Strain-specific requirements of susceptibility to rhesus enteric calicivirus infection.

Recently, we identified the coxsackie and adenovirus receptor (CAR) as the entry receptor for rhesus enteric calicivirus (ReCV) isolate FT285 and demonstrated that co-expression of the CAR and the type B histo-blood group antigen (HBGA) is required to convert the resistant CHO cell line susceptible to infection. To address whether the CAR is also the functional entry receptor for other ReCV isolates and the requirement for specific HBGAs or other glycans, here we used a panel of recombinant CHO cell lines expressing the CAR and the type A, B, or H HBGAs alone or in combination. Infection studies with three diverse ReCV strains, the prototype GI.1 Tulane virus (TV), GI.2 ReCV-FT285, and GI.3 ReCV-FT7, identified that cell surface expression of the CAR is an absolute requirement for all three strains to promote susceptibility to infection, while the requirement for HBGAs varies among the strains. In addition to the CAR, ReCV-FT285 and TV require type A or B HBGAs for infection. In the absence of HBGAs, TV, but not Re-CV FT285, can also utilize sialic acids, while ReCV-FT7 infection is HBGA-independent and relies on CAR and sialic acid expression. In summary, we demonstrated strain-specific diversity of susceptibility requirements for ReCV infections and that CAR, type A and B HBGA, and sialic acid expression control susceptibility to infection with the three ReCV isolates studied. Our study also indicates that the correlation between in vitro HBGA binding and HBGAs required for infection is relatively high, but not absolute. This has direct implications for human noroviruses.IMPORTANCEHuman noroviruses (HuNoVs) are important enteric pathogens. The lack of a robust HuNoV cell culture system is a bottleneck for HuNoV cell culture-based studies. Often, cell culture-adapted caliciviruses that rapidly replicate in conventional cell lines and recapitulate biological features of HuNoVs are utilized as surrogates. Particularly, rhesus enteric caliciviruses (ReCVs) display remarkable similarities, including the primate host, clinical manifestation of gastroenteritis, genetic/antigenic diversity, and reliance on histo-blood group antigens (HBGAs) for attachment. While the HuNoV entry receptor(s) is unknown, the coxsackie and adenovirus receptor (CAR) has recently been identified as the ReCV entry receptor. Here, we identified the CAR, the type A and B HBGAs, and sialic acids as critical cell surface molecules controlling susceptibility to ReCV infections. The CAR is required for all ReCV isolates studied. However, the requirement for the different carbohydrate molecules varies among different ReCV strains. Our findings have direct implications for HuNoVs.

Ocular manifestation of hand, foot, and mouth disease : A case series.

Virus-related illnesses are a common phenomenon, especially in the colder months of the year. They usually manifest with cough, cold, and other flu-associated symptoms. They affect people of all ages and genders. In recent years, also virus-associated ocular symptoms have been documented repeatedly. One of the viruses known to cause these is the Coxsackievirus A, which causes hand, foot, and mouth disease. Three cases of these virus-associated macular changes are described below. In all three cases, the symptoms occurred unilaterally and with little time delay to the virus-typical general changes. Complete functional remission occurred in all cases, whereby permanent changes in the pigment epithelium were observed.

Experimental infection of foot and mouth disease virus (FMDV) upregulates the expression of Coxsackie and adenovirus receptor (CAR) in the myocardium of suckling mice.

The relative overexpression of Coxsackie and adenoviral receptor (CAR) predisposes children to viral myocarditis. As the foot and mouth disease virus (FMDV) causes fatal myocarditis in calves, lambs, and piglets and belongs to the same family as the Coxsackie virus, we investigated the role of CAR in FMDV induced myocarditis in the suckling mice model. Swiss albino suckling mice of 5 days (n = 24) were divided into two equal groups. One group was inoculated with suckling mice adapted FMDV serotype O at 10 LD50, while the other group served as uninfected control. In addition, adult mice (n = 12) served as the control for age related CAR expression and lack of pathogenicity to FMDV. The establishment of myocarditis was confirmed by histopathological changes typical of myocarditis along with immunolocalization of FMDV antigens in the heart of suckling mice. The FMDV inoculated suckling mice group showed a significant upregulation of CAR transcripts by 2.5 folds, overexpression of CAR protein by densitometric analysis of immunoblots, and intense immunolocalization of CAR in the sarcolemma and intercalated discs of cardiomyocytes as compared to the uninfected suckling mice group and adult mice. It was concluded that FMDV infection induced overexpression of CAR in the myocardium of suckling mice.

Huntingtin-interacting protein family members have a conserved pro-viral function from Caenorhabditis elegans to humans.

Huntingtin-interacting protein family members are evolutionarily conserved from yeast to humans, and they are known to be key factors in clathrin-mediated endocytosis. Here we identified the Caenorhabditis elegans protein huntingtin-interacting protein-related 1 (HIPR-1) as a host factor essential for Orsay virus infection of C. elegans Ablation of HIPR-1 resulted in a greater than 10,000-fold reduction in viral RNA, which could be rescued by ectopic expression of HIPR-1. Viral RNA replication from an endogenous transgene replicon system was not affected by lack of HIPR-1, suggesting that HIPR-1 plays a role during an early, prereplication virus life-cycle stage. Ectopic expression of HIPR-1 mutants demonstrated that neither the clathrin light chain-binding domain nor the clathrin heavy chain-binding motif were needed for virus infection, whereas the inositol phospholipid-binding and F-actin-binding domains were essential. In human cell culture, deletion of the human HIP orthologs HIP1 and HIP1R led to decreased infection by Coxsackie B3 virus. Finally, ectopic expression of a chimeric HIPR-1 harboring the human HIP1 ANTH (AP180 N-terminal homology) domain rescued Orsay infection in C. elegans, demonstrating conservation of its function through evolution. Collectively, these findings further our knowledge of cellular factors impacting viral infection in C. elegans and humans.

Increased reports of severe myocarditis associated with enterovirus infection in neonates, United Kingdom, 27 June 2022 to 26 April 2023.

Enteroviruses are a common cause of seasonal childhood infections. The vast majority of enterovirus infections are mild and self-limiting, although neonates can sometimes develop severe disease. Myocarditis is a rare complication of enterovirus infection. Between June 2022 and April 2023, twenty cases of severe neonatal enteroviral myocarditis caused by coxsackie B viruses were reported in the United Kingdom. Sixteen required critical care support and two died. Enterovirus PCR on whole blood was the most sensitive diagnostic test. We describe the initial public health investigation into this cluster and aim to raise awareness among paediatricians, laboratories and public health specialists.

Introduction and Differential Diagnosis of Monkeypox in Argentina, 2022.

We report detection of cases of monkeypox virus infection in Argentina in the context of a marked increase in confounding cases of atypical hand-foot-and-mouth syndrome caused by enterovirus coxsackie A6. We recommend performing an accurate differential virological diagnosis for exanthematous disease in suspected monkeypox cases.

Cardiomyocyte Expression of ZO-1 Is Essential for Normal Atrioventricular Conduction but Does Not Alter Ventricular Function.

RATIONALE: ZO-1 (Zonula occludens-1), a plasma membrane-associated scaffolding protein regulates signal transduction, transcription, and cellular communication. Global deletion of ZO-1 in the mouse is lethal by embryonic day 11.5. The function of ZO-1 in cardiac myocytes (CM) is largely unknown. OBJECTIVE: To determine the function of CM ZO-1 in the intact heart, given its binding to other CM proteins that have been shown instrumental in normal cardiac conduction and function. METHODS AND RESULTS: We generated ZO-1 CM-specific knockout (KO) mice using α-Myosin Heavy Chain-nuclear Cre (ZO-1cKO) and investigated physiological and electrophysiological function by echocardiography, surface ECG and conscious telemetry, intracardiac electrograms and pacing, and optical mapping studies. ZO-1cKO mice were viable, had normal Mendelian ratios, and had a normal lifespan. Ventricular morphometry and function were not significantly different between the ZO-1cKO versus control (CTL) mice, basally in young or aged mice, or even when hearts were subjected to hemodynamic loading. Atrial mass was increased in ZO-1cKO. Electrophysiological and optical mapping studies indicated high-grade atrioventricular (A-V) block in ZO-1cKO comparing to CTL hearts. While ZO-1-associated proteins such as vinculin, connexin 43, N-cadherin, and α-catenin showed no significant change with the loss of ZO-1, Connexin-45 and Coxsackie-adenovirus (CAR) proteins were reduced in atria of ZO-1cKO. Further, with loss of ZO-1, ZO-2 protein was increased significantly in ventricular CM in a presumed compensatory manner but was still not detected in the AV nodal myocytes. Importantly, the expression of the sodium channel protein NaV1.5 was altered in AV nodal cells of the ZO-1cKO versus CTL. CONCLUSIONS: ZO-1 protein has a unique physiological role in cardiac nodal tissue. This is in alignment with its known interaction with CAR and Cx45, and a new function in regulating the expression of NaV1.5 in AV node. Uniquely, ZO-1 is dispensable for function of the working myocardium.

Human Coxsackie- and adenovirus receptor is a putative target of neutrophil elastase-mediated shedding.

BACKGROUND: During viral-induced myocarditis, immune cells migrate towards the site of infection and secrete proteases, which in turn can act as sheddases by cleaving extracellular domains of transmembrane proteins. We were interested in the shedding of the Coxsackie- and adenovirus receptor (CAR) that acts as an entry receptor for both eponymous viruses, which cause myocarditis. CAR shedding by secreted immune proteases could result in a favourable outcome of myocarditis as CAR's extracellular domain would be removed from the cardiomyocytes' surface leading to decreased susceptibility to ongoing viral infections. METHODS AND RESULTS: In this work, matrix metalloproteinases and serine proteinases were screened for their proteolytic activity towards human CAR. Whereas matrix metalloproteinases, proteinase 3, and cathepsin G did not cleave human recombinant CAR or only within long incubation times, neutrophil elastase showed a distinct cleavage pattern of CAR's extracellular domain that was time- and dose-dependent. Neutrophil elastase cleaves CAR at its membrane-proximal immunoglobulin domain as we determined by nanoLC-MS/MS. Furthermore, neutrophil elastase treatment of cells reduced CAR surface levels as seen by flow cytometry and immunofluorescence microscopy. CONCLUSIONS: With this study, we show that CAR might be a target for shedding by neutrophil elastase.

Hand-foot-mouth disease in puerperium.

Our case report describes a case of an otherwise predominantly childhood disease in a young adult woman with a good socioeconomic background who developed pruritic exanthema on the 2nd day after spontaneous delivery. The aim of the paper is to characterize the disease and to describe the possible risks for mother and child according to the available literature, as well as complications not only in puerperium but also during pregnancy.

Role of Selenium in Viral Infections with a Major Focus on SARS-CoV-2.

Viral infections have afflicted human health and despite great advancements in scientific knowledge and technologies, continue to affect our society today. The current coronavirus (COVID-19) pandemic has put a spotlight on the need to review the evidence on the impact of nutritional strategies to maintain a healthy immune system, particularly in instances where there are limited therapeutic treatments. Selenium, an essential trace element in humans, has a long history of lowering the occurrence and severity of viral infections. Much of the benefits derived from selenium are due to its incorporation into selenocysteine, an important component of proteins known as selenoproteins. Viral infections are associated with an increase in reactive oxygen species and may result in oxidative stress. Studies suggest that selenium deficiency alters immune response and viral infection by increasing oxidative stress and the rate of mutations in the viral genome, leading to an increase in pathogenicity and damage to the host. This review examines viral infections, including the novel SARS-CoV-2, in the context of selenium, in order to inform potential nutritional strategies to maintain a healthy immune system.

Semi-quantification of antibody-dependent enhancement (ADE) in the uptake of Adenovirus serotype 5 into THP-1 cells.

Replication defective recombinant Ad5 vectors (rAdV5) are extensively explored for its applications in gene therapy and vaccine delivery. Ad5 enter into monocytes and macrophages through CAR independent route as an immune complex termed as antibody-dependent enhancement (ADE). We developed an effective method for estimating the ADE of rAdV5 encoding GFP (rAdV5-GFP) into THP-1 cells, using fluorimetric semi-quantification of GFP. Initially, twenty numbers of human sera samples were screened in HeLa cells for anti-Ad5 antibody titer using neutralization assay. Uptake of rAdV5-GFP in THP-1 cells was observed only after pre-incubation with the serially diluted human sera which are attributed to ADE. The optimal dilution which showed the maximum GFP expression as per the fluorescence microscopic analysis in THP-1 cells was used for further analysis. Fluorimetric analysis of the THP-1 cell lysate showed a maximum GFP intensity of 17058 RFU, which was equivalent to the 0.397 pmoles of Alexa Fluor 488 under the same experimental condition. Similarly, immunoblot analysis of GFP in THP-1 cell lysate and HeLa cell lysate confirmed the entry of rAdV5-GFP into the cells. The assay can serve as a platform for understanding the molecular events involved in ADE for the uptake of viruses into immune cells.

Antiviral potential of garlic (Allium sativum) and its organosulfur compounds: A systematic update of pre-clinical and clinical data.

BACKGROUND: Garlic (Allium sativum L.) is a common herb consumed worldwide as functional food and traditional remedy for the prevention of infectious diseases since ancient time. Garlic and its active organosulfur compounds (OSCs) have been reported to alleviate a number of viral infections in pre-clinical and clinical investigations. However, so far no systematic review on its antiviral effects and the underlying molecular mechanisms exists. SCOPE AND APPROACH: The aim of this review is to systematically summarize pre-clinical and clinical investigations on antiviral effects of garlic and its OSCs as well as to further analyse recent findings on the mechanisms that underpin these antiviral actions. PubMed, Cochrane library, Google Scholar and Science Direct databases were searched and articles up to June 2020 were included in this review. KEY FINDINGS AND CONCLUSIONS: Pre-clinical data demonstrated that garlic and its OSCs have potential antiviral activity against different human, animal and plant pathogenic viruses through blocking viral entry into host cells, inhibiting viral RNA polymerase, reverse transcriptase, DNA synthesis and immediate-early gene 1(IEG1) transcription, as well as through downregulating the extracellular-signal-regulated kinase (ERK)/mitogen activated protein kinase (MAPK) signaling pathway. The alleviation of viral infection was also shown to link with immunomodulatory effects of garlic and its OSCs. Clinical studies further demonstrated a prophylactic effect of garlic in the prevention of widespread viral infections in humans through enhancing the immune response. This review highlights that garlic possesses significant antiviral activity and can be used prophylactically in the prevention of viral infections.

[New aspects in the histopathology of infectious skin diseases]. / Neue Aspekte zur Histopathologie bei Hautinfektionen.

BACKGROUND: An infectious pathogenesis should always be considered in inflammatory infiltrates in the skin. While some organisms can be recognized on hematoxylin-eosin staining (e.g. yeasts, leishmania), histochemical and immunohistochemical stainings are available for others. OBJECTIVES: If no organisms are seen in a section, the diagnosis of an infection cannot be made with surety, but the pattern of the inflammatory infiltrate can still be suggestive of an infectious process. New or little-known reaction patterns and difficulties in differential diagnosis will be demonstrated. MATERIALS AND METHODS: Selective literature review and analysis of individual cases. RESULTS: Studies using molecular techniques to identify organisms in biopsy specimens have helped to better characterize the histomorphological spectrum of skin infiltrates in infectious skin diseases. Apart from unusual herpes simplex and varicella zoster infections, the histopathology of coxsackie virus and measles exanthem, borreliosis, syphilis, and of cutaneous leishmaniasis is demonstrated. For numerous organisms, molecular tests have been established that can be used on the formalin-fixed, paraffin-embedded material. CONCLUSIONS: Selected skin infections demonstrate the broad histomorphological spectrum of skin infiltrates induced by infectious organisms. It is important for histopathologists to know which reaction pattern requires them to alert the clinician to necessary ancillary diagnostics (culture, serology) and when to consider molecular diagnostics to be performed on the biopsy specimen.

Coxsackie Myocarditis with Severe Methicillin-resistant Staphylococcus aureus Sepsis, Multi-organ Dysfunction Syndrome, and Posterior Epidural Spinal Abscess: A Case Report.

AIM: The aim of this paper is to present an interesting case of viral myocarditis complicated by sepsis, its sequelae, including multi-organ dysfunction syndrome, and the approach to manage it successfully. BACKGROUND: Viral myocarditis is an inflammatory disease of myocardium, often leading to residual heart disease. Commonly, dengue and Coxsackie B viruses are the causative agents. Patients usually present with dyspnea, fever, and signs of heart failure. A possibility of bacterial sepsis should not be overlooked, given similar presentations may occur. CASE DESCRIPTION: A 21-year-old male presented with acute onset breathlessness, fever, chills, and severe neck pain. On a detailed workup, he was found to have features suggestive of viral myocarditis, bacterial sepsis, with bilateral pleural loculations, a posterior epidural spinal abscess. Elimination of infectious foci, along with a decision to stick to the ongoing antibiotics, instead of stepping up to the last available ones proved beneficial. Meticulous balance of diuretics and inotropes saved the patient's life from what turned out to be coxsackie myocarditis. CONCLUSION: Here, we present the case of a young male who came in with congestive heart failure due to Coxsackie myocarditis and his condition complicated by severe sepsis. CLINICAL SIGNIFICANCE: Up to 10% of the cases of coxsackie myocarditis progress to chronic dilated cardiomyopathy. The management is usually conservative, and antiviral agents have shown no role in speedy recovery. Elimination of infectious foci aggressively is of prime importance in the treatment of bacterial sepsis. A careful balance of inotropes, diuretics, and fluid management is needed to get the patient into remission in such cases. HOW TO CITE THIS ARTICLE: Morkar DN, Agarwal R, Patil RS. Coxsackie Myocarditis with Severe Methicillin-resistant Staphylococcus aureus Sepsis, Multi-organ Dysfunction Syndrome, and Posterior Epidural Spinal Abscess: A Case Report. Indian J Crit Care Med 2020;24(1):73-76.

Pathological and molecular studies on Coxsackie virus A-16 isolated from hand, foot, and mouth disease cases in India: Approach using neonatal mouse model.

The present study highlights pathogenesis and molecular aspects of Coxsackie virus A-16 (CVA-16) strains isolated from hand, foot, and mouth disease (HFMD) cases from India using a neonatal mice model. ICR mice were intraperitoneally inoculated with CVA-16/311 strain isolated from HFMD cases. Mice developed hind and forelimb paralysis on day 3 of post infection. Histopathological observations of hind limb muscles showed necrosis, dissolution of muscle fiber cells, infiltration of inflammatory cells, marked dilated ventricle, hemorrhages, and neuronal degeneration in the brain. Immunohistochemical studies revealed high expression of CVA-16/311-specific viral antigen in limb muscles, brain, heart from day 3 till day 7 of post-infection. VP1 gene-based reverse transcription polymerase chain reaction conducted in RNA samples of different tissue organs of infected mice followed by sequencing of the positive amplimers revealed presence of CVA-16/311-specific viral sequences. Phylogenetic analysis based on the VP1 gene showed the presence of B1c sub genotype of CVA-16/311 strain in targeted tissue organs. Sequence analysis revealed major genetic changes in heart, skeletal muscle tissues at the nucleotide and amino acid levels. Genetic changes occurred in organs of mice might predict some potential targets and might act as markers of virulence for neuronal tropism. Pathogenesis and molecular studies of CVA-16 strains isolated from HFMD cases using neonatal mice model was conducted for the first time from India.

Benign acute viral myositis in African migrants: A clinical, serological, and pathological study.

BACKGROUND: Several viruses have been described as causes of acquired inflammatory myopathies; however, the mechanisms by which they cause muscle disease are still unclear. The aim of this study was to describe the laboratory features of benign acute myositis in a small case series. METHODS: A detailed pathological and serological analysis was performed in five African migrants who developed an acute viral myositis complicated by rhabdomyolysis. RESULTS: Muscle biopsies clearly documented an inflammatory myopathy with histological features similar to polymyositis including CD8+ T cells surrounding and invading nonnecrotic muscle fibers, CD68+ macrophages and major histocompatibility complex class I antigen upregulation. In addition, positivity for myositis-specific antibodies (MSA), in particular anti-aminoacyl tRNA synthetases, was found in the serum of two patients. CONCLUSIONS: Our study demonstrated that T-cell mediated injury occurs in muscle of patients with acute viral myositis, and that MSA may be present in the serum of these patients.

Acute unilateral maculopathy associated with adult onset of hand, foot and mouth disease: a case report.

BACKGROUND: To report the case of a 31-year-old patient with Hand, Foot and Mouth Disease (HFMD) and concurrent acute monocular maculopathy, and to describe multimodal imaging findings never before described including optical coherence tomography angiography (OCT-A). CASE PRESENTATION: Nine days after the onset of clinically highly probable but not laboratory-verified HFMD, a 31-year old male noticed a central scotoma, distorted lines and loss of visual acuity (Snellen visual acuity 20/400) in his right eye. Funduscopy revealed focal alterations in the retinal pigmented epithelium (RPE) and yellow retinal dots corresponding to focal dots of decreased fundus autofluorescence (FAF) surrounded by increased FAF. Spectral domain optical coherence tomography (SD-OCT) demonstrated irregularities in the ellipsoide zone, hyperreflective dots above the RPE and RPE thickening. Fundus fluorescein angiography (FAG) revealed central hypofluorescence in the macular area in the early phase, as well as increasing focal hyperfluorescence in the late phase corresponding with RPE defects observed in FAF. Indocyanine green angiography (ICGA) showed central hypofluorescence in the early and late phase, corresponding with areas of reduced flow in the choroidea and choriocapillaris as apparent in OCT-A. Visual acuity improved within 3 months without any systemic or local therapy. At his three-month follow-up, SD-OCT revealed subtle subretinal fluid that resolved spontaneously over time. No signs of choroidal neovascularization were observed. Twelve months following the onset of symptoms Snellen visual acuity was 400/400. Multimodal imaging revealed subtly changed, decreased FAF while the choroidal architecture recovered completely as demonstrated by OCT-A. CONCLUSIONS: HFMD-associated maculopahty is an uncommon but important differential diagnosis of chorioretinitis with macular involvement. The prognosis can be good and the initially observed morphological pathologies such as impaired perfusion of the choroidal vessels can recover spontaneously over a period lasting 12 months. OCT-A can be employed as a non-invasive tool to detect the reduced perfusion of the choroidal vessels and for monitoring the disease course.

Tanshinone IIA Ameliorate Coxsackie Virus B3-Induced Viral Myocarditis through the Inhibition of Inflammation and Modulation T Helper 1/T Helper 2 Balance in Mice.

To investigate the effect of Tanshinone IIA (TSA) on viral myocarditis (VMC). VMC animal model was established using BALB/c mice by intraperitoneally injecting Coxsackie virus B3 (CVB3). The mice were randomly divided into control group, model group, and TSA group. We detected the survival rate, the heart weight to body weight (HW/BW) ratio and hemodynamic and cardiac function parameters. The pathological features of VMC were measured through H&E staining. The expression of serum enzyme, inflammatory cytokines, and T helper (Th)1/Th2 markers was also investigated. TSA remarkably alleviated CVB3-caused myocardial injury, decreased the HW/BW ratio, and improved survival rate. TSA obviously improved hemodynamic parameters and reversed the damage to the heart pump function. Furthermore, the serum levels of lactate dehydrogenase, creatine kinase, and Th1 cytokines in the TSA group were significantly lower than those in the VMC group, and TSA treatment significantly improved the pathological condition. The interferon-gamma (IFN-γ) and interleukin-2 (IL-2) levels in VMC model group was higher than control group, and lower levels of IL-4 and IL-10 were identified. However, TSA treatment elevated IL-4 and IL-10 levels and decreased IFN-γ and IL-2 levels. TSA could effectively protect the myocardium against CVB3-induced myocarditis by the inhibition of inflammation and modulation Th1/Th2 balance in mice.

[Atypical variant of hand-foot-mouth disease]. / Atypische Hand-Fuß-Mund-Krankheit.

An atypical variant of hand-foot-mouth disease (HFMD) has sporadically been reported in recent years, with outbreaks in Europe, Asia, the USA and South America. A new lineage of Coxsackie virus A6 has been identified as the causative agent, a virus-type belonging to the group of enteroviruses. HFMD is transmitted through droplet infection or through faecal-oral transmission. The disease may begin with a prodromal stage and is often accompanied by fever and malaise. Typical skin findings include a papular and vesiculobullous exanthema that might be accompanied by confluent blisters (bullae), crusting, and ulceration. In contrast to "classic" HFMD, predilection sites include the dorsal aspects of the hands and feet, forearms, lower legs, neck and trunk. Oral lesions may be present, but are less often seen compared to "classic" HFMD. The course of the disease is self-limiting, with complete resolution usually within 7-14 days after disease onset. The treatment of atypical HFMD is usually symptomatic. A diagnosis of atypical HFMD might be challenging due to the polymorphous presentation of the disease. This review describes a rarely reported but more frequently diagnosed viral condition.