Causes of morbilliform rash in a highly immunised English population

Differential diagnosis of fever and rash cases negative for measles and rubella to complement surveillance activities

In the quest to eliminate measles virus (MV) and rubella virus (Ruv), every suspected case must be properly identified and diagnosed. Since 2017, in Milan (Italy), a total of 978 measles and rubella suspected cases (fever and rash) were investigated and 310 were not laboratory confirmed (discarded cases). To improve surveillance activities, we investigated the presence in discarded cases of 8 other viral pathogens commonly associated with rash: human herpesvirus 6 (HHV-6) and 7 (HHV-7), parvovirus B19 (B19V), enterovirus (EV), Epstein-Barr virus (EBV), human adenovirus (HAdV), cytomegalovirus (HCMV), and SARS-CoV-2. Differential diagnosis was carried out on 289 discarded cases by multiplex real-time PCR assays. At least one pathogen was detected in 188 cases (65.1%) with HHV-7 being the most frequently detected virus. No difference in the number of detected infections overtime was observed and infections were identified in all age groups. As expected, most HHV-6, EV, HAdV, and HCMV-positive cases were found in children aged 0-4 years and HHV-7 was most frequent in the 15-39 age group. In light of the World Health Organization measles elimination goal, the introduction of laboratory methods for differential diagnosis is required for the final classification of clinically compatible cases. The used screening panel allowed us to increase the percentage of virus-positive cases to 87.5%, allowing us to clarify viral involvement and epidemiology, improve diagnosis, and strengthen surveillance activities. As all investigated pathogens were detected, this diagnostic panel was a suitable tool to complement MV and RuV surveillance activities.

An evaluation of the clinical features of measles virus infection for diagnosis in children within a limited resources setting

BACKGROUND

Measles is a recurrent health problem in both advanced and developed countries. The World Health Organization (WHO) recommends anti-measles immunoglobulin M (Ig M) as the standard method of detecting the virus; however, many areas still present the inability to perform a serology test of anti-measles IgM. Therefore, a typical clinical feature is necessary to establish the diagnosis of measles. The objective of this study was to evaluate hyperpigmented rash and other clinical features as the diagnostic tools with respect to measles, especially in an outbreak setting.

METHODS

In this observational diagnostic study, the inclusion criteria were as follows: between 6 and 144 months of age, fever, maculopapular rash for 3 days or more, accompanied by a cough, or coryza, or conjunctivitis. Those with a prior history of measles vaccination (1-6 weeks) were excluded, in addition to those with histories of corticosteroid for 2 weeks or more and immunocompromised conditions. The samples were taken from Dr. Soetomo General Academic Hospital in Surabaya, Indonesia. We evaluated the sensitivity, specificity, the positive predictive value, and the negative predictive value of such clinical features. Hyperpigmented rash was validated using Kappa and Mc Nemar tests. Anti-measles Ig M was considered as the gold standard.

RESULTS

This study gathered 82 participants. The clinical manifestations of all subjects included fever, cough, coryza, conjunctivitis, Koplik spots, and maculopapular rash (which turns into hyperpigmented rash along the course of the illness). Most maculopapular rashes turn out to be hyperpigmented (89%). Sensitivity, specificity, positive predictive value, and negative predictive values ​​of the combination of fever, maculopapular rash, and hyperpigmented rash were found to be at 90.7, 28.6, 93.2, and 22.2%, respectively. The Mc Nemar and Kappa tests showed p values of 0.774 and 0.119, respectively.

CONCLUSION

The combination of fever, maculopapular rash, and hyperpigmented rash can be used as a screening tool regarding measles infection in an outbreak setting, which can then be confirmed by anti-measles Ig M. Cough, coryza, and Koplik's spot can be added to this combination, albeit with a slight reduction of sensitivity value.

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.

Normative Thyroid Volume by Ultrasonography in a Nigerian Pediatric Population

The objective was to establish normal thyroid volume in healthy infants and children, in a select Nigerian population. Using a portable ultrasound equipment with a 7.5-MHz transducer, 500 apparently healthy pediatric patients were sonographically evaluated. The volume for each thyroid lobe was obtained, as well as the summation of both left and right thyroid volumes, which represented the total volume. The mean and median thyroid volumes for the subgroups were 0.69 ± 0.38 cm3/0.7 cm3 (<1 year), 1.50 ± 0.68 cm3/1.4 cm3 (1–5 years), 2.75 ± 0.94 cm3/2.6 cm3 (6–10 years), 4.47 ± 2.83 cm3/3.7 cm3 (11–15 years), and 7.47 ± 4.81 cm3/5.9 cm3 (16 and 17 years). There was a significant difference ( P = .000) between the population studied and the World Health Organization/International Council for Control of Iodine Deficiency Disorders reference values. The baseline values derived for thyroid dimensions may form the basis for thyroid screening in these asymptomatic children.

Saliva and viral infections

Over the last 10 years there have been only a handful of publications dealing with the oral virome, which is in contrast to the oral microbiome, an area that has seen considerable interest. Here, we survey viral infections in general and then focus on those viruses that are found in and/or are transmitted via the oral cavity; norovirus, rabies, human papillomavirus, Epstein‐Barr virus, herpes simplex viruses, hepatitis C virus, and HIV. Increasingly, viral infections have been diagnosed using an oral sample (e.g. saliva mucosal transudate or an oral swab) instead of blood or urine. The results of two studies using a rapid and semi‐quantitative lateral flow assay format demonstrating the correlation of HIV anti‐IgG/sIgA detection with saliva and serum samples are presented. When immediate detection of infection is important, point‐of‐care devices that obtain a non‐invasive sample from the oral cavity can be used to provide a first line diagnosis to assist in determining appropriate counselling and therapeutic path for an increasing number of diseases.

Insights into epidemiology of human parvovirus B19 and detection of an unusual genotype 2 variant, Bulgaria, 2004 to 2013

The present study aimed to determine the role of human parvovirus В19 (B19V) as an aetiological agent in measles and rubella negative fever/rash patients from Bulgaria between 2004 and 2013. A total of 1,266 sera from all over the country were tested for B19V IgM antibodies and all positives were further investigated by polymerase chain reaction (PCR). Overall, 280 sera (22%) were B19V IgM positive and 227 of these (81%) were also PCR positive. The highest number of IgM positives was found among five to nine year-old children (27%). Eight infected women gave birth to healthy children; one fetus was aborted with hydrops fetalis. Of the 55 genetic sequences obtained, 54 belonged to genotype 1a and one grouped as a genotype 2 outlier. Phylogenetic analysis of all available genotype 2 sequences covering the 994 nucleotide non-structural protein 1(NS1)/capsid viral protein 1 (VP1) unique region junction, showed that only one other sequence grouped with the outlier strain, forming a clearly distinct and well-supported cluster of genotype 2 (between-group genetic distance: 3.32%). In accordance with B19V nomenclature, this cluster may represent a new subgenotype 2b. The study showed that B19V infections may be falsely identified as rubella or measles in ca 22% of cases, emphasising the need for laboratory confirmation.

Drug hypersensitivity in children: report from the pediatric task force of the EAACI Drug Allergy Interest Group

When questioned, about 10% of the parents report suspected hypersensitivity to at least one drug in their children. However, only a few of these reactions can be confirmed as allergic after a diagnostic workup. There is still a lack of knowledge on drug hypersensitivity (DH) epidemiology, clinical spectrum, and appropriate diagnostic methods particularly in children. Meanwhile, the tools used for DH management in adults are applied also for children. Whereas this appears generally acceptable, some aspects of DH and management differ with age. Most reactions in children are still attributed to betalactams. Some manifestations, such as nonsteroidal anti-inflammatory drug-associated angioedema and serum sickness-like reactions, are more frequent among young patients as compared to adults. Risk factors such as viral infections are particularly frequent in children, making the diagnosis challenging. The practicability and validity of skin test and other diagnostic procedures need further assessment in children. This study presents an up-to-date review on epidemiology, clinical spectrum, diagnostic tools, and current management of DH in children. A new general algorithm for the study of these reactions in children is proposed. Data are presented focusing on reported differences between pediatric and adult patients, also identifying unmet needs to be addressed in further research.

Isolation and genetic characterization of enterovirus in patients with febrile rash illness

Measles and rubella virus are usually considered as the causative agents in patients with febrile rash illness (FRI). However, investigators have identified that enteroviruses are also associated with FRI, and the present study was undertaken to investigate this association. In the study, 20 throat swab samples were collected from patients suffering from rash and fever between April and July in 2013. The 20 samples tested negative for measles virus, but all were positive when reverse transcription-polymerase chain reaction was performed using enterovirus universal primers. Specifically, five tested positive for Coxsackie B3 virus (CVB3). The titers of the five CVB3 isolates were 10^6.5, 10^6.4, 10^7.5, 10^6.5 and 10^6.5 tissue culture infectious dose₅₀/100 µl respectively. The partial VP1 sequences of the five CVB3 isolates were identical to each other and were closely associated with the CVB3/MKP and CVB3/Macocy strains, which are known to induce myocarditis and neonatal diseases of the central nervous system. In conclusion, CVB3 may cause symptoms of fever and rash and should be differentiated from measles, rubella and other infectious pathogens. The five CVB3 isolates described in the study were genetically similar to each other and to other local CVB3 strains. The results provide further data on the viral pathogen spectrum associated with FRI.

Amoxicillin allergy in children: five-day drug provocation test in the diagnosis of nonimmediate reactions

BACKGROUND

The drug provocation test (DPT) is the gold standard to rule out drug hypersensitivity. There are standardized DPT protocols to diagnose immediate reactions to drugs, but not for nonimmediate reactions.

OBJECTIVE

The aim of this study was to show the sensitivity and specificity of an allergy work-up that included a 5-day DPT in children with histories of nonimmediate reactions to amoxicillin through focusing on a pediatric population with histories of immediate and nonimmediate reactions to amoxicillin.

METHODS

Two hundred consecutive patients with histories of amoxicillin reactions referred to the Allergy Unit of Anna Meyer Children's Hospital for suspected drug allergy from 2008 to 2011 underwent in vivo tests with the culprit drug according to European Academy of Allergy and Clinical Immunology guidelines. Moreover, most of those children, regardless of the skin tests results, were challenged with amoxicillin for a total of 5 days.

RESULTS

In 4 years, 200 patients were evaluated for a history of drug hypersensitivity to amoxicillin. The majority of patients (76%) had a history of mild nonimmediate reactions. All 200 patients underwent skin tests, and 9 of 200 tested positive. A total of 177 DPTs were performed with amoxicillin for 5 days in each child. Diagnosis of amoxicillin allergy was confirmed by a DPT in 17 patients (9.6%); 14/17 had history of nonimmediate reactions; 4/14 (26.6%) reacted on day 5.

CONCLUSION

According to our results, a long-term DPT protocol increases the sensitivity of the allergy work-up, and it should be recommended for patients with a history of amoxicillin nonimmediate reaction.

Surveillance and vaccination coverage of measles and rubella in Northern Italy

Measles and rubella are infectious diseases and humans are the only reservoir of these infections. Effective vaccines are available with the potential for measles (MV) and rubella (RuV) virus eradication. According to the World Health Organisation guidelines, a national plan was approved in Italy in 2013 to achieve the MV/RuV elimination by 2015, and active MV/RuV integrated surveillance initiated. Towards this purpose, a regional laboratory centre was set up on 1 September 2013 in Lombardy, Northern Italy. This paper aimed at: (1) evaluating measles-mumps-rubella (MMR) vaccine coverage and MV/RuV notified cases retrospectively; and (2) presenting the results of MV/RuV integrated surveillance (laboratory confirmed and viral genetic profiles).   The 95% target for MMR vaccine coverage was achieved in 2001, and coverage increased until 2007 (96.6%), but then a decreasing trend was observed. Since 2000 to 2014, 3026 rubella cases were notified, with nearly 58% of them in the 2002 epidemic. From 2009, less than 45 RuV cases per year were reported. From 2000 to 2014, 5024 measles cases were notified. Since 2008, three large outbreaks (in 2008, 2011, and 2013) were observed. From data obtained during our surveillance activity, there were no rubella cases, and 57.5% (46/80) collected samples were MV-positive by real-time RT-PCR. A fragment of the MV N gene was sequenced from 37 MV-positive samples; D8, D9, and B3 genotypes were detected. Data obtained retrospectively and from active surveillance underline the necessity to achieve and maintain high vaccination coverage and to improve surveillance and the effectiveness of healthcare actions.

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.

Rubella virus genotype 1G and echovirus 9 as etiologic agents of exanthematous diseases in Brazil: insights from phylogenetic analysis

The aim of the present study was to identify the rubella virus (RV) and enterovirus (EV) genotypes detected during the Epidemiological Surveillance on Exanthematic Febrile Diseases (VIGIFEX) study and to perform phylogenetic analysis. Ten RV- and four EV-positive oropharyngeal samples isolated from cell culture were subjected to RT-PCR and sequencing. Genotype 1G and echovirus 9 (E-9) was identified in RV- and EV-positive samples, respectively. The RV 1G genotype has been persisting in Brazil since 2000-2001. No evidence of E-9 being involved in exanthematic illness in Brazil has been reported previously. Differential laboratory diagnosis is essential for management of rash and fever disease.

Etiologies of rash and fever illnesses in Campinas, Brazil

BACKGROUND

Few population-based studies of infectious etiologies of fever-rash illnesses have been conducted. This study reports on enhanced febrile-rash illness surveillance in Campinas, Brazil, a setting of low measles and rubella virus transmission.

METHODS

Cases of febrile-rash illnesses in individuals aged <40 years that occurred during the period 1 May 2003-30 May 2004 were reported. Blood samples were collected for laboratory diagnostic confirmation, which included testing for adenovirus, dengue virus, Epstein-Barr virus (EBV), enterovirus, human herpes virus 6 (HHV6), measles virus, parvovirus-B19, Rickettsia rickettsii, rubella virus, and group A streptococci (GAS) infections. Notification rates were compared with the prestudy period.

RESULTS

A total of 1248 cases were notified, of which 519 (42%) had laboratory diagnosis. Of these, HHV-6 (312 cases), EBV (66 cases), parvovirus (30 cases), rubella virus (30 cases), and GAS (30 cases) were the most frequent causes of infection. Only 10 rubella cases met the rubella clinical case definition currently in use. Notification rates were higher during the study than in the prestudy period (181 vs 52.3 cases per 100,000 population aged <40 years).

CONCLUSIONS

Stimulating a passive surveillance system enhanced its sensitivity and resulted in additional rubella cases detected. In settings with rubella elimination goals, rubella testing may be considered for all cases of febrile-rash illness, regardless of suspected clinical diagnosis.

Rubella revisited: where are we on the road to disease elimination in Central Europe?

Rubella is a contagious viral disease with few complications except when contracted by pregnant women. Rubella infection in pregnancy can result in miscarriage, stillbirth or an infant born with congenital rubella syndrome (CRS) which comprises deafness, heart disease, cataracts and other permanent congenital manifestations. Clinical diagnosis of rubella is difficult due to overlapping symptoms with many other diseases and confirmation of rubella is not possible without laboratory testing. Effective vaccination programmes are critical to the elimination of rubella and prevention of CRS. Such programmes have been successful in several countries in Europe and around the world. However, rubella outbreaks still occur due to suboptimal vaccine coverage and in the past 10 years rubella has been reported in Central European countries such as Romania and Poland. Over the past decade the elimination of rubella and prevention of congenital rubella infection in Europe has been a high priority for the WHO European Regional Office. In 2010 the WHO regional committee for Europe renewed its commitment to the elimination of rubella and prevention of CRS with a new target of 2015. This paper examines the current situation for rubella and CRS in Central Europe and describes the different rubella vaccination programmes in the region. The Central European Vaccination Advisory Group (CEVAG) recommends that two doses of measles, mumps and rubella vaccine, MMR, should be given to all children. The first dose should be given between 12 and 15 months of age. The second dose can be given between the ages of 21 months and 13 years with the exact age of administration of the second dose depending on the situation specific to each country. All suspected rubella cases should be laboratory-confirmed and monitoring systems to detect and investigate cases of CRS should be strengthened.

Infection and immunity for human parvovirus B19 in patients with febrile exanthema

The contribution of parvovirus B19 (B19V) as a causative agent of febrile exanthema (FE) in Cordoba, Argentina, was analysed by detection of viral DNA, and specific IgM and IgG. Serum from 141 patients with FE who were negative for measles and rubella, collected during 2005-2009, plus serum from 31 healthy individuals, were assayed. B19V was the aetiological agent in 14·9% of all FE cases, and in 39·1% in an epidemic year (2007). B19V DNA was detected in 47·6% of IgM-positive FE patients, 30·2% of IgM-negative/IgG-positive FE patients, and 9·7% of healthy controls, indicating B19V long-term infection in ~10% of immunocompetent individuals. Persistent B19V DNA was significantly more frequent in children than adults and in males than females. All patients with acute B19V infection had rash and fever, 85·7% had adenopathy, and only 14·3% had arthropathy. This is the first follow-up study of markers of infection and immunity for B19V infection in Argentina.

Parvovirus B19 infection in human pregnancy

Human parvovirus B19 infection is widespread. Approximately 30-50% of pregnant women are nonimmune, and vertical transmission is common following maternal infection in pregnancy. Fetal infection may be associated with a normal outcome, but fetal death may also occur without ultrasound evidence of infectious sequelae. B19 infection should be considered in any case of nonimmune hydrops. Diagnosis is mainly through serology and polymerase chain reaction. Surveillance requires sequential ultrasound and Doppler screening for signs of fetal anaemia, heart failure and hydrops. Immunoglobulins, antiviral and vaccination are not yet available, but intrauterine transfusion in selected cases can be life saving.

[Frequency of measles, rubella, dengue and erythema infectiosum among suspected cases of measles and rubella in the State of Pernambuco between 2001 and 2004]

This study had the aim of investigating the frequency of measles, rubella, dengue and erythema infectiosum among suspected cases of measles and/or rubella in the state of Pernambuco, Brazil. A total of 1,161 serum samples collected between 2001 and 2004 were tested for these four viral diseases, using enzyme immunoassays to detect IgM antibodies. Out of this total, 276 (23.8%) samples were positive for one of the four viral diseases analyzed. There were 196 positive cases (16.9%) for dengue, 38 (3.3%) for erythema infectiosum (parvovirus B19), 32 (2.8%) for rubella and 10 (0.9%) for measles. Among the suspected cases of measles and rubella, dengue infection was the most frequent, followed by parvovirus B19. The similarity of the clinical manifestations among rash diseases contributes towards making it difficult to diagnose measles, rubella, dengue and erythema infectiosum on clinical grounds alone. It must be emphasized that the four tests used were insufficient for diagnosing 76.2% of the febrile and rash diseases notified. This is the first study bringing evidence of human parvovirus B19 circulation in Pernambuco.

Echovírus 6 associado à doença exantemática

Exantema viral é considerado problema comum em regiões tropicais, afetando principalmente crianças. Diversos exantemas cutâneos estão associados a infecções por Enterovirus. Amostras biológicas provenientes de uma criança apresentando exantema generalizado foram enviadas ao Laboratório de Vírus Entéricos do Instituto Adolfo Lutz para a realização do diagnóstico laboratorial. Amostra viral isolada em RD (human rhabdomyosarcoma cells) foi submetida à reação em cadeia pela polimerase apresentando um produto de 437 pares de base, característico de gênero Enterovirus. O sorotipo echovirus 6 (E-6) foi identificado por ensaio de imunofluorescência indireta. Em adição, as amostras pareadas de soro apresentaram soroconversão para E-6. Até o momento, não há relatos do envolvimento de E-6 associado a doenças exantemáticas no Brasil, enfatizando a importância da vigilância epidemiológica para essas doenças e suas complicações.

Chapter 7 Global Supply of Virus-Safe Drinking Water

This chapter illustrates the recommendations and guidelines of the World Health Organization (WHO) concerning water, sanitation, and health. The recommendations and guidelines are evaluated in the light of disease caused by human pathogenic viruses. The guidelines outline a preventive management framework for safe drinking water. The framework includes health-based targets to assist national authorities who are normally responsible to set the targets for the protection of public health from risks by exposure to drinking water. Assessing the adequacy of systems, defining and monitoring control measures, and establishing management plans are the three components of the so-called water safety plans. Achievement of health-based targets may be verified by independent surveillance to assess the safety of the drinking water through additional verification or audit-based approaches. This framework for safe drinking water can be adapted according to environmental, social, economic, and cultural circumstances of drinking water provision on the national, regional, and local level. The chapter concludes that viruses could be considered as biocolloids with specific properties such as size, shape, structure, charge, composition, and genome. These viral characteristics determine their behavior in the environment, resistance to natural inactivation and treatment, and disinfection processes. For each (re-)emerging virus these properties may be known or could be assessed predicting the effectiveness of possible intervention measures for prevention of waterborne disease.

Rubella

Rubella is associated with an 80% risk of congenital abnormalities if acquired in the first 12 weeks of pregnancy. Reinfection in early pregnancy presents a much smaller risk. Prenatal diagnosis may be useful to assess the risk to the fetus. Congenital rubella is a progressive disease and some abnormalities will not be present at birth. Rubella and congenital rubella are usually diagnosed by detection of rubella-specific IgM; it may be difficult to confirm a diagnosis of congenital rubella in children over 3 months of age. Rubella vaccines are usually combined with measles and mumps vaccines. Their use has enabled some industrialised countries to eliminate rubella and congenital rubella. Countries should ensure that susceptible women of child-bearing age and health care workers are offered a rubella-containing vaccine. Rubella vaccine is contraindicated during pregnancy, but if a pregnant woman is inadvertently vaccinated it is not an indication for termination or prenatal diagnosis.

Sensitive and rapid diagnosis of human parvovirus B19 infection by loop-mediated isothermal amplification

BACKGROUND

Human parvovirus B19 (B19) infections exhibit various skin manifestations that are similar to and hence hard to distinguish from many other skin diseases. The virological diagnosis of B19 infection is usually based on time-consuming serological tests and polymerase chain reaction (PCR).

OBJECTIVES

In this study, a DNA amplification method, loop-mediated isothermal amplification (LAMP), was used for the diagnosis of B19 infection and was compared with PCR.

METHODS

Ten patients with acute B19 infection and 16 patients with other skin diseases were enrolled. Sera and pharyngeal swabs were used directly as the templates in LAMP. The LAMP reaction was carried out at 63 degrees C for 1 h in a heat block. The reaction products were judged visually, by adding SYBR Green I into the tubes, and by gel electrophoresis.

RESULTS

B19 DNA was detected by LAMP in 10 sera and all of seven tested pharyngeal swabs of 10 patients with acute B19 infection but not in samples from 16 patients with other skin diseases. The results were in agreement with those obtained by PCR except for one case. The reason for the single discrepancy may be that the sensitivity of LAMP is 10(2) times higher than PCR.

CONCLUSIONS

Detection of B19 DNA by LAMP in serum and especially in the pharynx is a rapid and convenient method for the diagnosis of acute B19 infection.

Acute human parvovirus B-19 infection in hospitalized children: A serologic and molecular survey

BACKGROUND

The extent and clinical manifestations of acute human parvovirus B19 (B19) infection were assessed in previously healthy hospitalized children admitted with clinical syndromes potentially associated the virus.

PATIENTS AND METHODS

The study was prospective and was conducted between October 2002 and August 2004 in the pediatric departments of 3 hospitals in Israel. The survey included previously healthy children who were hospitalized with 1 or more of the following acute diseases: acute nonallergic exanthema, fever for >1 week, aplastic anemia or pancytopenia, acute nonbacterial arthropathy, immune thrombocytopenic purpura (ITP), Henoch-Schönlein purpura (HSP) and aseptic meningitis. A control group of children with a proven, non-B19 infection was also studied. Serum samples obtained from each child on admission were tested for B19 DNA by real-time PCR and B19 IgM by ELISA. Acute B19 infection was defined by the following criteria: positive serum B19-DNA and/or B19 IgM, negative serum B19 IgG, and no other proven infection.

RESULTS

Overall, 167 children were included in the study. The mean age was 5.5 +/- 4.6 years (range, 0.5-17), males and females equally divided. Acute B19 infection was demonstrated in 12.6% (n = 21) of the children. Both tests were performed in 19 children and were positive in 10 (53%). In 7 and 2 children, only B19-DNA or B19 IgM, respectively, was positive. Acute B19 infection was documented in 27% (10/39) of children who presented with a variety of acute exanthema diseases; 9% (5/57) of children with acute arthropathy (all 5 had transient synovitis); 10% (2/21) of children with fever >1 week, both presented as mononucleosis syndrome; and in 44% (4/9) of children with transient pancytopenia or aplastic anemia. No acute B19 infection was demonstrated in 15 children with ITP, 9 with HSP, and 6 with aseptic meningitis and among 70 children in the control group. By logistic regression analysis, manifestations significantly associated with acute B19 infection were exanthema (OR 2.9; 95% CI = 1.1-7.5), anemia (OR 6.35; 95% CI = 2.2-18.2) and leucopenia (OR 4.14; 95% CI =1.2-14.2).

CONCLUSIONS

Acute B19 infection was documented among 12.6% of children hospitalized with clinical syndrome potentially associated with the virus. Clinical and laboratory features associated with acute B19 infection were exanthema, anemia and leucopenia. Determination of both serum B19-DNA and serum B19 IgM should be performed for the accurate diagnosis of acute B19 infection.

Development and evaluation of Varicella zoster virus ELISA for oral fluid suitable for epidemiological studies

An enzyme-linked immunosorbent assay (ELISA) for detection of Varicella zoster virus (VZV) antibodies in oral fluid is described. The assay was optimised and evaluated using paired serum and oral fluid from healthy adult volunteers (n = 205) and preschool children (n = 98), oral fluid samples collected for routine measles, mumps and rubella testing (n = 537) and samples from a study of atopic dermatitis (n = 252). As chickenpox is predominantly a childhood disease and most adults are immune, it was crucial to have samples from children aged 1-5 years to evaluate the assay. Mixture modelling of the oral fluid results was used to determine the optimum cut-off, sensitivity and specificity of the assay. Compared to paired sera tested by the same ELISA the sensitivity of the oral fluid assay was 93% and specificity 95.7% overall, varying slightly with age group. The assay was shown to have good potential for use in large-scale epidemiological studies.

Rubella

Maternal rubella is now rare in many developed countries that have rubella vaccination programmes. However, in many developing countries congenital rubella syndrome (CRS) remains a major cause of developmental anomalies, particularly blindness and deafness. WHO have provided recommendations for prevention of CRS, and, encouragingly, the number of countries introducing rubella vaccination programmes has risen. However, declining uptake rates due to concerns about the measles-mumps-rubella vaccine in the UK, and increasing numbers of cases in some European countries coupled with poor uptake rates might jeopardise this progress. Surveillance of postnatally and congenitally acquired infection is an essential component of CRS prevention since rubella is difficult to diagnose on clinical grounds alone. Laboratory differentiation of rubella from other rash-causing infections, such as measles, parvovirus B19, human herpesvirus 6, and enteroviruses in developed countries, and various endemic arboviruses is essential. Reverse transcriptase PCR and sequencing for diagnosis and molecular epidemiological investigation and detection of rubella-specific IgG and IgM salivary antibody responses in oral fluid are now available.