Acute Viral Syndrome Research Articles

Small Anellovirus Infections in Korean Children

To the Editor: Recently, Jones et al. (1) identified circular DNA sequences, classified as Anellovirus genus, in plasma from patients with acute viral infection syndromes. These anelloviruses were then labeled as “small anellovirus (SAV)” because of their smaller genomes when compared with Torque Teno Virus (TTV) and Torque Teno Mini Virus (TTMV), which have small, circular, single-stranded DNA genomes. Although anelloviruses are not associated with any specific disease, TTV has been suggested to play a role in acute respiratory disease (ARD) and in asthma of children (2,3). Kawasaki disease and Henoch-Schonlein purpura are important vasculitis disorders in children, possibly triggered by unknown infectious agents. Recently, Gergely et al. (4) reported that molecular mimicry involving TTV and the generation of autoantibodies may have a role in the pathogenesis of systemic lupus erythematosus. The purpose of our study was to investigate the prevalence of SAV and its association with various clinical diseases in children. The study population comprised 81 serum samples from healthy children and 151 serum samples from children hospitalized with hepatitis (81 cases), ARD (40 cases), Kawasaki disease (12 cases), or Henoch-Schonlein purpura (18 cases) during the period January 2002–June 2006. Nasopharyngeal aspirates paired with serum samples were collected from 34 children with ARD, including upper respiratory tract infections, pneumonia, and acute bronchiolitis. Samples were collected after informed consent was obtained at admission from patients’ parents. PCRs for SAV were performed to amplify a 5′ noncoding region of SAV with specific primers, as described previously (5). PCR products were directly sequenced, and nucleotide sequences were registered in GenBank (accession nos. {type:entrez-nucleotide,attrs:{text:DQ978791,term_id:119656310,term_text:DQ978791}}DQ978791–DQ9788810). The χ2 test with Yates correction and Mann-Whitney U-test were used for statistical comparison by using MedCalc (MedCalc Software, Mariakerke, Belgium). A p value <0.05 was defined as statistically significant. In our study population, serum SAV DNA was detected in 28 (34.5%) of 81 children in the control group and in 66 (43.7%) of 151 children in the disease group. In the healthy control group, the SAV-positive rate was 7.4% (6/81) in children <12 months of age, 16.0% (13/81) in children 1–4 years of age, and 11.1% (9/81) in children 5–15 years of age. In the disease group, the SAV-positive rate was 35.8% (29/81) in patients with hepatitis, 67.5% (27/40) in ARD, 50% (6/12) in Kawasaki disease, and 22.2% (4/18) in Henoch-Schonlein purpura, respectively (Table). Among 34 nasopharyngeal aspirates collected from children with ARD, SAV DNA was detected in 19 (55.9%). Codetection of SAV and respiratory syncytial virus in nasopharyngeal aspirates was observed in 4 patients. Table Prevalence of SAV viremia in the study population, Republic of Korea, January 2002–June 2006* Percent similarity of nucleotide sequence of PCR products was 99% among SAV isolates. To our knowledge, this is the first report of SAV infections in children. The prevalence and role of SAV in clinical diseases have yet to be determined. Recently, Biagini et al. (5) reported that the prevalence of SAV infection was 20% (12/60) in French blood donors. In an Italian study (6), the positive rate of SAV DNA was 9.1% (5/55) in patients with hepatitis C compared with 8.6% (3/35) in healthy controls. Thus, the prevalence of SAV in Korean children is much higher than rates reported in adults from other countries (5,6). Further studies are needed to confirm this finding. In our study, the prevalence of SAV did not differ significantly between the hepatitis group and the healthy control group. Our results indicate that SAV presence does not appear to have a defining role in hepatitis, as do TTV or TTMV infection (7). In a previous study, several groups of viruses including TTV were ruled out as etiologic agents of Kawasaki disease (8), findings similar to those of our study. We found that the prevalence of SAV was significantly higher in ARD and that SAV-positive serum results were consistent with those of nasopharyngeal aspirates in 76% (26/34). These findings suggest that the respiratory tract may be a transmission route of SAV in children. In conclusion, we confirmed the presence of SAV in serum samples and nasopharyngeal aspirates from Korean children. A significantly higher detection of SAV DNA was observed in children with ARD compared with healthy children or children with other clinical diseases.

Viral Infection Induced Acute Megaloblastic Anemia: A Case Series.

We have documented a series of ten patients presenting with symptomatic anemia and a recent history of constitutional symptoms such as fever, myalgias and diarrhea. They were mildly icteric and had severe pallor. Lymphadenopathy and organomegaly were absent. Peripheral blood smears showed reactive lymphocytes, which are typically seen in viral infections and in addition severe megaloblastic changes consisting of hypersegmentation of neutrophils, macro ovalocytes, leukopenia and thrombocytopenia were noted. Indirect bilirubinemia, elevated serum LDH and low haptoglobins were documented. Direct Coombs was negative in all the patients. Bone marrow aspiration revealed megaloblastic changes. Autoimmune hemolytic anemia, Pernicious anemia, Malaria, T.T.P, Aplastic anemia and HIV were excluded in all the patients. They had diagnostically low serum cobalamin and folate levels and the cytopenias normalized with parenteral vitamin supplementation. None of the patients received steroids or antiviral treatment.Was the viral syndrome causally related to the megaloblastic anemia or was a preexisting megaloblastic anemia being brought to the attention of the clinician by the acute viral syndrome? This puzzling question was solved when a patient who had a normal complete blood count in March 2005 at our institute, developed severe pancytopenia after a febrile illness in October 2005. Another patient in the series had normal hemoglobin and had actually donated a unit of blood one month prior to his admission with diarrhea and severe pancytopenia.The next question that we faced was regarding the identity of the virus. We initially performed a lymphadenitis panel (Euro Immune) consisting of 16 common viral markers. Epstein Barr virus (EBV) was positive in the initial case. An EBV Immunofluorescence panel (Euro Immune) was done in all the subsequent patients. This test was positive in 6 out of the10 patients, they were positive for EBV Capsid IgG, EBV Capsid IgM, and EBV early antigen Ig G (acute infection markers). EBV nuclear antigen IG G (chronic infection marker) was negative.It should be noted that none of the patients had neurological deficits despite having diagnostically low cobalamine levels and this we presume is due to the acute onset of illness not allowing enough time for the development of neurological symptoms. There were quite a few patients seen in this period of time with typical EBV infection without any megaloblastic changes and similarly there were patients with overt megaloblastic anemia without any features of EBV infection. Hence there must be a patient specific characteristic that predisposes them to acute megaloblastic anemia on developing the viral infection. Since only two of these ten patients are pure vegans and since none were malnourished we have to look for a non nutritional cause for this predisposition. An acute coombs negative hemolytic anemia due to the viral infection can explain the cytpenias but the low B12 levels and the prompt response to B12 supplementation are unexplained.We feel that this is a new syndrome of reversible viral induced acute onset megaloblastic anemia. There exists a possibility that this is a new strain of EBV virus, and we have stored the sera of all the patients for future epidemiological purposes. We are recommending that physicians should consider B12/folate supplementation in acute EBV syndromes and obtain follow-up CBC one month after the illness. We believe that further work has to be done before a definite association between EBV and megaloblastic anemia can be established.

Parvoviruses PARV4 and PARV5 and Hepatitis C Virus

To the Editor: Parvoviruses are small, nonenveloped DNA viruses that infect both vertebrate and invertebrate hosts. Until recently, parvovirus B19 and adeno-associated viruses, which belong to the genera Erythrovirus and Dependovirus, respectively, were the only known members of the family Parvoviridae that infected humans (1). However, 2 recent publications have identified 2 distinct, novel parvoviruses in humans by using the DNase sequence–independent single-primer amplification technique and a related method (2,3). The first of these viruses, termed PARV4, was observed in a patient with symptoms of acute viral infection syndrome after high-risk behavior for infection with HIV-1, although the patient was subsequently confirmed as negative for HIV-1 (2). The second parvovirus was identified in respiratory samples from children with lower respiratory tract infections and termed human bocavirus (3). Parvovirus B19 is a frequent contaminant of plasma pools that are used in the manufacture of blood products, which results in high viral loads in pools and viral transmission in recipients of clotting factors (4). We identified PARV4 in such pools (5), albeit at a lower frequency and titer than parvovirus B19, when parvovirus B19 was not excluded by screening with nucleic acid amplification techniques. Sequence analysis identified a second genotype of PARV4, which we have termed PARV5, that shares ≈92% nucleotide identity with PARV4 (5). PARV4 was originally identified in a plasma sample from a homeless, injection drug user with fatigue, night sweats, pharyngitis, neck stiffness, vomiting, diarrhea, arthralgia, and confusion (2). This person was coinfected with hepatitis B virus. In this study, we looked retrospectively for PARV4 and PARV5 in blood samples from a similar cohort of persons, many of whom were known to be infected with hepatitis C virus (HCV) (as determined by the presence of both HCV RNA and antibodies to HCV), and some of whom were intravenous drug users (IVDUs) (6). Blood samples were collected from 26 cadavers in London and the surrounding area as part of a study to investigate the inhibition of nucleic acid amplification techniques for bloodborne viruses in tissue samples (6). The cohort was composed of 10 HCV RNA–positive IVDUs, 8 HCV RNA–positive non-IVDUs, 4 HCV RNA–negative IVDUs, and 4 HCV RNA–negative non-IVDUs (Table). Nucleic acid was extracted as previously described (4) by using the MagNA Pure LC instrument (Roche, Basel, Switzerland). PCR was performed with primers specific for the second open reading frame (ORF2) in the PARV4 genome (2), which is homologous to the VP1 capsid of parvovirus B19. Primers PVORF2F (5′-AGGAGCAGCAAACAAACTCAGAC-3′) and PVORF2R (5′-TCCTTCATCGCGGCTGTCACTAA-3′) amplify a 268-bp region of ORF2 (nucleotides 2710–2977, GenBank accession no. {type:entrez-nucleotide,attrs:{text:AY622943,term_id:52854178,term_text:AY622943}}AY622943). The PCRs were performed and analyzed as previously described (5). The assay is highly specific (no cross-reactivity with parvovirus B19) and sensitive (detects 5–10 copies of PARV4 virus DNA per reaction). Table Analysis of 26 cadavers for parvoviruses PARV4 and PARV5* PCR products were cloned, sequenced, and compared with the prototype PARV4. Two blood samples were positive for PARV4, and a third sample was positive for PARV5, with 99%–100% nucleotide identity. These positive samples were from HCV RNA–positive IVDUs (Table). The titer of PARV4 and PARV5 DNA in the positive samples was low and did not exceed >700 copies/mL of plasma, as determined by using a consensus TaqMan assay (J. Fryer, unpub. data). None of the other blood samples tested was positive for PARV4 and PARV5, including those for persons who were HCV RNA negative and not IVDUs. In our previous study (5) of >130 fractionation pools (composed of thousands of units from screened healthy donors) for PARV4, the only positive pools were from North America and no European pools were positive for PARV4 or PARV5. These viruses may be present in such pools but diluted to undetectable levels. In the present study, PARV4 and PARV5 have been identified in blood samples obtained from persons from the United Kingdom. For parvovirus B19, there is evidence of persistent virus infection, at low levels, in bone marrow of previously exposed persons (7) and in plasma of immunocompromised and immunocompetent persons (8,9). There is also evidence for the lifelong persistence of parvovirus B19 (genotypes 1 and 2) in tissues such as skin and synovia (10). PARV4 and PARV5 virus genomes share only limited homology with parvovirus B19 (<30% amino acid similarity). Although they have been detected in blood and plasma, nothing is known about the role of these viruses in human disease or their ability to persist in infected persons, healthy or otherwise. Further studies will be required to determine the prevalence of PARV4 and PARV5 in healthy persons compared with its prevalence in those with chronic infections and at high risk, such as IVDUs, and to investigate the nature of persistence of these novel viruses.

New DNA Viruses Identified in Patients with Acute Viral Infection Syndrome

A sequence-independent PCR amplification method was used to identify viral nucleic acids in the plasma samples of 25 individuals presenting with symptoms of acute viral infection following high-risk behavior for human immunodeficiency virus type 1 transmission. GB virus C/hepatitis G virus was identified in three individuals and hepatitis B virus in one individual. Three previously undescribed DNA viruses were also detected, a parvovirus and two viruses related to TT virus (TTV). Nucleic acids in human plasma that were distantly related to bacterial sequences or with no detectable similarities to known sequences were also found. Nearly complete viral genome sequencing and phylogenetic analysis confirmed the presence of a new parvovirus distinct from known human and animal parvoviruses and of two related TTV-like viruses highly divergent from both the TTV and TTV-like minivirus groups. The detection of two previously undescribed viral species in a small group of individuals presenting acute viral syndrome with unknown etiology indicates that a rich yield of new human viruses may be readily identifiable using simple methods of sequence-independent nucleic acid amplification and limited sequencing.

A current review of Ebola virus: pathogenesis, clinical presentation, and diagnostic assessment.

Ebola hemorrhagic fever (EHF) is an acute viral syndrome that presents with fever and an ensuing bleeding diathesis that is marked by high mortality in human and nonhuman primates. Fatality rates are between 50% and 100%. Due to its lethal nature, this filovirus is classified as a biological class 4 pathogen. The natural reservoir of the virus is unknown. As a result, little is understood about how Ebola virus is transmitted or how it replicates in its host. Although the primary source of infection is unknown, the epidemiologic mode of transmission is well defined. A variety of tests have proven to be specific and useful for Ebola virus identification. There is no FDA-approved antiviral treatment for EHF. Incubation ranges from 2 to 21 days. Patients who are able to mount an immune response to the virus will begin to recover in 7 to 10 days and start a period of prolonged convalescence. Supportive management of infected patients is the primary method of treatment, with particular attention to maintenance of hydration, circulatory volume, blood pressure, and the provision of supplemental oxygen. Since there is no specific treatment outside of supportive management and palliative care, containment of this potentially lethal virus is paramount. In almost all outbreaks of EHF, the fatality rate among health care workers with documented infections was higher than that of non-health care workers.

Acute seroconversion of HIV infection in the ambulatory care setting.

Patients frequently visit ambulatory care settings with acute human immunodeficiency virus (HIV) seroconversion illness, but the illness is often misdiagnosed. This acute viral syndrome, or seroconversion illness, occurs after initial exposure to the HIV virus; it is often resolved before the development of HIV-specific antibodies. Primary HIV infection refers to the 12 months following infection; it includes an acute time period after exposure when routine HIV antibody testing is negative. Primary HIV infection is recognized with the help of a detailed screening history. Diagnosis is confirmed through laboratory tests that detect virus presence. The accurate diagnosis of primary HIV infection can have a beneficial effect on the patient's clinical course and also on public health prevention efforts.

EPSTEIN-BARR VIRUS-ASSOCIATED LYMPHOPROLIFERATIVE DISEASE AND VACCINES

S27 Epstein-Barr virus (EBV) infection results not only in the acute viral syndrome, infections mononucleosis (IM) but also in a number of geographically defined tumours. These tumours can be characterised in terms of the extent of expression of EBV latent antigens which include the EBV nuclear antigens (EBNA1-6) and the transmembrane proteins, LMP1 and 2. It has become increasingly evident that cytotoxic T lymphocytes (CTL) play a major role in limiting the expansion of EBV-infected B lymphocytes during primary EBV infection and following convalescence. There is very strong focussing of this CTL response towards recognition of epitopes within EBNA2-6 (Rickinson and Moss, 1997) and away from the malignancy-associated transmembrane EBV protein, LMP1. It seems highly likely that the EBV-associated immunohiastic lymphomas (IL) that arise following organ transplantation emerge as a result of the unrestricted proliferation of EBV-infected B cells in the inumunosuppressed graft recipient. Effective treatment of IL arising in bone marrow transplant patients has recently been developed and involves the adoptive transfer of donor CTL with specificity towards epitopes within the EBNA2-6 proteins. At this stage it is not clear the extent to which this procedure will find application in the treatment of IL following solid organ engraftment although early indications are encouraging. The opportunities for effective EBV CTL-based immunotherapy in the treatment of nasopharyngeal carcinoma (NPC) is reduced since the available target antigens are limited to EBNA1 and LMP1. CTL-based therapy will undoubtedly be influenced by the ability of these malignant cells to endogenously process and present target epitopes for immune recognition by CTLs. Analysis of NPC cells in fresh tumour biopsies and short-term established lines revealed normal expression of the MHC-encoded peptide transporters TAP-1 and TAP-2 together with high levels of HLA class 1 alleles on the cell surface suggesting that peptides are available for binding to nascent MHC molecules in the endoplasmic reticulum. The phenotype of the final EBV-associated malignancy to be considered. Burkitt's lymphoma (BL) appears designed to resist CTL recognition. Thus surface expression of MHC class I alleles and TAP1 and 2 expression are down-regulated and EBV antigen expression is restricted to EBNA1. Surprisingly, class II expression on BL cells is high, and efficient processing of CD4-restricted CTL epitopes through this pathway has been demonstrated. It seems likely that effective treatment of BL will revolve around protocols designed to reverse its undifferentiated phenotype. Interestingly, CD40 ligand treatment of BL cells reverses some of the features of the BL phenotype which is associated with CTL resistance.

Evolutionary pattern of human immunodeficiency virus (HIV) replication and distribution in lymph nodes following primary infection: implications for antiviral therapy.

Evolutionary patterns of virus replication and distribution in lymphoid tissue during the early phases of HIV infection have not been delineated. Lymph node (LN) biopsies were excised from patients at different times after the estimated time of primary infection. Within 3 months of the acute viral syndrome, HIV was mostly present in individual virus-expressing cells in LNs; trapping of virions in the follicular dendritic cell (FDC) network was minimal or absent, but was the predominant form of HIV detected in LNs of subjects with chronic infection, either recent (4-20 months after primary infection) or long-term (>2-3 years after primary infection). Plasma viremia was significantly higher in patients during the first 3 months than in those recently infected; however, there were no significant differences in the number of virus-expressing cells per square millimeter of LN tissue in these two groups. Numbers of virus-expressing cells in lymphoid tissue were significantly lower in the subjects with long-term infection than in the other two groups. Therefore, during the transition from primary to chronic HIV infection, the level of HIV replication in lymphoid tissue remains elevated despite the fact that viremia is significantly downregulated. These findings have implications for therapeutic strategies in primary HIV infection and in recent seroconvertors.

Clinical evaluation of fecal lactoferrin and α 1-antitrypsin in pediatric gastrointestinal infections

Abstract To investigate the pathophysiology of acute gastrointestinal infections in the pediatric field, daily fecal excretion of lactoferrin (Lf) and α 1-antitrypsin (AT) was examined in pediatric patients with acute viral gastroenteritis syndrome (AVGS) ( n = 17) or bacterial enterocolitis ( n = 10) and in control children ( n = 27). The pathogenic bacteria were Salmonella species ( n = 4), Campylobacter jejuni ( n = 3), pathogenic Escherichia coli ( n = 2) and Clostridiumdifficile ( n = 1). A greater daily fecal excretion was found in the AVGS and bacterial enterocolitis groups when compared with the control group. In addition, fecal AT excretion was significantly greater in the bacterial infection group than in the AVGS and control groups. The latter two groups showed no significant difference. The AT clearance (ATC) was calculated based on the fecal and serum AT levels. ATC was greatest in the bacterial infection group. In the AVGS group, ATC was also greater than in the control group but not statistically significant. Generally, the fecal AT content is thought to reflect protein loss, while the fecal Lf content seems to reflect the inflammatory response. Fecal Lf content differed between the AVGS and bacterial enterocolitis groups. The difference in the Lf level may come from differences in the extent of neutrophil infiltration into the bowel. We conclude that simultaneous assay of Lf and AT is useful for evaluation of the pathophysiology of gastrointestinal infection.

Oral Candidiasis as a Marker of Acute Retroviral Illness

All reported clinical characteristics of acute retroviral illness with the human immunodeficiency virus (HIV) are nonspecific. Signs and symptoms described are associated with a variety of acute infections. We report the cases of three patients in whom the acute retroviral illness was characterized by transient oral candidiasis and unexplained high lactate dehydrogenase values, with or without transient pulmonary infiltrate, in the context of an acute febrile illness. The clinical findings correlated with a severe reduction in the number of CD4 cells. We believe that thrush could be a marker of acute retroviral infection, as it is not a feature of any other heterophil-negative mononucleosis-like syndrome. We propose that in any patient having transient thrush and acute viral syndrome, the possibility of HIV infection should be aggressively pursued serologically, regardless of the patient's HIV risk status, provided that the usual causes of candidiasis (eg, diabetes mellitus, antibiotic use, and dentures) can be excluded.

Diagnosis of Human Immunodeficiency Virus Infection in Seronegative Homosexuals Presenting With an Acute Viral Syndrome

Early diagnosis of acute human immunodeficiency virus (HIV) infection is difficult because patients may be seronegative for HIV at the time of presentation. We have used a serum HIV antigen (HIV-Ag) enzyme immunoassay (EIA) to diagnose acute HIV infection in four high-risk patients. The clinical syndrome in these four patients was characterized by fever (four), rash (three), myalgias-arthralgias (three), and pharyngitis (two). All patients had spontaneous resolution of their symptoms within eight to 12 days. Serum HIV antibody, as measured by a commercially available screening EIA and by Western blot analysis, was negative in all patients at time of presentation and all seroconverted on subsequent testing. Human immunodeficiency virus was isolated from two of two patients during the acute illness. Initial serum samples from all four patients were positive for HIV-Ag. Serum samples of three of four patients became negative for HIV-Ag and positive for HIV antibody. These data suggest that serum HIV-Ag detection by EIA may be useful in the diagnosis of the acute syndrome caused by HIV infection.

Diagnosis of human immunodeficiency virus infection in seronegative homosexuals presenting with an acute viral syndrome

Diagnosis of human immunodeficiency virus infection in seronegative homosexuals presenting with an acute viral syndrome

Elevated Nitroblue Tetrazolium Dye Reduction Test Response in Acute Viral Respiratory Disease

Increased NBT dye reduction test responsiveness of neutrophil leukocytes has been observed in 14 of 17 infants with acute viral respiratory syndromes. Syndromes studied included croup, bronchiolitis, and pneumonia and were caused by parainfluenza virus types 1, 2, and 3, respiratory syncytial virus, influenza A virus, and adenovirus 1. NBT test elevation occurred early in every case of bronchiolitis and viral pneumonia and was associated with infections by all groups of viruses. On the other hand, NBT test results were normal or near-normal in a majority of cases of upper airway disease such as croup.