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Multilocus genotyping of Theileria parva isolates associated with a live vaccination trial in Kenya provides evidence for transmission of immunizing parasites into local tick and cattle populations
- Source :
- Transboundary and Emerging Diseases. 67:88-98
- Publication Year :
- 2020
- Publisher :
- Hindawi Limited, 2020.
-
Abstract
- The live infection and treatment (ITM) vaccination procedure using the trivalent Muguga cocktail is increasingly being used to control East Coast fever, with potential implications for Theileria parva population genetic structure in the field. Transmission of the Kiambu V T. parva component to unvaccinated cattle has previously been described in Uganda. We monitored the T. parva carrier state in vaccinated and control animals on a farm in West Kenya where an ITM stabilate derived from the Kenyan T. parva Marikebuni stock was evaluated for field efficacy. A nested PCR-based Marikebuni-specific marker identified a carrier state in nine of ten vaccinated animals, detectable for a period of two years. We used 22 variable number tandem repeat (VNTR) markers to determine multilocus genotypes (MLGs) of 19 T. parva schizont-infected lymphocyte isolates derived from cattle and field ticks. Two isolates from unimmunized cattle were identical to the Marikebuni vaccination stock. Two cattle isolates were identical to a Muguga cocktail component Kiambu V. Seven isolates from ticks exhibited MLGs that were identical to the Serengeti/Muguga vaccine stocks. Six cattle and two tick-derived stocks exhibited unique MLGs. The data strongly suggest transmission of immunizing genotypes, from Marikebuni vaccine-induced carrier cattle to unimmunized cattle. It is possible that genotypes similar to those in the Muguga cocktail are present in the field in Western Kenya. An alternative hypothesis is that these parasites may have originated from vaccine trial sites in Eastern Uganda. If correct, this suggests that T. parva stocks used for immunization can potentially be disseminated 125 km beyond the immediate vaccination site. Regardless of their origin, the data provide evidence that genotypes similar to those in the Muguga cocktail are circulating in the field in East Africa, alleviating concerns about dissemination of 'alien' T. parva germplasm through live vaccination.
- Subjects :
- Veterinary medicine
Genotype
040301 veterinary sciences
Theileria parva
Population
Cattle Diseases
Tick
Vaccines, Attenuated
Polymerase Chain Reaction
0403 veterinary science
03 medical and health sciences
Ticks
parasitic diseases
Animals
East Coast fever
Uganda
education
030304 developmental biology
0303 health sciences
education.field_of_study
General Veterinary
General Immunology and Microbiology
biology
Vaccination
Vaccine trial
04 agricultural and veterinary sciences
General Medicine
biology.organism_classification
Kenya
Theileriasis
Variable number tandem repeat
Tick-Borne Diseases
Cattle
Immunization
Multilocus Sequence Typing
Subjects
Details
- ISSN :
- 18651682 and 18651674
- Volume :
- 67
- Database :
- OpenAIRE
- Journal :
- Transboundary and Emerging Diseases
- Accession number :
- edsair.doi.dedup.....61964a75ca361b4a36bdde898f43e2ed