Electron microscopy of cowdria rickettsia ruminantium cowdry, in the endothelial cells of the vertebrate host. Efficient highthroughput molecular method to detect ehrlichia. Detection of cowdria ruminantium in blood and bone marrow. Here, an indirect elisa based on purified antigen, a competitive elisa using a recombinant major antigenic protein map. Arecombinant antigen fromtheheartwater agent cowdria ruminatium reactive withantibodies insome southeastern united states whitetailed deer odocoileus virginianus, butnotcattle, sera jonathan b. Ehrlichia ruminantium in amblyomma variegatum and domestic. A serological survey in mozambique to detect antibodies to cowdria ruminantium, the etiologic agent of heartwater, revealed a seroprevalence of 8. Nitric oxide is produced by cowdria ruminantiuminfected.
The cowdria ruminantium groe operon microbiology society. Isolation and transmission of cowdria ruminantium causal agent of heartwater disease in blue nile province, sudan. The causative organism is an obligate intracellular parasite, previously known as cowdria ruminantium. Efficient highthroughput molecular method to detect. Nitric oxide no is a labile inorganic free radical produced by no synthase from the substrate larginine in various cells and tissues including endothelial cells. Isolation and transmission of cowdria ruminantium causal. Serological tests for cowdria ruminantium infection have been hampered by low specificity. Molecular evidence led to reclassification of several organisms in the order rickettsiales, and it is now classified as ehrlichia ruminantium. The assay did not detect dna of ehrlichia chaffeensis, which is closely related to c. Production of alpha interferon in cowdria ruminantiuminfected cattle and its effect on infected endothelial cell cultures. Pdf a mathematical model of the transmission dynamics of cowdria ruminantium by.
Detection of antibodies to cowdria ruminantium in the serum of domestic ruminants by indirect elisa martinez d. Everyday low prices and free delivery on eligible orders. Cowdria ruminantium pdf ehrlichia ruminantium formerly cowdria ruminantium. Cowdria ruminantium is the cause of a serious tickborne disease of domestic ruminants, known as heartwater or cowdriosis. A dna probe, pcs20, previously described for use in detection of cowdria ruminantium infections in amblyomma variegatum the principal vector of heartwater hybridized with c. A cowdria ruminantium genomic dna library was constructed in the expression vector lambda zapii, and an immunoreactive clone, designated lambda cr9. Ehrlichia ruminantium formerly cowdria ruminantium is a tickborne rickettsial pathogen that infects cattle, causing heartwater or cowdriosis.
Ehrlichia ruminantium, amblyomma variegatum, heartwater, caribbean, west indies. Cowdria ruminantium was isolated from sheep by subinoculation of blood into a goat. Heartwater cowdriosis is a tickborne disease of cattle, sheep, goats and some wild ruminants that is caused by a rickettsia, ehrlichia ruminantium, previously known as cowdria ruminantium. Genome size and genetic map of cowdria ruminantium. Cowdria ruminantium, heartwater, epidemiology, transmission modelling, endemic stability. Initially the tick was confined to guadeloupe, antigua, and marie galante, but in 1948 it invaded martinique and subsequently spread to 14 other islands barre et al. Fcmbased methods to measure cowdriainduced lymphoblastogenesis, dna synthesis, and interleukin2 receptor il2r expression by tcell subsets were compared. Pdf investigating the epidemiology of heartwater cowdria. This bacterium is transmitted by amblyomma ticks and is present in subsaharan africa, islands in the indian ocean and the caribbean, where it represents a threat to the american mainland. Heartwater was diagnosed in sheep at the umm banein livestock research station, blue nile province, sudan. The disease affects cattle, sheep and goats, and also some. Heartwater cowdria ruminantium infection as a cause of.
Ehrlichia cowdria ruminantium is a gramnegative, intracellular rickettsial organism in the order of rickettsiales. Heartwater is a ticktransmitted disease of ruminants caused by ehrlichia ruminantium. Ehrlichia ruminantium is the causal agent of heartwater, a ruminant. A immunoblots of 30 cattle sera mashona from a heartwaterfree area of zimbabwe banket where minimal tick control is practiced show frequent reaction with the 32. We have previously reported that the pcs20 pcr detection assay for cowdria ruminantium, the causative agent of heartwater disease of ruminants, is more sensitive than xenodiagnosis and the pcs20 dna probe for the detection of infection in the vector amblyomma ticks. Multilocus sequence typing of ehrlichia ruminantium strains from. The effect of subclinical experimental cowdria ruminantium. A glycosylated recombinant subunit candidate vaccine. It is caused by ehrlichia ruminantium formerly cowdria ruminantium an intracellular gramnegative coccal bacterium also referred to as rickettsia ruminantium. It causes high mortalities in sheep, goats, and cattle and is of major economic importance to livestock production and development in subsaharan africa and on several caribbean islands 28, 36, 44. Ehrlichia ruminantium major antigenic protein gene map1. Development and persistence of cowdria ruminantium. Ehrlichia ruminantium is the causal agent of heartwater, a fatal tropical disease affecting ruminants with important economic impacts. Onderstepoort journal ofveterinary research, 54, 303 1987 criteria th.
Endothelial cell cultures were established from several wild african mammalian species. The disease is spread by bont ticks, which are members of the genus amblyomma. Mahan 1, 2 1 university of floridausaidsadc heartwater research project, p. Production of alpha interferon in cowdria ruminantium. The disease is caused by an intracellular pathogen, ehrlichia ruminantium and may be fatal within days of the onset of clinical signs with mortality rates of up to 90% in susceptible hosts. Ehrlichia formerly cowdria ruminantium is a rickettsial bacterium family anaplasmataceae, order rickettsiales.
Heartwater also known as cowdriosis, nintas, and ehrlichiosis is a tickborne rickettsial disease of domestic and wild ruminants. Investigating the epidemiology of heartwater cowdria. Tthe in vitro culture system for this rickettsia, developed less than a decade ago, is responsible for the great majority of research accomplishments currently being reported in the areas of epidemiology, diagnosis and control of heartwater. This study documented the effect on the productivity of dorpermerino cross ewes when they became infected with cowdria ruminantium as would occur in an endemically stable state. One group was infected on multiple occasions with c. We identified polymorphic immunodominant antigens by elisa and immunoblot. Detection of the agent of heartwater, cowdria ruminantium. Heartwater also known as cowdriosis is an acute, fatal, noncontagious, infectious, tickborne rickettsial disease of ruminants caused by ehrlichia ruminantium formerly cowdria ruminantium and transmitted by amblyomma ticks.
Sequencing of the insert from this clone revealed two open reading frames, encoding peptides of 10462 and 58697 kda respectively. Heartwaterexposed cattle were widespread on the ranch and overall seroprevalence was use of a specific immunogenic region on the cowdria ruminantium map1 protein in a serological assay. Ehrlichia ruminantium an overview sciencedirect topics. The prevalence of cowdria ruminantium in free living adult amblyomma hebraeum collected at a communal grazing area and in 2 wildlife reserves in south africa. Blood and bone marrow samples from healthy, freeranging zimbabwean ungulates were taken during translocation from areas harboring amblyomma ticks and tested for the presence of c. Development of an in vitro cloning method for cowdria. The immunodominant 32kilodalton protein of cowdria ruminantium is conserved within the genus ehrlichia. Ehrlichia ruminantium formerly cowdria ruminantium. Evaluation of several flow cytometric assays for the. Google scholar jongejan f, morzaria sp, shariff oa, abdalla hm. Cowdria ruminantium was isolated from plasma of clinically affected. It occurs in colonies or morulae with a predilection for the vascular endothelium and stains blue with giemsa stain. Organism heartwater epidemiologyhidrocarditis infecciosa. Various aspects of the development and life cycle of cowdria ruminantium are discussed.
Ehrlichia ruminantium, ticks, pcs20, automated dna extraction. A chemically defined medium for the growth of cowdria ruminantium. Sequence heterogeneity of the major antigenic protein 1. Cowdria ruminantium causes severe, often fatal disease in domestic ruminants, whereas wildlife species usually are not affected. The prevalence of cowdria ruminantium in freeliving adult amblyomma hebraeum collected at a communal grazing area and in 2 wildlife reserves in south africa. Under natural conditions, e ruminantium is transmitted by amblyomma ticks. Heartwater, or cowdriosis, is a tickborne disease of domestic and wild ruminants that is endemic in the caribbean and subsaharan africa. The purification of cowdria ruminantium is important for severa reasons. Cowdria ruminantium is a tickborne rickettsia which causes severe disease in ruminants. Downloaddescargar libro dibujo tecnico basico henry cecil spencer. Pdf the prevalence of cowdria ruminantium in freeliving. Detection of cowdria ruminantium by means of a dna probe. Due to the presence of competent tick vectors in north.
A cowdria ruminantium genomic dna library was constructed in the expression vector. There was a problem providing the content you requested these data, which are consistent with a smaller immunofluorescencebased survey 3suggest a considerable difference in exposure to c. Apparently organisms initially develop in the gut epithelial cells of ticks and subsequent stages of c. Adultamblyomma lepidum ticks fed as nymphs on this goat transmitted heartwater to a friesian bos taurus calf. Longterm cultures were established from three ruminants, sable antelope hippotragus niger, buffalo syncerus caffer, and eland tragelaphus oryx, and from an omnivore, the bushpig potamochoerus porcus. Mahan 1998 growth of cowdria ruminantium in tissue culture endothelial cell lines from wild african mammals. Characterization of variable immunodominant antigens of. Amblyomma variegatum, the tropical bont tick, occurs widely in africa and was introduced into the caribbean in the early 1800s uilenberg et al. Pdf diagnosis of ehrlichia ruminantium in ruminants in central. Pcr sensitivity varied with tick infection intensity and was high. Pdf the objective of this study was to determine the prevalence of ehrlichia ruminantium causative agent of heartwater disease in. The pattern of outcome measures incidence, casefatality and. Current status of in vitro cultivation of cowdria ruminantium.
No ticks were obtained from grenada and puerto rico, islands regarded to be free of a. Small, gram negative, pleomorphic coccus, and obligate. A chemically defined medium for the growth of cowdria. Different breeds of cattle were experimentally infected with palm river, a zimbabwean isolate, or ball3, a south african isolate of cowdria ruminantium, derived from tissue culture or tick or blood stabilates. Ehrlichia ruminantium is an obligate intracellular bac.
Lopes pereira,3 wendela wapenaar,2 afonso langa,3 and frans jongejan2,4 division of bacteriology1 and division of parasitology and tropical veterinary medicine,2 department of infectious diseases. Pdf an immunoblotting diagnostic assay for heartwater. The processes described are supported by empirical data. The rickettsial bacterium ehrlichia ruminantium is the causative agent of heartwater in ruminants. Heartwater caused by cowdria ruminantium infection is the most important tickborne disease of ruminants in southern africa. The tickborne rickettsia cowdria ruminantium has a chlamydialike developmental cycle. 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. A substantial elevation of nitrite levels indicative of no production occurred in cultures of cowdria ruminantium infected bovine pulmonary endothelial cells bpec incubated in medium alone. A mathematical model of the transmission dynamics of cowdria ruminantium by the ixodid tick amblyomma hebraeum in the bovine host is developed and used to investigate the epidemiology of heartwater across a range of vector challenge. Translocation of 10 serologically negative goats from tete to farms in the south resulted in.
This organism is pleomorphic, measuring from 400 to more than 1,000 nm diameter. Diversity of ehrlichia ruminantium major antigenic protein. Heartwater cowdria ruminantium infection as a cause of postrestocking mortality of goats in mozambique cornelis p. The disease is widespread in most of subsaharan africa and on several islands in the caribbean, where it is a serious constraint to animal production. Different vaccines with various efficacies have been produced.
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