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At least 1,063 records · Page 59Linked to original sources
PubMed1978

Bovine abortion associated with Anaplasma marginale.

During the period from June 1974 to June 1975, five bovine fetuses between seven to nine months old were received for necropsy from four different counties of the S. Paulo State, Brazil. All of them were from brucellosis-free herds. Necropsy revealed slight liver enlargement generally accompanied by capsular petechial hemorrhages. Enlargement and congestion of the spleen, epicardial and endocardial petechiae were present in three fetuses and one of them had lungs with some hemorrhagic lobules. Cardiac blood films of all the fetuses stained by the Pappenheim's panoptic method showed Anaplasma marginale in two to 20% of red corpuscles. When stained with acridine orange and immunofluorescent methods blood films of the first fetus specifically showed A. marginale.

Abortion, Spontaneous↗
PubMed1984

Immune serum against Anaplasma marginale initial bodies neutralizes infectivity for cattle.

The first demonstration of immune serum-mediated neutralization of Anaplasma marginale and identification of the involved surface antigens is presented. Anaplasma marginale initial bodies were purified from parasitized erythrocytes by using ultrasonic disruption and differential centrifugation. The initial bodies were morphologically intact, as determined by electron microscopy, were not agglutinated by anti-bovine erythrocyte sera, and were infective. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated minimal erythrocytic contamination in the purified initial bodies. Rabbit antisera against initial bodies completely neutralized the infectivity of purified initial bodies for splenectomized calves, whereas normal rabbit serum did not alter infectivity. Nine initial body proteins were surface radioiodinated by using lactoperoxidase, and five of these were precipitated by the neutralizing antibody (105,000, 86,000, 61,000, 36,000, and 31,000 apparent m.w.). The results demonstrate that initial body determinants capable of inducing neutralizing antibody are present. The identification of surface radiolabeled proteins immunoprecipitated by the neutralizing antibody provides candidates to be tested as protective immunogens in cattle.

Anaplasma↗
PubMed1978

Ultrastructure of anaplasmal inclusions (Pawhuska isolate) and their appendages in intact and hemolyzed erythrocytes and in complement-fixation antigen.

Hemolysis of parasitized erythrocytes augmented visualization of the anaplasmal inclusion, including its initial bodies, inclusion membrane, and inclusion appendage ("tail" or "band"). A dense attachment complex joined the appendage to the inclusion membrane (wall of the inclusion vacuole). The inclusion appendage consisted of tightly packed, interconnected laminae and assumed loop, dumbbell, and comet configurations described by other workers. The erythrocytic plasmalemma and the inclusion membrane had a thickness of 9.0 +/- 0.8 nm and similar structures. The initial bodies were covered by a thin inner organismic membrane (7.0 +/- 0.7 nm thick) attached to the organismic chromatin, an intermembranous matrix, and by an outer membranous sheath or pellicle (12.5 +/- 1.2 nm thick). Dense granular aggregates (24 to 40 nm in diameter) within chromatin clumps were the only structures in the initial body remotely similar to ribosomes, yet they were too large, were never free of chromatin, and appeared to disappear upon hemolysis. Complement-fixation antigen prepared by fractionation contained initial bodies, inclusion appendages, a few mitochondria, vesicularized membranes, and stromal debris. The preparatory treatment caused segregation of the organismic chromatin into independent dense particles 103 +/- 12 nm in diameter still bound by inner organismic membrane. Similar particles were seen also in the plasma and inclusion vacuoles of hemolyzed erythrocytes.

Anaplasma↗
PubMed1983

Ultrastructural aspects of intraerythrocytic development of a Venezuelan strain of Anaplasma marginale.

Blood samples from splenectomized calves infected with a Venezuelan strain of Anaplasma marginale were studied by electron microscope. A. marginale appears to invade erythrocytes by the invagination of the host cell plasma membrane. The parasite reproduces by binary or multiple fission, changing from a rounded to an irregularly polyhedral form during and after division. The mature Anaplasma, within the host red cell modifies the erythrocytes cytoplasma and external membrane producing pores through which the parasite can escape without lysing the host erythrocyte.

Anaplasmataceae↗
PubMed1983

Influence of parasitemia level at feeding on development of Anaplasma marginale Theiler in Dermacentor andersoni Stiles.

Four splenectomized dairy calves were inoculated with a Virginia isolate of Anaplasma marginale Theiler and served as an infective source (donor) for laboratory-reared Dermacentor andersoni Stiles nymphs. Two donor calves developed higher parasitemias during tick feeding than did the 2 other donor calves. One month after molting, adult ticks were incubated at 37 C for 2.5 days to stimulate development of colonies of A marginale, and homogenates of gut were made from ticks fed on each donor calf. Eight susceptible, splenectomized dairy calves (2 per donor calf) were each inoculated IV with the gut homogenates collected from 50 adult ticks and were monitored for patent A marginale infection. Gut tissues from these same groups of ticks were processed for histologic studies. Homogenates from ticks infected on donor calves with lower parasitemias caused infections with longer prepatent periods (av, 43.25 days) than did similar homogenates made from ticks infected by feeding on donor calves with higher parasitemias (av, 31.0 days). Also, sections of gut tissues from ticks infected at the lower parasitemias contained fewer (av, 0.65) colonies/0.001 mm2 of tissue examined than did those from ticks infected at higher parasitemias (av, 6.31).

Anaplasma↗
PubMed1980

Demonstration of Anaplasma marginale Theiler in ticks by tick transmission, animal inoculation, and fluorescent antibody studies.

Cattle were inoculated with a Virginia isolate of Anaplasma marginale Theiler and served as an infective source for laboratory-reared Dermacentor andersoni Stiles and D variabilis (Say) nymphs. Transstadial transmission of A marginale was demonstrated by feeding the newly molted adult ticks of both species on susceptible cattle and by inoculation of gut and salivary gland homogenates collected from adult ticks at postattachment days 5 and 7. Oral secretions collected from the same group of ticks and inoculated into a susceptible cow did not cause infection. Fluorescent antibody studies of infected tick gut and salivary glands were positive, although smears of tick oral secretions were negative for fluorescence.

Anaplasma↗
PubMed1982

Influence of increased temperature on Anaplasma marginale Theiler in the gut of Dermacentor andersoni stiles.

Three splenectomized dairy calves were inoculated with a Virginia isolate of Anaplasma marginale Theiler and served as an infective source for laboratory-reared Dermacentor andersoni Stiles nymphs. One month after molting, groups of adult ticks were incubated at 37 C for 0, 1.5, 2.5, and 7 days. Gut homogenates were made from ticks representing each incubation period. Twenty-four susceptible, splenectomized dairy calves were each inoculated IV with a gut homogenate extracted from 50 adult ticks and monitored for patent A marginale infection. The prepatent periods were determined and used as a measure of infectivity. Gut homogenates made from ticks that had been incubated for 2.5 days produced infections with the shortest prepatent periods, an average of 28.5 days among 3 trials.

Anaplasma↗
PubMed1982

Serologic evidence of Anaplasma marginale infection in Illinois white-tailed deer.

A total of 175 deer and 54 cattle from Crab Orchard National Wildlife Refuge in southern Illinois were tested for antibody to Anaplasma marginale, using the capillary tube agglutination test. A total of 12 (6.9%) deer and 7 (13%) cattle were serologically positive. Serologic prevalence in deer increased from 0 at 6 months of age to 14% at 2 1/2 or more years of age. Cattle less than approximately 1 year of age were not seropositive.

Anaplasmosis↗
PubMed1982

The effect of incubation and prefeeding of infected Rhipicephalus simus nymphae and adults on the transmission of Anaplasma marginale.

Two batches of unfed Rhipicephalus simus nymphae carrying Anaplasma marginale were incubated for 72 h and 96 h respectively at 37 degrees C. Fifty ticks were triturated at a time and the homogenates were used to infect susceptible cattle. Others were prefed on a bovine host for 72 h before tick suspensions were prepared. The same procedure was followed, using a single batch of infected adult ticks. Incubation had no effect on the infectivity of the nymphal homogenates, but prefeeding of nymphae reduced the prepatent period by 8 days in 1 of the 2 attempts. In the case of the adult ticks both incubation and prefeeding reduced prepatent periods by 5 and 8 days respectively.

Anaplasmosis↗
PubMed1980

Demonstration of Anaplasma marginale Theiler in Dermacentor variabilis (Say) by ferritin-conjugated antibody technique.

Cattle were inoculated with a Virginia isolate of Anaplasma marginale Theiler and served as an infective source for laboratory-reared Dermacentor variabilis (Say) nymphs. Transstadial transmission of A marginale was demonstrated by feeding the newly molted adult ticks on susceptible cattle and by inoculation of gut homogenates collected from adult ticks at postattachment day 6. A similar gut homogenate from the same group of ticks was caused to react with A marginale-bovine antisera that had been conjugated with ferritin. The homogenate contained organisms similar to those observed in the gut of adult feeding ticks that were infected as nymphs and the labeling of the outer membrane confirmed that organisms observed were A marginale. A gut homogenate prepared from control ticks did not cause infection when inoculated into a susceptible cow and no organisms were demonstrated.

Anaplasma↗
PubMed1980

Anaplasma marginale in bovine erythrocyte cultures.

Bovine erythrocytes infected with Anaplasma marginale were standardized with normal bovine erythrocytes at 1.4% and 3.5% parasitemia and cultured under low oxygen pressure at 37 C. The number of erythrocytes infected by A marginale appeared to increase 3.3-fold by day 11 and 4.5-fold by day 3, as determined by microscopic examination of Giemsa-stained thin films of the culture suspension. Anaplasma parasites in experimental cultures were proven to be viable and pathogenic by calf inoculation for up to 16 days.

Anaplasma↗
PubMed1981

Transmission of Anaplasma marginale Theiler by Dermacentor andersoni Stiles and Dermacentor variabilis (Say).

Cattle were inoculated with a Virginia isolate of Anaplasma marginale Theiler and served as an infective source for laboratory-reared Dermacentor andersoni Stiles and D variabilis (Say) nymphs. Following a molt and subsequent feeding of adult ticks on susceptible cows, transstadial transmission of A marginale occurred from cattle with parasitemias ranging from undetectable (in a carrier cow) to a peak of 27% (in an acutely ill cow). Homogenates of gut tissue from unfed, incubated, and feeding adult ticks that were infected as nymphs were all infective; however, the prepatent period varied according to treatment of ticks after they had molted to the adult stage. Prepatent periods of infections in calves resulting from injection of homogenated tissue from unfed adult ticks was 29 and 34 days longer than the prepatent periods that developed in calves exposed to homogenated tissue from ticks that were feeding or incubated at 37 C for 3 days. Transovarial transmission did not occur when F1 larvae, hatched from eggs produced by female ticks known to be infective, fed on susceptible cattle.

Anaplasmosis↗
PubMed1981

Recrudescence of Anaplasma marginale induced by immunosuppression with cyclophosphamide.

Eight doses of cyclophosphamide (5 mg/kg), at 2-day intervals between doses, were administered IV to Anaplasma-carrier splenectomized calves. Significant decreases in serum immunoglobulins, diminished complement-fixing antibody response, and transitory leukopenia were associated with the treatment. Recrudescence of clinical Anaplasma infection occurred after the 5th dose of cyclophosphate was given and was characterized by rapid increase in parasitemia, marked decrease in PCV, and mortality. The results of the present study indicated that humoral mediated immunity may contribute to the maintenance of a state of equilibrium in the host-parasite relationship and that suppression of humoral immune responses may alter the course and outcome of infection in Anaplasma carriers.

Anaplasmosis↗
PubMed1980

Isolation of Anaplasma marginale from Rhipicephalus simus males.

Approximately 100 adult Rhipicephalus simus from a batch known to be infected with Anaplasma marginale were used to infest an ox. Fifty male ticks were manually removed from the animal's ears 9 days after infestation. These ticks were triturated and a stabilate was prepared which was injected intravenously into 2 susceptible oxen. Both these animals became infected with A. marginale. The prepatent periods following inoculation of the tick suspensions before and after freezing in liquid nitrogen were 16 and 17 days respectively.

Anaplasma↗
PubMed1978

Serum levels of conglutinin, complement, and immunoconglutinin in cattle infected with Anaplasma marginale.

Sera from 10 splenectomized yearling cattle given massive doses of Anaplasma marginale (peracute cases) were assayed for conglutinin and complement. Sera from 5 nonsplenectomized yearling cattle given smaller doses (acute cases) were assayed for conglutinin, immunoconglutinin, and complement. In the peracute cases, conglutinating activity disappeared within 6 days after the cattle inoculated. In the acute cases, conglutining began to disappear at 3 weeks after inoculation and had disappeared at peak parasitemia at 4 weeks. Conglutinin returned by 7 weeks after inoculation. In the same acute cases, immunoconglutinain appeared at 6 weeks after inoculation and then slowly disappeared. The complement levels in the peracute and acute cases did not change appreciably.

Agglutination Tests↗