Atypical exanthems associated with Parvovirus B19 (B19V) infection in children and adults

Oral and cutaneous manifestations of viral and bacterial infections: Not only COVID-19 disease

Globalization entails several medical problems along with economic and social complications. Migrations from other continents, increasing numbers of tourists worldwide, and importation of foreign parasites (eg, Aedes albopictus) have made diseases previously unknown in Europe a reality. The rapid spread of the coronavirus disease 2019 pandemic throughout the world is a warning that other epidemics are still possible. Most, if not all of these diseases, transmitted by viruses or bacteria, present with cutaneous symptoms and signs that are highly important for a speedy diagnosis, a fundamental concept for arresting the diseases and saving lives. Dermatologists play a significant role in delineating cutaneous and mucosal lesions that are often lumped together as dermatitis. We provide a review of many of these cutaneous and mucosal lesions that sometimes are forgotten or even ignored.

SARS-CoV-2 infection: the same virus can cause different cutaneous manifestations

Linked Article:  Galván Casas et al. Br J Dermatol 2020; 183:71–77.

Prospective study of blood viral load of Epstein-Barr virus, herpes virus type 6 and human parvovirus B19 in Crohn's disease: Does therapy matter?

BACKGROUND

The interplay between inflammatory bowel disease (IBD) and DNA viruses, such as Epstein-Barr (EBV), human parvovirus B19 (HPVB19) and human herpes type 6 (HHV6) is scarcely studied. The main aim of this prospective study is to screen for EBV, HSV6, and HPVB19 DNA viremia in adult patients with stable Crohn's disease (CD), correlating the results with IBD treatment.

METHODS

From July 2015 - March 2017, 100 patients were enrolled and divided in four groups of 25 participants each, according to in course treatment. Blood collections were performed every 5 months in all patients. Antibodies for EBV and HPVB19 were screened and repeated if negative. Blood EBV DNA, HPVB19 DNA, and HHV6 DNA were quantified by quantitative real-time Polymerase Chain Reaction.

RESULTS

Patients had evidence of EBV (100 %) and HPVB19 (70 %) past infection. Across the study timeline, EBV-DNA, HPVB19-DNA, and HHV6-DNA were detected in the blood of 25, 11, and 7 patients, respectively. Viremia was detected only once in 72 %, 73 %, and 86 % of the patients in the studied period, for EBV, HPVB19, and HHV6, respectively. We did not find significant differences between treatment groups, independently of the viral cut-off for the three viruses.

CONCLUSIONS

The detection of EBV, HPVB19, and HHV6 viremia, in stable CD patients, was not impacted by biological/immunosuppressant therapy. Although attractive as a non-invasive technique, this approach did not prove to be useful in stable patients. More and larger studies are needed to address the relevance of these viruses on IBD course, in stable patients and during exacerbations.

Prevalence and disease association of human parvovirus B19 in Iran: a systematic review

Aim: The prevalence of human parvovirus B19 (B19V) and its association with other diseases in Iran are yet to be systematically assessed. This study aimed to evaluate the prevalence and disease association of B19V across Iran from 2000 to 2019. Methods: The literature search, based on different keywords in different databases, was performed. A total of 29 eligible studies were included and the essential information was collected from each article. Results: The results of this study show a relatively high prevalence of the B19V-associated diseases in all age groups of the Iranian population. Conclusion: The transmission of B19V and its complications should be prevented by developing preventative strategies.

Oral fluid: Non-invasive alternative for parvovirus B19 diagnosis?

BACKGROUND

Infections with parvovirus B19 (B19V) have been associated with a wide range of disease manifestations of which erythema infectiosum (fifth disease) in children is most common. Clinical signs following infection of children with B19V can be similar to measles and rubella. Laboratory detection of B19V infections is based on detection of B19V-specific IgM antibodies by enzyme immunoassay (IgM-EIA) and/or B19V DNA by quantitative PCR (qPCR) on blood samples. The need for invasive sampling can be a barrier for public health diagnostics.

OBJECTIVES

To evaluate the use of a dual target B19V-qPCR directed against the NS1 and VP2 of B19V on oral fluid samples as a non-invasive alternative for laboratory diagnosis of B19V infections in children below 12 years of age with exanthema.

STUDY DESIGN

Oral fluid and serum samples were collected from 116 children with exanthema. All serum samples were tested by IgM-EIA/IgG-EIA, while all oral fluid and 56 serum samples were tested by B19V-qPCR.

RESULTS

B19V-specific IgM antibodies were detected in 25 of 116 children in the study. B19V DNA was detected in oral fluid in 17 of the 25 children who were IgM positive, as well as two children who were IgM-equivocal or negative. The child with the equivocal IgM had a high quantity of B19V DNA in oral fluid (7 log IU/ml), compatible with an acute B19V infection. The IgM-negative child was IgG-positive and 4 log IU/ml B19V DNA was detected in the oral fluid sample, suggesting an acute infection and a falsely negative IgM. Sample size calculations indicated that oral fluid samples for qPCR should be collected from 2 to 3 children during outbreaks of exanthema to achieve similar sensitivity as IgM-EIA for one child (≥0.9) to confirm or exclude B19V.

CONCLUSIONS

Results indicate that oral fluid samples are a suitable public health alternative for detection of B19V infections, potentially lowering the barriers for sampling.

Severe atypical hand-foot-and-mouth disease in adults due to coxsackievirus A6: Clinical presentation and phylogenesis of CV-A6 strains

BACKGROUND

Typically, hand-foot-and-mouth disease (HFMD) is a mild childhood illness associated with coxsackievirus (CV)-A16, CV-A6, enterovirus (EV)-A71.

OBJECTIVES

To identify the viral agents associated with severe cases of atypical HFMD in Italy.

STUDY DESIGN

Epidemiologically unrelated cases of severe atypical HFMD admitted to the Emergency Room (ER) of IRCCS San Martino IST (Genoa, Italy) in 2014-2016 were investigated. Serologic screening for viral positivity was performed against exanthem-inducing agents. Ten cases with serology indicative of recent EV infection were selected. Molecular assays were used to detect viral genomes in blood [EVs, Parvovirus B19 (PVB19), herpesviruses (CMV; EBV, HHV-6, -7, -8)].

RESULTS

CV-A6 was detected in 10 cases of severe atypical HFMD. Two cases were also infected with PVB19. Herpesviruses were not detected. Phylogenetic analysis mapped the CV-A6 strains into a single cluster related to two recent isolates from a German and an Asian child. Fever, systemic symptoms, severe vasculitis-like rash, and enanthem were predominant at presentation. Spontaneous recovery occurred in 1-3 weeks.

CONCLUSIONS

CV-A6 is emerging as a frequent cause of severe atypical HFMD in Italian adults. This viral agent is disseminating worldwide. Dermatologists must identify the manifold alterations caused by EVs and understand the diagnostic power of current virology methods.

Contemporary infectious exanthems: an update

An exanthem is a skin rash that may be associated with mucous membrane eruption, fever or other symptoms. It may develop as manifestation of an infectious disease or as adverse reaction to drugs. Beside the ‘classical exanthems’ commonly occurring in childhood, other exanthems, defined as ‘atypical’ for the different morphology and causal agents, may occur. Among the atypical exanthems with infectious etiology, viral, bacterial, parasitic and helminth infections are implicated. We describe herein etiology and epidemiology of the atypical exanthems caused by infectious agents. In case of exanthem, to make a correct etiological diagnosis is crucial for both the patient and community concerning issues such as time off school, immunizations and risk in pregnancy and immunocompromised individuals.

Human Parvoviruses

Parvovirus B19 (B19V) and human bocavirus 1 (HBoV1), members of the large Parvoviridae family, are human pathogens responsible for a variety of diseases. For B19V in particular, host features determine disease manifestations. These viruses are prevalent worldwide and are culturable in vitro, and serological and molecular assays are available but require careful interpretation of results. Additional human parvoviruses, including HBoV2 to -4, human parvovirus 4 (PARV4), and human bufavirus (BuV) are also reviewed. The full spectrum of parvovirus disease in humans has yet to be established. Candidate recombinant B19V vaccines have been developed but may not be commercially feasible. We review relevant features of the molecular and cellular biology of these viruses, and the human immune response that they elicit, which have allowed a deep understanding of pathophysiology.

Viral exanthems: An update on laboratory testing of the adult patient

Although classic viral exanthems of childhood are well described, they are rarely differentiated in adults. Laboratory techniques for viral identification have advanced without substantial literature to suggest how a dermatologist ought to conduct a cost-effective and diagnostic viral panel. Certain clinical features such as petechiae, vesicles, and dusky macular or morbilliform exanthems point strongly toward a viral exanthem. Differentiation of drug and viral causes of morbilliform eruptions has proven difficult. It is possible that with further diagnostic refinement that unnecessary and fruitless workups of an exanthem and unneeded discontinuation of drugs can be avoided. We review viral exanthems based on clinical features and discuss the available and optimal laboratory techniques to assist the dermatologist in a targeted workup.