higashimoto yuki

Varicella-zoster virus (VZV) causes varicella in children, establishes lifelong latency and reactivates to cause herpes zoster later in life. Implementation of routine varicella vaccination in Japan since 2014 has reduced varicella cases, however, breakthrough varicella still occurs. This study aimed to clarify the current distribution of VZV clade among pediatric varicella patients and adults with VZV-associated central nervous system (CNS) infections in Japan. Skin swabs were collected from varicella patients (< 15 years) in Aichi Prefecture (September 2015-August 2017). Cerebrospinal fluid (CSF) samples were obtained from adult patients (> 15 years) with VZV-associated CNS infections (November 2014-June 2023). VZV DNA was detected by PCR, and its clade was determined by sequencing open reading frame (ORF) 22 and ORF37 regions. Wild-type and Oka vaccine strains were distinguished by loop-mediated isothermal amplification (LAMP) method. Of 124 pediatric swab samples and 62 adult CSF samples 94.4% belonged to clade 2 and 4.8% clade 1. No clade 1 samples were detected in CSF samples. No vaccine strain was detected. Clinical characteristics did not differ significantly among clades. Clade 2 VZV predominates in both pediatric varicella and adult VZV-related CNS infections in Japan with sporadic clade 1 varicella cases.

BACKGROUND: Recent studies have reported the possible link between adeno-associated virus 2 (AAV2) and severe pediatric acute hepatitis. It has been suggested that aberrant AAV2 replication initiated by coinfection with "helper viruses" such as human adenovirus and human herpesvirus-6B (HHV-6B) may induce abnormal immune responses. Encephalitis/encephalopathy is a severe complication of primary HHV-6B infection, but the underlying mechanisms remain unclear. This study analyzed the association between AAV2 coinfection and neurologic complications of primary HHV-6B infection in children. METHODS: Preserved serum samples obtained from 36 patients with HHV-6B-associated encephalitis/encephalopathy, 39 with febrile seizure, and 83 without neurologic complications were retrospectively analyzed. Primary HHV-6B infection was confirmed if HHV-6B DNA was detected and the HHV-6B antibody was negative in serum. AAV2 and HHV-6 DNA loads were quantitated using real-time PCR. RESULTS: AAV2 was detected in 4 (11%) and 3 (8%) patients in the encephalitis/encephalopathy and febrile seizure groups, respectively. In contrast, AAV2 was undetectable in 83 patients without neurologic complications. AAV2 detection frequency was significantly higher in the encephalitis/encephalopathy and febrile seizure groups compared with the no neurologic complications group ( P = 0.01 and P = 0.03, respectively). Among 4 patients with HHV-6B-associated encephalitis/encephalopathy, AAV2 DNA was detected in the cerebrospinal fluid of 2 patients. Serum HHV-6B DNA load was not significantly different among patients who were AAV2 positive or AAV negative and with or without neurologic complications. CONCLUSIONS: These findings suggest that coinfection of AAV2 and HHV-6B is associated with neurologic complications such as encephalitis/encephalopathy and febrile seizure in children.

OBJECTIVE: To elucidate the trends and clinical features of virologically diagnosed breakthrough varicella (BV) 9 years after implementation of the universal vaccination program in Japan. PATIENTS AND METHODS: Study participants were patients with suspected varicella less than 15 years of age who visited 1 of 15 pediatric clinics in the Nagoya VZV Study Group between September 2015 and August 2023. Practitioners collected patient samples and information such as background characteristics, clinical symptoms, and immunization status. All patients had varicella confirmed by real-time polymerase chain reaction assays. RESULTS: Of 719 patients with suspected varicella, 512 had laboratory-diagnosed varicella and available information on vaccination status. They were divided into 3 groups: 167 with natural varicella, 250 with BV and 1 dose of vaccine, and 95 with BV and 2 doses. The monthly number of patients with varicella decreased gradually during the observation period. Typical seasonal peaks were observed until the 2019-2020 season. The proportion of patients with BV, particularly BV after 2 doses of vaccine, gradually increased. Patients with BV and 2 doses had a significantly lower median age (5 years) than those with 1 dose (6 years) (p < 0.001). The transmission route for BV was unknown in approximately 30-50 % of patients. Duration of fever was significantly longer (p = 0.0138) and the number of skin eruptions was also significantly higher (p = 0.0013) in the 1-dose group than in the 2-dose group. CONCLUSIONS: Although the number of pediatric patients with varicella declined after implementation of national immunization with 2 doses of varicella vaccine, the proportion of patients with BV, especially those who received 2 doses, gradually increased. Clinical symptoms were significantly milder in patients with BV and 2 doses. Laboratory diagnosis of varicella is becoming increasingly important due to an increase in the proportion of patients with BV who have mild symptoms.

The recent clinical features of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections in young children in developed countries remain unclear. This study investigated the clinical features of EBV and CMV infections and the latest seroepidemiology in Japan. Seroprevalence was analyzed 303 stored serum samples using commercial Enzyme Immunosorbent Assay kits, and viral infections were investigated in a cohort of febrile children under 5 years of age. After maternal antibody levels declined, the seroprevalences of EBV and CMV gradually increased by adolescence to 42.9% and 57.1%, respectively. Among 2,732 febrile children, serum EBV and CMV DNAs were detected in 1.76% and 1.24%, respectively. Of 25 primary EBV-infected patients, 15 (60.0%) had infectious mononucleosis (IM) with significantly higher IM frequency, WBC, atypical lymphocyte ratios, AST, ALT, LDH, and EBV DNA load compared to EBV-reactivated patients. No CMV DNA-positive patients had IM. Among primary EBV-infected patients, those with IM were older and had more atypical lymphocytes and higher EBV DNA load than those without IM. The age of primary EBV infection appears to have decreased compared to reports from Western countries in the 1990s. Even among children under 5 years of age, 60.0% of those with primary EBV infection developed IM.

Supply shortage of blood culture bottles occurred between July and September 2024, which substantially impacted infectious diseases practice globally. However, blood culture practice in the post shortage period is not well documented. We described how the standard blood culture practice was restored after the resumption of their supply.