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PubMed2002

Vaccination of cattle with Anaplasma marginale derived from tick cell culture and bovine erythrocytes followed by challenge-exposure with infected ticks.

Anaplasmosis, a hemolytic disease of cattle caused by the tick-borne pathogen Anaplasma marginale (Rickettsiales: Anaplasmataceae) has been controlled using killed vaccines made with antigen harvested from infected bovine erythrocytes. We recently developed a cell culture system for propagation of A. marginale in a continuous tick cell line. In this study, we performed a cattle trial to compare the bovine response to vaccination with A. marginale harvested from tick cell culture or bovine erythrocytes. All immunized and control cattle were then challenge-exposed by allowing male Dermacentor variabilis infected with A. marginale to feed and transmit the pathogen. Nine yearling cattle (three per group) were used for this study and were immunized with cell culture-derived A. marginale, erythrocyte-derived A. marginale or received adjuvant only to serve as controls. Each vaccine dose contained approximately 2 x 10(10) A. marginale and three immunizations were administered at weeks 1, 4 and 6. At week 8, cattle were challenge-exposed by allowing 60 D. variabilis male that were infected with A. marginale as adults to feed on the cattle. Antibody responses of cattle against major surface proteins (MSP) 1a, 1b and 5, as determined by ELISAs, peaked 2 weeks after the last immunization. Cattle immunized with infected IDE8 cell-derived antigens had a preferential recognition for MSP1b while cattle immunized with erythrocyte-derived antigens had a preferential recognition for MSP1a. Protection efficacy was evaluated using the percent infected erythrocytes (PPE), the packed cell volume (PCV), and the prepatent period. A. marginale-immunized cattle showed lower PPE and higher PCV values when compared to control animals and did not display clinical anaplasmosis. The cell culture-derived A. marginale shows promise for use as antigen in development of a new killed vaccine for anaplasmosis.

Anaplasma↗
PubMed2005

Potential vertebrate reservoir hosts and invertebrate vectors of Anaplasma marginale and A. phagocytophilum in central Spain.

Organisms in the genus Anaplasma are obligate intracellular pathogens that multiply in both vertebrate and invertebrate hosts. The type species, A. marginale, causes bovine anaplasmosis and only infects ticks and ruminants. A. phagocytophilum causes human and animal granulocytic anaplasmosis, and genetically closely related strains show a wide host range, including ticks, ruminants, rodents, equids, canids, birds, and humans. Recent reports demonstrated that A. marginale and A. phagocytophilum co-exist in geographic areas and that concurrent infections occur in ruminants and ticks. In this study, we characterized A. marginale and A. phagocytophilum infections in wild and domestic animals, and ticks collected in central Spain by serology, PCR, and sequence of 16S rRNA genotypes. Species tested included humans, cattle, dogs, rodents, Iberian red deer, European wild boar, birds, and ticks. Species of hematophagous Diptera were analyzed as potential mechanical vectors of Anaplasma spp. A. marginale was detected in tabanids, ticks, cattle, and deer, while A. phagocytophilum was detected in ticks, deer, cattle, and birds. Concurrent infections of the two Anaplasma were found in cattle and deer. These results illustrate the complexity of the epizootiology of A. marginale and A. phagocytophilum in regions where both pathogens co-exist and share common reservoir hosts and vectors. The increasing contact between wildlife, domestic animals, and human populations increases the risk of outbreaks of human and bovine anaplasmosis, and the difficulty of implementing surveillance and control measures.

Anaplasma marginale↗
PubMed1996

Strategies to interrupt the development of Anaplasma marginale in its tick vector. The effect of bovine-derived antibodies.

Anaplasma marginale is a rickettsia transmitted by ticks that invades and multiplies in bovine erythrocytes causing the disease anaplasmosis. A complex developmental cycle occurs within ticks that begins in midgut cells, with subsequent infection in gut muscle cells. Final development occurs in salivary glands from where the rickettsia is transmitted to the vertebrate host. At each site of development, A. marginale multiplies within membrane-bound inclusions. Attempts to control anaplasmosis have focused on cattle and have included immunization and prophylactic treatment with tetracyclines. New strategies for control of anaplasmosis are being focused on the tick vector. Development of vaccines against hemoparasites in ticks may be feasible because vertebrate host immunoglobulins appear to cross the midgut epithelium of invertebrates and enter the hemolymph without breakdown. We tested the effect of A. marginale antibodies ingested by ticks with the bloodmeal on infections in ticks. Cattle were immunized with purified outer membrane proteins of erythrocytic-derived parasites. Infections in ticks exposed to the immunized cattle were determined using an Anaplasma-specific DNA probe, light and electron microscopy, and tick transmission studies. Vaccine-derived antibodies did not appear to affect the development and transmission of A. marginale in ticks. Further studies are needed to determine if bovine antibodies remain intact within ticks and whether the tick stage of A. marginale has unique surface antigens from the erythrocytic stage.

Anaplasma↗
PubMed2002

Selective in vivo depletion of CD4(+) T lymphocytes with anti-CD4 monoclonal antibody during acute infection of calves with Anaplasma marginale.

To investigate the in vivo role of CD4(+) T lymphocytes during acute anaplasmosis, thymectomized calves were selectively depleted of CD4(+) T lymphocytes by treatment with anti-CD4 monoclonal antibody (MAb) and were then infected with the Florida strain of Anaplasma marginale in two sequential experiments (experiments 1 and 2). Treatment of thymectomized calves with a total of 5.0 mg of anti-CD4 MAb/kg of body weight during the 1st week followed by 0.3-mg/kg doses administered twice weekly for 7 weeks resulted in significant depletion of CD3(+) CD4(+) and CD4(+) CD45R(+) (naive) T lymphocytes from blood, spleen, and peripheral lymph nodes for the duration of the 8-week study, compared to the results for thymectomized control calves treated with a subclass-matched MAb. All calves became parasitemic and pyretic following experimental infection with A. marginale, and decreases in packed cell volume (PCV) coincided with peak parasitemia. No significant differences in PCV or parasitemia were observed between treatment groups. Thymectomized calves treated with anti-CD4 MAb were able to mount an anti-A. marginale antibody response, although in experiment 2, anti-CD4 MAb-treated calves had four- to sixfold lower immunoglobulin G1 (IgG1) and no detectable IgG2 anti-A. marginale major surface protein 2-specific antibody titers compared to thymectomized control calves treated with a subclass-matched MAb. At the level of CD4(+)-T-lymphocyte depletion achieved and experimental anaplasmosis induced, thymectomized anti-CD4 MAb-treated calves were able to control acute anaplasmosis. This was in contrast to the prediction that significant depletion of CD4(+) T lymphocytes would abrogate resistance to acute infection.

Acute Disease↗
PubMed1986

Detection of an Anaplasma marginale common surface protein present in all stages of infection.

The establishment and maintenance of anaplasmosis-free cattle herds is impaired due to the lack of a rapid, sensitive, and specific serologic test to detect persistently infected cattle which serve as carriers for the organism. To develop an improved diagnostic test for anaplasmosis we screened Anaplasma marginale initial body proteins to identify a protein common to antigenically different isolates that is recognized by the host immune system at all stages of infection. Seronegative cattle were infected with either the Florida, Virginia, or North Texas isolate of A. marginale and monitored for infection by daily examination of Wright-stained blood smears for parasitized erythrocytes. Sera from cattle at different stages of infection, from acute through persistent, were used to immunoprecipitate A. marginale proteins that were metabolically radiolabeled with [35S]methionine or surface radiolabeled with 125I. Multiple A. marginale proteins were recognized by using sera either undiluted or at 1:10; however, only four or five proteins were sufficiently antigenic to elicit antibody reactive with a 1:1,000 serum dilution. A single protein with an apparent molecular mass of 86 kilodaltons was consistently recognized at all stages of infection regardless of the isolate used to infect the cattle. This protein was demonstrated to be on the surface of the A. marginale initial body and to be water soluble. We propose use of this 86-kilodalton protein to develop an improved serologic test for diagnosis of bovine anaplasmosis.

Anaplasma↗
PubMed1984

Response of cattle upon reexposure to Anaplasma marginale after elimination of chronic carrier infections.

Sixteen cattle serotest-negative for anaplasmosis with either no previous exposure (2 animals) or cleared 8 months earlier of their carrier state by chemotherapy (14 animals) were each exposed to Anaplasma marginale. Anaplasma serotest titers were determined by complement-fixation and rapid card agglutination tests conducted during a 63-day trial period. Serologic reactions indicated that all cattle (both groups) were converted to seropositive by the 21st day after exposure. Fluctuations in PCV were seen in the 2 groups between days 21 and 35. However, parasitemia levels were detectable only in the 2 previously unexposed control cattle. Three splenectomized calves, given 10 ml of blood from 3 of the former carrier cattle 14 days after the latter were reexposed, developed severe clinical and hematologic signs of anaplasmosis and seroconverted from negative to positive on both serologic tests. The need to acquire a better understanding of immunity in anaplasmosis is discussed.

Anaplasma↗
PubMed1982

Elimination of naturally acquired chronic Anaplasma marginale infections with a long-acting oxytetracycline injectable.

Four injections of a long-acting oxytetracycline (20 mg/kg) were administered at 3-day intervals to 14 naturally infected anaplasmosis carrier cattle. Individual anaplasma serology titers were evaluated, using complement-fixation and rapid card-agglutination tests at frequent intervals during a 180-day posttreatment period. Serologic results indicated fluctuating complement-fixation titers during the trial period. However, at trial termination, 12 of 14 animals were negative by complement-fixation testing and all animals were card-test negative. Eight splenectomized calves given 10 ml of blood from the medicated cows at their posttreatment day 150 failed to manifest any clinical, hematologic, or serologic signs of anaplasmosis during 56 days. Susceptibility to anaplasmosis challenge exposure was demonstrated by positive clinical and serotest reactions when 3 of the recipient calves were inoculated with blood from a parasitemic carrier calf.

Agglutination Tests↗
PubMed2004

Incidence and prevalence of infection with Anaplasma phagocytophilum. Prospective study in healthy individuals exposed to ticks.

The seroprevalence of human granulocytic anaplasmosis (former human granulocytic ehrlichiosis, HGE) has been documented in several studies, but little data exists on incidence rates in healthy individuals. In a prospective study, we tested 125 healthy adults (mean age 43 years)--workers of the Bialowieza Primeval Forest National Park, north-eastern Poland--for Anaplasma phagocytophilum IgG antibodies using an indirect immunofluorescence antibody assay, and for Borrelia burgdorferi IgG with ELISA in a 12-month interval. The data concerning clinical symptoms consistent with human granulocytic anaplasmosis were collected using a standardized questionnaire. Of these 125 subjects, 9 were anti-A. phagocytophilum positive at the study entry. Four participants (3.2 %) seroconverted from IgG negative to positive during the observation period. Three subjects (2.4 %) converted from initially anti-A. phagocytophilum positive to negative. Specific IgG antibodies against Borrelia burgdorferi were detected in 27 (21.6 %) individuals. Concurrence of Borrelia burgdorferi and Anaplasma phagocytophilum was observed in 3.2 %, whereas 4 % were Anaplasma phagocytophilum IgG positive and Borrelia burgdorferi IgG negative (not significant). Clinical symptoms associated with human granulocytic anaplasmosis were not present in seroconverting individuals. The obtained results confirm the occurrence of Anaplasma phagocytophilum infection in north-eastern Poland with asymptomatic clinical course.

Adult↗
PubMed2004

Detecting DNAs of Anaplasma phagocytophilum and Babesia in the blood of patients suspected of Lyme disease.

Co-occurrence of granulocytic anaplasmosis, borreliosis and babesiosis in humans is a result of common vectors for the respective pathogens of these diseases, most commonly ticks from the genus Ixodes. Studies on ticks in Europe and also in Poland have shown that several pathogens may co-occur in individuals of I. ricnus. A total of 96 hospitalised patients infected or suspected of being infected with borreliosis were screened for A. phagocytophilum and Babesia sp. DNA. Positive results of PCRs for A. phagocytophilum DNA were obtained for 10 patients, 8 of whom were diagnosed with borreliosis earlier, and 4 of whom were diagnosed with tick-borne encephalitis (on the basis of serological studies of serum and cerebrospinal fluid). None of the 10 patients had clinical or biochemical markers of anaplasmosis, corroborating the existence of asymptomatic anaplasmosis or self-limiting course. in Europe. Similarly, Babesia DNA was not found in the blood of any of the patients. The results of the studies show that in diagnosing tick-borne diseases, clinical examinations should consider infection by two or even three tick-borne pathogens.

Adolescent↗
PubMed2005

Risk of tick-borne bacterial diseases among workers of Roztocze National Park (south-eastern Poland).

The objective of the present study was to assess the risk of borreliosis and anaplasmosis (ehrlichiosis) among the forestry workers of the Roztocze National Park (south-eastern Poland) by examination of Ixodes ricinus ticks living in park area with PCR method, and by the serological and clinical examination of the workers. In 406 examined ticks, the prevalence of infection with Borrelia burgdorferi sensu lato was 11.5 %. The nested PCR reaction for determining the genospecies showed that the most common was Borrelia burgdorferi sensu stricto (55.3 % of total positive) followed by Borrelia afzelii (38.3 %). As many as 6.1 % out of 115 examined ticks showed the presence of Anaplasma phagocytophilum DNA. The infection rate was high in males and females (14.3 % and 11.1 % respectively) and low in nymphs (1.5 %). In 46 out 113 examined forestry workers (40.7 %) the presence of specific IgG and/or IgM antibodies against Borrelia burgdorferi sensu lato was found in ELISA test, while only 4 out of 56 urban blood donors showed a positive response (p<0.0001). The prevalence of IgG antibodies against Anaplasma phagocytophilum determined with the use of indirect immunofluorescence test (IFA) was 17.7 % in forestry workers compared to 5.4 % in reference group of blood donors (p<0.05). No correlation was found between the presence of antibodies to A. phagocytophilum and to B. burgdorferi s. l. Clinical investigations of 113 forestry workers showed 3 cases of borreliosis (2.7 %) and no cases of anaplasmosis (ehrlichiosis). In conclusion, forestry workers of the Roztocze National Park in south-eastern Poland are often exposed to Ixodes ricinus ticks infected with Borrelia burgdorferi and Anaplasma phagocytophilum, and show a high proportion of asymptomatic borreliosis and anaplasmosis (ehrlichiosis) manifested by a positive serologic response, while the number of clinical cases is relatively low.

Adult↗
PubMed2006

Distribution, seasonality, and hosts of the Rocky Mountain wood tick in the United States.

Anaplasma marginale Theiler is a tick-borne pathogen that causes anaplasmosis in cattle. There are approximately 20 tick species worldwide that are implicated as vectors of this pathogen. In the United States, Dermacentor andersoni Stiles and Dermacentor variabilis (Say) are the principal vectors. The risk of transmission of anaplasmosis to cattle has been largely based on the distribution of D. andersoni in the United States. We developed a centralized geographic database that incorporates collection records for D. andersoni from two large national databases. We reviewed the geographic records in each database and postings from MEDLINE and AGRICOLA to produce a national county-level distribution map based on a total of 5,898 records. The records spanned the period from 1903 through 2001 with the majority between 1921 to 1940. Populations of D. andersoni were recorded from 267 counties in 14 states and were distinguished as either established or reported. We found 180 counties with established populations of D. andersoni and 87 counties with reported occurrences in 14 states with the majority of established populations reported from Montana, Idaho, and Oregon. D. andersoni populations in the United States currently extend from the western portions of Nebraska and the Dakotas westward to the Cascade Mountains and from the northern counties of Arizona and New Mexico northward to the Canadian border. The data will be useful for identifying regions at increased risk of acquiring anaplasmosis in the United States. Based upon the database collection records, we also present a summary of recorded hosts for D. andersoni and comments on its seasonal occurrence.

Animals↗
PubMed1979

Serologic profile of exotic deer at Point Reyes National Seashore.

Serotests were conducted on axis (Axis axis) and fallow (Dama dama) deer at Point Reyes National Seashore to determine their status with respect to nine diseases enzootic to the native black-tailed deer (Odocoileus hemionus columbianus) or to resident dairy cattle. In the exotic deer, the proportion of animals that were seropositive included: anaplasmosis, 35%; bluetongue, 48%; brucellosis, 0%; bovine viral diarrhea, 2%; infectious bovine rhinotracheitis, 3%; leptospirosis, 7%; parainfluenza-3, 49%; toxoplasmosis, 8%; and Q fever, 51%. The prevalence of antibodies among a small sample of the black-tailed deer included anaplasmosis, 100%; toxoplasmosis, 29%; and Q fever, 57%. The antibody prevalences in a sample of dairy cattle in the area included anaplasmosis, 19%; toxoplasmosis, 8%; and Q fever, 100%.

Animals↗
PubMed1994

[Field trial of an attenuated vaccine against heartwater disease].

The results are given of a field trial using a Senegalese stock of Cowdria ruminantium which had been attenuated by passage in cell culture. Thirty vaccinated and thirty control sheep were exposed in the Niayes region of Senegal and were monitored daily. In the control group, 22 animals died of heartwater, associated in one case with anaplasmosis. In the vaccinated group, 13 animals died; Cowdria was found only in two sheep which had previously suffered from ehrlichiosis or anaplasmosis; three other cases of ehrlichiosis and two of anaplasmosis were also observed among these 13 animals. The resistance of the two vaccinated animals which showed Cowdria in their cerebral cortex was apparently lowered by the intercurrent infections. The other animals of the vaccinated group showed no evidence of Cowdria infection.

Animals↗
PubMed1978

Methods to improve the health of cattle in the tropics: immunisation and chemoprophylaxis against haemoparasitic infections.

A study of methods to improve the health of native cattle in tropical areas of Colombia showed an advantage using immunisation techniques against haemoparasitic infections in comparison with other control methods. The control of anaplasmosis and babesiosis by immunisation of cattle with fully virulent Anaplasma marginale, Babesia argentina and B. bigemina is feasible in tropical cattle when the postimmunisation reaction is controlled by appropriate drug therapy. Chemoprophylaxis was found less effective in controlling haemoparasitic diseases; however, treated was found less effective in controlling haemoparasitic diseases; however, treated cattle surviving the acute stage of infection showed weight gains not significantly different from those of the immunised calves. Both methods were found to be advantageous with calves born and raised in an endemic area of anaplasmosis and babesiosis. Tick and gastrointestinal parasitic control without haemoparasitic control in calves had an advantage over no control system at all. These methods though were inferior to the immunisation and chemoprophylactic techniques.

Anaplasmosis↗
PubMed2002

Detection of the Anaplasma centralevaccine strain and specific differentiation from Anaplasma marginale in vaccinated and infected cattle.

Bovine anaplasmosis caused by the intraerythrocytic rickettsia Anaplasma marginale is the most prevalent tick-borne disease of cattle worldwide. The most efficient method to control anaplasmosis is by vaccination using live Anaplasma centrale, a closely related species or subspecies of low pathogenicity that is capable of inducing significant protection against the more virulent A. marginale. In the present study, we applied PCR assays to detect and discriminate field infection with A. marginale from A. centrale persistently infected vaccinates. Direct and one-stage nested PCR were based on A. centrale mbp58 specific sequence, with the assay sensitivity level of 0.00001% for nested PCR performed in a single amplification step. Size polymorphism in the A. marginale msp1 alpha gene among strains was used to design a PCR capable of discriminating between the Israel T and NT strains of A. marginale and the encoded MSP1a size polymorphism was confirmed by immunoprecipitation. The detection of A. centrale in 72% of vaccinated field-grazing cattle clearly indicated that the majority of vaccinated cattle remain carriers. A. marginalewas detected in 64% of these vaccinated cattle, demonstrating that, as expected, natural transmission occurs within the endemic region. The lack of severe A. marginaleoutbreaks in this region, despite ongoing transmission, is consistent with protection being provided by widespread vaccination with A. centrale.

Anaplasma↗
PubMed2006

Reduction of tick infections with Anaplasma marginale and A. phagocytophilum by targeting the tick protective antigen subolesin.

Subolesin was recently shown by both gene silencing and immunization with the recombinant protein to protect against tick infestations, and to cause reduced tick survival and degeneration of gut and salivary gland tissues. In this research, we extended these studies by testing whether targeting subolesin by RNAi or vaccination interfered with the ability of ticks to become infected with two tick-borne pathogens, Anaplasma marginale which causes bovine anaplasmosis and Anaplasma phagocytophilum, the causative agent of human granulocytin anaplasmosis. For the A. marginale studies, Dermacentor variabilis males were injected with subolesin dsRNA or saline and then were allowed to feed on cattle with ascending rickettsemias, while for the A. phagocytophilum studies, mice were immunized with the recombinant subolesin protein, infected with the pathogen and then infested with larval Ixodes scapularis. Tick infections were determined by quantitative polymerase chain reaction of gut and salivary gland tissues. In both experimental approaches, tick infections were significantly reduced. These results suggest that subolesin appears to be a candidate vaccine antigen that may contribute to control of multiple tick species and the reduction of tick-borne pathogens.

Anaplasma marginale↗
PubMed2006

Estimated direct economic costs associated with tick-borne diseases on cattle in Tanzania.

Tick-borne diseases, namely, anaplasmosis, babesiosis, cowdriosis and theileriosis, constrain cattle production and improvement in Tanzania, leading to considerable economic losses. A simple spreadsheet model was used to estimate the economic losses resulting from production losses, treatment and control costs associated with tick-borne diseases (TBD) in Tanzania. Model parameters included the national cattle population, reported TBD morbidity, fatality risk, and chemotherapy and control measures used. The total annual national loss due TBD was estimated to be 364 million USD, including an estimated mortality of 1.3 million cattle. Theileriosis accounted for 68% of the total loss, while anaplasmosis and babesiosis each accounted for 13% and cowdriosis accounted for 6% of the total loss. Costs associated with mortality, chemotherapy and acaricide application accounted for 49%, 21% and 14% of the total estimated annual TBD losses, respectively, infection and treatment method milk loss and weight loss accounted for 1%, 6% and 9% of the total annual loss, respectively. Despite the inadequacies of the data used, the results give evidence that tick-borne diseases inflict substantial economic losses on cattle production and resource use in Tanzania.

Anaplasmosis↗
PubMed1995

Strategies for the control of one-host ticks and relationship with tick-borne diseases in South America.

A variety of hemoparasites occurs in ruminants of South America (12 degrees 00'N-56 degrees 00'S), but there is consensus on the significant economic impact of babesiosis (Babesia bovis and Babesia bigemina) and anaplasmosis (Anaplasma marginale). The tick vector for the Babesia spp. for the whole region is Boophilus microplus which has been the most important target in control/eradication programs. Boophilus microplus and many different hematophagous diptera species are considered vectors of A. marginale. In areas where babesiosis and anaplasmosis are present, the wide range of climates (tropical, subtropical, temperate), husbandry practices (subsistence, extensive, intensive), and tick control strategies has led to the concepts of enzootic stability and instability. Within this framework, six control strategies for Boophilus microplus can be identified: (1) absolute tick control--with the establishment of quarantine areas and the implementation of state legislation; (2) absolute tick control in marginal areas--using local epidemiological knowledge, strategic treatments, quarantine areas and the intervention of the state; (3) prophylactic treatment--with a predetermined acaricide treatment schedule aimed at reducing tick burdens to an acceptably low level; (4) threshold treatment--acaricides are applied by the farmer whenever the number of ticks on cattle exceed a threshold level; (5) opportunistic treatment--acaricides are applied when cattle are assembled for other purposes; (6) integrated tick control--principally involving the combination of acaricides with the use of tick-resistant crossbred cattle.

Anaplasmosis↗