Important Clinical Features of Japanese Spotted Fever.

Masamitsu Noguchi,Naohisa Yamazoe,Yousuke C Takemura,Mitsukazu Miyazaki,Shizuka Oshita

doi:10.4269/ajtmh.17-0576

Abstract

.Japanese spotted fever (JSF) is a zoonosis transmitted by ticks carrying the pathogen Rickettsia japonica. The classic triad of JSF symptoms is high fever, erythema, and tick bite eschar. About 200 people in Japan develop the disease every year. Japanese spotted fever is also a potentially fatal disease. At Minami-Ise Municipal Hospital in Japan, 55 patients were diagnosed with JSF from 2007 to 2015, which was equivalent to 4.3% of the total JSF cases in Japan. In this retrospective study, we examined the medical records of these 55 JSF cases. Fever, erythema, eschar, and elevated C-reactive protein (CRP) are characteristic clinical features of the disease. We confirmed four of these in the reviewed cases; however, eschar was not present in occasional cases. We confirmed that eosinopenia appeared in nearly all cases. Using fever, erythema, elevated CRP, and eosinopenia in diagnostic screening, our positivity rate was 90.9%. In our clinical practice, including eosinopenia improves the initial diagnosis of JSF.

Highlights

Japanese spotted fever (JSF) was first described by Mahara et al.[1] in 1984
At Minami-Ise Municipal Hospital in Japan, 55 patients were diagnosed with JSF from 2007 to 2015, which was equivalent to 4.3% of the total JSF cases in Japan
We examined the medical records of these 55 JSF cases

Summary

Introduction

Japanese spotted fever (JSF) was first described by Mahara et al.[1] in 1984. Japanese spotted fever emerges mainly during warm seasons, from April to November.[2,3] The disease occurs mainly in warm areas along the Pacific side of southwest and central Japan[2,4,5,6]; there have been reports of cases along the Sea of Japan coast and Korea.[7,8,9] In Mie Prefecture, JSF has been reported on the south side of the Miya River,[10] an area that includes the town of Minami-Ise. Over a nearly 8-year period from May 2007 to January 2015, there were 1,276 cases of JSF reported in Japan, with 277 cases in Mie Prefecture (21.7% of the total for Japan) and 55 cases at MinamiIse Municipal Hospital (4.3% of the total for Japan). Japanese spotted fever is caused by Rickettsia japonica. The main laboratory findings among JSF cases include leukocytosis or leukopenia, thrombocytopenia, elevated C-reactive protein (CRP), and elevated liver enzymes.[2,3]

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