Role of human herpesvirus 6 infection in young Brazilian children with rash illnesses

The Eruptive Fevers at Sixes and Sevens

Sixth Disease (roseola infantum) and its primary causative agent, HHV-6, share names that numerically concur. This article examines and answers the question of whether that correspondence is by design or coincidental by briefly reviewing the history and nomenclature of the HHV viruses and the classic febrile rashes of childhood while highlighting some clinical and microbiologic features of HHV-6 infection.

Roseola Infantum: An Updated Review

BACKGROUND

Roseola infantum is a common viral disease that occurs during childhood worldwide.

OBJECTIVE

The purpose of this article is to familiarize pediatricians with the clinical manifestations, evaluation, diagnosis, and management of roseola infantum.

METHODS

A search was conducted in April, 2022, in PubMed Clinical Queries using the key terms "roseola infantum" OR "exanthem subitum" OR "sixth disease". The search strategy included all clinical trials, observational studies, and reviews published within the past 10 years. Only papers published in the English literature were included in this review. The information retrieved from the above search was used in the compilation of the present article.

RESULTS

Roseola infantum is a viral illness characterized by high fever that lasts 3 to 4 days, followed by the sudden appearance of rash at defervescence. The disease occurs most frequently in children between 6 months and 2 years of age. Human herpesvirus-6 (HHV-6) is the major cause of roseola infantum, followed by HHV-7. Transmission of the infection most likely results from the asymptomatic shedding of the virus in the saliva of the caregivers or other close contacts. Characteristically, the rash is discrete, rose-pink in color, circular or elliptical, macular or maculopapular, measuring 2 to 3 mm in diameter. The eruption is first seen on the trunk. It then spreads to the neck and proximal extremities. Typically, the rash blanches on pressure and subsides in 2 to 4 days without sequelae. Most children look well otherwise and appear to be happy, active, alert, and playful. The diagnosis is mainly clinical. Febrile seizures occur in 10 to 15 % of children with roseola infantum during the febrile period. In general, serious complications are rare and occur more often in individuals who are immunocompromised. There is no specific treatment. An antipyretic may be used to reduce fever and discomfort.

CONCLUSION

Roseola infantum is generally a benign and self-limited disease. Failure to recognize this condition may result in undue parental fear, unnecessary investigations, delay in treatment for conditions that mimic roseola infantum and complications from roseola infantum, unnecessary treatment of roseola infantum per se, and misuse of healthcare expenditure.

Beyond arboviruses: A multicenter study to evaluate differential diagnosis of rash diseases and acute febrile illness cases in Rio de Janeiro, Brazil

INTRODUCTION

A wide variety of viruses can cause rash diseases (RDs) or acute febrile illness (AFIs) in children, adolescents and adults; however, approximately 19% of RD cases and 40% of AFI cases remain without a defined etiology. Parvovirus B19 (B19V) and herpesvirus infection can also cause RD and/or AFI, and in some risk groups, these infections can become persistent (or latent) and may require hospital treatment. Since these infections do not have mandatory reporting, they can be hidden by other diseases, such as those caused by arboviruses (e.g., dengue virus). In this context, the aim of this study was to pursue the differential laboratory diagnoses of B19V and herpesvirus infections in patients with RD and AFI, without a defined etiology, seen in hospitals and/or reference centers for infectious diseases in Rio de Janeiro.

METHODS

A total of 114 participants were enrolled in the study, including 54 children and 60 adults. B19V infection was assessed by real-time PCR (qPCR) and ELISA (anti-B19V IgM and IgG). EBV was assessed through qPCR, and betaherpesviruses (HCMV, HHV-6 and HHV-7) were assessed through multiplex qPCR. Sociodemographic and clinical data were obtained from the medical record data of these participants.

RESULTS

The median age of children with RD was 2 years (interquartile range (IQR): 5), and 55.6% were male. Among adults with AFI, the median age was 38 years (IQR: 21), and 56.7% were female. Regarding RD patients, viral prevalence (and load) were 5.5%(104IU/mL), 3.4%(104IU/mL), 5.5%(104IU/mL) and 11.1%(105IU/mL) for B19V, EBV, HCMV and HHV-6 infection, respectively, and in AFI patients they were 6.6%(105IU/mL), 1.6%(103IU/mL), 3.3%(104IU/mL) for B19V, HCMV and HHV-6, respectively. HHV-7 was not detected in RD or AFI patients.

CONCLUSION

These results suggest the importance of including B19V and herpesviruses in the differential laboratory diagnoses for patients with RD and AFI, not only for epidemiological purposes but also for the proper management of the patient.

Molecular Detection of Human Herpes Viruses in Suspected Measles Serum Samples from Senegal, 2014 to 2017

Herpesviruses are known to cause a diversity of clinical syndromes, ranging from minor cutaneous lesions to life-threatening illnesses, especially in immunocompromised hosts. Here, we investigate retrospectively the contribution of five human herpesviruses, including herpes simplex virus Cytomegalovirus (CMV), the Epstein-Barr virus (EBV), human herpesvirus 6, and varicella zoster virus (VZV) in serum samples collected from measles suspected patients with at least fever and rash. Sera specimens were first tested for serological evidence of measles and rubella virus infection by ELISA, and DNA extracted from an aliquot of each clinical specimen for molecular detection of human herpes viruses by RT-qPCR. A total of 3,358 specimens have been collected and tested for herpes viruses. Nearly half of the overall suspected cases were children younger than 5 years (49.4%). Of the 3,358 sera tested by ELISA, 227 (6.7%) were measles laboratory confirmed and 152 (4.5%) rubella laboratory confirmed. Herpes viruses were detected in 1763 (52.5%), and VZV was the most common with 44.3%, followed by EBV with 10.7%. Coinfections were found in 352 (20%) cases, and the most common co-detections were VZV/EBV or VZV/CMV (169 and 81 cases, respectively). A clear seasonal pattern of VZV, EBV, and CMV identification was observed, with the highest incidence between February and April each year. Results of this investigation provide more insights into cutaneous rash syndrome etiologies in patients sampled in the framework of measles/rubella surveillance in Senegal, which is useful for the guidance of both case definition revision and clinical practice as well as for public health policy.

Etiology of maculopapular rash in measles and rubella suspected patients from Belarus

As a result of successful implementation of the measles/rubella elimination program, the etiology of more and more double negative cases remains elusive. The present study determined the role of different viruses as causative agents in measles or rubella suspected cases in Belarus. A total of 856 sera sent to the WHO National Laboratory between 2009 and 2011 were tested for specific IgM antibodies to measles virus (MV), rubella virus (RV) and human parvovirus B19 (B19V). The negatives were further investigated for antibodies to enterovirus (EV) and adenovirus (AdV). Children of up to 3 years were tested for IgM antibodies to human herpesvirus 6 (HHV6). A viral etiology was identified in 451 (52.7%) cases, with 6.1% of the samples being positive for MV; 2.6% for RV; 26.2% for B19V; 9.7% for EV; 4.6% for AdV; and 3.6% for HHV6. Almost all measles and rubella cases occurred during limited outbreaks in 2011 and nearly all patients were at least 15 years old. B19V, EV and AdV infections were prevalent both in children and adults and were found throughout the 3 years. B19V occurred mainly in 3-10 years old children and 20-29 years old adults. EV infection was most common in children up to 6 years of age and AdV was confirmed mainly in 3-6 years old children. HHV6 infection was mostly detected in 6-11 months old infants. Laboratory investigation of measles/rubella suspected cases also for B19V, EV, AdV and HHV6 allows diagnosing more than half of all cases, thus strengthening rash/fever disease surveillance in Belarus.

Clinical impact of primary infection with roseoloviruses

The roseoloviruses, human herpesvirus-6A -6B and -7 (HHV-6A, HHV-6B and HHV-7) cause acute infection, establish latency, and in the case of HHV-6A and HHV-6B, whole virus can integrate into the host chromosome. Primary infection with HHV-6B occurs in nearly all children and was first linked to the clinical syndrome roseola infantum. However, roseolovirus infection results in a spectrum of clinical disease, ranging from asymptomatic infection to acute febrile illnesses with severe neurologic complications and accounts for a significant portion of healthcare utilization by young children. Recent advances have underscored the association of HHV-6B and HHV-7 primary infection with febrile status epilepticus as well as the role of reactivation of latent infection in encephalitis following cord blood stem cell transplantation.

Human herpesviruses 6, 7, and 8 from a dermatologic perspective

Human herpesviruses (HHVs) have frequently been suspected as etiologic agents or cofactors in cutaneous disease. However, clearly established associations are rare. Investigations into an etiologic association between HHVs and cutaneous disease are complicated by the ubiquity and nearly universal prevalence of some herpesviruses. This article summarizes the associations between cutaneous disease and HHV-6, HHV-7, and HHV-8. In addition to a personal library of references, the PubMed database of biomedical literature was searched using the following Medical Subject Heading terms: HHV-6, HHV-7, and HHV-8, each in conjunction with cutaneous manifestations, virology, epidemiology, dermatopathology, and therapeutics, between 1998 and March 2011. Free-text searches with known or suspected disease associations were added for broader coverage. The results have been summarized to provide a practical review for the physician likely to encounter cutaneous diseases.

Diagnosis of human herpesvirus 6B primary infection by polymerase chain reaction in young children with exanthematic disease

INTRODUCTION

Exanthem subitum is a classical rash disease of early childhood caused by human herpesvirus 6B (HHV-6B). However, the rash is frequently misdiagnosed as that of either measles or rubella.

METHODS

In this study, a nested multiplex polymerase chain reaction (PCR) was used to diagnose HHV-6B primary infection, differentiate it from infections caused by HHV-6A and compare it to antibody avidity tests. The samples were separated into case group and control group according to the results of the indirect immunofluorescence assay (IFA) technique.

RESULTS

From the saliva samples analyzed, HHV-6A DNA was detected in 3.2% of the case group and in 2.6% of the control group. Regarding HHV-6B, PCR detected viral DNA in 4.8% of the case group and in 1.3% of the control group. Among the serum samples studied, a frequency of 1.7% was determined for HHV-6A in the case group and 1.2% in the control group. PCR did not detect HHV-6B DNA in serum samples. The sensitivity and specificity of the PCR technique ranged from 0% to 4.8% and 97.5% to 100%, respectively, compared to IFA.

CONCLUSIONS

The PCR technique was not suitable for diagnosing primary infection by HHV-6B in children with exanthematic disease and should not substitute the IFA.

The accuracy of anti-human herpesvirus 6 IgM detection in children with recent primary infection

Human herpesvirus 6 (HHV-6) has been shown to infect almost all children by 4 years of age. Even with a typical clinical presentation, HHV-6 infection is misdiagnosed frequently as measles or rubella. The aim of this study was to assess the accuracy of the IgM test for detection of recent primary HHV-6 infection. The study was conducted between January, 1998 and December, 2006 at primary health care units in Niterói, Rio de Janeiro, Brazil. Sera from 185 children, in whom measles, rubella, dengue fever and parvovirus B19 infections were excluded, were studied for anti-HHV-6 IgG and IgM antibodies using an indirect immunofluorescence test. Seventy-one (38.4%) of the children had evidence of primary HHV-6 infection. Taking the IgG avidity test as the "gold standard", the following results for IgM were obtained-sensitivity: 76.1%; specificity: 87.5%; accuracy: 82.4%. This study confirmed the low accuracy of IgM detection for the diagnosis of primary HHV-6 infection.