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Tickborne relapsing fever diagnosis obscured by malaria, Togo.
Umeå University, Faculty of Medicine, Molecular Biology (Faculty of Medicine). (Bergström)
Umeå University, Faculty of Medicine, Molecular Biology (Faculty of Medicine). (Bergström)
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2007 (English)In: Emerging Infectious Diseases, ISSN 1080-6040, E-ISSN 1080-6059, Vol. 13, no 1, 117-123 p.Article in journal (Refereed) Published
Abstract [en]

Given the prevalence of relapsing fever (RF) in Senegal, this disease may cause illness and death in other areas of West Africa. We performed a cross-sectional, clinic-based study to investigate the presence of RF in Togo during 2002-2004. Blood samples from patients with fever were examined for RF spirochetes by microscopy, PCR, and DNA sequencing of amplicons and for antibodies to the glycerophosphodiester phosphodiesterase antigen. Although no spirochetes were seen in blood smears, approximately 10% of the patients were positive by PCR and approximately 13% were seropositive for spirochetes. DNA sequencing demonstrated that Borrelia crocidurae and B. duttonii were present. Most patients were treated for malaria whether or not plasmodia were observed. Thus, many RF patients originally had a misdiagnosis of malaria, which resulted in ineffective treatment. The inability of microscopic analysis to detect spirochetes compared with PCR demonstrates the need for tests with greater sensitivity.

Place, publisher, year, edition, pages
2007. Vol. 13, no 1, 117-123 p.
Keyword [en]
Adolescent, Adult, Anti-Bacterial Agents/therapeutic use, Antimalarials/therapeutic use, Child, Child; Preschool, Female, Humans, Infant, Malaria/*complications/drug therapy/*epidemiology, Male, Relapsing Fever/*complications/*diagnosis/drug therapy/epidemiology, Togo/epidemiology
Identifiers
URN: urn:nbn:se:umu:diva-12891PubMedID: 17370524OAI: oai:DiVA.org:umu-12891DiVA: diva2:152562
Available from: 2007-10-03 Created: 2007-10-03 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Pathobiology of African relapsing fever Borrelia
Open this publication in new window or tab >>Pathobiology of African relapsing fever Borrelia
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Relapsing fever (RF) is a disease caused by tick- or louse-transmitted bacteria of the genus Borrelia. It occurs worldwide but is most common in Africa where it is one of the most prevalent bacterial diseases. The main manifestation is a recurring fever which coincides with massive numbers of bacteria in the blood. Severity ranges from asymptomatic to fatal.

RF is usually considered a transient disease. In contrast, B. duttonii causes a persistent, residual brain infection in C57BL/6 mice which remains long time after the bacteria are cleared from the blood. The host gene expression pattern is indistinguishable from that of uninfected animals, indicating that persistent bacteria are not recognized by the immune system nor do they cause noticeable tissue damage. This is probably due to the quite low number of bacteria residing in the brain. The silent infection can be reactivated by immunosuppression allowing bacteria to re-enter the blood. To investigate if the residual infection is in a quiescent state or if the bacteria are actively dividing, mice with residual brain infection were treated with the cell-wall disrupting antibiotic ceftriaxone, which is only active against dividing bacteria. Since all mice were cured by ceftriaxone we conclude that the bacteria are actively growing in the brain rather than being in a latent, dormant state. The brain is used as an immunoprivileged site to escape host immune defence and probably as a reservoir for bacteria.

RF is a common cause of pregnancy complications, miscarriage and neonatal death in sub-Saharan Africa. We established a murine model of gestational relapsing fever to study the pathological development of these complications. B. duttonii infection during pregnancy results in intrauterine growth retardation as well as placental damage and inflammation. Spirochetes cross the maternal-foetal barrier, resulting in congenital infection. Further, pregnancy has a protective effect, resulting in milder disease during pregnancy.

A clinic-based study to investigate the presence of RF in Togo was performed. Blood from patients with fever were examined for RF by microscopy, GlpQ ELISA and PCR. About 10% of the patients were positive by PCR and 13% had antibodies to GlpQ. Many RF patients originally had a misdiagnosis of malaria, which resulted in ineffective treatment. The inability of microscopic analysis to detect spirochetes demonstrates the need for tests with greater sensitivity. To provide simple, fast, cheap and sensitive diagnostics using equipment available in small health centres, a method based on enrichment of bacteria by centrifugation and detection by Giemsa staining was developed which detects <10 spirochetes/ml.

To study the phylogeny of RF, IGS and glpQ were sequenced and neighbor joining trees were constructed. B. persica and B. hispanica were distant from the other species iswhereas B. crocidurae appeared to be a heterogeneous species. B. duttonii is polyphyletic in relation to B. recurrentis suggesting that the two species may in fact be the same or have a polyphyletic origin.

Place, publisher, year, edition, pages
Umeå: Molekylärbiologi (Medicinska fakulteten), 2007. 92 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1137
Keyword
borrelia, persistence, meningitis, pregnancy, latency, immune privileged sites
National Category
Microbiology in the medical area
Identifiers
urn:nbn:se:umu:diva-1452 (URN)978-91-7264-430-4 (ISBN)
Public defence
2007-12-14, Major Groove, 6L, Inst. Molekylärbiologi, UMEÅ, 09:00 (English)
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Available from: 2007-11-26 Created: 2007-11-26 Last updated: 2009-05-27Bibliographically approved

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