Project:

Multi-sectoral strategy for brucellosis control in Eastern Africa

Time: 2018-2021, see final report.

Supported by: LEAP-Agri, BLE

Goals: Our aim is to methodically identify and address obstacles towards the deployment of interventions for the sustainable minimization of the prevalence of brucellosis in these livestock production systems. The innovation questions the project wants to address include (1) What is the status of brucellosis in various livestock reared in the E. African regions, (2) What is the extent of distribution of livestock and human brucellosis in the E. African region, (3) what brucella biovars/genomes are involved in the causation of brucellosis in livestock and humans in E. African region?, (4) What vaccine types can be adopted for the control / prevention of livestock brucellosis in E. African region?, (5) What are the infrastructural / human capacity needs for brucellosis management in E. African region?, and (6) what are the knowledge gaps among various E. African stakeholders regarding brucellosis awareness, biosafety and biosecurity?. These specific research questions will be addressed by a team of local veterinarians, local medical doctors and sociologists with a strong backing of international experts. The findings will participatorily be used to develop, implement and test locally adapted control platforms. From the above, the proposal falls in line with the LEAP-Agri 2017 call’s Research and innovation focus 1: sustainable intensification.Indicative area - Animal and crop health, from farm to international scales, to develop sustainable approaches to optimise resource efficiency, minimise production losses and avoid geographical spreading of diseases/pathogens.

Research performed at Hohenheim University

Classical diagnostic techniques enable differentiation of Brucella isolates down to the biovar level. They are not suitable for the differentiation of an outbreak strain and to trace back the source and the route of dissemination of outbreak strains.

One of the approaches best recognized to obtain valuable discrimination in Brucella is Multi Locus Variable Number Tandem Repeat (VNTR) Analysis (MLVA).

Several MLVA-protocols have been published like MLVA-21. However, after several steps of refinement a 16-marker MLVA was established and is now used worldwide as the method of choice. Several Mutation rate variability between loci in Brucella allows this method to discriminate closely related strains (through highly mutable loci), as well as yield useful information at the phylogenetic/taxonomic level (through relatively conserved ones). MLVA data can be easily generated by PCR followed by length separation of the fragments, but comparison between laboratories remains problematic because some fragment analysis platforms, such as agarose gel electrophoresis (AE), are unable to resolve ambiguities at specific loci, impeding the exchange of results between laboratories equipped with different technical platforms. To avoid these constraints, a protocol has been developed by an italian group using multiplex PCR and multicolor capillary electrophoresis (CE). This protocol will be established by the PhD student at the Hohenheim laboratory on the ABI 3130 platform. Nonetheless, both types, AE and CE, of fragment analysis will be tested to allow for the transfer of either a low-cost or a high-end protocol to laboratories in other countries.

The actual genotype will be determined after translation of the PCR-fragment lengths into a copy-code (number of repeats for every marker). This 16-marker allele-code will be used to calculate a cluster analysis by UPGMA (Bionumerics software). The actual genotypes will be made available to the international MLVAbank for Microbes Genotyping for comparison (http://microbesgenotyping.i2bc.paris-saclay.fr/databases/view/907/).

In combination with epidemiological metadata like date and side of sample collection the cluster analysis enables the tracking of regional and temporal dissemination of outbreak strains.

Project:

Comparative studies on the immunogenicity and safety of the live spore animal vaccine versus recombinant peptide and DNA vaccine candidates in rabbits and goats

Time: 2013-2014, see final report

Supported by: DFG, GZ: BE 2157/4-1

Goals: In this project DNA-vectors containing signal sequences for targeted expression of the antigens have been constructed and tested. Our plasmids use lysosome-associated membrane protein (LAMP1) and tissue plasminogen activator (TPA) to stimulate humoral immune responses and ubiquitin to stimulate cell mediated immunity. Three modern adjuvants were used. A lipopeptide adjuvant is used for protein vaccinations. For DNA vaccination two regulatory adjuvants are used. The mouse interferon-ß promoter stimulator 1 (mIPS1) is used in combination with a truncated PA/LF fusion protein and the MHC class II transactivator (CIITA) is co-administered with rPA and rBclA encoding plasmids.

To evaluate the protective potential of an immune response elicited in goats tests for passive protection of A/J mice against a lethal infection with spores of the Sterne vaccine strain by intra-peritoneal administration of the serum of a vaccinated animal are used.

Role: Main investigator

Project: Immunoprophylaxis and molecular epidemiology of anthrax and the fate of Bacillus anthracis in living vectors and the environment of Namibia and South Africa

Time: 2009-2013, see final report

Supported by: DFG, GZ: BE 2157/3-1

Goals:The project proposed encompasses (1) investigations of the molecular and environmental epidemiology of anthrax in South Africa and Namibia, (2) studies on the fate of Bacillus (B.) anthracis in environmental habitats and within insect vectors and (3) studies in laboratory rodents and goats to compare the immunogenicity, protective efficacy, and safety of recombinant peptide and DNA vaccine candidates with those of the live spore vaccine licensed in these countries. The project will address the genetic diversity of B. anthracis, circulating in livestock, wildlife and humans and in environmental habitats and the relationship between genotype and spatial, temporal and host distribution, using modern molecular fingerprinting techniques. The roles of water holes and other so-called “concentrator areas” and of free living amoebae in the epidemiology of anthrax in wild life parks and their surroundings will be investigated in microcosm and field studies. Vaccine protection trials will be carried out to test acellular bacterial and toxoid antigens, individually and in combination, and a plasmid DNA vaccine encoding various antigens. The feasibility of giving antibiotics at the same time as immunisation with acellular vaccines as a possible treatment schedule during an outbreak will be studied. Underpinning the science is the aim to support the academic and professional careers of young Namibian, South African and German scientists through exchange of personnel and technological skills within the framework of a multi-national academic network.

Role: Main investigator

Project: Ausbau der Datenbank zur molekularepidemiologischen Analytik von Bacillus anthracis Stämmen mit Etablierung der SNR (Sinlge Nucleotide Repeat)-Typisierungsmethode.

Time: 2008-2010

Supported by: Ministry of Defense  of the Fed. Rep. Germ.

Goals: Genotyping of strain collections and molecular epidemiological analysis of anthrax outbreaks.

Role: Main investigator

Project: Therapy of infections with B. anthracis by monoclonal antibodies against the lethal toxin  in combination with an antibacterial phage lysin.

Time: 2005-2008

Supported by: Ministry of Defense  of the Fed. Rep. Germ.

Goals: Development and testing of new approaches for the therapy of Anthrax.

Role: Main investigator

Project: Development and testing of monoclonal antibodies against the thermo-stable antigen of B. anthracis

Time: 2005-2007

Supported by: Ministry of Defense  of the Fed. Rep. Germ.

Goals: Development and testing of a simple and fast diagnostic protocol based on a serological reaction between heat treated antigens and monoclonal antibodies.

Role: Main investigator

Project: Molecular epidemiological analysis of isolates of B. anthracis and improvement of the diagnosis of B. anthracis by using recombinant phage lysins.

Time: 2004-2007

Supported by: Ministry of Defense  of the Fed. Rep. Germ.

Goals: Establishment of fingerprinting (MLVA, SNP-Analysis) for epidemiological characterization of field isolates. Usage of a recombinant phage lysin for diagnostic purposes.

Role: Main investigator

Project: Anthrax-Euronet

Time: 2004-2007

Supported by: European Commission

Goals: Standardization and harmonization of protocols and methods for the development and testing of vaccines and therapeutics agains anthrax

Role: Workpackage leader

Project: Testing of recombinant vaccine candidates on immunogenicity and induction of a protective immunity against an infection with B. anthracis

Time: 2001-2004

Supported by: Ministry of Defense  of the Fed. Rep. Germ.

Goals: Testing of already developed vaccine candidates in animal trials, comparison of various immunization schemes in various mice strains and in rabbits

Role: Main investigator

Project: Development and testing of a live Salmonella vaccine which can be administered orally against infection with B. anthracis

Time: 1999-2001

Supported by: Ministry of Defense  of the Fed. Rep. Germ.

Goals: Development of pro- and eucaryotic expression cassettes for B. anthracis antigens and characterization in vitro

Role: Main investigator