Clinical and epidemiological analysis of 18 cases of Japanese spotted fever in Zigui County / 中华检验医学杂志

Objective:The epidemiological and clinical characteristics of 18 cases of Japanese spotted fever (JSF) in Zigui County were analyzed in order to improve the prevention and treatment of JSF.Methods:This is a case series analysis. The epidemiological and clinical data, laboratory tests and imaging characteristics of 18 JSF cases with median age of 60 years (54, 68) identified by The People′s Hospital of Zigui from April 2021 to August 2022 were collected and analyzed retrospectively.Results:Most (17/18) of the patients were farmers and all had a field exposure history. The patient′s onset was from April to October. Spring and autumn were the seasons with the highest incidence of JSF. The first symptoms of patients were high fever, headache, and fatigue. Of the 18 cases, 15 had a rash and 12 presented an eschar and 3 had neither rash nor eschar. In addition, 10 of 18 cases experienced edema of both lower extremities, and 3 got disturbance of consciousness. Laboratory tests found that 15 patients had abnormal white blood cells and 11 patients had decreased platelets. C-reactive protein, procalcitonin, D-dimer, lactate dehydrogenase, and alpha-hydroxybutyrate dehydrogenase were elevated in all patients; 13 patients with elevated alanine aminotransferase, 14 patients with elevated aspartate transamination. Kidney damage caused by Rickettsia japonica infection showed by abnormal proteinuria in 11 of the patients. Conclusions:The most common clinical manifestations of JSF are non-specific indications such as high fever, chills, fatigue, headache. The eschar and rash, which are the main features of Rickettsia infection, are not present in all patients, resulting delay of diagnosis or misdiagnosis. Medical workers should be more alert to rickettsial infections in patients with fever of unknown origin, especially in seasons of high incidence of spotted fever. Early diagnosis and correct antibiotic treatment shall be given according to the patient′s clinical manifestations, laboratory results and imaging test to control disease progression.

Seroprevalence of Rickettsia japonica on an Island Where a Korean Patient with Japanese Spotted Fever was First Identified / 감염과화학요법

BACKGROUND: Spotted fever group rickettsiosis occurs worldwide and includes various causative organisms depending on the region and clinical features. In Korea, previous studies have shown that several kinds of spotted fever rickettsiae have been identified in ticks, and in stored sera obtained from febrile patients. Previously, it was difficult to correlate the results of serologic or molecular biologic tests with the clinical or epidemiological features of this disease in humans. In 2004, the first Korean patient with Japanese spotted fever (JSF) was identified on Mueui Island, Incheon, Korea. To estimate the prevalence of JSF and to compare the incidence of JSF with those of other infectious diseases endemic to Korea, we performed a serosurvey of Japanese spotted fever and other rickettsiosis (scrub typhus and murine typhus), hemorrhagic fever with renal syndrome and leptospirosis on the island where the patient had been living. MATERIALS AND METHODS: In October 2004, we performed a seroprevalence survey of Mueui Island where nearly 300 persons resided. There were 91 persons who participated in the survey and answered the questionnaire. The participants included 30 healthy subjects receiving a check up at the Health Promotion Center at Inha University Hospital, and 30 patients with rheumatoid factor as control groups for the serologic tests. RESULTS: Of the 91 residents, only one person showed a positive reaction to R. japonica at a titer of 1:80. IgG antibodies against O. tsutsugamushi were positive at a titer of 1:32 in 3 persons, and those against R. typhi were at 1:32 in 1 person and at 1:64 in 2 persons. Serum IgG antibodies to Hantan virus were positive at a dilution of 1:64 in 2 persons and those to leptospira were negative. All 30 healthy persons and 30 patients with rheumatoid factor in the control group showed negative results in 1:40 diluted sera. CONCLUSION: This study demonstrates that the seroprevalence of R. japonica is not as high in Korea as it is in Japan. Further studies should be performed in a large number of patients, including residents of other islands and the Korean peninsula.

Seroprevalence of Rickettsia japonica on an Island Where a Korean Patient with Japanese Spotted Fever was First Identified / 감염과화학요법

BACKGROUND: Spotted fever group rickettsiosis occurs worldwide and includes various causative organisms depending on the region and clinical features. In Korea, previous studies have shown that several kinds of spotted fever rickettsiae have been identified in ticks, and in stored sera obtained from febrile patients. Previously, it was difficult to correlate the results of serologic or molecular biologic tests with the clinical or epidemiological features of this disease in humans. In 2004, the first Korean patient with Japanese spotted fever (JSF) was identified on Mueui Island, Incheon, Korea. To estimate the prevalence of JSF and to compare the incidence of JSF with those of other infectious diseases endemic to Korea, we performed a serosurvey of Japanese spotted fever and other rickettsiosis (scrub typhus and murine typhus), hemorrhagic fever with renal syndrome and leptospirosis on the island where the patient had been living. MATERIALS AND METHODS: In October 2004, we performed a seroprevalence survey of Mueui Island where nearly 300 persons resided. There were 91 persons who participated in the survey and answered the questionnaire. The participants included 30 healthy subjects receiving a check up at the Health Promotion Center at Inha University Hospital, and 30 patients with rheumatoid factor as control groups for the serologic tests. RESULTS: Of the 91 residents, only one person showed a positive reaction to R. japonica at a titer of 1:80. IgG antibodies against O. tsutsugamushi were positive at a titer of 1:32 in 3 persons, and those against R. typhi were at 1:32 in 1 person and at 1:64 in 2 persons. Serum IgG antibodies to Hantan virus were positive at a dilution of 1:64 in 2 persons and those to leptospira were negative. All 30 healthy persons and 30 patients with rheumatoid factor in the control group showed negative results in 1:40 diluted sera. CONCLUSION: This study demonstrates that the seroprevalence of R. japonica is not as high in Korea as it is in Japan. Further studies should be performed in a large number of patients, including residents of other islands and the Korean peninsula.