Browsing by Author "Kasaija, Paul"

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    Antigen gene and variable number tandem repeat (VNTR) diversity in Theileria parva parasites from Ankole cattle in south‐western Uganda: Evidence for conservation in antigen gene sequences combined with extensive polymorphism at VNTR loci
    (Transboundary and emerging diseases, 2020) Nanteza, Anne; Obara, Isaiah; Kasaija, Paul; Mwega, Elisa; Kabi, Fredrick; Salih, Diaeldin A.; Njahira, Moses; Njuguna, Joyce; Odongo, David; Bishop, Richard P.; Skilton, Rob A.; Ahmed, Jabbar; Clausen, Peter‐Henning; Lubega, George W.
    Theileria parva is a tick‐transmitted apicomplexan protozoan parasite that infects lymphocytes of cattle and African Cape buffalo (Syncerus caffer), causing a frequently fatal disease of cattle in eastern, central and southern Africa. A live vaccination procedure, known as infection and treatment method (ITM), the most frequently used version of which comprises the Muguga, Serengeti‐transformed and Kiambu 5 stocks of T. parva, delivered as a trivalent cocktail, is generally effective. However, it does not always induce 100% protection against heterologous parasite challenge. Knowledge of the genetic diversity of T. parva in target cattle populations is therefore important prior to extensive vaccine deployment. This study investigated the extent of genetic diversity within T. parva field isolates derived from Ankole (Bos taurus) cattle in south‐western Uganda using 14 variable number tandem repeat (VNTR) satellite loci and the sequences of two antigen‐encoding genes that are targets of CD8+T‐cell responses induced by ITM, designated Tp1 and Tp2. The findings revealed a T. parva prevalence of 51% confirming endemicity of the parasite in south‐western Uganda. Cattle‐derived T. parva VNTR genotypes revealed a high degree of polymorphism. However, all of the T. parva Tp1 and Tp2 alleles identified in this study have been reported previously, indicating that they are widespread geographically in East Africa and highly conserved.
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    Evaluation of effectiveness and safety of Subolesin anti-tick vaccine in Ugandan multi-site field trial
    (NPJ Vaccines, 2024) Kabi, Fredrick; Marinela, Contreras; Semakula, Jimmy; MartaSánchez-Sánchez; Clara, Muñoz-Hernández; Mugerwa, Swidiq; Kasaija, Paul; Kirunda, Halid; Gabrieladela, Fuente; Ruben, Fernandez-Melgar; Marta, Rafael; Isabel, G. Fernández de Mera; Matovu, Moses; Kyakuwa, Ivan; Dhikusooka, Moses; Nsereko, Godfrey; Boma, Paul; Bugeza, James; Mwesigwa, Moses; Namukasa, Agnes; Obonyo, Philip; Ssekabunga, Nicholas; Adyero, Okeny E.; Rutaisire, Justus; Christian, Gortazar; José de la Fuente
    Vaccines are the most effective and sustainable intervention to control ticks and tick-borne disease (TBD). Using a personalized vaccine design based on regional tick genotypes, a Rhipicephalus appendiculatus Subolesin protective antigen was used in a field trial evaluating tick vaccine efficacy, effectiveness, and safety in cattle infested with multiple tick species in different Ugandan agro ecological zones. Vaccination with SUB was safe with a protective capacity against anemia and infection, and reduced the number of infested cattle, tick fitness (feeding and reproduction)with vaccine effectivenessagainstmultipletickspeciesbetween93.2%at167-196dayspost-vaccination(dpv)and 61.4% at 251–327 dpv. Total integrated vaccine efficacy/effectiveness was estimated as 98.8%. The Subolesin-based vaccine is protective against multiple cattle tick infestations under field conditions in Uganda. These results support registration and commercialization of the vaccine to reduce tick populations and associated risks for human and animal TBD and chemical acaracides in Uganda.
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    Monitoring the Subolesin Vaccine Field Trial for Safer Control of Cattle Ticks Amidst Increasing Acaricide Resistance in Uganda
    (Vaccines, 2022) Kabi, Fredrick; Dhikusooka, Moses; Matovu, Moses; Mugerwa, Swidiq; Kasaija, Paul; Emudong, Patrick; Kirunda, Halid; Contreras, Marinela; Gortazar, Christian; De la Fuente, Jose
    A collaboration program was established between the group of Health and Biotechnology (SaBio) of the IREC Institute of Game and Wildlife Research (CSIC-UCLM-JCCM, Spain) and the National Agricultural Research Organization of Uganda (NARO) for the development of vaccines for the control of cattle ticks in Uganda. Controlled pen trials identified a tick protective antigen, Rhipicephalus appendiculatus Subolesin, and a cross-species-effective vaccine formulation. As the next step, a controlled vaccine field trial has been approved by Ugandan state regulatory authorities, the Uganda National Council for Science and Technology (UNCST) and the National Drug Authority (NDA), to evaluate the efficacy and effectiveness of the vaccine formulation for the control of cattle tick infestations under field conditions. The results of this trial may lead to the approval of the vaccine for application in Uganda to improve cattle health and production while reducing the use of acaricides.