Jpn. J. Infect. Dis., 57, 229-235, 2004
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Invited Review
Terrestrial Distribution of the Lyme Borreliosis Agent Borrelia burgdorferi Sensu Lato in East Asia
Toshiyuki Masuzawa*
Department of Microbiology and COE Program in the 21st Century, University of Shizuoka School of Pharmaceutical Sciences, Shizuoka 422-8526, Japan
(Received September 3, 2004)
*Corresponding author: Mailing address: Department of Microbiology and COE Program in the 21st Century, University of Shizuoka School of Pharmaceutical Sciences, Yada 52-1, Shizuoka 422-8526, Japan. Tel: +81-54-264-5710, Fax: +81-54-264-5715, E-mail: masuzawa@u-shizuoka-ken.ac.jp
This article is an Invited Review based on a lecture presented at the 5th Infectious Diseases Forum at the National Institute of Infectious Diseases, Tokyo, 19 - 20 January 2004.
CONTENTS:
1. Introduction
2. Lyme borreliosis agents and their classification
3. Relationship to the Borrelia burgdorferi sl complex
3-1. Transmission
3-2. Vectors
3-3. Reservoir
3-4. Clinical manifestation
4. B. burgdorferi sl complex found in Japan
5. Geographical distribution of B. burgdorferi sl in East
Asia
6. Geographical distribution of B. burgdorferi sl in the
boundary between Asia and Europe
7. Conclusion
SUMMARY: Lyme borreliosis is the most prevalent tick-borne zoonosis and an important emerging infection in Europe, North America, and Far Eastern countries. The geographical distribution of Borrelia spp. and the relationship between Borrelia spp. and tick spp. in East Asian countries have been studied. In Northern Asian countries, Ixodes persulcatus carries Eurasian-type Borrelia garinii (20047 type), Borrelia afzelii, and Asian-type B. garinii (variant NT29), whereas Borrelia burgdorferi sensu stricto has not been isolated. In contrast, Asian-type B. garinii has not been found in the European vector tick Ixodes ricinus. These Borrelia spp. cause Lyme borreliosis in their respective countries. The specificity between Borrelia spp. and tick spp. has been confirmed from studies in the Moscow region, which is a sympatric region for the tick spp. I. persulcatus and I. ricinus. In Southeast Asian countries including the southernmost island of Okinawa, the Borrelia valaisiana-related genomic group is carried by Ixodes granulatus. In Japan, a similar borrelia strain Am501, is transmitted by Ixodes columnae. Ixodes ovatus transmits Borrelia japonica but not other species. On other hand, in central China and Nepal, the ticks harbor Borrelia sinica. It is believed that these molecular epidemiological surveys will provide useful information for the diagnoses and prevention of Lyme borreliosis in these countries.