The Experts below are selected from a list of 690 Experts worldwide ranked by ideXlab platform
Mohamed Aziz Darghouth - One of the best experts on this subject based on the ideXlab platform.
-
current status of Tropical Theileriosis in northern africa a review of recent epidemiological investigations and implications for control
Transboundary and Emerging Diseases, 2020Co-Authors: Mohamed Gharbi, Mohamed Aziz Darghouth, Ouarda Ayadi, D A Salih, Khawla Elati, Amira A T Alhosary, Abdelrahim El M Hussein, Moez Mhadhbi, Mediha Khamassi Khbou, Shawgi M. HassanAbstract:Tropical Theileriosis caused by the apicomplexan hemoparasite Theileria annulata is a tick-borne disease that constraints livestock production in parts of Europe, Asia and Africa. Four Hyalomma tick species transmit T. annulata in at least eight Africa countries (Mauritania, Morocco, Algeria, Tunisia, Egypt, Sudan, South Sudan and Ethiopia). The two dominant T. annulata vector ticks present in Africa, H. scupense and H. anatolicum, underlie two different patterns of transmission, which in turn greatly influence the epidemiology of Tropical Theileriosis. H. dromedarii and H. lusitanicum are also capable of transmitting T. annulata in North Africa, but their roles are associated with specific production systems and agro-ecological contexts. The emergence of resistance to the most widely used theilericidal compound, buparvaquone, continues to limit the effectiveness of chemotherapy. In addition, acaricide use is increasingly becoming unsustainable. Deployable T. annulata attenuated live vaccines established from local strains in Tunisia, Sudan and Egypt are available, and recent work has indicated that these vaccines can be protective under conditions of natural transmission. However, vaccination programmes may vary over space and time due to differences in the prevalence of disease amongst cattle populations, as well seasonal variation in vector activity. We review recent descriptive and analytical surveys on the epidemiology of T. annulata infection with reference to (a) demographic aspects such as breeds and ages of cattle herds previously exposed to distinct T. annulata infection pressures and (b) seasonal dynamics of tick activity and disease transmission. We then discuss how the wider endemic patterns that we delineate can underpin the development and execution of future vaccination programmes. We also outline options for integrated control measures targeting tick vectors and husbandry practices.
-
Development and Evaluation of a Loop-mediated Isothermal Amplification Assay for Rapid Detection of Theileria annulata Targeting the Cytochrome B Gene.
Iranian Journal of Parasitology, 2018Co-Authors: Melek Chaouch, Mohamed Aziz Darghouth, Moez Mhadhbi, Sassi Limam, Souha BenabderrazakAbstract:Background : Theileria annulata is an economically important cattle disease in North Africa that occurs in subTropical and Tropical areas. Accurate and rapid, molecular diagnosis of Tropical Theileriosis is an important issue that allows early treatment and, prevents transmission. We developed and validated a Theileria annulata specific LAMP assay targeting the cytochrome b multicopy gene, in order to increase the DNA detection sensitivity. Methods : The methodology was used to evaluate the occurrences of T. annulata in 88 field samples collected in Northern Tunisia during 2013-2014. The specificity and sensitivity of the LAMP assays were compared to conventional cytochrome b PCR and routine microscopy commonly used on naturally infected cattle blood samples. Results : The PCR assay showed a sensitivity of 70% and specificity around 75%. Our LAMP assay showed a suitable sensitivity 78.7% and specificity 87.5%, with, however, positive (98.4%) and negative (29.1%) predictive values. Conclusion : The LAMP assay is a simple and convenient diagnostic tool for Tropical Theileriosis. Moreover, LAMP does not require experienced staff and specialized equipment for sampling procedures and it is practical outside laboratories and can be used for field diagnosis.
-
dermatological signs in bovine Tropical Theileriosis t heileria annulata infection a review
Revue Scientifique Et Technique De L Office International Des Epizooties, 2017Co-Authors: Mohamed Gharbi, K Souidi, M A Boussaadoun, Ahmed Rejeb, S Jabloun, A Gnaoui, Mohamed Aziz DarghouthAbstract:Bovine Tropical Theileriosis (Theileria annulata infection) is an important tick-borne disease in several regions of the world. This paper describes two clinical cases of Tropical Theileriosis in northern Tunisia with the uncommon sign of skin nodules. The density of nodules was estimated at 15-20 per 10 cm2; they were distributed over the animal's body and were 0.5-2 cm in diameter. Microscopic examination of the skin nodules 18 days after treatment onset showed a perivascular infiltrate of lymphocytes, macrophages and eosinophils. Nevertheless, no schizonts were observed. Appropriate treatment led to the recovery of one of the two animals with total disappearance of the skin lesions; the other animal died. A review of clinical cases of Tropical Theileriosis (T. annulata infection) with cutaneous lesions is presented. Various dermatological signs are described in the literature: skin nodules, haemorrhagic lesions, cutaneous gangrene, etc. Most authors reported the presence of schizonts in the nodular lesions. Dermatological involvement in bovine Tropical Theileriosis should be considered by field veterinarians and should be differentiated from other diseases with dermatological signs.
-
control of Tropical Theileriosis theileria annulata infection in cattle in north africa
Asian Pacific Journal of Tropical Disease, 2015Co-Authors: Mohamed Gharbi, Mohamed Aziz DarghouthAbstract:Tropical Theileriosis (Theileria annulata infection) is a protozoan disease of cattle transmitted by Hyalomma ticks. This parasite is causing high losses in several countries in South Europe, North Africa and Asia. Indeed, both symptomatic and subclinical forms are present in infected animals causing live weight decrease, milk yield decrease, abortions and in some cases death. Due to its high medical and financial impact, the control of this disease is of paramount importance. It can be implemented through five control measures: (i) treatment of infected animals with theilericidal drugs and other symptomatic treatments (this option is used for the treatment of animals and is insufficient to eradicate the parasite), (ii) use of acaricides in animals which contain several side effects for humans, animals and the environment, (iii) roughcasting and smoothing of the outer and inner surfaces of the cattle buildings for endophilic tick species (this control option is expensive but leads to the eradication of the parasite from the farm), (iv) vaccination against ticks, a control option used with success against Rhipicephalus (Boophilus) species but not still available for Hyalomma ticks and (v) vaccination against the parasite with live attenuated vaccines. These control options were presented in the paper and their advantages and limits were discussed. The implementation of one (or more) of these control options should take into account other considerations (social, political, etc.); they sometimes cause the failure of the control action.
-
engineering attenuated virulence of a theileria annulata infected macrophage
PLOS Neglected Tropical Diseases, 2014Co-Authors: Mohamed Aziz Darghouth, Moez Mhadhbi, Nadia Echebli, Marie Chaussepied, Catherine Vayssettes, James P Di Santo, Gordon LangsleyAbstract:Live attenuated vaccines are used to combat Tropical Theileriosis in North Africa, the Middle East, India, and China. The attenuation process is empirical and occurs only after many months, sometimes years, of in vitro culture of virulent clinical isolates. During this extensive culturing, attenuated lines lose their vaccine potential. To circumvent this we engineered the rapid ablation of the host cell transcription factor c-Jun, and within only 3 weeks the line engineered for loss of c-Jun activation displayed in vitro correlates of attenuation such as loss of adhesion, reduced MMP9 gelatinase activity, and diminished capacity to traverse Matrigel. Specific ablation of a single infected host cell virulence trait (c-Jun) induced a complete failure of Theileria annulata–transformed macrophages to disseminate, whereas virulent macrophages disseminated to the kidneys, spleen, and lungs of Rag2/γC mice. Thus, in this heterologous mouse model loss of c-Jun expression led to ablation of dissemination of T. annulata–infected and transformed macrophages. The generation of Theileria-infected macrophages genetically engineered for ablation of a specific host cell virulence trait now makes possible experimental vaccination of calves to address how loss of macrophage dissemination impacts the disease pathology of Tropical Theileriosis.
Jabbar S. Ahmed - One of the best experts on this subject based on the ideXlab platform.
-
Tropical Theileriosis cytotoxic t lymphocyte response to vaccination
Vaccine, 2008Co-Authors: Ulrike Seitzer, Jabbar S. AhmedAbstract:Cattle which survive an infection with Theileria annulata become effectively immune to challenge with the same parasite strain, and are thought to be protected against a heterologous strain of the parasite. T-cells play a crucial role in both induction and maintenance of immunity to T. annulata. The generation of cytotoxic T lymphocytes (CTL) is closely related to the control of the infection – macroschizont-infected cells are killed in an MHC class I restricted manner. Any strain-specificity induced by immunisation is likely to be manifested by CTL. Besides CTLs, CD4+ T-cells also play an important role in protective immunity to T. annulata infection.
-
development of a competitive elisa for detection of theileria annulata infection
Transboundary and Emerging Diseases, 2008Co-Authors: S. Renneker, J Dobschanski, Birgit Kullmann, Jabbar S. Ahmed, Brian Shiels, Andy Tait, Mohammed A. Bakheit, S. Gerber, Daneel Geysen, Ulrike SeitzerAbstract:Summary In previous studies, Theileria annulata surface protein (TaSP) was identified as an immunodominant antigen and successfully used to develop and validate a recombinant-protein-based ELISA for the detection of circulating antibodies in serum of T. annulata–infected animals. In this study, the same antigen was used to develop a competitive ELISA (cELISA) using a monoclonal antibody that was found to bind to TaSP. The cELISA accurately differentiated T. annulata-infected from uninfected animals and demonstrated a satisfactory performance with a calculated sensitivity and specificity of 77.4% and 100%, respectively. Thus the test proved its suitability for the diagnosis of Tropical Theileriosis and has application for use in serological surveys to monitor the prevalence of the disease or identify carrier animals with high specificity.
-
development of a competitive elisa for detection of theileria annulata infection
Transboundary and Emerging Diseases, 2008Co-Authors: S. Renneker, J Dobschanski, Birgit Kullmann, Jabbar S. Ahmed, Brian Shiels, Andy Tait, Mohammed A. Bakheit, S. Gerber, Daneel Geysen, Ulrike SeitzerAbstract:Summary In previous studies, Theileria annulata surface protein (TaSP) was identified as an immunodominant antigen and successfully used to develop and validate a recombinant-protein-based ELISA for the detection of circulating antibodies in serum of T. annulata–infected animals. In this study, the same antigen was used to develop a competitive ELISA (cELISA) using a monoclonal antibody that was found to bind to TaSP. The cELISA accurately differentiated T. annulata-infected from uninfected animals and demonstrated a satisfactory performance with a calculated sensitivity and specificity of 77.4% and 100%, respectively. Thus the test proved its suitability for the diagnosis of Tropical Theileriosis and has application for use in serological surveys to monitor the prevalence of the disease or identify carrier animals with high specificity.
-
development and evaluation of a loop mediated isothermal amplification method for diagnosis of Tropical Theileriosis
Transboundary and Emerging Diseases, 2008Co-Authors: D A Salih, Ulrike Seitzer, Mohammed A. Bakheit, Zhijie Liu, Awadia M Ali, A El M Hussein, H Unger, G Viljoen, Jabbar S. AhmedAbstract:Summary A loop-mediated isothermal amplification (LAMP) assay was developed and evaluated for diagnosis of Tropical Theileriosis. A set of six primers was designed based on the unique gene of Theileria annulata (Theileria annulata strain Ankara hypothetical protein (GeneDB TA04795). The protocol for the reaction was setup and the specificity and sensitivity of the assay were established. The specificity experiment showed that LAMP primers amplified T. annulata DNA successfully, while no amplification was seen for Theileria parva, Theileria mutans, Theileria sergenti, Theileria sinensis, Babesia bovis as well as bovine genomic DNA and water control. When the sensitivity of LAMP assay was compared with that of conventional PCR a 10-fold higher sensitivity was found, with a detection limit of 10 pg/ll of genomic DNA isolated from a T. annulata-infected cell line. The LAMP product was confirmed by restriction digestion and staining with SYBR Green I. Furthermore, the LAMP assay was applied for the diagnosis of T. annulata in field samples and compared with reverse line blot (RLB), demonstrating that results of the LAMP assay corresponded to those of RLB. These results indicate that the LAMP assay is rapid and simple to run, cost-effective, sensitive and specific and has potential usefulness for application in epidemiological studies on T. annulata infection of cattle.
-
innate immunity to Tropical Theileriosis
Innate Immunity, 2008Co-Authors: Jabbar S. Ahmed, Elizabeth Glass, D A Salih, Ulrike SeitzerAbstract:The intracellular protozoan parasite Theileria annulata causes a severe, and often fatal, disease of pure and cross-bred cattle in Tropical and subTropical countries. The present review refers to the importance of innate immunity as far as it is known to date in this infectious disease. Specifically, macrophages and the mediators produced by these cells are outlined. In addition, the latest findings concerning cattle breed differences in susceptibility to T. annulata infection in relation to macrophage activation are discussed.
Ulrike Seitzer - One of the best experts on this subject based on the ideXlab platform.
-
epidemiological studies on Tropical Theileriosis theileria annulata infection of cattle in kurdistan region iraq
Parasitology Research, 2010Co-Authors: Adel Talib Alsaeed, Ulrike Seitzer, Lokman Taib Omer, Jassim Abdo, Gholamreza Habibi, D A Salih, Jabbar AhmedAbstract:In an ad hoc survey conducted during 2006, the epidemiology of Tropical Theileriosis in Kurdistan Region, Iraq, was addressed. For this purpose, a total of 299 blood samples were collected from female cattle older than 1 year reared under open system management in Duhok (n = 99), Sulaimanyia (n = 100) and Erbil (n = 100) governorates. The samples were subjected to TaSP indirect ELISA as well as polymerase chain reaction (PCR) and nested PCR assays. The results indicated that the seroprevalence was 77.9%, and PCR reported an infection rate of 68.9% in the Kurdistan Region of Iraq. The implication of the results in the epidemiology of Tropical Theileriosis in the region is discussed with emphasis on comparisons between the two tests used and recommendations for the future work are outlined.
-
Tropical Theileriosis cytotoxic t lymphocyte response to vaccination
Vaccine, 2008Co-Authors: Ulrike Seitzer, Jabbar S. AhmedAbstract:Cattle which survive an infection with Theileria annulata become effectively immune to challenge with the same parasite strain, and are thought to be protected against a heterologous strain of the parasite. T-cells play a crucial role in both induction and maintenance of immunity to T. annulata. The generation of cytotoxic T lymphocytes (CTL) is closely related to the control of the infection – macroschizont-infected cells are killed in an MHC class I restricted manner. Any strain-specificity induced by immunisation is likely to be manifested by CTL. Besides CTLs, CD4+ T-cells also play an important role in protective immunity to T. annulata infection.
-
development of a competitive elisa for detection of theileria annulata infection
Transboundary and Emerging Diseases, 2008Co-Authors: S. Renneker, J Dobschanski, Birgit Kullmann, Jabbar S. Ahmed, Brian Shiels, Andy Tait, Mohammed A. Bakheit, S. Gerber, Daneel Geysen, Ulrike SeitzerAbstract:Summary In previous studies, Theileria annulata surface protein (TaSP) was identified as an immunodominant antigen and successfully used to develop and validate a recombinant-protein-based ELISA for the detection of circulating antibodies in serum of T. annulata–infected animals. In this study, the same antigen was used to develop a competitive ELISA (cELISA) using a monoclonal antibody that was found to bind to TaSP. The cELISA accurately differentiated T. annulata-infected from uninfected animals and demonstrated a satisfactory performance with a calculated sensitivity and specificity of 77.4% and 100%, respectively. Thus the test proved its suitability for the diagnosis of Tropical Theileriosis and has application for use in serological surveys to monitor the prevalence of the disease or identify carrier animals with high specificity.
-
development of a competitive elisa for detection of theileria annulata infection
Transboundary and Emerging Diseases, 2008Co-Authors: S. Renneker, J Dobschanski, Birgit Kullmann, Jabbar S. Ahmed, Brian Shiels, Andy Tait, Mohammed A. Bakheit, S. Gerber, Daneel Geysen, Ulrike SeitzerAbstract:Summary In previous studies, Theileria annulata surface protein (TaSP) was identified as an immunodominant antigen and successfully used to develop and validate a recombinant-protein-based ELISA for the detection of circulating antibodies in serum of T. annulata–infected animals. In this study, the same antigen was used to develop a competitive ELISA (cELISA) using a monoclonal antibody that was found to bind to TaSP. The cELISA accurately differentiated T. annulata-infected from uninfected animals and demonstrated a satisfactory performance with a calculated sensitivity and specificity of 77.4% and 100%, respectively. Thus the test proved its suitability for the diagnosis of Tropical Theileriosis and has application for use in serological surveys to monitor the prevalence of the disease or identify carrier animals with high specificity.
-
development and evaluation of a loop mediated isothermal amplification method for diagnosis of Tropical Theileriosis
Transboundary and Emerging Diseases, 2008Co-Authors: D A Salih, Ulrike Seitzer, Mohammed A. Bakheit, Zhijie Liu, Awadia M Ali, A El M Hussein, H Unger, G Viljoen, Jabbar S. AhmedAbstract:Summary A loop-mediated isothermal amplification (LAMP) assay was developed and evaluated for diagnosis of Tropical Theileriosis. A set of six primers was designed based on the unique gene of Theileria annulata (Theileria annulata strain Ankara hypothetical protein (GeneDB TA04795). The protocol for the reaction was setup and the specificity and sensitivity of the assay were established. The specificity experiment showed that LAMP primers amplified T. annulata DNA successfully, while no amplification was seen for Theileria parva, Theileria mutans, Theileria sergenti, Theileria sinensis, Babesia bovis as well as bovine genomic DNA and water control. When the sensitivity of LAMP assay was compared with that of conventional PCR a 10-fold higher sensitivity was found, with a detection limit of 10 pg/ll of genomic DNA isolated from a T. annulata-infected cell line. The LAMP product was confirmed by restriction digestion and staining with SYBR Green I. Furthermore, the LAMP assay was applied for the diagnosis of T. annulata in field samples and compared with reverse line blot (RLB), demonstrating that results of the LAMP assay corresponded to those of RLB. These results indicate that the LAMP assay is rapid and simple to run, cost-effective, sensitive and specific and has potential usefulness for application in epidemiological studies on T. annulata infection of cattle.
R L Spooner - One of the best experts on this subject based on the ideXlab platform.
-
proinflammatory cytokine expression by theileria annulata infected cell lines correlates with the pathology they cause in vivo
Vaccine, 2001Co-Authors: Simon P Graham, D J Brown, Zati Vatansever, A K Nichani, John D M Campbell, Rachel Adamson, Elizabeth Glass, Louise H Taylor, D. Waddington, R L SpoonerAbstract:Control of Theileria annulata is currently best achieved by the use of live attenuated cell line vaccines. However, the mechanisms underlying attenuation are unclear and there is a need to rapidly produce new cell line vaccines, which could safely and effectively vaccinate cattle against Tropical Theileriosis. There is increasing evidence to suggest that proinflammatory cytokines produced by T. annulata infected cells play a central role in both pathology and immune evasion. This study aimed to test this hypothesis and to evaluate cytokine expression as a marker of virulence. The pathogenicity and protective efficacy of cloned T. annulata cell lines that expressed different levels of proinflammatory cytokines were compared. In two independent trials using different stocks of T. annulata, cell lines that expressed higher levels of proinflammatory cytokines induced severe reactions, and in some cases death, when used to vaccinate groups of cattle. In contrast, low cytokine expressing lines induced low post-vaccinal reactions. The results clearly demonstrated that cytokine expression by T. annulata infected cells could be used as a marker of virulence and provided strong evidence to support a role for cytokines in the induction of pathology. Both high and low cytokine expressing cell lines protected cattle against heterologous challenge infection, offering the possibility of using cytokine expression to rapidly select new safe, potent vaccines against Tropical Theileriosis without the need for culture attenuation.
-
innate and adaptive immune responses co operate to protect cattle against theileria annulata
Parasitology Today, 1999Co-Authors: Patricia M. Preston, Jd Campbell, Jabbar S. Ahmed, Frans Jongejan, Brian Shiels, F R Hall, Mohamed Aziz Darghouth, Elizabeth Glass, R L Spooner, C.g.d. BrownAbstract:For many years it was assumed that Theileria annulata resembled T. parva, parasitizing lymphocytes and causing lymphoproliferative disease, with the two species being controlled by similar protective immune responses. Patricia Preston et al. here review the evidence that has led to a different view of T. annulata. It is now thought that the schizonts of T. annulata inhabit macrophages and B cells, and that Tropical Theileriosis is not a lymphoproliferative disease. Both innate and adaptive responses contribute to recovery from infection and resistance to challenge and cytokines produced by infected and uninfected cells influence the outcome of infection. Partial protection has been stimulated recently by defined recombinant antigens; efficacy depended upon the delivery system.
-
macrophages behaving badly infected cells and subversion of immune responses to theileria annulata
Parasitology Today, 1999Co-Authors: J D M Campbel, R L SpoonerAbstract:Abstract The protozoan parasite Theileria annulata is the causative agent of the tick-borne disease Tropical Theileriosis, responsible for morbidity and mortality of cattle in many developing countries. Here, John Campbell and Roger Spooner discuss how the parasite might evade immune destruction during an acute primary infection. Theileria annulata macroschizont-infected macrophages act as over-efficient antigen-presenting cells within the infected draining lymph node. Infected cells activate CD4 + and CD8 + T cells abnormally, giving rise to a cascade of cytokine production. This altered immune response does not reject the parasitized cells, and might actively participate in the growth of the developing parasite.
-
the use of an enzyme linked immunosorbent assay for Tropical Theileriosis research in morocco
Preventive Veterinary Medicine, 1996Co-Authors: M. Kachani, H. Ouhelli, E J Flach, S Williamson, El M Hasnaoui, R L SpoonerAbstract:An enzyme-linked immunosorbent assay (ELISA) using sonicated purified Theileria annulata piroplasms was compared with an indirect immunofluorescent antibody test (IFAT) during a vaccination trial in cattle to test different doses and passage numbers of an attenuated T. annulata-infected lymphoblastoid cell-line, and also with Giemsa-stained blood smears during an epidemiological field study of Tropical Theileriosis in Morocco. The sensitivities of both the ELISA (0.56) and the IFAT using T. annulata piroplasm antigen (0.56) were lower than the IFAT using schizont antigen (0.94) for detecting serum antibodies from 18 cattle immunised 38 days previously with cell-line. The ELISA was, however, the most sensitive test after 180 days (0.50 compared with 0.06 for the piroplasm IFAT and 0.39 for the schizont IFAT), and each test detected antibodies in all sera after challenge with live T. annulata sporozoites. There were minor differences in the ability of blood smear examinations and the ELISA to detect infected and uninfected cattle in the field study at the start and end of the disease season. Initially, the sensitivity and specificity of blood smears were both 0.96 and for the ELISA were 0.83 and 0.86, whereas at the end of the season sensitivity and specificity of blood smears were 0.96 and 0.86 and for the ELISA were 0.95 and 0.94. The specificity of the ELISA was affected by the presence of calves with colostral antibodies, and if these were disregarded the specificities before and after the season were 0.94 and 1.00.
-
factors influencing the transmission and incidence of Tropical Theileriosis theileria annulata infection of cattle in morocco
Veterinary Parasitology, 1995Co-Authors: E J Flach, H. Ouhelli, D. Waddington, M Oudich, R L SpoonerAbstract:A longitudinal epidemiological investigation of Tropical Theileriosis was carried out in an endemic region of Morocco during the 1991 disease season. This involved approximately 220 cross-bred cattle on 15 farms. Data were collected on the frequency of existing infections, the size of the vector tick population and the incidences of new infections and clinical disease, and these were then analysed using statistical models. The prevalence of subclinically infected carriers of Theileria annulata, the number of adult Hyalomma detritum, the vector, and the probability of becoming newly infected with T. annulata increased significantly with the age of cattle, although the age effect on new infections may be a result of increased tick numbers on older animals. The probability of clinical disease in newly infected cattle was not significantly influenced by age or by the number of adult ticks, but was significantly positively associated with the cattle population on the farm. The number of H. detritum nymphs counted on cattle in the autumn was related significantly to the previous adult tick count on the same animal.
Mohammed A. Bakheit - One of the best experts on this subject based on the ideXlab platform.
-
development of a competitive elisa for detection of theileria annulata infection
Transboundary and Emerging Diseases, 2008Co-Authors: S. Renneker, J Dobschanski, Birgit Kullmann, Jabbar S. Ahmed, Brian Shiels, Andy Tait, Mohammed A. Bakheit, S. Gerber, Daneel Geysen, Ulrike SeitzerAbstract:Summary In previous studies, Theileria annulata surface protein (TaSP) was identified as an immunodominant antigen and successfully used to develop and validate a recombinant-protein-based ELISA for the detection of circulating antibodies in serum of T. annulata–infected animals. In this study, the same antigen was used to develop a competitive ELISA (cELISA) using a monoclonal antibody that was found to bind to TaSP. The cELISA accurately differentiated T. annulata-infected from uninfected animals and demonstrated a satisfactory performance with a calculated sensitivity and specificity of 77.4% and 100%, respectively. Thus the test proved its suitability for the diagnosis of Tropical Theileriosis and has application for use in serological surveys to monitor the prevalence of the disease or identify carrier animals with high specificity.
-
development of a competitive elisa for detection of theileria annulata infection
Transboundary and Emerging Diseases, 2008Co-Authors: S. Renneker, J Dobschanski, Birgit Kullmann, Jabbar S. Ahmed, Brian Shiels, Andy Tait, Mohammed A. Bakheit, S. Gerber, Daneel Geysen, Ulrike SeitzerAbstract:Summary In previous studies, Theileria annulata surface protein (TaSP) was identified as an immunodominant antigen and successfully used to develop and validate a recombinant-protein-based ELISA for the detection of circulating antibodies in serum of T. annulata–infected animals. In this study, the same antigen was used to develop a competitive ELISA (cELISA) using a monoclonal antibody that was found to bind to TaSP. The cELISA accurately differentiated T. annulata-infected from uninfected animals and demonstrated a satisfactory performance with a calculated sensitivity and specificity of 77.4% and 100%, respectively. Thus the test proved its suitability for the diagnosis of Tropical Theileriosis and has application for use in serological surveys to monitor the prevalence of the disease or identify carrier animals with high specificity.
-
development and evaluation of a loop mediated isothermal amplification method for diagnosis of Tropical Theileriosis
Transboundary and Emerging Diseases, 2008Co-Authors: D A Salih, Ulrike Seitzer, Mohammed A. Bakheit, Zhijie Liu, Awadia M Ali, A El M Hussein, H Unger, G Viljoen, Jabbar S. AhmedAbstract:Summary A loop-mediated isothermal amplification (LAMP) assay was developed and evaluated for diagnosis of Tropical Theileriosis. A set of six primers was designed based on the unique gene of Theileria annulata (Theileria annulata strain Ankara hypothetical protein (GeneDB TA04795). The protocol for the reaction was setup and the specificity and sensitivity of the assay were established. The specificity experiment showed that LAMP primers amplified T. annulata DNA successfully, while no amplification was seen for Theileria parva, Theileria mutans, Theileria sergenti, Theileria sinensis, Babesia bovis as well as bovine genomic DNA and water control. When the sensitivity of LAMP assay was compared with that of conventional PCR a 10-fold higher sensitivity was found, with a detection limit of 10 pg/ll of genomic DNA isolated from a T. annulata-infected cell line. The LAMP product was confirmed by restriction digestion and staining with SYBR Green I. Furthermore, the LAMP assay was applied for the diagnosis of T. annulata in field samples and compared with reverse line blot (RLB), demonstrating that results of the LAMP assay corresponded to those of RLB. These results indicate that the LAMP assay is rapid and simple to run, cost-effective, sensitive and specific and has potential usefulness for application in epidemiological studies on T. annulata infection of cattle.
-
from molecule to diagnostic tool theileria annulata surface protein tasp
Parasitology Research, 2007Co-Authors: Ulrike Seitzer, Leonhard Schnittger, Dia Eldin A Salih, Daniel Haller, Mohammed A. Bakheit, Jabbar S. AhmedAbstract:Isolation and characterization of the Theileria annulata macroshizont stage protein TaSP showed that this parasite surface membrane protein is a highly antigenic protein suitable for the development of diagnostic tools for Tropical Theileriosis. An enzyme-linked immunosorbent assay (ELISA) for the detection of circulating antibodies against Theileria annulata was established and validated using the recombinantly expressed TaSP protein. The ELISA has subsequently been applied for cross-sectional surveys to determine the distribution and prevalence of Tropical Theileriosis in Sudan.
-
Application of the recombinant Theileria annulata surface protein in an indirect ELISA for the diagnosis of Tropical Theileriosis.
Parasitology research, 2004Co-Authors: Mohammed A. Bakheit, Leonhard Schnittger, Dia Eldin A Salih, Kati Boguslawski, Doreen Beyer, M. Fadl, Jabbar S. AhmedAbstract:The recombinant surface protein of Theileria annulata (TaSP) was used in the standardization and validation of an enzyme linked immunosorbent assay (ELISA) for the detection of circulating antibodies against Tropical Theileriosis. ELISA data were expressed as the percentage positivity (PP) of the reactivity of an internal positive control. A total of 50 sera samples from a disease-free area were used for the calculation of the cut-off value which served as a threshold between the positive and the negative sera samples. This was determined as the mean PP plus two standard deviations or the twice the mean PP of the results obtained with these negative samples. The obtained thresholds were 17.8% and 18.3%, respectively. Accordingly, the reactivity of 140 field sera samples collected at random from an area known to be endemic for Tropical Theileriosis in Sudan was determined as PP values which were then compared to the results obtained using the indirect fluorescence antibody test (IFAT) from the same samples. Both tests showed a high degree of correlation. The TaSP-ELISA had a sensitivity of 99.1% and specificity of 90.47% when taking the IFAT as a reference test. Our test has proved its suitability for the diagnosis of Tropical Theileriosis and could be used in serological surveys to map out the prevalence of the disease or to monitor vaccination efficiencies in disease-free populations.
