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At least 973 records · Page 54Linked to original sources

PubMed2004

Seroprevalence of tick-borne infections in forestry rangers from northeastern Italy.

The aim of this study was to estimate the seroprevalence of antibodies to Borrelia burgdorferi, Anaplasma phagocitophilum and tick-borne encephalitis (TBE) virus, and risk factors, in forestry rangers from the Friuli-Venezia-Giulia region in northeastern Italy. Sera from 181 forestry rangers were examined with two-tiered serological tests for TBE, Lyme borreliosis and ehrlichiosis. Information about risk factors such as job location, residence, number of tick bites and outdoor leisure activities was collected with a questionnaire. Seropositivity was 0.6% for TBE virus, 23.2% for Lyme borreliosis and 0.6% for ehrlichiosis. Lyme borreliosis positivity, as determined by Western blot, was associated with working in the foothills, with gardening in the northeastern part of the region, and with a history of yearly tick bites. Risk factors were similar when a case of Lyme borreliosis was defined either by Western blot positivity or by clinical history.

Adult↗

PubMed2006

Seroprevalence of human granulocytic anaplasmosis in Berlin/Brandenburg, Germany: an 8-year survey.

This study investigated the seroprevalence of antibodies against Anaplasma phagocytophilum in Berlin/Brandenburg, north-eastern Germany. During 1994-2001, 422 sera from patients with proven tick-exposure (specimens with antibodies against Borrelia burgdorferi) were compared with 249 control sera. Using indirect fluorescent antibody testing, significantly more positive samples were detected among Borrelia antibody-positive specimens (4.5%, 95% CI 2.5-6.5%) than among controls (1.2%, 95% CI 0.5-1.9%; p < 0.05). While six (2.2%, 95% CI 1.3-3.1%) samples were positive among Borrelia antibody-positive sera between 1994 and 1997, 13 (8.7%, 95% CI 6.9-10.5%) were positive between 1998 and 2001 (p < 0.01), indicating an uneven annual seroprevalence.

Adolescent↗

PubMed1998

Bovine babesiosis and anaplasmosis follow-up on cattle relocated in an endemic area for hemoparasitic diseases.

A multiplex PCR/DNA probe assay was used to monitor Babesia bovis, B. bigemina and Anaplasma marginale infection in cattle introduced to a Boophilus microplus-infested area in Veracruz, Mexico. Eight intact, 18-month-old, cross-bred beef cattle (four naive, Group A; four Babesia species--premunized, Group B) were immediately exposed to ticks after arrival and were clinically monitored from day 6 to day 98 post-exposure (PE) to ticks. Blood sample analysis for DNA detection by the MPCR/DNA probe assay showed that Group A animals were infected with B. bovis from day 11 up to day 22 PE, requiring treatment on days 17-20. Group B animals were detected positive to B. bovis on days 17-20, did not require treatment and remained persistently infected from days 70 to 84 PE. Treatment of Group A animals delayed the infection with B. bigemina. These animals became positive to the parasite on days 63-77 PE. In contrast, Group B animals (untreated) showed B. bigemina infection on days 21-26 and 63-84 PE. One animal was positive for A. marginale infection on days 63-66 PE, the rest of the animals became so on days 80-98 PE. All infected animals required treatment with oxytetracycline. Monitoring the triple hemoparasite infection with the MPCR/DNA probe assay provided important epidemiological information. Thus, precautionary measures can be established when cattle are moved to a babesiosis/anaplasmosis risk area.

Anaplasma↗

PubMed2000

Anaplasmosis control. Past, present, and future.

Control methods for anaplasmosis have not changed markedly during the past 50 years and include arthropod control, chemoprophylaxsis, vaccination, and maintenance of an Anaplasma-free herd. Control measures implemented vary with geographic location, and depend on availability, cost, and the feasibility of application. Vaccination has been an effective means of preventing outbreaks of anaplasmosis, but these vaccines, both live and inactivated, are dependent on bovine blood as the source of infection or antigen. Blood-derived vaccines are difficult to standardize and bear the risk of transmitting other bovine pathogens inapparent at the time of blood collection. Extensive purification is required to remove bovine cell membranes, which may cause side effects. Most importantly, geographic isolates of A. marginale are often not cross-protective. Development of a tick cell culture system for A. marginale shows promise as a source of antigen for development of an improved inactivated vaccine in the near future that is free from bovine pathogens. Development of an antigenically defined molecular vaccine appears to be a realistic goal, although further research is required to determine epitopes involved in both humoral and cellular immunity, to define antigenic variation during cyclic rickettsemia, and to develop effective delivery systems for optimization of the immune response.

Anaplasma↗

PubMed2002

Tick-borne diseases (TBDs) of dairy cows in a Mediterranean environment: a clinical, serological, and hematological study.

A longitudinal study of tick-borne diseases (TBDs) in Southern Italy was carried out by monitoring two dairy farms (A and B) located in the Apulia Region. On each farm ten calves and ten heifers were observed monthly from May 1999 to February 2001 for clinical signs and blood parameters; antibodies against Babesia bigemina and Anaplasma marginale using an ELISA test were also monitored for the first eight months of the study. Totals of 28 and 14 cases of TBDs were observed in the complete herds of Farms A and B, respectively. Timing of disease appearance, categories of animals affected and changes in blood parameters are discussed.

Anaplasma↗

PubMed2003

Genetic diversity of bacterial agents detected in ticks removed from asymptomatic patients in northeastern Italy.

A total of 360 ticks were removed from 353 asymptomatic subjects in Belluno Province, Italy and surrounding areas, from 1998 to 2001. Ticks were identified as Ixodes ricinus (357), Ixodes hexagonus (1), Rhipicephalus sanguineus (1), and Ixodes ventalloi (1). Tick DNA was investigated by PCR and subsequent sequencing of amplified products to identity associated bacterial agents. Primers targeting different genes of Rickettsia (gltA and OmpA), Borrelia (16S rDNA, rpoB), Francisella (16S rDNA), and all genera members of the Anaplasmataceae (16S rDNA), were used. DNA of bacterial agents was identified in 28 Ixodes ricinus specimens (7.8%). Rickettsia helvetica was detected in 7 ticks. Rickettsia sp. IRS4 and Borrelia afzelii was detected in 4 ticks each. B. garinii and B. valaisiana were identified in one tick each. Anaplasma phagocytophilum, the agent of human granulocytic ehrlichiosis, was identified in 1 specimen of I. ricinus. A new Ehrlichia sp. ("Candidatus Ehrlichia walkerii", sp. nov.) was identified in 10 I. ricinus specimens.

Anaplasma phagocytophilum↗

PubMed2003

Human granulocytic ehrlichiosis in Slovenia.

Several reports indicate the presence of infection with Anaplasma phagocytophila in Europe. The first case with confirmed human granulocytic ehrlichiosis was reported from Slovenia in 1997. By 2002, 13 patients have been discovered in a prospective study on the etiology of febrile illnesses occurring within six weeks following a tick bite, conducted at the Department of Infectious Diseases, University Medical Centre, Ljubljana, Slovenia. The diagnosis was established by molecular identification of ehrlichial organisms and/or by seroconversion to A. phagocytophila. None of the patients had detectable morulae on blood smear examination. Clinical characteristics and laboratory findings were similar to those reported from the United States. The severity of the illness was mild to moderately severe. All patients recovered rapidly and without sequelae. HGE should be included in the differential diagnosis of febrile illnesses occurring after a tick bite in Slovenia.

Adult↗

PubMed2003

Early induction and late abrogation of respiratory burst in A. phagocytophilum-infected neutrophils.

Human granulocytic ehrlichiosis is an emerging tick-borne disease caused by the obligate intracellular pathogen, Anaplasma phagocytophilum. This organism is unique because it survives and propagates in neutrophil vacuoles. During phagocytosis professional phagocytes increase oxygen consumption (respiratory burst) through the activity of NADPH-oxidase, which generates superoxide anion (O2(-)) and hydrogen peroxide (H(2)O(2)). We assayed the ability of A. phagocytophilum-infected neutrophils to generate O2(-) in response to early infection (0, 3, and 5 hours) by using 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), a fluorogenic probe commonly used to detect cellular production of reactive oxygen species (ROS). Our flow cytometric analyses showed that cell-free A. phagocytophilum induced respiratory burst 6.9-fold greater than that of LPS, an effect still evident to a lesser degree after 3 h, but absent by 5h. A. phagocytophilum initially induces and then represses respiratory burst in neutrophils. The long-term reduction in respiratory burst activity may be important for survival of A. phagocytophilum and other infectious agents in neutrophils. The effect of this may be to generate a limited functional equivalent of chronic granulomatous disease that predisposes to infections by opportunistic pathogens.

Anaplasma phagocytophilum↗

PubMed1978

A comparison of 4 serological tests in the detection of humoral antibodies to anaplasmosis in cattle.

A capillary agglutination (CA), a complement fixation (CF), a plate agglutination (PT) and an indirect fluorescent antibody (IFA) test to detect humoral antibodies to Anaplasma marginale are described. Serums from 3, 4 or 5 groups of cattle were used to examine the efficiency of the tests. Agreement between all 4 tests was 86.6%. Agreement between pairs of tests was greater. The CF test was the most sensitive while the PT test was the least sensitive. However the PT could be carried out very rapidly and was suggested as the best screening test, providing improved antigen preparation techniques could increase sensitivity. The CA, CF and IFA tests all showed a stronger homologous antibody reaction when A. marginale antigen was tested against serums obtained from cattle infected with either A. marginale or A. centrale. Antibodies in the A. marginale serums were first detected by day 7 post-inoculation, rose to peak around day 29 and were still present on day 200. Antibodies in the A. centrale serums were first detected by day 29 rose to a peak around day 50 and had disappeared by day 150.

Agglutination Tests↗

PubMed1988

Bovine leucosis virus contamination of a vaccine produced in vivo against bovine babesiosis and anaplasmosis.

Contamination of a batch of tick fever (babesiosis and anaplasmosis) vaccine with bovine leucosis virus (BLV) was detected when a herd, in the final stages of an enzootic bovine leucosis (EBL) accreditation program, developed a large number of seropositive cattle following use of tick fever vaccine. Investigations incriminated a single calf used to produce Anaplasma centrale vaccine from which 13,959 doses were distributed. The failure of this calf to give a positive agar gel immunodiffusion (AGID) test before use was not fully explained. A total of 22,627 cattle from 111 herds receiving contaminated vaccine was tested to validate claims for compensation. Results showed infection rates of 62% and 51.8% in vaccinated dairy and beef cattle, respectively, compared with 6.1% and 1.5% in non-vaccinated cattle in the same herds. The results also indicated that infection did not spread from vaccinated to non-vaccinated in-contact cattle. Heavy reliance is now placed on purchase of calves for vaccine production from EBL accredited-free herds and on transmission tests from the calves to sheep to prevent a recurrence of contamination. The need for a BLV antigen detection test, with the sensitivity of the sheep transmission test but simpler and faster to perform, is evident.

Anaplasma↗

PubMed2003

Serological evidence of exposure to tick fever organisms in young cattle on Queensland dairy farms.

OBJECTIVES: To compare the features of farms on which the exposure of young cattle to tick fever organisms is sufficient to ensure that immunity is high and the risk of clinical disease is low (endemic stability) with those of farms on which exposure is insufficient to induce widespread immunity (hence without endemic stability); to examine the relationships between the management of ticks and tick fever, and endemic stability to Babesia bovis, B. bigemina and Anaplasma marginale. DESIGN: Cross-sectional study of 874 cattle between the ages of 6 and 15 months on 64 dairy farms, from three centres in south-eastern Queensland (Mutdapilly, Dayboro and Kenilworth) and one centre in far-north Queensland (Malanda). PROCEDURE: Blood samples collected from between 5 and 20 calves from each farm were submitted for serological assay to determine exposure to B. bovis, B. bigemina and A. marginale. A questionnaire about the farm characteristics and the management of ticks and tick fever was completed with each farmer. RESULTS: On 73% of farms, confirmed clinical cases of tick fever were recalled by the farmer, indicating that tick fever was a threat on most farms. The majority of herds in the study (54 of 64) did not have sufficient numbers of seropositive animals aged between 6 and 15 months to have a low risk of tick fever. Region had an effect on the likelihood of endemic stability for all tick fever organisms. Cattle near Malanda in Far-north Queensland were more likely to be seropositive to B. bovis and B. bigemina. The method, strategy and intensity of tick control were not related to the likelihood of endemic stability when the effect of region was considered. The decision to leave a few ticks on cattle in an effort to induce endemic stability did increase the likelihood of endemic stability to A. marginale. However, in practical terms, it was ineffective, because only 26% of these farms had endemic stability against all three organisms. CONCLUSIONS: Given the low proportion of farms that have endemic stability to the tick fever organisms and the high likelihood of clinical disease, vaccination is recommended to protect dairy cattle from tick fever throughout the tick infested area of Queensland. However, further work is required to determine the economic value of vaccination, taking into account the costs of vaccination, of outbreaks and the protective value of vaccination.

Anaplasma marginale↗

PubMed2002

Transcript heterogeneity of the p44 multigene family in a human granulocytic ehrlichiosis agent transmitted by ticks.

Human granulocytic ehrlichiosis (HGE) is an emerging tick-borne zoonosis caused by a strain of Anaplasma phagocytophila called the HGE agent, an obligatory intracellular bacterium. The agent expresses immunodominant 44-kDa outer membrane proteins (P44s) encoded by a multigene family. The present study established an experimental process for transmission of the HGE agent from infected mice (a reservoir model) to nymphal Ixodes scapularis ticks (a biological vector) and subsequently to horses (a patient model) by the adult infected ticks. Overall, a total of 20 different p44 transcripts were detected in the mammals, ticks, and cell cultures. Among them, a transcript from a p44-18 gene was major at acute stage in mice and horses but minor in ticks. Both mRNA and protein produced from the p44-18 gene were detected in the HGE agent cultivated in HL-60 cells at 37 degrees C, but their expression levels decreased in the organisms cultivated at 24 degrees C, suggesting that temperature is one of the factors that influence the expression of members of the p44 multigene family. Several additional p44 transcripts that were not detected in the mammals at the acute stage of infection were detected in ticks. Phylogenetic analysis of the 20 different p44 transcripts revealed that the major transcripts found in mammals and ticks were distinct, suggesting a difference in surface properties between populations of the HGE agent in different host environments. The present study provides new information for understanding the role of the p44 multigene family in transmission of the HGE agent between mammals and ticks.

Amino Acid Sequence↗

PubMed2005

Molecular evidence of tick-transmitted infections in dogs and cats in the United Kingdom.

PCR analysis was used to determine the prevalence of tick-transmitted infections in 120 systemically ill dogs and 60 cats recruited over a period of three months from 52 veterinary practices in the UK. The animals had not travelled outside the UK and had one or more of the following clinical criteria: acute or recurrent pyrexia, anaemia and/or thrombocytopenia, polyarthritis/muscle pain, splenomegaly/lymphadenopathy, and intraocular inflammation with systemic signs. Blood samples from the animals were tested for the presence of DNA from Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum by using simple PCR targeting. B. burgdorferi sensu lato was detected in five dogs and two cats, and A. phagocytophilum was detected in one dog and one cat. These results provide the first molecular evidence of naturally occurring B. burgdorferi sensu lato infection in cats in the UK and confirm that A. phagocytophilum infection is present in cats. There were no statistically significant associations between the infections and the clinical signs shown by the dogs and cats.

Anaplasma phagocytophilum↗

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↗

PubMed2006

Use of serum C-reactive protein as an early marker of inflammatory activity in canine type II immune-mediated polyarthritis: case report.

BACKGROUND: Monitoring systemic inflammatory activity during steroid therapy of canine immune-mediated polyarthritis (IMPA) is difficult and mainly relies on clinical signs. CASE PRESENTATION: Canine serum C-reactive protein (CRP) was measured serially and blinded during a 27-week follow-up period of a case of Anaplasma phagocytophilia induced type II immune-mediated polyarthritis. CONCLUSION: WBC was, as expected, observed not to reflect the inflammatory activity during steroid treatment in a clinical useful manner, whereas, CRP is suggested a valuable unbiased marker of inflammatory activity during steroid treatment in this case.

Anaplasma phagocytophilum↗

PubMed2005

Enhancement of antigen acquisition by dendritic cells and MHC class II-restricted epitope presentation to CD4+ T cells using VP22 DNA vaccine vectors that promote intercellular spreading following initial transfection.

Induction of immune responses against microbial antigens using DNA is an attractive strategy to mimic the immunity induced by live vaccines. Although DNA vaccines are efficacious in murine models, the requirement for multiple immunizations using high doses in outbred animals and humans has hindered deployment. This requirement is, in part, a result of poor vaccine spreading and suboptimal DC transfection efficiency. Incorporation of a signal that directs intercellular spreading of a DNA-encoded antigen is proposed to mimic live vaccine spreading and increase dendritic cell (DC) presentation. Bovine herpes virus 1 tegument protein, BVP22, is capable of trafficking to surrounding cells. To test the hypothesis that BVP22 enhances spreading and antigen presentation to CD4+ T cells, a DNA construct containing BVP22, fused in-frame to a sequence encoding a T cell epitope of Anaplasma marginale, was generated. A construct with reversed BVP22 sequence served as a negative control. Immunocytometric analysis of transfected primary keratinocytes, human embryonic kidney 293, COS-7, and Chinese hamster ovary cells showed that BVP22 enhanced intercellular spreading by > or = 150-fold. Flow cytometric analysis of antigen-presenting cells (APCs) positively selected from cocultures of transfected cells and APCs showed that 5% of test APCs were antigen-positive, compared with 0.6% of control APCs. Antigen-specific CD4+ T cell proliferation demonstrated that BVP22 enhanced DC antigen presentation by > or = 20-fold. This first report of the ability of BVP22 to increase DNA-encoded antigen acquisition by DCs and macrophages, with subsequent enhancement of major histocompatibility complex class II-restricted CD4+ T cell responses, supports incorporating a spreading motif in a DNA vaccine to target CD4+ T cell-dependent immunity in outbred animals.

Anaplasma marginale↗

PubMed2005

Innate immune tissue injury and murine HGA: tissue injury in the murine model of granulocytic anaplasmosis relates to host innate immune response and not pathogen load.

Anaplasma phagocytophilum is an obligate intracellular tick-borne bacterium that propagates within neutrophils and causes human and animal granulocytic anaplasmosis (HGA). In the murine model of HGA, host immune response plays a more important role in histopathologic lesions than does pathogen load. We examined the role of CYBB, NOS2, and TNFalpha as effectors of innate immune-related injury. Our hypothesis is that the innate immune response to A. phagocytophilum results in inflammatory histopathology, but does not control the pathogen.

Anaplasma phagocytophilum↗

PubMed2006

Molecular diagnosis of granulocytic anaplasmosis and infectious cyclic thrombocytopenia by PCR-RFLP.

Anaplasma phagocytophilum (A. phagocytophilum, formerly Ehrlichia phagocytophila) is a tick-borne pathogen responsible for tick-borne fever in ruminants, equine granulocytic ehrlichiosis (EGE) in horses, canine granulocytic ehrlichiosis (CGE) in dogs, and for human granulocytic ehrlichiosis (HGE). Human cases have been registered in many countries with a broad range of symptoms and pathogenicity. This article focused on Sardinia as the prevalence in humans was almost seven times higher than in the rest of Italy. To evaluate the risk, blood samples were collected from dogs and horses on the island. Genomic DNA was extracted from the buffy coat and amplified by heminested polymerase chain reaction (PCR) using the groEL gene primers. The first PCR reaction amplified a 624-bp fragment for both A. phagocytophilum and A. platys while the second PCR reaction amplified 573-bp and 515-bp fragments for the above two pathogens, respectively. Six A. phagocytophilum samples were PCR positive (3 dogs and 3 horses) while another dog was A. platys PCR positive. A phylogenetic analysis was conducted with A. phagocytophilum sequences in GenBank from the United States, Slovenia, Switzerland, Germany, UK, Austria, and Czech Republic. Surprisingly, the related phylogenetic tree showed that the Sardinian isolates were closer to the American isolates, which were showing highest mortality rates than from the other two European lineages.

Anaplasma phagocytophilum↗