High serum folate values in lambs experimentally infected with Anaplasma phagocytophilum.
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ABSTRACT:
SUBMITTER: Kleppa KE
PROVIDER: S-EPMC1712220 | biostudies-literature | 2003
REPOSITORIES: biostudies-literature
Publications
High serum folate values in lambs experimentally infected with Anaplasma phagocytophilum.
Acta veterinaria Scandinavica 20030101 3-4
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Project description:Anaplasma phagocytophilum has long been known to cause tick-borne fever in ruminants and has been identified more recently as the causative agent of the emerging disease human granulocytic anaplasmosis. The related organism Anaplasma marginale uses gene conversion of the expression site for two major outer membrane proteins (OMPs) to generate extensive sequence and antigenic variation in these OMPs. This is thought to present a continuously varying repertoire of epitopes to the mammalian host and allow disease persistence. Recent genomic and structural data on human strains of A. phagocytophilum, together with animal studies in model systems, have implicated an orthologous OMP of A. phagocytophilum in a similar mechanism of variation. However, to date there has been little investigation of the mechanisms of antigenic variation or disease persistence in hosts naturally infected with field strains of A. phagocytophilum. Approximately 300,000 lambs in Norway suffer severe disease caused by A. phagocytophilum annually. We show here the persistent and cyclic nature of infection in these animals that is accompanied by loosely programmed sequence variation of the major OMP expression site in each rickettsemic peak. These data will allow analysis of interactions between A. phagocytophilum and the host immune system in naturally occurring persistent infections and provide an important comparison with enduring infections of cattle caused by A. marginale.
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Project description:Anaplasma phagocytophilum, which causes the disease tick-borne fever (TBF), is the most important tick-borne pathogen in European animals. TBF may contribute to severe welfare challenges and economic losses in the Norwegian sheep industry. The bacterium causes a persistent infection in sheep and several other animal species. The objective of this study was to investigate whether intrauterine transmission occurs in persistently infected sheep. The study included thirteen 5-6-month-old unmated ewes, of which twelve were experimentally infected with A. phagocytophilum (GenBank acc. no. M73220). Four to six weeks later, all ewes were mated, and nine became pregnant. Blood samples were collected from these ewes and their offspring. If the lamb died, tissue samples were collected. The samples were analyzed with real-time PCR (qPCR) targeting the msp2 gene. PCR-positive samples were further analyzed by semi-nested PCR and 16S rDNA sequencing. A total of 20 lambs were born, of which six died within two days. Six newborn lambs (30%) were PCR-positive (qPCR), of which one was verified by 16S rDNA sequencing. The present study indicates that intrauterine transmission of A. phagocytophilum in persistently infected sheep may occur. The importance of these findings for the epidemiology of A. phagocytophilum needs to be further investigated.
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Project description:Five-month-old lambs were simultaneously infected with different doses of two 16S rRNA genetic variants of Anaplasma phagocytophilum and thereafter followed for clinical observation and blood sampling. The result of the study indicates a unidirectional suppression of genotypes in infected lambs, at least during a certain period of an A. phagocytophilum infection.
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Project description:BackgroundAnaplasma phagocytophilum (formerly Ehrlichia phagocytophila) is an obligate intracellular bacterium causing the disease tick-borne fever (TBF) in domestic ruminants. An effective vaccine against the infection has been demanded for livestock by sheep farmers and veterinary practitioners for years.FindingsIn the present study, we immunized lambs with an inactivated suspension of 1 × 10(8) killed A. phagocytophilum organisms mixed with adjuvant (Montanide ISA 61VG; Seppic). Twelve 9-months-old lambs of the Norwegian White Sheep breed were used. A full two-dose series of immunization was given subcutaneously to six lambs with a 4 week interval between injections. One month after the last immunization, all lambs were challenged with the homologous viable variant of A. phagocytophilum. After challenge, all lambs showed clinical responses for several days, although the immunized lambs reacted with an anamnestic response, i.e. significant reduction in infection rate and a significantly higher antibody titer.ConclusionImmunization with inactivated A. phagocytophilum did not protect lambs TBF.
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Project description:THREE INDEPENDENT REPLICATES AND ARE THE CONTROL NON-INFECTED CELLS: GSM49939, GSM49940, GSM49941 THREE INFECTED INDEPEDENDENT REPLICATES: GSM49942, GSM49943, GSM49944 Keywords: ordered
2005-07-29 | GSE2600 | GEO
Project description:We report Anaplasma phagocytophilum infection of Ixodes persulcatus and I. ovatus ticks in Japan. Unique p44/msp2 paralogs (and/or 16S rRNA genes) were detected in tick tissues, salivary glands, and spleens of experimentally infected mice. These findings indicate the public health threat of anaplasmosis in Japan.
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Project description:The transmission dynamics of Anaplasma phagocytophilum strains circulating within juvenile members of a sheep flock grazing on an Ixodes ricinus-infested pasture in southern Norway were monitored. PCR-based detection of the bacterial p44 fragments in the blood of 16 lambs sampled weekly for 16 weeks following their release into pasture revealed rickettsemia in all animals, with an increasing proportion of infected animals as the survey progressed. Comparison of partial msp4 sequences obtained from infected blood samples revealed 24 distinct genotypes, some of which were repeatedly encountered, occurring in up to six sheep over a 14-week period, whereas others were observed only once. Individual sheep were infected by up to five distinct genotypes, with a specific genotype being encountered for between one and three consecutive weeks, and in some sheep, genotypes detected early in the study were also present in later samples. In general, detection of A. phagocytophilum by PCR correlated well with the observation of infected neutrophils in blood smears. Together these results reveal a previously unrecognized diversity of A. phagocytophilum strains simultaneously circulating within an infected population in an area of endemicity and are consistent with a remarkably dynamic transmission of strains among infected animals.
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Project description:Anaplasma phagocytophilum are obligatory intracellular bacteria that preferentially replicate inside leukocytes by utilizing biological compounds and processes of these primary host defensive cells. In this study, bioinformatics analysis was conducted to further characterize A. phagocytophilum-host interactions using the neutrophil-like model of human Caucasian promyelocytic leukemia HL60 cells. We detected a hierarchy of molecules involved in A. phagocytophilum-HL60 interactions with overrepresentation in infected human cells of proteins involved in the reactive oxygen species (ROS) pathway and cell surface monocyte markers. As A. phagocytophilum phagocytosis by neutrophils is inhibited, the results suggested a possible explanation for our bioinformatics data: radical oxygen compounds could induce the killing of bacteria activating NETosis, a unique form of defense mechanism resulting in cell death that is characterized by the release of decondensed chromatin and granular contents to the extracellular space, forming neutrophil extracellular traps (NETs) to eliminate invading microorganisms. Thus, we confirmed the existence of a low NETosis induced in A. phagocytophilum-infected cells by immunofluorescence (IF) experiments. These results provide new insights into the complex mechanisms that govern immune response during A. phagocytophilum host interactions.
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Project description:Tick-borne encephalitis virus (TBEV) is a zoonotic pathogen which may cause tick-borne encephalitis (TBE) in humans and animals. More than 10,000 cases of TBE are reported annually in Europe and Asia. However, the knowledge on TBE in animals is limited. Co-infection with Anaplasma phagocytophilum and louping ill virus (LIV), a close relative to TBEV, in sheep has been found to cause more severe disease than single LIV or A. phagocytophilum infection. The aim of this study was to investigate TBEV infection and co-infection of TBEV and A. phagocytophilum in lambs. A total of 30 lambs, aged five to six months, were used. The experiment was divided into two. In part one, pre- and post-infection of TBEV and A. phagocytophilum was investigated (group 1 to 4), while in part two, co-infection of TBEV and A. phagocytophilum was investigated (group 5 and 6). Blood samples were drawn, and rectal temperature was measured daily. Lambs inoculated with TBEV displayed no clinical symptoms, but had a short or non-detectable viremia by reverse transcription real-time PCR. All lambs inoculated with TBEV developed neutralizing TBEV antibodies. Our study is in accordance with previous studies, and indicates that TBEV rarely causes symptomatic disease in ruminants. All lambs inoculated with A. phagocytophilum developed fever and clinical symptoms of tick-borne fever, and A. phagocytophilum was present in the blood samples of all infected lambs, shown by qPCR. Significantly higher mean TBEV titer was detected in the group co-infected with TBEV and A. phagocytophilum, compared to the groups pre- or post-infected with A. phagocytophilum. These results indicate that co-infection with TBEV and A. phagocytophilum in sheep stimulates an increased TBEV antibody response.
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Project description:Human granulocytic Anaplasmosis (HGA), is a tick-borne infectious disease transmitted by ticks, resulting in acute feverish episodes. The etiological agent is the bacteria Anaplasma phagocytophilum; which is spread by ticks of the genus Ixodes spp. to complete its life cycle. In Mexico, there is only one case report. The primary challenge is understanding how other bacteria affect or overlap with the clinical manifestation of the disease. Sample collection occurred over the period September 2017 through October 2019. Blood samples from human subjects were obtained immediately after they signed consent forms. We analyzed for the presence for A. phagocytophilum by serological (IFA IgG two times) and PCR targeting 16SrRNA and groEL genes, followed by DNA sequencing. All patients with a history of travel abroad were dismissed for this project. In total, 1924 patients participated and of these, 1014 samples across the country were analyzed. Of these, 85 (8.38%) had IFA results that ranged from 1:384 to 1:896. Of the positive samples, 7.10% were used for PCR. Significant clinical manifestations included: dizziness, nausea, petechial, epistaxis, enlarged liver and/or spleen and thrombocytopenia. Hospitalization of at least 1.5 days was necessary for 3.2% of patients. None of the cases analyzed were lethal. This is the first clinical manifestations along with serological test results and molecular analysis confirmed the presence of A. phagocytophilum resulting in HGA in patients from Mexico. Health institutions and medical practitioners in general should include diagnostic testing for HGA among high risk populations and should recognize it as a vector-borne emerging infectious disease in Mexico.
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