Publications by authors named "Antoinette Josemans"

Theileria parva are intracellular protozoal parasites responsible for three disease syndromes in cattle, namely East Coast fever (ECF), Corridor disease (CD) and Zimbabwean theileriosis. The increase in reports of CD outbreaks in recent years has raised questions about the probability of adaptation of buffalo-derived T. parva strains in cattle herds adjacent to game reserves.

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parasites commonly infect African wild artiodactyls. In rare roan () and sable () antelopes, sp. (sable)-associated calf mortalities constrain breeding programs.

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is a protozoan parasite transmitted by the brown-eared ticks, and . Buffaloes are the parasite's ancestral host, with cattle being the most recent host. The parasite has two transmission modes namely, cattle-cattle and buffalo-cattle transmission.

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Heartwater is an economically important tick-borne disease of ruminants in Africa. The current commercial vaccine uses live Ehrlichia ruminantium from blood of infected sheep, requires antibiotic treatment during infection, needs to be administered intravenously and does not protect against all South African isolates. An attenuated tissue culture vaccine not requiring antibiotic treatment and effective against different field strains in small groups of goats and sheep was reported previously.

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Three isolates of Ehrlichia ruminantium (Kümm 2, Omatjenne and Riverside), the causative agent of heartwater in domestic ruminants, were isolated in Ixodes scapularis (IDE8) tick cell cultures using the leukocyte fraction of infected sheep blood. All stocks were successfully propagated in IDE8 cells, whereas initiation attempts using endothelial cell cultures were unsuccessful. Therefore, the new technique should be included in any attempt to isolate field strains of E.

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Theileriosis is a tick-borne disease caused by intracellular protozoa of the genus Theileria. The most important species in cattle are Theileria annulata and Theileria parva. Both species transform leucocyte host cells, resulting in their uncontrolled proliferation and immortalization.

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The are apicomplexan parasites transmitted by ticks to vertebrate hosts. Most species exhibit some form of host or vector specificity, since under endemic conditions only a limited number of tick species act as vectors and not all vertebrate hosts are able to maintain a persistent carrier state. Data for sp.

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Tick-borne diseases caused by Theileria are of economic importance in domestic and wildlife ruminants. The majority of Theileria infects a limited number of host species, supporting the concept of host specificity. However, some Theileria seem to be generalists challenging the host specificity paradigm, such as Theileria sp.

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Article Synopsis
  • - Canine leishmaniasis, caused by Leishmania protozoa and transmitted by sandflies, is an exotic disease in South Africa, affecting dogs, humans, and wildlife.
  • - A risk assessment study aimed to evaluate the probability of this disease entering South Africa through imported dogs, identifying 11 risk factors and analyzing data on diagnostic tests from 44 exporting countries.
  • - The study found a moderate risk of Leishmania introduction and suggested risk mitigation strategies, including wildlife surveillance and monitoring of sandfly populations, due to reported cases in neighboring regions.
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Quantitative real-time PCR assays previously developed for the detection of Theileria equi and Babesia caballi, were combined in a single multiplex TaqMan qPCR platform for the simultaneous detection of both heamoprotozoan parasites in equids. The multiplex equine piroplasmosis (M-EP) qPCR assay was shown to be efficient and specific. The detection limit was determined to be 1.

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The use of bioinformatics tools to search for possible vaccine candidates has been successful in recent years. In an attempt to search for additional vaccine candidates or improve the current heartwater vaccine design, a genome-wide transcriptional profile of E. ruminantium (Welgevonden strain) replicating in bovine endothelial cells (BA886) and Ixodes scapularis embryonic tick cells (IDE8) was performed.

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Ehrlichia canis, the etiologic agent of canine ehrlichiosis, is an obligate intracytoplasmic Gram-negative tick-borne bacterium belonging to the Anaplasmataceae family. E. canis is distributed worldwide and can cause serious and fatal infections in dogs.

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A real-time PCR assay based on TaqMan probe chemistry was developed for the detection of Theileria parva DNA in blood samples. It uses a Theileria genus-specific PCR primer set and a T. parva-specific probe to amplify and hybridize with a species-specific part of the 18S rRNA gene of the parasite.

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Here we describe the in vitro isolation, propagation, and characterization of a Theileria species from roan antelope (Hippotragus equinus). Cultures were initiated using parts of a prescapular lymph node of an infected roan antelope. After 16 days of culture propagation, the first subculture was carried out; thereafter, subcultures were carried out twice a week.

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Mononuclear cells were isolated from the peripheral blood of a buffalo infected with a Theileria sp. using density gradient centrifugation, and the cells were put into culture flasks covered by a monolayer of bovine endothelial cells. Twenty days after culture initiation, cells containing macroschizonts were detected in Giemsa-stained smears.

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The attenuated Ehrlichia ruminantium (Welgevonden) stock provides protection against a virulent homologous needle challenge in Merino sheep and Boer goats against heartwater. In this study, cryopreserved stabilates were tested for their suitability as a vaccine in Merino sheep. Vaccination did not produce disease and upon challenge with the virulent homologous stock all animals were fully protected.

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Heartwater is a tick-borne disease of ruminants caused by the intracellular rickettsia Ehrlichia ruminantium. The only commercially available immunization procedure involves infecting animals with cryopreserved sheep blood containing virulent E. ruminantium organisms, followed by treatment with tetracyclines when fever develops.

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Heartwater, a tick-borne disease of domestic and wild ruminants, is caused by the intracellular rickettsia Ehrlichia ruminantium (previously known as Cowdria ruminantium). It is a major constraint to livestock production throughout subSaharan Africa, and it threatens to invade the Americas, yet there is no immediate prospect of an effective vaccine. A shotgun genome sequencing project was undertaken in the expectation that access to the complete protein coding repertoire of the organism will facilitate the search for vaccine candidate genes.

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An effective culture system for Ehrlichia (Cowdria) ruminantium comb. nov. was first established in 1985 and many stocks were subsequently isolated and propagated in vitro.

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