It is caused by ehrlichia ruminantium formerly cowdria ruminantium an intracellular gramnegative coccal bacterium also referred to as rickettsia ruminantium. Isolation and transmission of cowdria ruminantium causal agent of heartwater disease in blue nile province, sudan. Translocation of 10 serologically negative goats from tete to farms in the south resulted in. Due to the presence of competent tick vectors in north. The pattern of outcome measures incidence, casefatality and. Ehrlichia ruminantium is the causal agent of heartwater, a fatal tropical disease affecting ruminants with important economic impacts. Ehrlichia ruminantium formerly cowdria ruminantium. Ehrlichia ruminantium an overview sciencedirect topics. Classification of the causative agent ehrlichia ruminantium formerly cowdria ruminantium order rickettsiales, family anaplasmataceae small, gram negative, pleomorphic coccus, and obligate intracellular parasite.
It occurs in colonies or morulae with a predilection for the vascular endothelium and stains blue with giemsa stain. Here, an indirect elisa based on purified antigen, a competitive elisa using a recombinant major antigenic protein map. Pcr sensitivity varied with tick infection intensity and was high. We identified polymorphic immunodominant antigens by elisa and immunoblot. Pdf diagnosis of ehrlichia ruminantium in ruminants in central. Cowdria ruminantium was isolated from plasma of clinically affected. 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. Sequence heterogeneity of the major antigenic protein 1. Heartwater was diagnosed in sheep at the umm banein livestock research station, blue nile province, sudan. Heartwater, or cowdriosis, is a tickborne disease of domestic and wild ruminants that is endemic in the caribbean and subsaharan africa.
Downloaddescargar libro dibujo tecnico basico henry cecil spencer. Everyday low prices and free delivery on eligible orders. 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. Mahan 1998 growth of cowdria ruminantium in tissue culture endothelial cell lines from wild african mammals. Evaluation of several flow cytometric assays for the. Detection of antibodies to cowdria ruminantium in the serum of domestic ruminants by indirect elisa martinez d.
Google scholar jongejan f, morzaria sp, shariff oa, abdalla hm. Efficient highthroughput molecular method to detect ehrlichia. Arecombinant antigen fromtheheartwater agent cowdria ruminatium reactive withantibodies insome southeastern united states whitetailed deer odocoileus virginianus, butnotcattle, sera jonathan b. One group was infected on multiple occasions with c. Current status of in vitro cultivation of cowdria ruminantium. Ehrlichia cowdria ruminantium is a gramnegative, intracellular rickettsial organism in the order of rickettsiales. Ehrlichia ruminantium in amblyomma variegatum and domestic. Apparently organisms initially develop in the gut epithelial cells of ticks and subsequent stages of c. 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 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. 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. The purification of cowdria ruminantium is important for severa reasons. Ehrlichia formerly cowdria ruminantium is a rickettsial bacterium family anaplasmataceae, order rickettsiales. Pdf a mathematical model of the transmission dynamics of cowdria ruminantium by. Ehrlichia ruminantium formerly cowdria ruminantium is a tickborne rickettsial pathogen that infects cattle, causing heartwater or cowdriosis. The processes described are supported by empirical data. Onderstepoort journal ofveterinary research, 54, 303 1987 criteria th. Production of alpha interferon in cowdria ruminantium. A flock of 152 breeding ewes was randomly divided into two matched groups. Detection of cowdria ruminantium by means of a dna probe.
Development of an in vitro cloning method for cowdria. Cowdria ruminantium was isolated from sheep by subinoculation of blood into a goat. 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. A cowdria ruminantium genomic dna library was constructed in the expression vector lambda zapii, and an immunoreactive clone, designated lambda cr9. The prevalence of cowdria ruminantium in freeliving adult amblyomma hebraeum collected at a communal grazing area and in 2 wildlife reserves in south africa. Diversity of ehrlichia ruminantium major antigenic protein. Fcmbased methods to measure cowdriainduced lymphoblastogenesis, dna synthesis, and interleukin2 receptor il2r expression by tcell subsets were compared. Heartwater cowdria ruminantium infection as a cause of postrestocking mortality of goats in mozambique cornelis p. Heartwater also known as cowdriosis, nintas, and ehrlichiosis is a tickborne rickettsial disease of domestic and wild ruminants. 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. 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. 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.
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. Cowdria ruminantium is the cause of a serious tickborne disease of domestic ruminants, known as heartwater or cowdriosis. Cowdria ruminantium is a tickborne rickettsia which causes severe disease in ruminants. Detection of cowdria ruminantium in blood and bone marrow. The effect of subclinical experimental cowdria ruminantium. Ehrlichia ruminantium major antigenic protein gene map1. 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. Translocation of 10 serologically negative goats from tete to farms in the south resulted in two clinical cases of heartwater that. Cowdria ruminantium causes severe, often fatal disease in domestic ruminants, whereas wildlife species usually are not affected. Ehrlichia ruminantium, ticks, pcs20, automated dna extraction. The tickborne rickettsia cowdria ruminantium has a chlamydialike developmental cycle. Here, we further assessed the reliability of the pcr assay and applied it to field ticks. Molecular evidence led to reclassification of several organisms in the order rickettsiales, and it is now classified as ehrlichia ruminantium. The immunodominant 32kilodalton protein of cowdria ruminantium is conserved within the genus ehrlichia.
Multilocus sequence typing of ehrlichia ruminantium strains from. Heartwater is a ticktransmitted disease of ruminants caused by ehrlichia ruminantium. Under natural conditions, e ruminantium is transmitted by amblyomma ticks. Heartwater caused by cowdria ruminantium infection is the most important tickborne disease of ruminants in southern africa. 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. Detection of the agent of heartwater, cowdria ruminantium. The organism belongs to the tribe ehrlichieae, which contains obligate intracellular pathogens, causing several important animal and human diseases. A chemically defined medium for the growth of cowdria. Development and persistence of cowdria ruminantium. Heartwater cowdria ruminantium infection as a cause of. A serological survey in mozambique to detect antibodies to cowdria ruminantium, the etiologic agent of heartwater, revealed a seroprevalence of 8.
Serological tests for cowdria ruminantium infection have been hampered by low specificity. Genome size and genetic map of 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. Different vaccines with various efficacies have been produced. 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.
A glycosylated recombinant subunit candidate vaccine. Investigating the epidemiology of heartwater cowdria. Various aspects of the development and life cycle of cowdria ruminantium are discussed. No ticks were obtained from grenada and puerto rico, islands regarded to be free of a. 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. 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. Cowdria ruminantium pdf ehrlichia ruminantium formerly cowdria ruminantium. The assay did not detect dna of ehrlichia chaffeensis, which is closely related to c.
Nitric oxide is produced by cowdria ruminantiuminfected. The disease is spread by bont ticks, which are members of the genus amblyomma. 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. Pdf investigating the epidemiology of heartwater cowdria. Mahan 1, 2 1 university of floridausaidsadc heartwater research project, p. Production of alpha interferon in cowdria ruminantiuminfected cattle and its effect on infected endothelial cell cultures. Ehrlichia ruminantium is the causal agent of heartwater, a ruminant. Cowdria ruminantium, heartwater, epidemiology, transmission modelling, endemic stability. Sequencing of the insert from this clone revealed two open reading frames, encoding peptides of 10462 and 58697 kda respectively. 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. Electron microscopy of cowdria rickettsia ruminantium cowdry, in the endothelial cells of the vertebrate host. Characterization of variable immunodominant antigens of.
A cowdria ruminantium genomic dna library was constructed in the expression vector. A chemically defined medium for the growth of cowdria ruminantium. This organism is pleomorphic, measuring from 400 to more than 1,000 nm diameter. 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.
Endothelial cell cultures were established from several wild african mammalian species. Your use of this pdf, the bioone complete website, and all posted and associated content indicates. Detection of antibodies to cowdria ruminantium 2 of. 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. 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. Ehrlichia ruminantium, amblyomma variegatum, heartwater, caribbean, west indies.
Using serum from a goat immune to the gardel stock of cowdria isolated in guadeloupe adsorbed on antigen of. Ehrlichia ruminantium is an obligate intracellular bac. The rickettsial bacterium ehrlichia ruminantium is the causative agent of heartwater in ruminants. The disease affects cattle, sheep and goats, and also some. Organism heartwater epidemiologyhidrocarditis infecciosa.
Pdf the objective of this study was to determine the prevalence of ehrlichia ruminantium causative agent of heartwater disease in. 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. Adultamblyomma lepidum ticks fed as nymphs on this goat transmitted heartwater to a friesian bos taurus calf. Pdf the prevalence of cowdria ruminantium in freeliving. Amblyomma variegatum, the tropical bont tick, occurs widely in africa and was introduced into the caribbean in the early 1800s uilenberg et al. Pdf an immunoblotting diagnostic assay for heartwater. The causative organism is an obligate intracellular parasite, previously known as cowdria ruminantium. Isolation and transmission of cowdria ruminantium causal. Small, gram negative, pleomorphic coccus, and obligate.