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Cureus 2022 Mar 9;14(3):e23007. Epub 2022 Mar 9.

Internal Medicine, St. Joseph's Regional Medical Center, Paterson, USA.

Human herpesvirus-6 (HHV-6) is a virus known for causing the highly contagious infection, roseola infantum, and has been associated with causing encephalitis in pediatric patients and less commonly in adult patients as well. Regardless of the patient's age, the primary HHV-6 infection could be complicated by neurological sequelae including encephalitis, acute encephalopathy with biphasic seizures syndrome, or demyelinating disease. HHV-6 encephalitis does occur in an adult as a primary infection or reactivation. Read More

Pediatr Infect Dis J 2022 03;41(3):e90-e92

From the Department of Pediatrics, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.

Incidences of community-acquired infectious diseases other than COVID-19 decreased during the coronavirus disease 2019 pandemic; however, exanthema subitum incidence before (2016-2019) and during the pandemic (2020) in Niigata, Japan, did not substantially differ, although the proportion of age less than 1-year-old was lower in 2020. These findings suggest that exanthema subitum is transmitted mainly among family members, not in the community. Read More

PLoS One 2022 12;17(1):e0261332. Epub 2022 Jan 12.

Department of Infectious, Respiratory and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus, Nishihara-cho, Okinawa, Japan.

Recent reports indicate that respiratory infectious diseases were suppressed during the novel coronavirus disease-2019 (COVID-19) pandemic. COVID-19 led to behavioral changes aimed to control droplet transmission or contact transmission. In this study, we examined the incidence of common infectious diseases in Japan during the COVID-19 pandemic. Read More

Cureus 2021 Aug 14;13(8):e17183. Epub 2021 Aug 14.

Department of Infectious Diseases, Al Jalila Children's Specialty Hospital, Dubai, ARE.

Human herpesvirus 6 (HHV-6) is a member of the family. There are two HHV-6 species: HHV-6A and HHV-6B. HHV-6B causes the majority of documented primary infections and reactivation events. Read More

Dermatol Ther 2021 11 25;34(6):e15129. Epub 2021 Sep 25.

Infectious Disease Specialist - Department of Infectiology Diagnosis, State Program STI/AIDS Reference and Training Center of São Paulo, São Paulo, São Paulo State, Brazil.

Pityriasis rosea (PR) has been manifested in patients suffering from COVID-19 as well as after vaccine protocols against SARS-CoV-2. It has a possible association with the HHV-6B virus (roseola infantum) and can be controlled by antivirals such as acyclovir as well as by the amino acid l-Lysine that showed a positive result in reducing the number of lesions and healing time. The aim of this study was to report a case of PR after a second dose of Oxford-AstraZeneca, the adopted therapy and a brief literature review. Read More

Epilepsy Res 2021 Aug 8;174:106663. Epub 2021 May 8.

Department of Neurology, Hospital Materno Infantil Salta, Argentina. Electronic address:

Objective: We analyzed the records of 198 patients with West syndrome (WS) seen at a single pediatric neurology center in Argentina between June 2004 and June 2017. Five patients with infection-related spontaneous remission of the electroclinical manifestations were identified.

Methods: The following parameters were investigated: personal and family history, clinical characteristics of the seizures - mainly spasms - and EEG findings, type of treatment, and outcome. Read More

Brain Dev 2021 Sep 7;43(8):879-883. Epub 2021 May 7.

Department of Neurology, Nagano Children's Hospital, Azumino, Japan. Electronic address:

Background: The most common causative pathogen of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) was reported as HHV-6. Although excitotoxic injury with delayed neuronal death is considered to be a possible pathogenesis of AESD, the detailed pathophysiology remains unclear.

Case Presentation: We present a twelve-month-old girl with AESD due to HHV-6 primary infection. Read More

BMJ Paediatr Open 2021 2;5(1):e001034. Epub 2021 Apr 2.

Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.

Background: Epidemiological studies in Kawasaki disease (KD) have suggested infectious aetiology. During the COVID-19 pandemic, measures for mitigating SARS-CoV-2 transmission also suppress the circulation of other contagious microorganisms. The primary objective is to compare the number and incidence of KD before and during the COVID-19 pandemic in Japan, and the secondary objective is to investigate temporal association between the KD epidemiology and activities of SARS-CoV-2 and other viral and bacterial infections. Read More

J Pediatr Hematol Oncol 2022 01;44(1):e296-e298

Pediatric Hematology/Oncology, Faculty of Medicine, Koç University, İstanbul, Turkey.

Introduction: Roseola infantum is always considered to be among the differential diagnosis of young patients with fever and leukopenia whom to be strictly isolated with the preliminary diagnosis of COVID-19 until otherwise proven during the pandemic.

Results: Human herpes virus-6 (HHV-6) polymerase chain reaction (PCR) blood test was performed in 4 of 7 patients with a clinical diagnosis of roseola infantum and all found to be HHV-6 PCR positive. The most striking laboratory finding in all patients was leukopenia. Read More

Scand J Immunol 2020 Dec 23;92(6):e12984. Epub 2020 Oct 23.

Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.

Human herpesvirus 6A (HHV-6A) and 6B (HHV-6B) are two closely related viruses that can infect cells of the central nervous system (CNS). The similarities between these viruses have made it difficult to separate them on serological level. The broad term HHV-6 remains when referring to studies where the two species were not distinguished, and as such, the seroprevalence is over 90% in the adult population. Read More

Microbiol Immunol 2020 Oct;64(10):703-711

Division of Clinical Virology, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.

Human herpesvirus 6A (HHV-6A) is a member of the genus Roseolovirus and the subfamily Betaherpesvirinae. It is similar to and human cytomegalovirus (HCMV). HHV-6A encodes a 41 kDa nuclear phosphoprotein, U27, which acts as a processivity factor in the replication of the viral DNA. Read More

PLoS Pathog 2020 07 23;16(7):e1008609. Epub 2020 Jul 23.

Division of Clinical Virology, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.

Primary infection of human herpesvirus 6B (HHV-6B) occurs in infants after the decline of maternal immunity and causes exanthema subitum accompanied by a high fever, and it occasionally develops into encephalitis resulting in neurological sequelae. There is no effective prophylaxis for HHV-6B, and its development is urgently needed. The glycoprotein complex gH/gL/gQ1/gQ2 (called 'tetramer of HHV-6B') on the virion surface is a viral ligand for its cellular receptor human CD134, and their interaction is thus essential for virus entry into the cells. Read More

Pediatr Infect Dis J 2020 08;39(8):e209-e211

Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.

During local small measles outbreak in Japan, 3 adolescents with febrile skin rash suspected as having measles were diagnosed with primary human herpesvirus (HHV)-7 infection. Primary HHV-7 infection can cause exanthem subitum in not only young children but also adolescents. HHV-7 should be considered as a possible causative agent for adolescent febrile skin rash during the measles outbreak. Read More

Transpl Infect Dis 2020 Oct 8;22(5):e13331. Epub 2020 Jun 8.

Deprtment of Child Health and Development, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.

Human herpesvirus-6 (HHV-6) is a common pathogen affecting the human population. Primary HHV-6 infection generally occurs during infancy and causes exanthema subitum. Moreover, HHV-6 may exhibit inherited chromosomally integrated HHV-6 (iciHHV-6) in certain individuals. Read More

Pediatr Neurol 2020 08 28;109:52-55. Epub 2020 Mar 28.

Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Japan.

Background: It is well known that febrile seizures are commonly occur in children with exanthem subitum. In this study, we compared the clinical features and backgrounds of patients with complex febrile seizures with and without primary human herpesvirus 6B infection.

Methods: Sixty-two patients were enrolled after experiencing their first febrile seizure. Read More

Clin Dermatol 2020 Jan - Feb;38(1):35-41. Epub 2019 Oct 25.

Sector of Dermatology and Post-Graduation Course in Dermatology, University Hospital and School of Medicine, Federal University of Rio de Janeiro, Brazil. Electronic address:

A rash is a disseminated eruption of cutaneous lesions with great variation in appearance, cause, and severity. When the physician is facing a rash, the history and physical examination of the patient are extremely important for the identification of the disease and its causal agent. There are various causes for a rash, which may be infectious, allergic, or rheumatologic, besides many others. Read More

BMJ Case Rep 2020 Mar 17;13(3). Epub 2020 Mar 17.

Department of Infectious Disease, University of Toledo Medical Center, Toledo, Ohio, USA.

Human herpesvirus 6 (HHV-6) infection is the cause of roseola infantum in children. The reactivation of HHV-6 is associated with multiple clinical syndromes including encephalitis and myelitis, especially in haematopoietic stem cell transplant recipients. However, the virus can cause encephalitis in other immunosuppressed as well as immunocompetent individuals. Read More

MSMR 2020 Feb;27(2):30-31

Antiviral Res 2020 04 7;176:104720. Epub 2020 Feb 7.

Institut für Virologie, Freie Universität Berlin, Robert von Ostertag-Straße 7-13, 14163, Berlin, Germany. Electronic address:

Human herpesvirus 6A (HHV-6A) and 6B (HHV-6B) are members of the genus Roseolovirus in the Betaherpesvirinae subfamily. HHV-6B infects humans in the first years of life, has a seroprevalence of more than 90% and causes Roseola Infantum, but less is known about HHV-6A. While most other herpesviruses maintain their latent genome as a circular episome, HHV-6A and HHV-6B (HHV-6A/B) have been shown to integrate their genome into the telomeres of infected cells. Read More

J Pediatric Infect Dis Soc 2021 Mar;10(2):175-178

Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Japan.

Immunocompetent sisters with chromosomally integrated human herpesvirus 6A (HHV-6A) transiently excreted HHV-6B genome in their saliva. They did not have past histories of exanthema subitum but had antibodies against HHV-6A and HHV-6B. This suggests that endogenous HHV-6A may modify the clinical features of HHV-6B coinfection. Read More

Infect Agent Cancer 2019 5;14:31. Epub 2019 Nov 5.

3College of Public Health, University of Nebraska, 984355 Medical Center, Omaha, NE 68198 USA.

Background: Human herpesvirus-6 (HHV-6) is a ubiquitous double-stranded DNA virus that can cause roseola infantum, encephalitis, and seizure disorders. Several studies have shown an association between HHV-6 and cancer but confirmation of an etiologic role is lacking. We reviewed the criteria for viral causation of cancer used by The International Agency for Research on Cancer (IARC) for six oncogenic viruses and applied criteria to published reports of HHV-6 and its association with Hodgkin lymphoma and brain tumors. Read More

J Infect Chemother 2020 Mar 1;26(3):251-256. Epub 2019 Nov 1.

Department of Pediatrics, National Hospital Organization Beppu Medical Center, 1473 Oaza-Uchikamado, Beppu, Oita, 874-0011, Japan. Electronic address:

Background: This study aimed to elucidate the etiologies and diagnostic errors of early-phase pediatric fever without an obvious cause.

Methods: This single-center, retrospective, descriptive study included 1334 febrile children hospitalized at Beppu Medical Center in Japan between 2014 and 2018. Eligibility criteria were age ≤12 years, axillary temperature ≥38. Read More

Cureus 2019 Aug 24;11(8):e5475. Epub 2019 Aug 24.

Critical Care, Maimonides Medical Center, Brooklyn, USA.

Human herpesvirus 6 (HHV-6) is a double-stranded DNA virus part of the Herpesviridae family that colonizes nearly 100% of the human population. The virus is known to be the etiologic agent of roseola infantum, a self-limited disease in childhood and reactivation of the virus later in life is linked to potentially severe manifestations, including encephalitis, in immunosuppressed patients. It is rare in immunocompetent patients, but there have been several reports of encephalitis due to HHV-6 reactivation. Read More

Drug Discov Ther 2019 ;13(4):232-238

Department of Neurosurgery, Fukuoka University Chikushi Hospital.

We present a case of a patient with drug-induced hypersensitivity syndrome (DIHS) caused by salazosulfapyridine combined with syndrome of inappropriate secretion of antidiuretic hormone (SIADH) caused by interstitial pneumonia (IP). A 67-year-old man with a past history of rheumatism (RA) presented with right hemiparalysis and aphasia as the chief complaints. A diagnosis of left embolic cerebral infarction following trial therapy for RA based on computed tomography findings was made, and external decompression was performed. Read More

Virus Res 2019 11 12;273:197757. Epub 2019 Sep 12.

Department of Experimental Medicine, "Sapienza" University of Rome, Italy; Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy. Electronic address:

HHV-6A and HHV-6B are ubiquitous human betaherpesviruses sharing more than 80% homology. HHV-6B is the most common cause of encephalitis in transplant patients and its primary infection may cause the exanthema subitum and febrile seizures in infants. HHV-6A and HHV-6B are able to infect several immune cell types such as T cells, monocytes and dendritic cells (DCs). Read More

Adv Virus Res 2019 21;104:283-312. Epub 2019 Jun 21.

Division of Clinical Virology, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan. Electronic address:

In this chapter, we present an overview on betaherpesvirus entry, with a focus on human cytomegalovirus, human herpesvirus 6A and human herpesvirus 6B. Human cytomegalovirus (HCMV) is a complex human pathogen with a genome of 235kb encoding more than 200 genes. It infects a broad range of cell types by switching its viral ligand on the virion, using the trimer gH/gL/gO for infection of fibroblasts and the pentamer gH/gL/UL128/UL130/UL131 for infection of other cells such as epithelial and endothelial cells, leading to membrane fusion mediated by the fusion protein gB. Read More

Pediatr Infect Dis J 2019 10;38(10):e248-e253

Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Japan.

Objective: This cohort study, based on the design of a prior study in the United States, was conducted to elucidate the clinical features of primary human herpesvirus-6B (HHV-6B) infection.

Methods: Between June 2014 and May 2016, febrile children younger than 5 years who visited the emergency room (ER) and underwent blood examination were enrolled in this study.

Results: Fifty-nine (12%) of the 491 patients were diagnosed with primary HHV-6B infection. Read More

J Pediatr 2019 09 14;212:228-231. Epub 2019 Jun 14.

Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO; Children's Hospital Colorado, Aurora, CO.

An immunocompetent toddler came to medication attention with gastroenteritis, complicated by encephalopathy and hepatitis. Multiplexed testing using a polymerase chain reaction meningitis panel was positive for human herpesvirus 6 (HHV-6). Clinical correlation, quantitative HHV-6 polymerase chain reaction, and metagenomic next-generation sequencing supported a likely diagnosis of primary HHV-6B infection. Read More

J Gen Virol 2019 01 14;100(1):89-98. Epub 2018 Nov 14.

1​Department of Experimental Medicine, "Sapienza" University of Rome, Italy.

Herpesviruses are known to manipulate autophagy to optimize their replication, counteract immune response and probably to promote tumourigenesis. This study explored, for the first time, the impact of human herpesvirus (HHV)-6 lytic infection on autophagy and demonstrated that HHV-6A and B (viruses sharing more than 80 % homology) differently affected this cellular process. Indeed, while HHV-6A (GS) infection of HSB2 cells promoted autophagy, HHV-6B (Z29) or the virus isolated from the serum of roseola infantum-affected patient-inhibited autophagy in Molt-3 cells or in PBMCs, respectively. Read More