Tick-Borne Relapsing Fever Borreliosis, Rural Senegal | CDC EID

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Volume 17, Number 5–May 2011
Dispatch
Tick-Borne Relapsing Fever Borreliosis, Rural Senegal
Philippe Parola, Georges Diatta, Cristina Socolovschi, Oleg Mediannikov, Adama Tall, Hubert Bassene, Jean François Trape, and Didier Raoult

Author affiliations: Université de la Méditerranée, Marseille, France (P. Parola, G. Diatta, C. Socolovschi, O. Mediannikov, H. Bassene, J.F. Trape, D. Raoult); and Institut Pasteur de Dakar, Dakar, Senegal (A. Tall)

Suggested citation for this article


Abstract
Detecting spirochetes remains challenging in cases of African tick-borne relapsing fever. Using real-time PCR specific for the 16S rRNA Borrelia gene, we found 27 (13%) of 206 samples from febrile patients in rural Senegal to be positive, whereas thick blood smear examinations conducted at dispensaries identified only 4 (2%) as positive.

Tick-borne relapsing fever (TBRF), caused by several species of Borrelia spirochetes, is transmitted to humans through the bites of soft ticks of the genus Ornithodoros (through infected saliva or entry of infected coxal fluid at the bite site) (1). Wild rodents and insectivores are common reservoir hosts. TBRF-endemic foci persist around the world, where each Borrelia species causing relapsing fever appears to be specific to its tick vector. TBRF is responsible for recurring fever associated with spirochetemia. In recent years, the extent of relapsing fever caused by infection with B. crocidurae, transmitted by O. sonrai ticks and its effects on public health have only just begun to emerge. In Senegal, Mali, Mauritania, and the Gambia, where this tick is endemic, 2%–70% of animal burrows are inhabited by this tick vector, and an average of 31% of ticks are infected by B. crocidurae (2,3).

In Senegal, TBRF caused by B. crocidurae was recently determined to be the most common bacterial infection affecting the human population (3). A conventional diagnosis of TBRF is based on the detection of spirochetes in blood smears sampled during the acute febrile phase. However, TBRF is underdiagnosed in most disease-endemic areas, where blood smears are screened only for malaria parasites. Therefore, we used specific semiquantitative PCR to evaluate the role of TBRF as a cause of fever among malaria smear–negative patients in rural Senegal.


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Tick-Borne Relapsing Fever Borreliosis, Rural Senegal | CDC EID


Suggested Citation for this Article
Parola P, Diatta G, Socolovschi C, Mediannikov O, Tall A, Bassene H, et al. Tick-borne relapsing fever borreliosis, rural Senegal. Emerg Infect Dis [serial on the Internet]. 2011 May [date cited]. http://www.cdc.gov/EID/content/17/5/883.htm


DOI: 10.3201/eid1705.100573


Comments to the Authors
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Didier Raoult, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes, UMR CNRS-IRD 6236-198, Faculté de Médecine, 27 Blvd Jean Moulin, 13385 Marseille CEDEX 5, France; email: didier.raoult@gmail.com