Browsing by Author "Bakirci, Serkan"

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Comparison of Protectiveness of Recombinant Babesia Ovis Apical Membrane Antigen 1 and B. Ovis-Infected Cell Line as Vaccines Against Ovine Babesiosis
(Elsevier Gmbh, 2020) Bilgic, Huseyin Bilgin; Hacilarlioglu, Selin; Bakirci, Serkan; Kose, Onur; Unlu, Ahmet Hakan; Aksulu, Ayca; Karagenc, Tulin
Babesiosis is a disease complex caused by unicellular Babesia parasites and among them, malignant ovine babesiosis caused by B. ovis has a devastating economical impact on the small ruminant industry. The control of disease is mainly based on chemotherapy and preventing animals from tick infestation and to date no vaccine is available against ovine babesiosis. The requirement for vaccination against B. ovis infection in endemically unstable regions is necessary for implementation of effective disease control measures. The aim of the present study was to evaluate the effectiveness of different immunisation protocols against disease in sheep experimentally vaccinated with recombinant B. ovis apical membrane antigen-1 (rBoAMA-1) and/or live, a B. ovis-infected cell line. Sheep were divided into four experimental groups, plus a control group. Animals were immunised either with the B. ovis stabilate, or with rBoAMA-1, or with both rBoAMA-1 and the B. ovis stabilate. Western blots and ELISAs indicated that immunisation with rBoAMA-1 resulted in generation of a specific response against the recombinant protein, but the degree of antibody response did not correlate with the level of induced protection against challenge. The strongest immune response was induced in animals co-immunised with the live B. ovis stabilate plus rBoAMA-1. Both the hematological and parasitological findings indicated that this co-immunisation regimen has vaccine potential to limit losses incurred by ovine babesiosis in endemic countries.
High Genetic Diversity and Differentiation of Thebabesia Ovispopulation in Turkey
(Wiley, 2020) Mira, Anabela; Unlu, Ahmet Hakan; Bilgic, Huseyin Bilgin; Bakirci, Serkan; Hacilarlioglu, Selin; Karagenc, Tulin; Schnittger, Leonhard
Babesia ovisis a tick-transmitted protozoan haemoparasite causing ovine babesiosis in sheep and goats leading to considerable economic loss in Turkey and neighbouring countries. There are no vaccines available, therapeutic drugs leave toxic residues in meat and milk, and tick vector control entails environmental risks. A panel of eight mini- and micro-satellite marker loci was developed and applied to study genetic diversity and substructuring ofB. ovisfrom western, central and eastern Turkey. A high genetic diversity (H-e = 0.799) was found for the sample of overallB. ovispopulation (n = 107) analyzed. Principle component analysis (PCoA) revealed the existence of three parasite subpopulations: (a) a small subpopulation of isolates from Aydin, western Turkey; (b) a second cluster predominantly generated by isolates from western Turkey; and (c) a third cluster predominantly formed by isolates from central and eastern Turkey. TwoB. ovisisolates from Israel included in the analysis clustered with isolates from central and eastern Turkey. This finding strongly suggests substructuring of a major Turkish population into western versus central-eastern subpopulations, while the additional smallerB. ovispopulation found in Aydin could have been introduced, more recently, to Turkey. STRUCTURE analysis suggests a limited exchange of parasite strains between the western and the central-eastern regions andvice versa, possibly due to limited trading of sheep. Importantly, evidence for recombinant genotypes was obtained in regionally interchanged parasite isolates. Important climatic differences between the western and the central/eastern region, with average yearly temperatures of 21 degrees C versus 15 degrees C, correspond with the identified geographical substructuring. We hypothesize that the different climatic conditions may result in variation in the activity of subpopulations ofRhipicephalusspp. tick vectors, which, in turn, could selectively maintain and transmit different parasite populations. These findings may have important implications for vaccine development and the spread of drug resistance.
Infection Dynamics of Theileria Annulata Over a Disease Season Following Cell Line Vaccination
(Elsevier Science Bv, 2019) Bilgic, Huseyin Bilgin; Aksulu, Ayca; Bakirci, Serkan; Unlu, Ahmet Hakan; Kose, Onur; Hacilarhoglu, Selin; Karagenc, Tulin
Tropical theileriosis is a tick-borne haemoparasitic disease of cattle caused by the protozoan parasite Theileria annulata. Globally, the economic impact of the disease is immense and enhanced control measures would improve livestock production in endemic regions. Immunisation with a live attenuated vaccine is an effective and widely used control method, however, the repeated use of live vaccines may have an impact on the field parasite population at a genetic level. Additionally, there has been an increasing number of reports of vaccine break-through cases in recent years. Thus, the present study was designed to evaluate the genetic composition of a parasite population over a disease season in a locality where live cell line vaccination is practised. A diverse range of parasite genotypes was identified and every T. annulata positive cattle blood sample harboured multiple parasite genotypes. An alteration in the major genotype and an increasing multiplicity of infection in individual animals was observed over the course of the disease season. Vaccination status was found not to effect within-host multiplicity of infection, while a significantly higher number of genotypes was detected in grazed cattle compared to non-grazed ones. A degree of genetic isolation was evident between parasite populations on a micro-geographic scale, which has not been reported previously for T. annulata. Analysis of parasite genotypes in vaccinated animals suggested only a transient effect of the vaccine genotype on the genetic diversity of the T. annulata population. The vaccine genotype was not detected among clones of two vaccine 'breakthrough' isolates and there is no suggestion that it was responsible for disease. The obtained data indicated that in the system studied there is no apparent risk of introducing the vaccine genotype into the population with only a transient effect on the genetic diversity of the parasite population during the disease season.
Prevalence of Tick-Borne Haemoparasites in Small Ruminants in Turkey and Diagnostic Sensitivity of Single-Pcr and Rlb
(Biomed Central Ltd, 2017) Bilgic, Huseyin Bilgin; Bakirci, Serkan; Kose, Onur; Unlu, Ahmet Hakan; Hacilarlioglu, Selin; Eren, Hasan; Karagenc, Tulin
Background: Tick-borne haemoparasitic diseases (TBHDs), caused by Theileria, Babesia, Anaplasma and Ehrlichia, are common in regions of the world where the distributions of host, pathogen and vector overlap. Many of these diseases threaten livestock production and some also represent a concern to human public health. The primary aim of this study was to determine the prevalence of the above-mentioned pathogens in a large number of blood samples (n = 1979) collected from sheep (n = 1727) and goats (n = 252) in Turkey. A secondary aim was to assess the diagnostic sensitivity of a number of species-specific polymerase chain reaction (PCR) tests and the reverse line blotting (RLB) assay. DNA samples were screened using species-specific PCR for the presence of Theileria ovis, Theileria sp. MK, T. lestoquardi, T. uilenbergi, T. luwenshuni, Babesia ovis, Anaplasma ovis and A. phagocytophilum while RLB was undertaken to test for the presence of all known Theileria, Babesia, Anaplasma and Ehrlichia species. The diagnostic sensitivity of these two approaches was then compared in terms of their ability to detect single species and mixed infections. Results: Overall, 84 and 74.43% of the small ruminants sampled were identified as hosting one or more pathogen(s) by species-specific PCR and RLB respectively. The presence of Theileria sp. OT1, T. luwenshuni and T. uilenbergi in Turkey was revealed for the first time while the presence of Babesia motasi, B. crassa and T. separata in Turkish small ruminants was confirmed using molecular methods. A high prevalence of mixed infection was evident, with PCR and RLB approaches indicating that 52.24 and 35.42% of animals were co-infected with multiple species, respectively. More than 80% of the mixed infections contained T. ovis and/or A. ovis. The RLB approach was found to be capable of detecting mixed infections with species such as Theileria sp. OT1, Theileria sp. OT3, T. separata, B. crassa and Babesia spp. Conclusion: The results indicated that pathogens causing TBHDs are highly prevalent in sheep and goats in Turkey. The diagnostic sensitivity of species-specific single PCR was generally higher than that of RLB. However, the latter approach was still capable of identifying a high proportion of individuals containing mixed-species infections. The use of species-specific single PCR is recommended to accurately estimate pathogen prevalence and to identify co-infected hosts.