Search

Since the Okinawan islands are located in the southernmost part of Japan, where the climate is subtropical, several episodes of influenza epidemics occur during the summer season. More recently, we have demonstrated that summer influenza epidemics occur every year. After the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began in January 2020, measures to avoid disease transmission have been widely promoted in Japan, such as the use of masks, handwashing, remote work, and cancellation of large events. These measures might also have reduced the spread of other infectious diseases, such as the seasonal influenza. Based on this background, we evaluated weekly influenza activity in the 2019/2020 season. After the SARS-CoV-2 pandemic, the summer influenza in the Okinawa prefecture disappeared in 2020. The reasons for the disappearance of summer influenza in Okinawa are discussed herein.

Molecular diagnostic methods have recently gained widespread use, and consequently, the importance of viral pathogens in community-acquired pneumonia (CAP) has undergone re-evaluation. Under these circumstances, the role of Chlamydophila pneumoniaeas a pathogen that causes CAP also needs to be reviewed.

Drug-induced pneumonitis is a disease encountered by pulmonologists in the clinical setting. The diagnosis generally considers the patient's clinical course and the results of peripheral blood tests, radiological examinations, and often bronchoscopic examinations. However, few studies have reported the association between radiological patterns such as ground-glass opacity (GGO) or consolidation, and bronchoalveolar lavage fluid (BALF) cell fractions. This study aimed to clarify this association.

Legionellapneumonia is a fatal disease caused by Legionella pneumophila, a bacterium belonging to the genus Legionella. The incidence of this disease has been increasing since 2005 and has continued to increase following the COVID-19 pandemic in Japan. Furthermore, Legionellapneumonia mortality rates have increased slightly since the pandemic due to some plausible reasons. The increased proportion of older patients with legionellosis might affect it because advanced age is a major risk factor for disease mortality. Additionally, physicians were focused on COVID-19 while examining febrile patients; therefore, they might have missed the early diagnosis of other respiratory infections, including Legionellapneumonia.

While the impact of respiratory virus infections has been well researched in some respiratory diseases, no clinical studies have discussed the subject of who would be more likely to develop respiratory virus infections among patients with various respiratory illnesses who come from different backgrounds. This study aimed to identify respiratory diseases that are frequently associated with respiratory virus infections along with the characteristics of patients who develop such infections in clinical settings. Tested specimens were obtained from the lower respiratory tract by bronchoscopy to provide more accurate data. Data of bronchoscopies at Ryukyu University Hospital between August 2012 and September 2016 were reviewed, and patients who underwent multiplex polymerase chain reaction (PCR) tests for detecting respiratory viruses in bronchoscopy specimens were retrospectively recruited for descriptive statistics. Differences among patients’ primary pulmonary diseases and backgrounds were compared between the PCR-positive and -negative patients, and multivariate statistical analysis was performed to analyze factors associated with a positive PCR test result. Overall, 756 bronchoscopies were performed during the study period and PCR tests were performed for 177 patients. Of them, 27 tested positive for respiratory viruses, mainly parainfluenza virus and rhinovirus, and out of those, 7 were hospitalized for >1 month. Overall, all patients did not experience typical upper respiratory infection symptoms. In positive patients, 13 and 7 had diagnoses of interstitial lung disease and bacterial pneumonia, respectively. The diagnoses of 3 bacterial pneumonia cases were changed to viral pneumonia after receiving their PCR-positive tests. Respiratory virus infections were confirmed in 14 patients on immunosuppressant therapy and 4 on maintenance dialysis. Multivariate analysis revealed that immunosuppressant therapy and maintenance dialysis were independently associated with respiratory virus infections. Viruses were commonly detected in patients with interstitial lung diseases and bacterial pneumonia, while few patients were diagnosed with pure viral pneumonia. These illnesses were considered to be induced by respiratory infections. Immunosuppressant therapy and maintenance dialysis were associated with respiratory virus infections. Multiplex PCR testing is an essential diagnostic tool for respiratory virus infections in immunocompromised patients.

Dectin‐1 is known as a sole receptor for β‐glucan, a major cell wall component of fungal microorganisms. In the current study, we examined the role of this molecule in the host defense to Cryptococcus neoformans, an opportunistic fungal pathogen in AIDS patients. There was no significant difference in the clinical course and cytokine production between dectin‐1 gene‐deficient and control mice. These results indicate that dectin‐1 is not likely essential for the development of host protective responses to C. neoformans.

Cryptococcal meningoencephalitis is a life‐threatening infectious disease in immunocompromised patients. Unmethylated CpG‐oligodeoxynucleotides (CpG‐ODN) protects hosts in a mouse model. In the present study, we tested the adjuvant effect of CpG‐ODN in anti‐fungal chemotherapy. Administration of either fluconazole (FLCZ) or CpG‐ODN was effective in extending survival, accelerating clearance of fungi and preventing disseminated infection. Combination of both agents provided more beneficial effect than either agent alone. Cytokine balance in the infected lungs was biased to Th1‐type response by CpG‐ODN, while FLCZ did not further promote. These results suggest that CpG‐ODN is a promising adjuvant in chemotherapy against this infection.