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  • 1.
    Andersson, Marie
    Umeå University, Faculty of Medicine, Molecular Biology (Faculty of Medicine).
    Immunopathogenesis of relapsing fever borreliosis2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Relapsing fever (RF) is caused by different species of Borrelia transmitted by soft ticks or by the human body louse. Illness is characterized by reappearing peaks of high concentrations of spirochetes in blood, concordant with fever peaks separated by asymptomatic periods. Neuroborreliosis is one of the most severe manifestations of RF borreliosis. To understand the immune response during early RF, we analyzed immune cells in brain and kidney of mice infected with B. crocidurae during the acute infection. Our results indicate that brain defense is comprised primarily of innate immune cells. Despite the infiltration of innate immune cells, Borrelia was not completely eradicated. A failure of the host brain to clear the bacteria may give the pathogen a niche where it can persist. Using our mouse model, we revealed that Borrelia duttonii could persist in the mouse brain for up to 270 days, without being present in the circulation. The infection was silent with no change in host gene expression, and the spirochetes could re-enter the circulation after immunosuppression. We propose that the brain is used by the pathogen to evade host immunity and serves as a possible natural reservoir for B. duttonii, a spirochete that has rarely been found in any mammalian host other than man. Borrelia-induced complications during pregnancy have been reported, and are especially common in RF. In our established mouse model of gestational RF, we could show that the fetuses suffered from severe pathology and growth retardation, probably as a consequence of placental destruction. We could also show trans-placental transmission of the bacteria leading to neonatal RF. Surprisingly, pregnant dams had a lower bacterial load and less severe disease, showing that pregnancy has a protective effect during RF. We have used the gestational RF model to investigate host factors favoring disease resolution. Because the spleen is the primary organ responsible for trapping and removing blood-borne pathogens, we have compared temporal changes in spleen immune cell populations and cytokine/chemokine induction during the infection. Spleens of pregnant mice had earlier neutrophil infiltration, as well as faster and higher production of pro-inflammatory mediators. This rapid, robust response suggests a more effective host defense. Thus, an enhanced pro-inflammatory response during pregnancy imparts a distinct advantage in controlling the severity of relapsing fever infection.

  • 2.
    Andersson, Marie
    et al.
    Umeå University, Faculty of Medicine, Molecular Biology (Faculty of Medicine).
    Nordstrand, Annika
    Shamaei-Tousi, Alireza
    Jansson, Anna
    Bergström, Sven
    Umeå University, Faculty of Medicine, Molecular Biology (Faculty of Medicine).
    Guo, Betty P
    Umeå University, Faculty of Medicine, Molecular Biology (Faculty of Medicine).
    In situ immune response in brain and kidney during early relapsing fever borreliosis.2007In: Journal of Neuroimmunology, ISSN 0165-5728, E-ISSN 1872-8421, Vol. 183, no 1-2, p. 26-32Article in journal (Refereed)
  • 3. Ekerfelt, C
    et al.
    Andersson, Marie
    Umeå University, Faculty of Medicine, Molecular Biology (Faculty of Medicine).
    Olausson, A
    Bergström, Sven
    Umeå University, Faculty of Medicine, Molecular Biology (Faculty of Medicine).
    Hultman, P
    Mercury exposure as a model for deviation of cytokine responses in expermental Lyme arthritis: HgCl2 treatment decreases T helper cell type 1-like responses and arthritis severity but delays eradication of Borrelia burgdorferi in C3H/HeN mice.2007In: Clinical and Experimental Immunology, Vol. 150, p. 189-197Article in journal (Refereed)
  • 4.
    Larsson, Christer
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Andersson, Marie
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Bergström, Sven
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Current issues in relapsing fever2009In: Current Opinion in Infectious Diseases, ISSN 0951-7375, E-ISSN 1473-6527, Vol. 22, no 5, p. 443-449Article, review/survey (Refereed)
    Abstract [en]

    PURPOSE OF REVIEW: Relapsing fever has the highest incidence of any bacterial disease in Africa and a massive epidemic potential due to current political turmoil in the Horn of Africa. This review focuses on recent advances in diagnostics, molecular biology and host-pathogen interactions. RECENT FINDINGS: Complete relapsing fever genomes have recently been published, and the first site-specific genetic knockout complementation has been performed. Relapsing fever has gone from being a neglected disease to garnering interest in aspects such as tissue invasion, membrane biochemistry and complement evasion. Relapsing fever symptoms are variable, and the disease is commonly misdiagnosed as, for example, malaria. Although relapsing fever is considered a transient disease, it persists as a residual infection in the brain, which can be reactivated on immunosuppression. Therefore, single-dose antibiotic treatment should be avoided. Instead, treatment should cover a longer period, similar to the recommended regime for Lyme disease. Relapsing fever is a common cause of pregnancy complications such as intrauterine growth retardation and placental damage with spirochaetes crossing the maternal-foetal barrier, resulting in congenital infection. SUMMARY: Although relapsing fever remains a big problem, recently described host-pathogen interactions, diagnostics and molecular biology advances such as completed genome sequences and the dawn of genetic tools have brought relapsing fever research into the 21st century.

  • 5.
    Larsson, Christer
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Andersson, Marie
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Guo, Betty P
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Nordstrand, Annika
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Hägerstrand, Inga
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Carlsson, Sara
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Bergström, Sven
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Complications of pregnancy and transplacental transmission of relapsing-fever borreliosis2006In: Journal of Infectious Diseases, ISSN 0022-1899, E-ISSN 1537-6613, Vol. 194, no 10, p. 1367-1374Article in journal (Refereed)
    Abstract [en]

    Relapsing-fever borreliosis caused by Borrelia duttonii is a common cause of complications of pregnancy, miscarriage, and neonatal death in sub-Saharan Africa. We established a murine model of gestational relapsing fever infection for the study of the pathological development of these complications. We demonstrate that B. duttonii infection during pregnancy results in intrauterine growth retardation, as well as placental damage and inflammation, impaired fetal circulation, and decreased maternal hemoglobin levels. We show that spirochetes frequently cross the maternal-fetal barrier, resulting in congenital infection. Furthermore, we compared the severity of infection in pregnant and nonpregnant mice and show that pregnancy has a protective effect. This model closely parallels the consequences of human gestational infection, and our results provide insight into the mechanisms behind the complications of pregnancy that have been reported in human relapsing-fever infection.

  • 6.
    Larsson, Christer
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Andersson, Marie
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Pelkonen, Jenni
    Guo, Betty
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Nordstrand, Annika
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Bergström, Sven
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Persistent brain infection and disease reactivation in relapsing fever borreliosis2006In: Microbes and infection, ISSN 1286-4579, E-ISSN 1769-714X, Vol. 8, no 8, p. 2213-2219Article in journal (Refereed)
    Abstract [en]

    Relapsing fever, an infection caused by Borrelia spirochetes, is generally considered a transient, self-limiting disease in humans. The present study reveals that murine infection by Borrelia duttonii can be reactivated after an extended time as a silent infection in the brain, with no bacteria appearing in the blood and spirochete load comparable to the numbers in an infected tick. The host cerebral gene expression pattern is indistinguishable from that of uninfected animals, indicating that persistent bacteria are not recognized by the immune system nor cause noticeable tissue damage. Silent infection can be reactivated by immunosuppression, inducing spirochetemia comparable to that of initial densities. B. duttonii has never been found in any host except man and the tick vector. We therefore propose the brain to be a possible natural reservoir of the spirochete. The view of relapsing fever as an acute disease should be extended to include in some cases prolonged persistence, a feature characteristic of the related spirochetal infections Lyme disease and syphilis.

  • 7.
    Lundqvist, Jenny
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Larsson, Christer
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Nelson, Maria
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Andersson, Marie
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Bergström, Sven
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Persson, Cathrine
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Concomitant Infection Decreases the Malaria Burden but Escalates Relapsing Fever Borreliosis2010In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 78, no 5, p. 1924-1930Article in journal (Refereed)
    Abstract [en]

    About 500 million cases of malaria occur annually. However, a substantial number of patients who actually have relapsing fever (RF) Borrelia can be misdiagnosed with malaria due to similar manifestations and geographic distribution of the two diseases. More alarmingly, high prevalence of concomitant infections with malaria and RF Borrelia has been reported. Therefore, we used a mouse model to study the effects of such mixed infection. We observed a 21-fold increase in spirochete titers, whereas the numbers of parasitized erythrocytes were reduced 15-fold. This may be explained by polarization of the host immune response towards the intracellular malaria parasite, resulting in unaffected extracellular spirochetes and hosts that succumb to sepsis. Mixed infection also resulted in severe malaria anemia with low hemoglobin levels, even though the parasite counts were low. Overall, co-infected animals had higher fatality rate and shorter time to death than both malaria and RF single infection. Furthermore, secondary malaria infection reactivated a quiescent RF brain infection, which is the first evidence of a clinically and biologically relevant cue for reactivation of RF Borrelia infection. Our study highlights the importance of investigating concomitant infections in vivo to elucidate the immune responses that are involved in the clinical outcome.

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