Successful dual antiviral therapy with remdesivir and ensitrelvir in a case of prolonged COVID-19 following B-cell depleting immunotherapy for malignant lymphoma.

Prolonged COVID-19 following B-cell depleting immunotherapy for malignant lymphoma is characterized by repeated cycles of remission followed by symptom recurrence, persistent detection of SARS-CoV-2, and profound humoral immunodeficiency. To the best of our knowledge, the present report is the first to describe dual antiviral therapy with remdesivir and ensitrelvir for prolonged COVID-19 following B-cell depleting immunotherapy for malignant lymphoma. A 59-year-old, female patient with a history of follicular lymphoma treated with obinutuzumab and bendamustine contracted COVID-19 despite receiving a single course of standard remdesivir therapy. She received dual antiviral therapy with remdesivir following a five-day course of oral ensitrelvir, which improved her clinical symptoms and chest radiology findings and cleared SARS-CoV-2 from respiratory samples. Dual antiviral therapy with remdesivir and ensitrelvir may be sufficient to stop viral replication and promote clinical resolution in prolonged COVID-19 following B-cell depleting immunotherapy for malignant lymphoma.

Impact of COVID-19 Pandemic on the Influenza Vaccination and Predictors of Influenza Vaccination in Japan: A Cross-sectional Study.

OBJECTIVE: With the current global pandemic of COVID-19, there is concern that an influenza outbreak could exacerbate the health care burden. Improving the influenza vaccination rate is becoming more critical because controlling the spread of influenza is essential for reducing excess mortality. Therefore, we investigated whether the influenza vaccination rate changed during the COVID-19 pandemic in Japan and identified the factors associated with influenza vaccination uptake. DESIGN: This cross-sectional study used data from an Internet survey with adjustments to approximate a nationally representative estimate using inverse probability weighting. SETTING: A total of 23 142 respondents, aged 15 to 80 years, were evaluated to estimate weighted percentages and prevalence ratios with 95% confidence intervals of influenza vaccination in the period 2020-2021. RESULTS: Overall, in the period 2020-2021, the influenza vaccination rate rose from 38.1% before the COVID-19 pandemic to 44.6%. "Using traditional media" was a positive predictor of influenza vaccination uptake. "Using social media," "COVID-19 vaccine hesitancy," and "living in a prefecture with a high proportion of COVID-19 cases" were negative predictors. CONCLUSIONS: It is crucial to use predictors of influenza vaccination, such as how to use the media, for promoting a more widespread influenza vaccination uptake. The results of this study may be helpful in improving influenza vaccination rates, which could reduce the burden on health care services during outbreaks of influenza and COVID-19.

Number of Patients with Influenza and COVID-19 Coinfection in a Single Japanese Hospital during the First Wave.

An individual may contract coronavirus disease 2019 (COVID-19) and influenza simultaneously; hence, adequate measures must be undertaken for the next winter in Japan. In preparation for the future, this study aimed to clarify the incidence of influenza coinfection in patients with COVID-19 during the previous winter. We conducted a retrospective study of the medical records of 193 patients diagnosed with COVID-19 between January 31, 2020, and April 23, 2020, in a single hospital. We evaluated the incidence of COVID-19 and influenza coinfection. Using rapid diagnostic testing, we found that no patient with COVID-19 was coinfected with influenza. Coinfection with influenza and COVID-19 was rare during the past winter in Japan.

An analysis of the radiological factors associated with respiratory failure in COVID-19 pneumonia and the CT features among different age categories.

PURPOSE: To investigate CT patterns of COVID-19 pneumonia associated with respiratory failure (RF) focused on the distribution of lesions. MATERIALS AND METHODS: Eighty-five patients with COVID-19 pneumonia were reviewed. CT findings were classified as follows: Type A; patchy ground glass attenuation (GGA) with/without air-space consolidation, Type B; non-segmental GGA with/without air-space consolidation in both the central and peripheral lung portions especially with subpleural spare, and Type C; non-segmental GGA with/without air-space consolidation predominantly distributed in the peripheral lung portion without subpleural spare. We analyzed CT patterns and clinical factors associated with RF, including age categories. RESULTS: The number of patients with Type A, B and C was 31 (37%), 24 (28%) and 30 (35%), respectively. Type C and hypertension were independently associated with RF. On comparing between Types B and C, the frequency of traction bronchiectasis was higher in Type C than in Type B (P < 0.001). The ratio of Type C in patients ≥ 65 years old (66%) was higher than in patients < 40 years old (P < 0.001) and 40-49 years old (P = 0.001). CONCLUSION: The Type C, increasing with age, was associated with RF. Traction bronchiectasis in the lesion was more frequent in Type C than in Type B. Secondary abstract A lesion adjacent to the pleura and hypertension is associated with respiratory failure in patients with COVID-19. The frequency of a lesion adjacent to the pleura increased with age. The distribution of lesions is a useful parameter to predict respiratory failure.

Prevalence of thromboembolic events and status of prophylactic anticoagulant therapy in hospitalized patients with COVID-19 in Japan.

INTRODUCTION: One of the most prominent and concerning complications associated with coronavirus disease 2019 (COVID-19) is venous and arterial thromboembolisms. The aim of the present study was to delineate the prevalence of thromboembolic events and the current status of prophylactic anticoagulation therapy in patients with COVID-19 in Japan. METHODS: Between February 1 and August 31, 2020, we performed a dual-center, retrospective cohort study based on data obtained from the medical charts of COVID-19 patients admitted to healthcare facilities in Japan. The primary outcome was any thromboembolic event including pulmonary embolism (PE), deep vein thrombosis (DVT), myocardial infarction, ischemic stroke and other systemic thromboemboli. RESULTS: During the study period, we extracted 628 consecutive patients admitted for COVID-19. Prophylactic anticoagulant therapy was administered in 63 (10%) patients of whom 20 (31.7%) were admitted to the intensive care unit (ICU). Thromboembolic events occurred in 18 (2.9%) patients (14.3% of patients in ICU and 2.2% of patients in the general wards). DVT were detected in 13 (2.1%) patients, PE in 11 (1.8%), and both DVT and PE in 6 (0.96%) patients. An increasing prevalence in thromboembolic events was noted with progressive clinical severity. Overall in-hospital mortality was 4.8%. CONCLUSIONS: Prophylactic anticoagulation therapy was administered in only 10% of all hospitalized COVID-19 patients. The prevalence of any thromboembolic events was 2.9% in COVID-19 patients with most events occurring in severe and critical patients. Therefore, prophylactic anticoagulation therapy may be warranted in severe and critical patients but in asymptomatic to moderate patients the practice remains controversial.

Development of a Risk Prediction Score to Identify High-Risk Groups for the Critical Coronavirus Disease 2019 (COVID-19) in Japan.

Coronavirus disease 2019 (COVID-19) emerged in mid-December 2019 and has rapidly spread worldwide. We conducted a retrospective analysis of data from patients with COVID-19 to construct a simple risk prediction score to be implemented in prehospital settings. Patients were classified into critical and non-critical groups based on disease severity during hospitalization. Multivariate analysis was performed to identify independent risk factors and develop a risk prediction score. A total of 234 patients were included in the study. The median age of the critical group was significantly older than that of the non-critical group (68.0 and 44.0 years, respectively), and the percentage of males in the critical group was higher than that in the non-critical group (90.2% and 60.6%, respectively). Multivariate analysis revealed that factors such as age ≥ 45 years, male sex, comorbidities such as hypertension and cancer, and having fever and dyspnea on admission were independently associated with the critical COVID-19 infection. No critical events were noted in patients with a total risk factor score of ≤ 2. Contrastingly, patients with a total risk factor score ≥ 4 were more likely to have critical COVID-19 infection. This risk prediction score may be useful in identifying critical COVID-19 infections.

Characteristics and outcomes of coronavirus disease 2019 (COVID-19) patients with cancer: a single-center retrospective observational study in Tokyo, Japan.

BACKGROUND: Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused an international outbreak of coronavirus disease 2019 (COVID-19), data on the clinical characteristics of COVID-19 patients with cancer are limited. This study aimed to evaluate the clinical characteristics and outcomes including mortality and viral shedding period in COVID-19 patients with cancer in Japan. METHODS: We retrospectively analyzed 32 patients with a history of cancer who were referred to our hospital between January 31, 2020 and May 25, 2020. We evaluated the association between clinical outcomes and potential prognostic factors using univariate analyses. RESULTS: The median age was 74.5 (range 24-90) years and 22 patients (69%) were men. A total of 11 patients (34%) died. Our analyses demonstrated that the mortality was significantly associated with lymphocyte count, albumin, lactate dehydrogenase, serum ferritin, and C-reactive protein on admission. The median period between illness onset and the first effective negative SARS-CoV-2 PCR result was 22 days (interquartile range 18-25) in survivors. Of four patients with hematological malignancy who developed COVID-19 within the rest period of chemotherapy, three died and the other patient, who received bendamustine plus rituximab therapy, had the longest duration of viral shedding (56 days). CONCLUSION: Our study suggested that the risk factors for mortality previously reported in general COVID-19 patients, including lymphocytopenia, were also effective in cancer patients. Patients who received cytotoxic chemotherapy recently or were treated with chemotherapy, which can lead to lymphocyte reduction, had poor prognosis and prolonged periods of viral shedding.

Case Report: A Patient with COVID-19 under Myelosuppression Induced by Chemotherapy.

COVID-19 has now spread globally, and 10-20% of the cases are thought to proceed to a severe condition. However, information on COVID-19 in immunodeficient patients remains limited. We treated a 56-year-old man who developed COVID-19 after chemotherapy for mantle cell lymphoma. After 1 month of prolonged fever, the patient's respiratory condition deteriorated rapidly, and he died. COVID-19 in immunocompromised patients after chemotherapy, even with mild symptoms, can cause rapid immune reconstitution and respiratory deterioration. Therefore, caution is advised until negative PCR test results for SARS-CoV-2 are confirmed.

Utility of the Rapid Antigen Detection Test E. histolytica Quik Chek for the Diagnosis of Entamoeba histolytica Infection in Nonendemic Situations.

Entamoeba histolytica infection is an increasingly common sexually transmitted infection in Japan. Currently, stool ova and parasite examination (O&P) is the only approved diagnostic method. Here, we assessed the utility of the commercially available rapid antigen detection test (Quik Chek) for E. histolytica A multicenter cross-sectional study was conducted. Stool samples that had been submitted for O&P were included. The samples were subjected to both Quik Chek and PCR, and the Quik Chek results were assessed in comparison with PCR as the reference standard. E. histolytica infection was confirmed in 5.8% (38/657) of the samples and comprised 20 diarrheal and 18 nondiarrheal cases. The overall sensitivity and specificity of Quik Chek were 44.7% (95% confidence interval, 30.1 to 60.3) and 99.8% (99.1 to 100), respectively. The sensitivity of Quik Chek was higher for diarrheal cases (60.0%) than for nondiarrheal cases (27.8%). Furthermore, the combined use of Quik Chek with O&P increased the sensitivity (78.9%), especially for diarrheal cases (up to 90%). The E. histolytica burden assessed by quantitative PCR was similar between Quik Chek-positive and -negative samples. The Quik Chek assay sensitivity was lower for cyst-containing stools than for trophozoite-containing stools, although it was shown that cultured E. histolytica clinical strains from Quik Chek-negative cyst-containing stools exhibited antigenicity in vitro The present study confirmed the high specificity of Quik Chek for E. histolytica infection. Combined use with O&P increased the sensitivity of detection, facilitating the use of Quik Chek in point-of-care settings in nonendemic situations.

Retrospective observational study of the use of artemether-lumefantrine in the treatment of malaria in Japan.

BACKGROUND: The Research Group on Chemotherapy of Tropical Diseases, Japan, introduced artemether-lumefantrine (AL) in late 2002, mainly for treating uncomplicated Plasmodium falciparum malaria. Because AL was on the market in Japan in March 2017, the effectiveness and safety of AL were analyzed to help medical personnel use AL optimally. METHODS: Case report forms submitted by the attending physicians were analyzed. When necessary, direct contact with the attending physicians was made to obtain detailed information. RESULTS: Effectiveness analysis was performed for 62 cases and safety analysis was performed for 66 cases. In P. falciparum malaria, the overall cure rate was 91.1% (51/56), of which the cure rates for Japanese and non-Japanese patients were 82.1% (23/28) and 100% (28/28), respectively. The successfully treated cases included severe P. falciparum malaria, with parasite densities exceeding 500,000/µL. Adverse events were reported in 14 patients, including delayed hemolytic anemia which occurred in the top four highest parasitemic cases. CONCLUSIONS: AL treatment failure in P. falciparum malaria may not be rare among non-immune individuals, including Japanese. The possibility of delayed hemolytic anemia, which occurs preferentially in high parasitemic cases, should be considered following AL treatment.

CLINICAL OUTCOMES OF CRYPTOCOCCAL MENINGITIS AMONG HIV-INFECTED PATIENTS IN THE ERA OF ANTIRETROVIRAL THERAPY.

Cryptococcal meningitis (CM) is a common opportunistic infection in HIV-infected patients and the clinical outcome can be severe. This study aimed to determine the survival rate and prognostic factors among HIV-infected patients with CM in the era of antiretroviral therapy (ART). Understanding of these facts may help clinicians to manage CM patients efficiently and patients with poor prognostic factors could be closely monitored. We conducted a retrospective cohort study among new cases of HIV-associated CM who were treated at Ramathibodi Hospital, Mahidol University, Thailand, during 2002-2013. Of 195 patients, 119 (61%) were male; the median (interquartile range, IQR) age was 33 (29-39) years. The median (IQR) CD4 cell count was 20 (9-44) cells/mm3. The median survival time was >12 years and the 75% survival time was 5 years. Using the Cox proportional hazard model, the factors associated with mortality were impaired consciousness [hazard ratio (HR)=2.38; 95% confidence interval (CI): 1.03-5.50], low initial cerebrospinal fluid (CSF) protein (≤60 mg/dl) (HR=2.88; 95%CI: 1.13-7.35), low initial CSF glucose (≤30 mg/dl) (HR=2.36; 95%CI: 1.01-5.51), high opening pressure during induction therapy (>25 cmH2O) (HR=2.90, 95%CI: 1.21-6.94), no ART (HR=14.8; 95%CI: 5.39-40.7) and relapse of CM (HR=4.31; 95%CI: 1.42-13.1). The HIV-associated CM survival rate in the ART era is higher than it was during the pre-ART era.

Underestimated Amoebic Appendicitis among HIV-1-Infected Individuals in Japan.

Entamoeba histolytica is not a common causative agent of acute appendicitis. However, amoebic appendicitis can sometimes be severe and life threatening, mainly due to a lack of awareness. Also, its frequency, clinical features, and pathogenesis remain unclear. The study subjects were HIV-1-infected individuals who presented with acute appendicitis and later underwent appendectomy at our hospital between 1996 and 2014. Formalin-fixed paraffin-embedded preserved appendix specimens were reexamined by periodic acid-Schiff (PAS) staining and PCR to identify undiagnosed amoebic appendicitis. Appendectomies were performed in 57 patients with acute appendicitis. The seroprevalence of E. histolytica was 33% (14/43) from the available stored sera. Based on the medical records, only 3 cases were clinically diagnosed as amoebic appendicitis, including 2 diagnosed at the time of appendectomy and 1 case diagnosed by rereview of the appendix after the development of postoperative complications. Retrospective analyses using PAS staining and PCR identified 3 and 3 more cases, respectively. Thus, E. histolytica infection was confirmed in 9 cases (15.8%) in the present study. Apart from a significantly higher leukocyte count in E. histolytica-positive patients than in negative patients (median, 13,760 versus 10,385 cells/µl, respectively, P = 0.02), there were no other differences in the clinical features of the PCR-positive and -negative groups. In conclusion, E. histolytica infection was confirmed in 9 (15.8%) of the appendicitis cases. However, only 3, including one diagnosed after intestinal perforation, were diagnosed before the present analyses. These results strongly suggest there is frequently a failure to detect trophozoites in routine examination, resulting in an underestimation of the incidence of amoebic appendicitis.

Incidence and Risk Factors for Incident Syphilis among HIV-1-Infected Men Who Have Sex with Men in a Large Urban HIV Clinic in Tokyo, 2008-2015.

BACKGROUND: The epidemiology of incident syphilis infection among HIV-1-infected men who have sex with men (MSM) largely remains unknown. METHODS: The incidence and risk factors for incident syphilis (positive TPHA and RPR> = 1:8) among HIV-1-infected MSM who visited a large HIV clinic in Tokyo for the first time between 2008 and 2013 were determined, using clinical data and stored blood samples taken every three months for screening and determination of the date of incident syphilis. Poisson regression compared the incidence of syphilis at different observation periods. RESULTS: Of 885 HIV-1-infected MSM with baseline data, 34% either presented with active syphilis at baseline (21%) or became infected with syphilis during follow-up (13%). After excluding 214 patients (MSM with syphilis at baseline (n = 190) and no follow-up syphilis test (n = 24)), of 671 men, 112 (17%) developed incident syphilis with an incidence of 43.7/1,000 person-years [95% CI, 36.5-52.3]. The incidence decreased slightly during observation period although the trend was not significant (2008-2009: 48.2/1,000 person-years, 2010-2011: 51.1/1,000 person-years, 2012-2013: 42.6/1,000 person-years, 2014 to 2015: 37.9/1,000 person-years, p = 0.315). Multivariable analysis identified young age (<33 years versus >40, HR 4.0, 95%CI 2.22-7.18, p<0.001), history of syphilis at baseline (HR 3.0, 95%CI 2.03-4.47, p<0.001), positive anti-amoeba antibody (HR 1.8, 95%CI 1.17-2.68, p = 0.006), and high baseline CD4 count (CD4 ≥350 /µL versus CD4 <200, HR 1.6, 95%CI 1.00-2.53, p = 0.050) as risk factors for incident syphilis. Incidence of syphilis was particularly high among young patients (age <33 years: 60.1/1,000 person-years). Interestingly, 37% of patients with incident syphilis were asymptomatic. CONCLUSIONS: Although incidence of syphilis did not increase during the observation period, it was high among HIV-1-infected MSM, especially among young HIV-1-infected MSM and those with history of syphilis, in Tokyo. Regular screening for syphilis needs to be strictly applied to this population.

[Malaria cases treated with artemether/lumefantrine in Japanese travelers].

Artemisinin-based combination therapy (ACT) has been the standard treatment for uncomplicated malaria. Although not licensed in Japan, artemether/lumefantrine (AL), one type of ACT, has been administered to patients with malaria since 2002 by the Research Group on Chemotherapy of Tropical Diseases. Herein, we reviewed malaria cases treated with AL in Japanese travelers. A retrospective study was conducted at the National Center for Global Health and Medicine from October 2005 to March 2013. There were 19 malaria patients treated with AL, and 10 falciparum malaria patients treated with AL only. In these 10 patients treated with AL only, the median time of fever clearance was 25.0 hours (range:14-66 hours), and the median time of parasite clearance was 36.0 hours (range:16-62 hours). There was a positive correlation between parasitemia and time from the start of therapy to the disappearance of the parasites. Parasitemia was higher (4.05% vs. 0.24%; p = 0.044) and parasite clearance time was longer (55.5 hours vs. 31.5 hours; p = 0.044) in the cases of recrudescence than non-recrudescence, respectively. Three of the 19 malaria patients showed recrudescence of malaria after treatment with AL. The reason that treatment failure was more frequently observed in this study than in previous reports may be related to poor absorption of lumefantrine owing to gastrointestinal symptoms, insufficiently ingested fatty foods, or high parasitemia on admission. The World Health Organization recommends that intravenous antimalarials should be administered in cases of severe malaria however, this is not applicable in Japan. Further studies are needed to distinguish patients with malaria who are treatable with ACT from those who should be treated initially with other intravenous antimalarials.

Endoscopic appearance of AIDS-related gastrointestinal lymphoma with c-MYC rearrangements: case report and literature review.

Acquired immune deficiency syndrome (AIDS)-related lymphoma (ARL) remains the main cause of AIDS-related deaths in the highly active anti-retroviral therapy (HAART) era. Recently, rearrangement of MYC is associated with poor prognosis in patients with diffuse large B-cell lymphoma. Here, we report a rare case of gastrointestinal (GI)-ARL with MYC rearrangements and coinfected with Epstein-Barr virus (EBV) infection presenting with various endoscopic findings. A 38-year-old homosexual man who presented with anemia and was diagnosed with an human immunodeficiency virus infection for the first time. GI endoscopy revealed multiple dish-like lesions, ulcerations, bloody spots, nodular masses with active bleeding in the stomach, erythematous flat lesions in the duodenum, and multiple nodular masses in the colon and rectum. Magnified endoscopy with narrow band imaging showed a honeycomb-like pattern without irregular microvessels in the dish-like lesions of the stomach. Biopsy specimens from the stomach, duodenum, colon, and rectum revealed diffuse large B-cell lymphoma concomitant with EBV infection that was detected by high tissue EBV-polymerase chain reaction levels and Epstein-Barr virus small RNAs in situ hybridization. Fluorescence in situ hybridization analysis revealed a fusion between the immunoglobulin heavy chain (IgH) and c-MYC genes, but not between the IgH and BCL2 loci. After 1-mo of treatment with HAART and R-CHOP, endoscopic appearance improved remarkably, and the histological features of the biopsy specimens revealed no evidence of lymphoma. However, he died from multiple organ failure on the 139(th) day after diagnosis. The cause of his poor outcome may be related to MYC rearrangement. The GI tract involvement in ARL is rarely reported, and its endoscopic findings are various and may be different from those in non-AIDS GI lymphoma; thus, we also conducted a literature review of GI-ARL cases.

[Clinical experience of primaquine use for treatment of vivax and ovale malaria in Japanese travelers].

Primaquine phosphate has been used to prevent relapse as a radical cure after the acute-phase treatment of vivax and ovale malaria however. Many vivax malaria relapses have been reported following a standard dose of primaquine (15 mg/day for 14 days). A higher dose of primaquine (30 mg/day for 14 days) decreases the relapse rate, and the concomitant risk of gastrointestinal side effects tends to disappear when the drug is administered with food. G6PD deficiency is rare in the Japanese population. Although the relapsed phenomenon is reported globally, the higher dose of primaquine is currently recommended in Japan only for those returning from Southeast Asia or Papua New Guinea. Cases of 18 Japanese, including 13 vivax malaria and 5 ovale malaria, prescribed primaquine at a referral center in Japan, were analyzed retrospectively from 2007-2011. Data on diagnosis, treatment, and outcome were extracted from medical records. Of the 18, 10 with vivax malaria were administered the higher dose of primaquine. We found that only one suffered relapse-a vivax malarial case returning from Brazil and treated with the standard dose of primaquine. No ovale malarial case suffered relapse. None, including the 10 prescribed the higher primaquine dose, experienced any adverse side effects. Based on our findings, we recommend a higher dose of primaquine be used to prevent relapse when treating Japanese suffering from vivax malaria.

Dengue virus type-3 infection in a traveler returning from Benin to Japan.

Dengue virus (DENV) infection is a major health threat for travelers. We describe here a case of dengue virus serotype-3 (DENV-3) infection in a traveler returning to Japan from the Republic of Benin. The isolated DENV-3 genotype 3 strain exhibited high sequence similarity to those from neighboring regions.

Clinical and radiological features of imported chikungunya fever in Japan: a study of six cases at the National Center for Global Health and Medicine.

Chikungunya fever (CHIKF) is currently distributed in Africa and in South and Southeast Asia; outbreaks have occurred periodically in the region over the past 50 years. After a large outbreak had occurred in countries in the western Indian Ocean region in 2005, several countries reported cases of CHIKF from travelers who had visited affected areas. In Japan, there have been only 15 cases of CHIKF patients so far, according to the National Institute of Infectious Diseases. Therefore, to evaluate the clinical and radiological features associated with the disease, we describe 6 imported cases of CHIKF. All of the patients had had prolonged arthralgia on admission to our hospital, and diagnosis was confirmed with specific antibodies by using an IgM-capture enzyme-linked immunoassay and a plaque reduction neutralizing antibody assay. Magnetic resonance imaging (MRI) of one patient revealed erosive arthritis and tenosynovitis during the convalescence stage. Clinicians should be aware of the late consequences of infection by the chikungunya virus (CHIKV) and recognize the possible association of subacute and chronic arthritis features. In addition, competent vectors of CHIKV, Aedes aegypti, can now be found in many temperate areas of the eastern and western hemispheres, including Japan. This fact raises concern that the virus could be introduced and become established in these areas. This necessitates an increased awareness of the disease, because imported cases are likely to contribute to the spread of CHIKV infection wherever the competent mosquito vectors are distributed.

[A Japanese patient with chikungunya fever returning from Flores Island, Indonesia].

We report a case of chikungunya fever, rarely seen by Japanese physicians. A 35-year-old Japanese man admitted September 12 for a 3-day fever had traveled to Flores island, Indonesia, July 14-Sep. 10. He had bilateral wrist arthralgia, mild bilateral finger swelling, and nonitching skin eruptions on the face, trunk, and both arms. The viral chikungunya genome was identified in serum on Sep. 12. Negative serum an-tichikungunya virus IgM antibodies on Sep. 12 became positive on Sep. 14, yielding the suspected diagnosis. Given the many Japanese visiting endemic chikungunya fever areas, Japanese physicians must learn to recognize such cases among travelers returning from such areas with fever, arthralgia, and skin eruptions.