the African continent.
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Affiliation(s)
- Kyoko Hayashida
- Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University, Sapporo-shi, Hokkaido 001-0020, Japan
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The role of nuclear technologies in the diagnosis and control of livestock diseases--a review. Trop Anim Health Prod 2013; 44:1341-66. [PMID: 22286376 PMCID: PMC3433664 DOI: 10.1007/s11250-012-0077-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2012] [Indexed: 01/15/2023]
Abstract
Nuclear and nuclear-related technologies have played an important role in animal health, particularly in relation to disease diagnosis and characterization of pathogenic organisms. This review focuses primarily on how and where nuclear technologies, both non-isotopic and isotopic methods, have made their impact in the past and where it might be expected they could have an impact in the future. The review outlines the extensive use of radiation attenuation in attempts to create vaccines for a multiplicity of pathogenic organisms and how the technology is being re-examined in the light of recent advances in irradiation techniques and cryopreservation/lyophilization that might obviate some of the problems of maintenance of viable, attenuate vaccines and their transport and use in the field. This approach could be used for a number of parasitic diseases where vaccination has been problematic and where investigations into the development of molecular vaccines have still failed to deliver satisfactory candidates for generating protective immune responses. Irradiation of antigens or serum samples also has its uses in diagnosis, especially when the samples need to be transported across international boundaries, or when handling the pathogens in question when carrying out a test presents serious health hazards to laboratory personnel. The present-day extensive use of enzyme immunoassays and molecular methods (e.g., polymerase chain reaction) for diagnosis and characterization of animal pathogens has its origins in the use of isotope-labeled antigens and antibodies. These isotopic techniques that included the use of 75Se, 32P, 125I, and 35S isotopes enabled a level of sensitivity and specificity that was hitherto unrealized, and it is prescient to remind ourselves of just how successful these technologies were, in spite of their infrequent use nowadays. Finally, the review looks at the potential for stable isotope analysis for a variety of applications--in the tracking of animal migrations, where the migrant are potential carriers of transboundary animal diseases, and where it would be useful to determine the origins of the carrier, e.g., Highly Pathogenic Avian Influenza and its dissemination by wild water fowl. Other applications could be in monitoring sequestered microbial culture (e.g., rinderpest virus) where in the case of accidental or deliberate release of infective culture it would be possible to identify the laboratory from which the isolate originated.
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Cytotoxic T lymphocytes from cattle immunized against Theileria parva exhibit pronounced cross-reactivity among different strain-specific epitopes of the Tp1 antigen. Vet Immunol Immunopathol 2012; 145:571-81. [DOI: 10.1016/j.vetimm.2011.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 12/08/2011] [Accepted: 12/13/2011] [Indexed: 11/16/2022]
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