Henriette van Heerden

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In a search for tools to distinguish antigenic variants of Ehrlichia ruminantium, we sequenced the major antigenic protein genes (map1 genes) of 21 different isolates and found that the sequence polymorphisms were too great to permit the design of probes which could be used as markers for immunogenicity. Phylogenetic comparison of the 21 deduced MAP1(More)
The Sterne 34F2 live spore vaccine (SLSV) developed in 1937 is the most widely used veterinary vaccine against anthrax. However, literature on the immunogenicity of this vaccine in a target ruminant host is scarce. In this study, we evaluated the humoral response to the Bacillus anthracis protective antigen (rPA), a recombinant bacillus collagen-like(More)
Ehrlichia ruminantium, the causative agent of heartwater, is a tick-borne pathogen infecting ruminants throughout sub-Saharan Africa and on some Caribbean islands. The most reliable test for E. ruminantium is PCR-based, but this gives positive results in some areas free of clinical heartwater and of the known Amblyomma spp. tick vectors. To investigate the(More)
Field-programmable gate arrays (FPGAs) allow circuit reconfiguration in the field, which adds to the flexibility of electronic systems. Applied to superconductive electronics, reprogrammability allows system functionality to be changed without remanufacturing the circuit or dismantling a cryogenic setup. We discuss the design issues relevant to a(More)
The diagnostic sensitivity (DSe) of the Rose Bengal test (RBT), the complement fixation test (CFT), the serum agglutination test (SAT), the competitive enzyme-linked immunosorbent assay (cELISA) and the indirect ELISA (iELISA) were determined in naturally infected cattle in KwaZulu-Natal province of South Africa with known infectious status from culture(More)
Immune responses of infected animals and humans have been reported to be directed against variable outer membrane proteins of Ehrlichia species that are encoded by polymorphic multigene families. In Ehrlichia (= Cowdria) ruminantium, two immunodominant proteins have been identified, namely major antigenic protein 1 (MAP1) and open reading frame 2 (ORF2).(More)
Serology is primarily used in the diagnosis of bovine brucellosis. Bacterial culture and isolation is the gold standard in diagnosing brucellosis but, like serology, it does not offer complete (100%) diagnostic sensitivity and specificity. Polymerase chain reaction (PCR) has been suggested to offer better specificity and sensitivity. In this study, we(More)
BACKGROUND Bacillus (B.) anthracis, the causal agent of anthrax, is effectively controlled by the Sterne live spore vaccine (34F2) in animals. However, live spore vaccines are not suitable for simultaneous vaccination and antibiotic treatment of animals being at risk of infection in an outbreak situation. Non-living vaccines could close this gap. RESULTS(More)
Heartwater is a serious tick-borne disease of ruminants caused by the rickettsial organism Ehrlichia (Cowdria) ruminantium. A diagnostic test, targeting the pCS20 genomic region and using PCR amplification and probe hybridization, detects E. ruminantium infection in ticks and animals. However, only the pCS20 sequence of the Crystal Springs E. ruminantium(More)