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At least 919 records · Page 51Linked to original sources
PubMed1989

Seroepidemiology of Anaplasma marginale in white-tailed deer (Odocoileus virginianus) from Louisiana.

Antibodies to Anaplasma marginale were detected by the indirect fluorescent antibody test (IFA) in six of 331 (2%) serum samples of white-tailed deer (Odocoileus virginianus) from Louisiana. None of the serum samples were positive using the A. marginale modified rapid card agglutination test. Of the six IFA positive sera retested by the complement fixation test four sera gave anticomplementary and two gave seropositive reactions. The low A. marginale reactor rate in this white-tailed deer population was probably a reflection of the lack of cohabitation between cattle and deer and the fact that the primary arthropod vectors in Louisiana are tabanids. The validity of the indirect fluorescent antibody test for A. marginale antibodies in white-tailed deer should be evaluated.

Agglutination Tests↗
PubMed1991

Serologic survey for selected microbial pathogens in bison from Kansas.

A serologic survey was conducted on an American bison (Bison bison) herd in Kansas for antibodies against Brucella spp., Leptospira interrogans serovar canicola, pomona, grippotyphosa, icterohaemorrhagiae, and hardjo, Anaplasma spp., bluetongue virus, infectious bovine rhinotracheitis virus and bovine viral diarrhea virus. There was an increase in prevalence of bluetongue antibodies from 38% in 1987 to 100% in 1989 in animals greater than or equal to 24-mo-old. Prevalences of antibodies against the other livestock pathogens were either negative or at levels associated with previous vaccination.

Anaplasmosis↗
PubMed1993

A retrospective serologic survey for Anaplasma spp. infection in three bighorn sheep (Ovis canadensis) populations in California.

Using an indirect immunofluorescence assay, we determined the prevalence of Anaplasma-reactive antibody in three herds of bighorn sheep, each a different subspecies and occupying a different habitat in California (USA). Antibodies to Anaplasma spp. were identified in none of twenty California bighorn (Ovis canadensis californiana) sampled from the Mt. Baxter herd, 11 of 17 peninsular bighorn (O. canadensis cremnobates) sampled in the Santa Rosa Mountains, and all 20 desert bighorn (O. canadensis nelsoni) sampled at Old Dad Peak/Kelso Mountains. Based on an assay and an adsorption technique, the titers most likely were due to Anaplasma ovis. The presence and species of tick vectors in each of the habitats, and the presence or absence of deer or livestock were identified as factors potentially influencing seroprevalence of antibodies.

Adsorption↗
PubMed1996

Susceptibility of elk (Cervus elaphus) to experimental infection with Anaplasma marginale and A. ovis.

Anaplasma ovis was experimentally transmitted from domestic sheep to elk (Cervus elaphus) and back to splenectomized sheep. No rickettsemias were detected but serum from three of seven experimentally inoculated elk developed Anaplasma spp.-reactive antibody as measured by indirect immunofluorescence (IIF) or by the rapid card agglutination and complement fixation assays. Three elk were experimentally infected with A. marginale. The rickettsiae were detected in blood of these elk and caused disease in a splenectomized domestic bovine calf after subinoculation of blood from the elk. All three elk had positive titers with IIF. No clinical signs of illness were noted in any elk inoculated with either Anaplasma species.

Anaplasma↗
PubMed1997

Serologic survey for infectious pathogens in free-ranging American bison.

From November 1991 through March 1992, we evaluated 101 free-ranging American bison (Bison bison) from Yellowstone National Park, Wyoming (USA) for exposure to infectious organisms that commonly infect cattle. No titers were detected for bluetongue virus, bovine leukemia virus, or Campylobacter fetus in these 101 bison. Detectable antibodies occurred against Anaplasma marginale (eight of 76, 11%), bovine respiratory syncytial virus (31 of 101, 31%), bovine viral diarrhea (31 of 101, 31%), bovine herpesvirus 1 (29 of 76, 38%), Leptospira interrogans icterohaemorrhagiae (four of 101, 4%), L interrogans hardjo (seven of 101, 7%), L interrogans autumnalis (one of 101, 1%), L interrogans bratislava (seven of 101, 7%), L interrogans australis (one of 101, 1%), and parainfluenza 3 virus (27 of 75, 36%). The low antibody titers and the lack of gross lesions are evidence that while previous exposure to infectious organisms may have occurred, none appeared to have active infections.

Anaplasma↗
PubMed2006

Genetic characterization of Anaplasma ovis strains from bighorn sheep in Montana.

Wildlife reservoir species and genetic diversity of Anaplasma ovis (Rickettsiales: Anaplasmataceae) have been poorly characterized. Bighorn sheep (Ovis canadensis), captured in Montana from December 2004 to January 2005, were tested for antibodies to Anaplasma spp.; the presence of A. ovis was determined by the characterization of major surface protein msp4 sequences. Anaplasma antibodies were detected in 25/180 (14%) sampled bighorn sheep and A. ovis msp4 sequences were amplified by polymerase chain reaction (PCR) and sequenced from 9/23 (39%) of seropositive animals. All animals were negative by PCR for the related pathogens, Anaplasma phagocytophilum and Anaplasma marginale. All msp4 sequences identified in the bighorn sheep were identical and corresponded to a single A. ovis genotype that was identical to a sheep isolate reported previously from Idaho. The finding of a single genotype of A. ovis in this wild herd of bighorn sheep was in contrast to the genetic diversity reported for A. marginale in cattle herds in the western United States and worldwide. These results demonstrated that bighorn sheep may be a wildlife reservoir of A. ovis in Montana.

Anaplasma ovis↗
PubMed1998

Epidemiology of tick-borne diseases of cattle in Botshabelo and Thaba Nchu in the Free State Province.

A seroepidemiological study was conducted on 151 cattle from the Botshabelo and Thaba Nchu areas in the central Free State Province of South Africa, two areas where small scale, peri-urban cattle farming is practised. An indirect fluorescent antibody test was used to test for Babesia bigemina and B. bovis antibodies. To test for Anaplasma marginale antibodies a competitive inhibition enzyme-linked immunosorbent assay method was used. There were no significant differences in serological test results between the cattle from Botshabelo and those from Thaba Nchu. The herd (two areas combined) had an average seroprevalence of 62.42% to B. bigemina, 19.47% to B. bovis and 98.60% to A. marginale. Based on the percentage of cattle that were seropositive to B. bigemina the immune status of cattle in the Botshabelo-Thaba Nchu area is approaching a situation of endemic stability. With reference to A. marginale, the high seroprevalence is indicative of a situation of endemic stability. The occurrence of B. bovis antibodies in the cattle is difficult to explain as Boophilus microplus ticks do not occur in the area in which the study was conducted.

Anaplasma↗
PubMed1975

Propagation of Anaplasma marginale in bovine lymph node cell culture.

Anaplasma marginale was propagated in cell cultures derived from bovine lymph node (LN). Treatment of host cells with diethylaminoethyl dextran (DEAE-D) before inoculation and centrifugation of inoculum onto the monolayers resulted in significant numerical increases of A marginale. The direct fluorescent antibody technique (FAT) was used for detection of the organism in culture. The rat was combined with the standard microscopic count procedure to obtain numerical estimates of the organism in cell culture. Infection of LN cells was irregular, with some cells containing many organisms and others containing none. The organisms were dispersed or in inclusions in the cytoplasm of LN cells. Numerical increases of organisms occurred within 6 hours and these were greatest at 12 to 24 hours. After 24 hours, the organisms decreased rapidly, but small numbers of them were observed for at least 7 days. The average generation time in culture was approximately 17.1 hours.

Anaplasma↗
PubMed2001

Evolution and function of tandem repeats in the major surface protein 1a of the ehrlichial pathogen Anaplasma marginale.

The major surface protein (MSP) 1a of the ehrlichial cattle pathogen Anaplasma marginale, encoded by the single-copy gene msp1alpha, has been shown to have a neutralization-sensitive epitope and to be an adhesin for bovine erythrocytes and tick cells. msp1alpha has been found to be a stable genetic marker for the identification of geographic isolates of A. marginale throughout development in acutely and persistently infected cattle and in ticks. The molecular weight of MSP1a varies among geographic isolates of A. marginale because of a varying number of tandemly repeated peptides of 28-29 amino acids. Variation in the sequence of the tandem repeats occurs within and among isolates, and may have resulted from evolutionary pressures exerted by ligand-receptor and host-parasite interactions. These repeated sequences include markers for tick transmissibility that may be important in the identification of ehrlichial pathogens because they may influence control strategies and the design of subunit vaccines.

Amino Acid Sequence↗
PubMed1975

Morphologic alterations of Anaplasma marginale in calves after treatment with oxytetracycline.

The morphologic features of Anaplasma marginale were determined after treatment of infected calves with oxytetracycline. By light microscopy, anaplasma bodies in erythrocytes of treated calves were enlarged and vacuolated, small and dense, or comma shaped. Several degenerated forms of anaplasma bodies were observed by electron microscopy. There was a blending of the 2 membranes surrounding initial bodies, aggregation of nucleoprotein at the periphery of the subunit, and vacuolation. A 2nd form of degeneration was coalescence of subunits in marginal bodies. A 3rd form of degeneration was unification of subunits of anaplasma bodies and clumping of nucleoprotein. A 4th form of degeneration was the persistence of an anaplasma body as a solitary, irregularly shaped mass containing electron-opaque clumps.

Anaplasma↗
PubMed2002

Applications of a cell culture system for studying the interaction of Anaplasma marginale with tick cells.

A cell culture system for the tick-borne rickettsia Anaplasma marginale offers new opportunities for research on this economically important pathogen of cattle. A. marginale multiplies in membrane-bound inclusions in host cells. Whereas erythrocytes appear to be the only site of infection in cattle, A. marginale undergoes a complex developmental cycle in ticks and transmission occurs via the salivary glands during feeding. We recently developed a cell culture system for A. marginale using a cell line derived from embryos of Ixodes scapularis. Here we review the use of this cell culture system for studying the interaction of A. marginale with tick cells. Several assays were developed using the A. marginale/tick cell system. An adhesion assay was developed for the identification of proteins required by A. marginale for adhesion to tick cells. The effect of antibodies against selected major surface proteins in inhibiting A. marginale infection was tested in an assay that allowed further confirmation of the role of surface proteins in the infection of tick cells. A drug screening assay for A. marginale was developed and provides a method of initial drug selection without the use of cattle. The culture system was used to test for enhancing effects of tick saliva and saliva components on A. marginale infection. The tick cell culture system has proved to be a good model for studying A. marginale-tick interactions. Information gained from these studies may be applicable to other closely related tick-borne pathogens that have been propagated in the same tick cell line.

Anaplasma↗
PubMed2002

Multiple infection in bovines from the tropics: observation of blood parasites by scanning and transmission electron microscope.

Blood samples from a splenectomized bovine, experimentally inoculated with blood from a field cow living in southwestern Venezuela, were processed for transmission and scanning electron microscopy. The blood sample showed multiple infection with hemoparasites of the genera Anaplasma marginale, Eperythrozoon wenyonii and Trypanosoma vivax. Scanning electron microscope showed that the blood from bovines with multiple infection had profound deformation in knob-like protruding structures with reduced cellular volume similar to echinocyte red blood cells. E. wenyonii parasites appear associated with the membrane, grouped in shallow to severe invaginations at the surface of the erythrocytes. The morphology of the parasites is predominantly rod-like; they also appear as coccoid-shaped and bifurcate or triskelion-shaped organisms. The organisms are present in pairs or clusters. T. vivax appeared with double flagella, which indicates active cellular division and infection processes. Transmission electron microscope study showed erythrocytes infected with intracytoplasmic bodies of A. marginale and with E. wenyonii embedded in the external membrane cell, with mature, juvenile and dividing forms present.

Anaplasma↗