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PubMed1980

Characterization of immune responses of cattle to erythrocyte stroma, Anaplasma antigen, and dodecanoic acid-conjugated Anaplasma antigen: cell-mediated immunity.

Sonically disrupted normal erythrocyte stroma (SES) and two anaplasma antigens (sonically disrupted anaplasma antigen; SAA, and French pressure cell disrupted anaplasma antigen; FAA) were prepared from normal and Anaplasma marginale-infected blood. The SAA and FAA antigens were chemically modified by conjugation with dodecanoic acid (SAADA and FAADA). Significant (P less than or equal to 0.05) anti-anaplasma lymphocyte-transformation responses were obtained from all cattle given SAA, SAADA, or FAADA vaccines. Only cows given SAA developed anti-anaplasma antibody. Mild antierythrocyte lymphocyte-transformation responses were obtained from most vaccinated animals. Delayed hypersensitivity to erythrocyte antigen was not detected. The SAA-vaccinated cows had the highest degree of protection in that they developed a smaller percentage of parasitemia and had less severe anemia than did other cattle in the study. The SAADA- and FAADA-vaccinated cattle developed a good cell-mediated immune response, but poor humoral immune response and had lower parasitemias than did challenge-exposed controls; but they developed severe anemia. It is suggested that cellular and humoral mechanisms are essential for protection in anaplasmosis. Evidence of protection from clinical anaplasmosis was not observed in SES-vaccinated cows.

Anaplasma↗
PubMed1977

Finite purification of Anaplasma marginale: serologic inactivity of the anaplasma body.

Anaplasma bodies finitely purified by affinity chromatography to eliminate all traces of erythrocytic stromata were not agglutinated by serum from calves having acute anaplasmosis. The stromata which were associated with the anaplasma bodies were also finitely purified and agglutinated with such serum. The evidence indicates that the antibody in anaplasmosis that is detected by agglutination tests is directed against the erythrocytic stromata and not against the finitely purified anaplasma bodies.

Anaplasma↗
PubMed1996

Preliminary studies on the effect of Anaplasma marginale antibodies ingested by Dermacentor andersoni ticks (Acari:Ixodidae) with their blood meal on infections in salivary glands.

The effect of Anaplasma marginale antibodies ingested with the tick blood meal was tested on infected male ticks that were allowed to feed on cattle immunized with the erythrocytic stage of A. marginale. The experiments were done in two trials. Trial 1 was done using splenectomized calves (two calves per treated and control groups) while ticks in trial 2 were fed on intact yearling cattle (four cattle per treated and control groups). The cattle were immunized with purified outer membrane proteins of erythrocyte-derived A. marginale using saponin (trial 1) or monophosphoryl lipid-A-trehalose dicorynomycolate adjuvant (trial 2). The corresponding control cattle received adjuvant only. All cattle were challenged using Dermacentor andersoni males infected as adults that were allowed to feed for 7 days. In trial 1, the ticks were allowed to feed a second time on susceptible calves to test whether exposure of ticks to immunized cattle affected their ability to transmit anaplasmosis. Infections in fed ticks were monitored by determining the infection rates in salivary glands with an A. marginale-specific RNA probe and light microscopy. Vaccine-derived antibodies ingested with the tick blood meal did not appear to affect the development of A. marginale in previously infected ticks. The infection rates in the salivary glands were not significantly different among ticks fed on immunized versus adjuvant control cattle. When the vaccine-exposed ticks in trial 1 were allowed to feed a second time on susceptible calves, the resulting clinical symptoms of anaplasmosis were similar to those of the controls. There was no statistically significant effect of tick exposure to the anti-erythrocytic stage antibody on the development of salivary gland infection or transmission of A. marginale by ticks.

Anaplasma↗
PubMed2006

Differences in the transmissibility of two Anaplasma phagocytophilum strains by the North American tick vector species, Ixodes pacificus and Ixodes scapularis (Acari: Ixodidae).

The etiologic agent of granulocytic anaplasmosis, Anaplasma phagocytophilum, has a circum-global distribution within the northern hemisphere and shows a host species predilection that varies by the geographic region in which the disease is found. Adaptation by the bacterium to a host species potentially contributes to the variation found worldwide but this is confounded by the bacterium's relationship with its tick vectors, all of which belong to the Ixodes ricinus group. We tested the hypothesis that tick vector species collected from geographic regions sympatric with particular A. phagocytophilum strains will show evidence of a higher degree of vector competence than will tick species and allopatric A. phagocytophilum strains. A reciprocal cross-transmission experiment was performed using an eastern and a western North American strain of A. phagocytophilum (Webster and MRK, respectively) and the two tick species, I. scapularis and I. pacificus, most commonly associated with human and animal transmission of the bacteria in the United States. The western tick, I. pacificus, showed a significantly higher vector competence for A. phagocytophilum than I. scapularis and the eastern isolate, Webster, was more transmissible than its western counterpart, MRK. These results indicate that geographic variation in host susceptibility to A. phagocytophilum strains may play a more important role in the epidemiology of granulocytic anaplasmosis than does the competence of its tick vectors to transmit the pathogen.

Anaplasma phagocytophilum↗
PubMed2005

Epidemiological aspects and economic impact of bovine theileriosis (East Coast fever) and its control: a preliminary assessment with special reference to Kibaha district, Tanzania.

A cross-sectional study based on clinical examination, inspection of herd health records and a questionnaire was designed to determine the epidemiology, economics and potential impact of immunisation against theileriosis in Tanzania. The results showed annual theileriosis costs to be US$ 205.40 per head, whereas the introduction of immunisation reduced this by 40-68% depending on the post immunisation dipping strategy adopted. Morbidity risk due to theileriosis was 0.048 in immunised and 0.235 in non-immunised cattle, and the difference was significant (chi(2)=66.7; P=0.000). The questionnaire results indicated that immunised cattle had a significantly (chi(2)=6; P=0.015) higher risk of anaplasmosis compared with non-immunised cattle, whereas the risk of bovine babesiosis did not differ significantly (chi(2)=0.06; P=0.807) between the two groups. Mortality risk due to anaplasmosis was 0.046 in immunised and 0.018 in non-immunised cattle and this difference was statistically significant (chi(2)=4.48; P=0.043). The theileriosis mortality risk was 0.203 in the non-immunised cattle, while the risk was 0.009 in the immunised cattle and these differences were also significant (chi(2)=103; P=0.000). It was concluded that farmers who have immunised their cattle may cautiously cut down acaricide application by 50% for extensively grazed herds and by 75% for zero grazed animals depending on the level of tick challenge at the herd level.

Animals↗
PubMed2004

Infection and blood transfusion: a guide to donor screening.

In recent years, blood-component therapy has become more accessible in veterinary practice. As with human medicine, care must be taken to minimize the risk of disease transmission from donor to recipient. Determining the appropriate diseases to screen for is complicated by regional variations in disease incidence, the existence of chronic carrier states for some diseases, the difficulty in screening-test selection, and testing cost. The feline diseases considered include retroviral infections, feline coronaviruses, ehrlichiosis (Ehrlichia canis-like), anaplasmosis (Anaplasma phagocytophilum), neorickettsiosis (Neorickettsia risticii), hemoplasmosis (Mycoplasma hemofelis and M. hemominutum, previously feline hemobartonellosis), and cytauxzoonosis (Cytauxzoon felis). The canine diseases considered in this paper include babesiosis (Babesia canis and B. gibsonii,) ehrlichiosis (E. canis and E. ewingii), anaplasmosis (A. phagocytophilum), neorickettsiosis (N. risticii var. atypicalis), leishmaniasis (Leishmania donovani complex), brucellosis (Brucella canis), hemoplasmosis (M. hemocanis, previously canine hemobartonellosis), and bartonellosis (Bartonella vinsonii).

Animals↗
PubMed1990

Molecular basis for surface antigen size polymorphisms and conservation of a neutralization-sensitive epitope in Anaplasma marginale.

Anaplasmosis is one of several tick-borne diseases severely constraining cattle production and usage in many parts of the world. Cattle can be protected from anaplasmosis by immunization with major surface protein 1, a surface protein of Anaplasma marginale carrying a neutralization-sensitive epitope. Marked size polymorphisms exist among different isolates of A. marginale in the AmF105 subunit of major surface protein 1, yet all isolates still contain the neutralization-sensitive epitope. To clarify the basis for these observations, the mspl alpha gene encoding AmF105 was cloned from four isolates and sequenced. The encoded polypeptides share a high degree of overall homology between isolates but contain a domain with various numbers of tandemly repeated sequences and three regions of clustered amino acid substitutions outside the repeat domain. The polypeptide size differences are completely explained by the variations in the numbers of tandem repeat units. We have mapped the neutralization-sensitive epitope to a sequence that is present within each repeat unit. These results identify a basis for size polymorphisms of the surface polypeptide antigen concomitant with B-cell epitope conservation in rickettsiae.

Amino Acid Sequence↗
PubMed1988

Molecular size variations in an immunoprotective protein complex among isolates of Anaplasma marginale.

A major surface protein complex from the Florida isolate of Anaplasma marginale has been previously shown to induce protection in immunized cattle and has been proposed as the basis of a subunit vaccine against anaplasmosis. This complex in the Florida isolate is composed of two noncovalently associated polypeptides with molecular masses of 105 and 100 kilodaltons (kDa). The analogous protein complex from four geographically different isolates of A. marginale was immunoprecipitated and compared with the protein complex of the Florida isolate. The polypeptides of the complex varied in apparent molecular mass among the isolates. By using antibodies recognizing epitopes on each polypeptide of the Florida isolate, the antigenic identity of the polypeptides in the analogous complexes was determined. The polypeptides recognized by the neutralizing monoclonal antibody 22B1, which recognizes a 105-kDa polypeptide in the Florida isolate, ranged from 70 to 100 kDa in the other isolates. Those polypeptides recognized by rabbit antiserum R911, which recognizes a 100-kDa polypeptide in the Florida isolate, ranged from 97 to 100 kDa. The surface-exposed peptides in the complexes were compared by limited enzymatic digestion to assess structural homology among isolates. Despite the marked variations in molecular weight, there were conserved peptides between the 22B1-reactive polypeptides and between the R911-reactive peptides. Determination of the role of the conserved peptides in inducing immunity will be critical in the application of these polypeptides as the basis of a subunit vaccine for bovine anaplasmosis.

Anaplasma↗
PubMed2005

The interactions of Anaplasma phagocytophilum, endothelial cells, and human neutrophils.

Ixodes scapularis ticks transmit Anaplasma phagocytophilum (Ap), agent of human granulocytic anaplasmosis (HGA). Invasion of neutrophil granulocytes (PMN) by Ap is the hallmark of the disease, but these short-lived phagocytes are not likely the sole cell type required for productive infection. We analyzed infection of microvascular endothelial cells during pathogenesis of anaplasmosis in vivo and in vitro. Organs from Ap-infected mice were processed for confocal microscopy 41 days p.i. Fluorescent labeling of heart and liver sections using anti-factor VIII and anti-MSP2 antibodies allowed colocalization of Ap and vascular endothelium, indicating infection. Ap rapidly invaded and grew within HMEC-1 human microvascular endothelial cells and readily transferred to PMN. Over 50% of PMN became infected within two hours of coincubation with HMEC-1. PMN adhered to, polarized, and migrated upon infected endothelial monolayers. The Ap receptor on human PMN is PSGL-1, and infected endothelial cells upregulate ICAM-1 (CD54), but the mechanisms of transfer of Ap remain unknown. To elucidate the cellular determinants involved, we tested relevant antibodies and lectins. Anti-PSGL-1 reduced infection of PMN, but did not inhibit adherence of PMN to Ap infected HMEC-1 cells while anti-CD18 did. Sialidase pretreatment increased, and EDTA and fucoidan decreased binding of Ap to HMEC-1, whereas several other lectins had no effect. An endothelial reservoir of Ap offers opportunities for ongoing, direct cell-to-cell infection of PMN, avoidance of host immune effectors, and completion of the Ap life cycle by infection of circulating leukocytes available for transfer to blood-feeding ticks.

Anaplasma phagocytophilum↗
PubMed2000

The role of parasitic diseases as causes of mortality in cattle in a high potential area of central Kenya: a quantitative analysis.

Postmortem records of cattle brought to the Veterinary School in Kabete near Nairobi were examined for a period of 15 years (1984-1998, inclusive) in order to establish the role that parasitic diseases played as causes of death. The cattle were mainly of exotic breeds but a few were crosses or of indigenous breeds. There was a total of 1413 cases of deaths from various diseases of which 177 (13%) were due to parasites. The tick-borne diseases were in high proportions and accounted for 84,7% among the parasitic causes, which represented 10,6% of all the deaths recorded. The main tick-borne disease was East Coast fever (ECF) (65%) followed by heartwater (10,2%), babesiosis (5,1%) and anaplasmosis (4,5%). Hydatidosis was responsible for 7,3% of deaths from parasitic causes. Deaths from ECF were recorded in all the 15 years and in high proportions compared to those due to heartwater (8/15), babesiosis (7/15) and anaplasmosis 5/15). Over the period under consideration, no decline was noted among various disease conditions despite advances made in controlling tick vectors and in the treatment of various parasitic conditions. The area covered by this study has the advantage of having several veterinary-related institutions close by. Hence knowledge and awareness about livestock diseases is relatively high compared to other parts of the country. It is therefore challenging to the Veterinary Department to examine the service delivery systems and other factors that may contribute to the persistent presence of these fatal parasitic conditions of cattle.

Animals↗
PubMed2004

Ixodes ricinus as a vector of Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum and Babesia microti in urban and suburban forests.

In the suburban and urban forests in the cities of Gdansk, Sopot and Gdynia (northern Poland), Ixodes ricinus ticks should be considered as the vector of pathogenic microorganisms that may cause significant diseases in wild and domestic animals and humans. These microorganisms include etiologic agents of Lyme disease, human anaplasmosis (HA) and babesiosis: Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum and Babesia microti, respectively. DNA extracts from 701 ticks collected in 15 localities were examined by PCR for the simultaneous detection of these 3 pathogens. Overall, 14 % were infected with A. phagocytophilum followed by 12.4 % with B. burgdorferi s.l. and 2.3 % with B. microti. In total, the percentage of infected females (32.9 %) was 2.4 times higher than in males (13.7 %) and 3.2 times higher than in nymphs (10.3 %). Among adult ticks (n = 303), 8.3 % were dually infected with A. phagocytophilum and B. burgdorferi s.l., 2.0 % with the agent of human anaplasmosis and B. microti and 0.3 % with borreliae and B. microti.

Anaplasma phagocytophilum↗
PubMed1991

Anaplasma marginale in Lepus nigricollis (Blanford) treated with oxytetracycline.

The objective of this study was to test the efficiency and acceptability of oxytetracycline hydrochloride (OTC) in anaplasmosis. Five mg OTC was the only drug given subcutaneous twice by a week to anaplasmotized Lepus nigricollis. The therapeutic results were judged in relation to the parasitized erythrocytes (PE) present, assessment of the clinical acceptability of OTC was perfect in anaplasmosis (Anaplasma marginale).

Journal Article↗
PubMed1983

Demonstration of Anaplasma marginale in hemolymph of Dermacentor andersoni by animal inoculation and by fluorescent-antibody technique.

Hemolymph was collected from adult Dermacentor andersoni Stiles that had been infected with Anaplasma marginale Theiler as nymphs. Before hemolymph was collected, the adult ticks were either incubated and unfed at 37 C for 2.5 days or fed for 6 days on sheep. Hemolymph collected from groups of 100 ticks was inoculated into susceptible splenectomized calves. Smears of hemolymph from the same groups of ticks were prepared for examination by fluorescent antibody technique. Hemolymph from incubated ticks caused anaplasmosis in 2 of 4 trials, and hemolymph from feeding ticks caused anaplasmosis in 4 of 4 trials. Moderately fluorescing bodies were demonstrated in some hemocytes from incubated ticks, whereas hemocytes from feeding ticks contained numerous clusters of brightly fluorescing bodies. Fluorescing bodies were not observed in hemocytes from control ticks.

Anaplasma↗
PubMed1988

Effect of chemotherapy on semen characteristics of Balami rams infected with Anaplasma ovis.

Six intact Balami rams were experimentally infected with Anaplasma ovis. Another six were infected one month after splenectomy and six others served as controls. Clinical manifestations of the disease, first observed between 5 to 7 days post-infection, were more severe and prolonged in the splenectomised-infected than in the intact-infected group. There was progressive deterioration in semen quality, which was also significantly more severe and prolonged in the splenectomised than in the intact-infected rams. Following treatment with long-acting terramycine, clinical recovery occurred earlier in the intact-infected (1-4 weeks) than in the splenectomised-infected group (5-7 weeks). A similar pattern was observed in post-treatment improvement in the sperimiogram. However, although the infected animals recovered clinically by 1-7 weeks post-treatment, restoration of the reproductive potential did not occur for 20 to 25 weeks. It appears that stress factors may aggravate the deliterious effects of anaplasmosis.

Anaplasmosis↗
PubMed1978

Methods to improve the health of cattle in the tropics: conclusions and economic appraisal.

The results of the immune responses of immunised and chemoprophylactically treated calves to tick-borne (Boophilus microplus) challenge indicate that the system of immunisation was effective in protecting cattle against Anaplasma marginale, Babesia argentina (bovis), and B. bigemina. However, chemoprophylaxis was effective only against Babesia spp. but not against A. marginale. Both methods showed a substantial advantage over no control system when using native cattle breeds in a zone endemic for bovine anaplasmosis and babesiosis. Based on the net economic gain per calf starting the experiment, sizeable differences were noted at 308 days between the calves in the immunised group, chemoprophylaxis group, tick and gastrointestinal parasite control group and the experiment control group.

Anaplasmosis↗
PubMed1987

Vaccination with Anaplasma centrale: response after an experimental challenge with Anaplasma marginale.

The haematological and clinical responses to vaccination with Anaplasma centrale and to subsequent challenge with Anaplasma marginale were evaluated. Twenty Holstein steers 14 to 16 months of age were divided into two groups of 12 and eight animals respectively (groups I and II). Group I was inoculated on day zero with 10(7) A. centrale-infected erythrocytes and group II was kept as a control. On day 125 both groups were challenged with 5 X 10(7) A. marginale-infected erythrocytes. A. centrale inoculation produced low parasitaemias (maximum mean 2.7%), moderate packed cell volume (PCV) falls (minimum mean 20.5%) and no clinical symptoms. After the challenge group I had significantly lower parasitaemia (maximum mean 2.3%) and higher PCV (minimum mean 20.1%) than group II (7.5% and 14.5% respectively). Four steers from group II developed acute anaplasmosis and required treatment.

Anaplasma↗
PubMed1977

The effect of natural exposure to Anaplasma and Babesia infections on native calves in an endemic area of Colombia.

The age at which native calves first became infected with Anaplasma marginale and Babesia bigemina and the effect of the infections as characterised by anaemia was determined by the biweekly examination of newly born calves on four ranches located in an endemic area of anaplasmosis and babesiosis on the north coast of Colombia. All of the calves examined became infected with A. marginale at 4-24 weeks of age and with B. bigemina at 2-34 weeks of age. The mean age at first infection with both haemoparasites was 11 weeks. A significant decrease occurred in the mean packed cell volumes of the calves following infection. However, the packed cell volumes returned to preinfection levels with 4 weeks following infection and most calves recovered from their first natural infections without apparent serious consequences. The mild clinical response and rapid recovery indicated that the protection of native calves through immunisation or other procedures prior to natural exposure would be of questionable value.

Age Factors↗
PubMed1986

Dynamics of Anaplasma marginale in splenectomised calves treated with either imidocarb or oxytetracycline.

Neither imidocarb dipropionate (at 5 mg/kg body weight intramuscularly once or twice at a seven-day interval) nor oxytetracycline hydrochloride (at 20 mg/kg body weight intramuscularly once or twice at a seven-day interval) given to animals in the prepatent period of anaplasmosis, prevented the eventual onset of infection. Both compounds delayed the onset of detectable parasitaemia but this action was more noticeable with oxytetracycline. Oxytetracycline given twice significantly reduced the severity of the primary infection but the secondary infection was more severe. Neither compound showed prophylactic properties even though both are effective in extending the prepatent period and, in the case of oxytetracycline, reducing the severity of infection.

Anaplasmosis↗