Opening ceremony by his Excellency Prof. Musa Tibin Musa, the Minister of Animal Resources and Fisheries in Sudan
During his welcome address, his Excellency Prof. Musa highlighted the importance of ticks and tick-borne diseases, particularly theileriosis. He greatly acknowledged the support of the DFG for research in animal health by providing training opportunities, technology transfer and scientific cooperation between German and African scientists. The meeting attracted the attention of the local media with TV stations reporting on its content of the meeting and its relevance for the control of ticks and tick-borne diseases. |
Monday 8th Feb. 2016 Scientific presentations
Jabbar Ahmed: Immune response to Theileria annulata-infection and vaccination: prospects for vaccine improvement.
In his presentation, Jabbar Ahmed highlighted the role T-lymphocytes in the control of T. annulata-infection, particularly the relevance of cytotoxic T-lymphocytes in specific killing of parasitized cells in an MHC-I-dependent manner. In the discussion, emphasis was given to the need to identify parasite molecules to be used as subunit vaccines in combination with attenuated vaccines. It was suggested that antigens of the sporozoite and piroplasm stages of the parasite also be considered. Candidate parasite molecules that were suggested included TaSP, TaD, Tps, TaMs and SPAG
Mohammed Gharbi: Economics of control of T. annulata-infection: Tunisia experience
The Tunisian team reported on studies initiated to investigate the economic impact of different control measures against Theileria-annulata infection. The analysis was carried out using samples collected from 49 Tunisian dairy farms with cases of tropical theileriosis. Morbidity,prevalence, production and demographic indicators were used to rank the potential costs and benefits of various Tropical Theileriosis control programs. The following control measures were analyzed:
- Vaccination with a local attenuated cell-line,
- Partial barn upgrading, based on first roughcasting then smoothing all the walls of the animal premises (inner and outer surfaces) and
- Application of acaricides to control the tick vector on cattle.
In the ensuing discussion of this presentation, the following recommendations were made:
- Due to the low number of the animals included in the study, the results should be interpreted with caution.
- The results of previous experiments where attenuated and subunit vaccines were used in combination, should also be included in these studies.
Jabbar Ahmed appreciated the epidemiological and socio-economic studies, but he also reiterated to the the Tunisian team the need to focus on the immunization trials using subunit and attenuated vaccines in future studies. He particularly asked the team to work out a plan for immunization experiments to be conducted in 2016.
Limia-Mubark-Elhag: T. annulata vaccination field trials: Sudan experience
Limia-Mubark-Elhag referred to the progress achieved in cell culture technology, which enabled the Sudanese team to create conditions for propagation and attenuation of two strains of T. annulata. Attenuation of Atbara and Hantoub cell lines was achieved at passages 90 and 72, respectively. Only mild clinical reactions were observed when 2x106 cells were inoculated in 5 sero-negative susceptible calves. A trial for evaluation of the vaccine efficacy using ground up tick suspension (GUTS) for challenging vaccinated calves has been attempted using homologous and heterogonous challenges. Limited safety and efficacy tests of the vaccine under field conditions have been undertaken in cross-bred animals.
Furthermore, Limia mentioned that the vaccine inoculated at a dose of 6.5x106 cells to pure Frisian (6 animals) and cross-bred Frisian x Kenana calves (7 animals), slightly raised the body temperature for a short duration and only few piroplasms and schizonts were detected in blood and lymph node smears. Interestingly, no untoward effects were detectable in all of the inoculated animals. Based on previous studies, the vaccine seed was considered sterile as it was free from any contamination of bacteria, fungi, Mycoplasma and extraneous viruses (El Haj 2010). Nevertheless, the effective dose that can protect cross-bred young calves (3-6 months of age), which are the target group of these vaccines, still needs to be determined in future experiments.
In addition, Limia referred to a number of constrains facing the group such as difficulties to obtain laboratory equipment and materials for cell culture.
Amira Al Hosary: T. annulata vaccine development and testing in Egypt
Amira Al Hosary highlighted the progress achieved during the first phase of the DFG project regarding diagnostic tools and training which enhanced the technical skills of the group for a rapid, accurate and effective detection of the parasite. Using molecular and serological methods the group succeeded to generate epidemiological data required to design integrated control measures against tropical theileriosis in Egypt.
As vaccination is an imperative measure against T. annulata-infection, the Egyptian team collected different isolates of the parasite and initiated studies to molecularly characterize these parasites and to culture them as cell lines for attenuation. For the assessment of attenuation the following criteria will be applied:
- In vitro analysis of up-and down regulation of parasite and host genes known to be involved in parasite attenuation such as MMP9 and TNF-alpha.
- Evaluation of the effectiveness of attenuation through inoculation of low- and high passaged cell lines into a small group of animals which will subsequently be monitored for parasitological, clinical and haematological parameters.
- Experimental immunization trials using:
- Live attenuated cell lines from the local strains.
- Combination of attenuated parasites and subunit vaccine (TaSP, Tams and TaD)
- Evaluation of the immunization efficacy and challenge.
Tuesday 9th Feb 2016 Country reports
Abdulrahim El Husein: Improvement of immunization against Theileria annulata by using a combination of cell line and BCG in Sudan
In the second phase of the project, the Sudanese team designed experiments aiming at improving the immunization against Theileria annulata-infection using Bacillus Calmette-Guérin (BCG) as a non-specific immune-stimulant on the host's response to vaccination with attenuated culture vaccines. For these experiments, 24 cross-bred animals were purchased from farms in the White Nile State in which no clinical cases of theileriosis have been reported.
Prof. Abdulrahim El-Husein summarized the obtained results as follows:
- The immunization did not induce clinical reactions in the animals as no substantial differences were recorded between the different groups regarding body temperature and haematological values (RBCs and WBCs counts, Hb and PCV values).
- BCG treatment did not affect the outcome of the immunization using cell culture vaccine.
Based on these results it was concluded that the cell line used in this study was attenuated. However, to check whether the immunized animals can withstand a field challenge under high tick pressure, they will soon be moved to a farm where cases of tropical theileriosis are known to occur. These animals will be monitored for clinical reactions and antibody responses using IFAT and or TaSP-based ELISA. A decision on whether this combination should also include subunit vaccines will be taken after the evaluation of the results emerging from the field challenge.
Mohamed Gharbi: Research activities planned in 2016, with special emphasis on immunization trials against tropical theileriosis
Mohamed Gharbi presented a work plan aimed at evaluating the efficacy of a combination of cell line and subunit vaccines under field conditions to be performed in enzootic stable farms in 2016. In this trial, Béja 280 cell line vaccine alone or in combination with a subunit vaccine will be used. The concept he presented is as follows
- Live attenuated cell lines from the local strains
- Combination of attenuated parasites and subunit vaccine (TaSP, TaMs and TaD)
- Subunit vaccine
- Evaluation of the immunization efficacy and challenge.
Jabbar Ahmed reminded the participants of the deliberations of the kick-off meeting held in Berlin from 4-5 of November, 2014, where it was recommended that the recombinant orthologue of Bm86 from Hyalomma spp be used to target both pathogen and tick. He stressed that this issue is still of particular interest. Vaccination of calves with Hd86, the Bm86 orthologue from Hyalomma scupense, led to a reduction in the number of engorged H. scupense nymphs by 60% (but had no effect on infestations with H. excavatum adults). Since the Tunisian group has some experience in this context, it was suggested that this issue be considered in further studies. Furthermore, it was suggested that the use of BCG be halted until the results of Sudan trial become available.
Other scientific presentations
Apart of the research efforts directly related to the DFG project, results of a number of other studies were presented by Sudanese scientists working in different regions of the country. For example:
- Prevalence of Theileria spp. piroplasms and T. annulata-specific antibodies among local and cross bred cattle in Nyala, South Darfour State. In a small scale study performed on samples collected from 100 animals, 31 samples were positive. These results could be confirmed by PCR.
- Ahmed Al Ghali: Bacterial infections and pathological complications associated with bovine tropical theileriosis. This presentation aimed at introducing a proposal to study a possible association of a bacterial infection with the pathogenesis of theileriosis. Since specific bacterial infections were not mentioned, the proposal was not further considered. Instead, it was suggested to look for co-infections with other tick-borne pathogens like Babesia and Anaplasma
- Mohamed Toum Elhaj: Situation of Acaricide resistance in Sudan.
- Mohammed Osman: Immunization with live attenuated schizonts against tropical theileriosis (Theileria annulata-infection) increases antibody titers in chronically infected cattle in Sudan.
- Bothina Bakor Mohammed Gaafar and Dr. Ismail Abdelrahim Abaker: Epidemiology of Theileria annulata in dairy cattle in Nyala area, Southern Darfur State, Sudan.
- Khalid Mohamed Taha: Theileriosis in River Nile State (Northern Sudan).
- SaraBashir: Assessment of Anti-theilerial Activity of Geldanamycin and 17-AAG against Theileria annulata: In vivo experiment. After the discussion of this proposal it was recommended not to pursue this idea, since a number of questions are not clear such as the issue of drug residues.
- Sara Bashir: Screening for new attenuation markers of in Theileria annulata-infected cell lines to be used for the development of live vaccine. Sara presented a detailed design of experiments for the assessment of up-or down-regulation of parasite and host cell molecules associated with attenuation. In this context, all partners agreed to send their cell lines to Sara.
Wednesday 10th Feb 2016: Site visits
The Director General of ARRC. Prof. Ibtisam Goreish,
The Director General described the scientific and administrative tasks of ARRC as an umbrella for research activities in veterinary sciences.
HE the Minister of Animal Resources and Fisheries.
HE Excellency Prof. Musa Tibin Musa highlighted the activities of his ministry regarding animal resources and fisheries with a special focus on ticks and tick-borne diseases. He acknowledged the DFG support and pledged his support for this project.
The Director General of CVRL.
The DG of CVRL Dr.Yousif Hussein Elamansoury highlighted the activities of CVRL in diagnosis of veterinary infections. He pledged his support for the DFG project and for the establishment of new cell culture laboratories.
Recommendations of the meeting
Education
- Education is an important part of the DFG-project. Therefore, it is recommended to offer further training opportunities at national and regional level,
- Involvement of young scientists in the DFG project,
- Exchanging program for PhD students between participating countries,
- Networking of research centers, universities and veterinary authorities.
Diagnosis
- Organization a technical workshop for LAMP,
- Technology transfer regarding recombinant protein production
- Need to explore possible collaboration with Malik Merza from Svanova (Sweden) or another company for the production of the recombinant TaSP protein,
- Use of TaSP for monitoring of the antibody response to vaccination,
- Technical workshop on RLB.
Attenuation
- Assessment of T.annulata- infected cell lines for attenuation markers. Sara Mohamed will take care of this issue.
- Molecular characterization of TP1 and TP2 genes in T.annualta-infected cell lines after different passages. Awadia Ali will take care of this issue.
- Transfer of different cell lines from different collaborating groups to Berlin for cryopreservation.
Vaccination
- Establishment of a new laboratory for tissue culture. The Director General of CVRL already agreed to provide the required support.
- Use of parasite and tick molecules as potential subunit vaccine candidates.
- Creation of infrastructure for the production of recombinant proteins.
List of the participants
Surname First name Country
Ahmed Jabbar Germany
El Hussein Abdel Rahim M. Sudan
Abdel Aleem Amira Adel Taha Egypt
Gharbi Mohamed Tunisia
Salih Diaeldin Sudan
Hassan Shawgi M. Sudan
Ali Awadia Sudan
Elsamani Rawia Sudan
El Ghali Ahmed Sudan
El Haj Limia Sudan
Osman Ilham Sudan
Sid Ahmed Abu Baker Sudan
Elhaj Mohammed Toum Sudan
Bashir Sarra Sudan
Abdel Gadir Selma Sudan
Hussein Ahmed Sudan
Badwi Magdi Sudan
Mostafa Amal Sudan
Goriesh Ibtisam Sudan
Siddig Ali Sudan
Abaker Ismail Sudan
Abakor Bothina Sudan
Osman Mohammed Sudan
Taha Khalid Sudan
Al Faki Asha Sudan
Ahmed Abdel Rahman Sudan
Berlin, 17 March 2016 Prof. Dr. Jabbar Sabir Ahmed