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PubMed1979

Current anaplasmosis control techniques in the United States.

A card test for detecting anaplasmosis, along with the complement-fixation test, has proved useful in identifying carrier animals. This identification, associated with treatment with tetracyclines, has been a basis for control in the southeast where anaplasmosis is endemic. The tetracyclines are used parenterally (terramycin 11 mg/kg, 10-14 days) or orally (2,2 to 11 mg/kg, 45-60 days). Notwithstanding these methods, anaplasmosis remains a problem and many animals require treatment to moderate the course of acute infection. A new drug, T-200 (a long-lasting terramycin), has been tested and found effective in treating acute infections (20 mg/kg, 1 time) and in cleaning carrier infections (20 mg/kg, 2 times at a 7-day interval). For several years, a killed adjuvant vaccine was extensively used to control anaplasmosis. The occurrence of neonatal isohemolytic anaemia in association with this vaccine has discouraged its use. This vaccine is still being marketed, but is usually used on selected animals. An attenuated Anaplasma vaccine of ovine origin has been developed, but is not licensed for use in the United States although it has been successfully used elsewhere.

Anaplasmosis↗
PubMed1980

Effects of phenol on card-agglutination and complement-fixation tests for bovine anaplasmosis.

Effects of adding phenol to sera used for the card-agglutination test (CAT) and for the micro-complement-fixation test (CFT) for bovine anaplasmosis were studied. Sera were obtained from 14 recently infected cattle, 17 cattle vaccinated with a killed anaplasmosis vaccine, 5 cattle in the carrier phase of the disease, and 45 cattle of unknown anaplasmosis status. Aliquots of sera were tested with and without phenol (0.25% final concentration). Phenol adversely affected the CAT by causing false-negative results. The CAT reactions of nonphenolized sera from recently infected cattle were all positive 4 weeks after inoculation, whereas CAT reactions of phenolized sera were not all positive until 10 weeks after inoculation. Nine non-phenolized sera from vaccinated cattle that were CAT-positive were CAT-negative after being phenolized. Phenolized sera from carrier cattle and from cattle of unknown anaplasmosis status were less reactive on the CAT than were nonphenolized sera. Effects of phenol on the CFT were not so obvious. Although phenol had little effect on end-titer results, it eliminated most prozones that cause false-negative CFT results at the 1:5 dilution. Without phenol, 30 of 215 sera would have been CFT-negative at this dilution because of prozones; with phenol, 6 would have been CFT-negative.

Agglutination Tests↗
PubMed1988

Epidemiology of bovine babesiosis and anaplasmosis in Zambia.

The serological prevalence of bovine babesiosis and anaplasmosis in the traditional farming sector of six provinces of Zambia was determined using the indirect fluorescent antibody test (IFAT) for babesiosis and the card agglutination test (CAT) for anaplasmosis. Antibodies to Babesia bigemina occurred throughout the country whereas the prevalence of B. bovis followed the distribution of its tick vector Boophilus microplus which is limited to the north-eastern part of the country. Low numbers of B. bovis serologically positive cattle were demonstrated in central and southern Province. Anaplasma spp. occurred throughout Zambia but the overall percentages of positive sera were low ranging between 14.7% and 38.6% using the CAT. Two hundred sera were retested for anaplasmosis using an enzyme-linked immunosorbent assay (ELISA). Sero-prevalence rates were 1.5 to 2.3-fold greater with the ELISA than with the card agglutination test.

Agglutination Tests↗
PubMed1989

Erythrocyte osmotic fragility and cation concentrations during experimentally induced bovine anaplasmosis.

1. The osmotic fragility, the concentrations of Na, K and Ca, the osmolality and the total ATPase activity of bovine erythrocytes from uninfected and Anaplasma marginale-infected bovines were studied in an attempt to correlate these parameters with the decrease in the cellular ATP concentration reported during bovine anaplasmosis. 2. The osmotic fragility found in infected bovine erythrocytes, at 0.52% NaCl, was about two times greater than that observed in non-infected bovines. The increase in osmotic fragility was directly related to the increase in intra-erythrocytic parasitemia. 3. The decrease in ATP concentration reported during bovine anaplasmosis could not be directly related to the increased fragility of these cells. The artificial depletion of erythrocytic ATP did not reproduce the same alteration in the osmotic response to NaCl. 4. The plasmatic and cytoplasmatic concentrations of Na, K and CA did not change significantly during bovine anaplasmosis, whereas the interior of the erythrocytes became hyperosmolal. 5. A. marginale-infected bovine erythrocyte membranes showed an increased ATPase activity when compared to control bovines. Parasite-enriched fractions also presented ATPase activity.

Adenosine Triphosphatases↗
PubMed2005

Seroprevalence of anaplasmosis among cattle in Switzerland in 1998 and 2003: no evidence of an emerging disease.

Anaplasma marginale infection in Europe has been limited to the Mediterranean and eastern countries, to Austria and to very sporadic cases in Switzerland. There are no reports of its occurrence in the countries north of Switzerland. A severe outbreak of anaplasmosis in August 2002 in a cattle farm in the canton Grisons, Switzerland, north of the Alps, with more than 300 cattle that had to be culled, came unexpected and gave reason to hypothesize presence of an increased yet undetected prevalence of A. marginale in Switzerland. Randomly selected bovine serum samples collected in 1998 and 2003 were tested using a competitive inhibitory ELISA (cELISA) to test the hypothesis. Our validation of the diagnostic sensitivity and specificity of this test, done in the outbreak herd, yielded 99.2 and 83.3%, respectively, probably underestimating the true specificity. The true seroprevalence of anaplasmosis in Swiss cattle determined by cELISA was likely to be zero with upper 95% confidence limits of 2.49% in the canton Grisons and 1.17% in the rest of Switzerland, respectively, in 1998. For 2003, these estimates were even lower. There was no significant difference in apparent prevalences between 1998 and 2003. In search of a possible reservoir, three chamoises out of 46 free ranging wild ruminants from the Swiss National Park, Grisons, tested positive in the cELISA. This reaction is in accordance with A. marginale or a cross reacting agent such as Anaplasma ovis. From our results we conclude that the hypothesis of an increased prevalence of anaplasmosis in cattle in Switzerland must be rejected.

Anaplasma marginale↗
PubMed1997

Bovine anaplasmosis prevalence in northern Veracruz state, Mexico.

In order to learn more about the presence of bovine anaplasmosis in northern Veracruz state, México, paired blood and serum samples from 368 cattle were subjected to polymerase chain reaction (PCR) and complement-fixation test (CFt). The overall prevalence of Anaplasma marginale by PCR was 69.2% and seroprevalence by CFt 54.6%. Age-specific prevalence was calculated for each test. Sixty-eight percent of animals from 0 to 3 months of age already were infected (PCR-positive), compared to only 42.4% positive by serology. CFt results suggested that presence of antibody increases with age up to 18 to 36 months, decreasing thereafter. Presence of the rickettsia seems to follow the same early pattern but with a new increase in animals 36 months or older. Serology results provided a biased picture of the true prevalence of anaplasmosis. Calculated specificity and sensitivity (63.5% and 68.2%) for CFt using PCR values as true values, appear very low and unreliable. The data generated by DNA-based surveys seem more appropriate to help design and implement control or eradication programs for bovine anaplasmosis.

Anaplasma↗
PubMed2000

Anaplasmosis control and diagnosis in South Africa.

Anaplasmosis is widespread in South Africa with more than 99% of the total cattle population at risk. Five tick species have been experimentally shown to be capable of transmitting Anaplasma in South Africa. Mechanical transmission through blood contaminated instruments and biting flies also occurs. Vaccination against Anaplasma marginale by administration of an Anaplasma centrale live-blood vaccine has been practiced in this country since 1912. Although generally a mild pathogen, Anaplasma centrale can cause severe clinical reactions following vaccination and also does not afford complete protection against all A. marginale isolates. Anaplasmosis vaccine is routinely available in a deep-frozen form and approximately 220,000 doses of vaccine are sold per annum. Microscopic examination of stained thin blood smears is still the most reliable and cost effective method of confirming a clinical diagnosis of anaplasmosis. Several diagnostic tests, such as the complement fixation tests, card agglutination test, and enzyme-linked immunosorbent assay (ELISA) have been developed to identify carrier cattle. A competitive inhibition ELISA test, based on antibody binding to a recombinant MSP-5 protein conserved among Anaplasma species, is routinely used at this laboratory.

Anaplasmosis↗
PubMed1978

Some effects of reduced energy intake on the development of anaplasmosis in Bos indicus cross steers.

Some effects of the plane of nutrition on the development of anaplasmosis in Brahman cross steers were investigated. Batches of 39 and 30 Brahman cross steers, aged approximately 27 months were each divided by stratified randomisation into 4 groups of similar mean PCV and body weight. Two similar experiments, designated A and B were conducted. Groups 1 and 2 were fed a ration of lucerne chaff at the rate of 1 M Cal ME/80 kg live weight/day for 8 weeks aimed to reduce body weight by approximately 5 kg/week. Animals in groups 3 and 4 were fed a ration for the same period aimed to increase body weight by approximately 2 kg/week. Groups 1 and 3 were then inoculated with approximately 10(10) Anaplasma marginale infected erythrocytes and the effects of the subsequent infections during the clinical and recovery phases were examined by measuring humoral antibody response, packed cell volume, parasitaemia and body weight. Groups 2 and 4 were uninfected controls. Anaplasmosis, as measured by three responses, was less severe in the starved animals of group 1. Significant differences in packed cell volume and parasitaemia were detected for short periods between the infected groups 1 and 3. Anaplasmosis caused losses of 6.2% and 5.9% in the mean body weight of group 3 animals in experiments A and B respectively. Most of this loss occurred during the clinical phase of the disease. The disease caused no apparent loss of weight in the infected animals of group 1.

Anaplasmosis↗
PubMed1986

Immunization with an isolate-common surface protein protects cattle against anaplasmosis.

Hemoparasitic diseases are endemic in half the world's livestock production areas and are the greatest obstacle to improved meat, milk, and fiber production in the Third World. The most prevalent of these diseases, anaplasmosis, occurs throughout tropical and subtropical regions and is responsible for 50,000 to 100,000 cattle deaths annually in the United States alone. Despite its prevalence and the severity of the losses, an effective immunoprophylaxis for anaplasmosis has not been developed. A neutralization-sensitive epitope on a surface protein with a molecular weight of 105,000 (Am 105) of the causative rickettsia Anaplasma marginale was identified by monoclonal antibody inhibition of infectivity. This epitope was determined to be common to eight isolates with antigenic, morphologic, and protein structural differences. Cattle immunized with Am 105 purified by immunoaffinity chromatography were protected against challenge with virulent Anaplasma marginale. The identification of Am 105 as bearing isolate-common epitopes capable of inducing protection in immunized cattle provides the basis for the development of an effective subunit vaccine for bovine anaplasmosis.

Anaplasma↗
PubMed1998

Evaluation of an enzyme-linked immunosorbent assay using recombinant major surface protein 5 for serological diagnosis of bovine anaplasmosis in Venezuela.

An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of bovine anaplasmosis with purified recombinant major surface protein 5 (MSP5) of Anaplasma marginale produced in Escherichia coli. Serum antibody responses against MSP5 were detected in calves experimentally infected with A. marginale as early as 21 days postinfection and reached maximum titers at 28 days postinfection. The MSP5 ELISA performed with serum samples taken from field cattle from different regions of Venezuela showed a seroprevalence of 47%, which seems to be in accordance with the reported epidemiological status of bovine anaplasmosis in Venezuela. Positive results obtained in the MSP5 ELISA were further confirmed by immunoblotting, with the recombinant MSP5 as the antigen. Thus, these results confirmed the importance of MSP5 as a suitable antigen for the serological diagnosis of bovine anaplasmosis.

Anaplasmosis↗
PubMed1994

Seroprevalence of bovine anaplasmosis in Oklahoma from 1977 to 1991.

The prevalence of anaplasmosis in Oklahoma cattle was determined on the basis of the standardized Anaplasma marginale complement fixation test on 20,155 sera submitted to the Oklahoma Animal Disease Diagnostic Laboratory during a 15-year period. Rates of seropositivity ranged from 4.7% to 17.6% on samples submitted for anaplasmosis testing of adult cows. The geographic distribution of recorded cases of anaplasmosis was 35 Oklahoma counties in 1977 and 48 Oklahoma counties in 1991.

Anaplasma↗
PubMed1977

Studies on pronghorn antelope (Antilocapra americana) as reservoirs of anaplasmosis in Montana.

Twenty-six pronghorn antelope (Antilocapra americana) were collected in an area of eastern Montana where bovine anaplasmosis is enzootic. Their sera were examined for evidence of anaplasmosis by the complement-fixation test. Strong false positive reactions (3+ and 4+ reactors) occurred for 19 of the sera tested; 6 sera were anticomplementary. Inoculation of antelope blood into anaplasmosis, and anaplasma bodies were not found in stained blood smears of antelope or recipient calves.

Anaplasmosis↗
PubMed1995

An assessment of the role of white-tailed deer in the epizootiology of anaplasmosis in the southeastern United States.

The role of white-tailed deer (Odocoileus virginianus) in the epizootiology of anaplasmosis in the southeastern United States was examined through retrospective and prospective serosurveys and by experimental infection studies. No serum antibody reactive to Anaplasma marginale was detected with an indirect fluorescent antibody (IFA) assay from any of 1,376 free-ranging deer sampled from 1968 through 1990 from 13 states and Puerto Rico. Thirty-one additional deer from three bovine anaplasmosis enzootic premises also were negative by IFA and Giemsa-stained blood films. Three captive deer given A. marginale intravenously developed antibodies 38 to 41 days post-inoculation (DPI) and remained seropositive for the duration of the study (161 to 287 DPI). At 42 DPI, rickettsemias of approximately 0.0001% infected erythrocytes were observed in all three deer using a DNA probe; low rickettsemias (maximum 0.01%) persisted through 56, 63, and 87 DPI, respectively. One deer had a recrudescent infection from 126 to 146 DPI (maximum rickettsemia 0.001%). We believe that white-tailed deer in the southeastern United States, even though susceptible to A. marginale infection, are not exposed naturally, even at enzootic sites. Furthermore, white-tailed deer did not develop rickettsemias sufficient to support mechanical transmission by biting flies, which is believed to be the primary means of anaplasmosis transmission in this region.

Anaplasma↗
PubMed1992

Anaplasmosis in Uganda. III. Parasitological and serological evidence of Anaplasma infection in Ugandan goats.

Randomly selected goat sera from north-western, central, and south-western regions of Uganda were analyzed parasitologically and serologically for evidence of anaplasmosis. Prevalence rates of 3.2% by parasitemia, 4.8% by card-agglutination test, and 12.9% by DOT-ELISA combined with western blotting were established. Parasitologically positive samples were consistently serologically positive. Positive samples were all from either the north-western or south-western regions of the country. Goats in these regions graze with cattle and are presumable exposed to the same tick species. There was no evidence of clinical caprine anaplasmosis, whereas bovine anaplasmosis cases are very common. Rhipicephalus evertsi was frequently observed on goats which cograze with cattle.

Anaplasma↗
PubMed2005

Epidemiology of human ehrlichiosis and anaplasmosis in the United States, 2001-2002.

During 2001 through 2002, 1,176 cases of the tick-borne diseases human monocytic ehrlichiosis (HME) and human granulocytic anaplasmosis (HGA) were reported to the Centers for Disease Control and Prevention (CDC) by 32 states through the National Electronic Telecommunications System for Surveillance. The average reported annual incidences for HME and HGA during 2001-2002 were 0.6 and 1.4 cases per million population, respectively; incidence was highest among men > 60 years of age. During this same interval, a total of 883 cases of HME and HGA were reported to CDC through a passive surveillance system of tick-borne disease case report forms (CRFs). The surveillance information retrieved from CRFs has allowed for qualitative evaluation of ehrlichiosis and anaplasmosis risk factors, severity, and diagnostic accuracy. Although these surveillance systems likely substantially under-represent the true burden of ehrlichiosis and anaplasmosis in the United States due to poor recognition and reporting, they represent the first compilation of national data since these diseases were made nationally notifiable. Continued and improved surveillance activities will progressively reinforce our understanding and awareness of these newly recognized zoonotic infections.

Adolescent↗
PubMed1987

Bovine anaplasmosis: susceptibility of seronegative cows from an infected herd to experimental infection with Anaplasma marginale.

Adult cows from an Anaplasma marginale-infected herd that were negative to the A marginale rapid card agglutination (RCA) and complement fixation (CF) tests for 1 to 4 years developed acute anaplasmosis after inoculation with 0.5 ml of blood from an A marginale carrier cow. The test cattle were as susceptible as the control cattle of similar ages. Also, 2 cows that had seroconverted from RCA/CF-positive to RCA/CF-negative status naturally were fully susceptible to anaplasmosis when they were experimentally infected. Results of the study indicated that indigenous seronegative cattle in anaplasmosis-enzootic regions probably do not have acquired or natural immunity to A marginale infection.

Agglutination Tests↗
PubMed1987

Ovine anaplasmosis: in utero transmission as it relates to stage of gestation.

Seventeen mature, pregnant, anaplasmosis-susceptible and 3 anaplasmosis-carrier ewes were used in Anaplasma ovis in utero transmission studies. Susceptible ewes were arbitrarily allotted to 3 groups, 4 each in groups A and C and 9 in group B, and were inoculated with whole blood from a carrier ewe. Each group was Anaplasma-exposed once during one of the thirds of pregnancy. In all ewes, resulting parasitemias were low and anemias were mild. Three carrier ewes comprised group D. Blood samples were obtained once during gestation from each fetus at various stages of development for evaluation and inoculation into splenectomized lambs. Blood obtained from neonates before nursing was also evaluated for Anaplasma presence. Parasitemia was not detected in any fetus or neonate; however, 3 of 16 splenectomized lambs inoculated with fetal or neonate blood developed acute anaplasmosis. Dams of fetuses/neonates with infective blood had been Anaplasma-exposed during their 2nd or last 3rd of pregnancy. Infective Anaplasma agents crossed the placental barrier as early as 130 days of gestation.

Anaplasmosis↗
PubMed1979

Epizootiology and control of anaplasmosis in south africa.

The history of bovine anaplasmosis, or tick-born gallsickness, since the discovery of Anaplasma marginale by Sir Arnold Theiler is briefly reviewed. The development of the Anaplasma centrale vaccine by Theiler, up to the composition of the present vaccine issued by Onderstepoort in which the original isolate is still passaged, is discussed in detail. Recent transmission studies at Onderstepoort have shown that 5 tick species are capable of transmitting anaplasmosis intrastadially, and intrastadial transmission, especially by adult male ticks, it is believed, could play an important role in the epizootiology of bovine anaplasmosis in South Africa. Disease incidence and tick distribution are discussed in relation to enzootic and epizootic conditions. Investigations have proved that the Onderstepoort A. centrale vaccine is not as avirulent in adult cattle as it was previously thought to be. The results of a field trial undertaken to test the infectivity of the vaccine, are given.

Anaplasma↗