Use of oral fluid samples for the investigation of outbreaks of human parvovirus B19 infection.

The use of oral fluid (OF) samples for serological diagnosis of parvovirus B19 infection during outbreaks of erythema infectiosum had already been demonstrated, but the feasibility of using OF for the characterization of B19 genotypes circulating during outbreaks has not been described. The aim of this study was to assess the use of "in-house" PCR-based assays as a powerful tool for a rapid diagnosis and molecular characterization of B19 strains in OF samples during outbreaks. Paired serum and OF samples collected from anti-B19 IgM-positive patients, during two outbreaks of ertythema infectiosum (1999-2000 and 2004-2005), were tested by conventional (cPCR) and quantitative PCR (qPCR). qPCR was more sensitive than cPCR for detecting B19-DNA in both OF and serum. Overall, OF presented lower viral load (9.97 × 106 UI/mL) than serum (2.42 × 1010 UI/mL) and this difference was statistically significant. All OF samples obtained from patients in the age group < 14 years presented low viral load (< 104 IU/mL). No correlation was found between viral load and the number of days of onset of rash. Sequence analysis from PCR positive OF samples confirmed the circulation of subgenotype 1a (G1a) during these outbreaks. Our findings indicate that PCR-based assays may fail to detect B19-DNA in approximately 50% of OF compared to serum samples. Nevertheless, our study has shown for the first time that the genome sequence of the amplicon from non-invasive clinical sample is useful for molecular genotyping and may be a tool to clarify the genetic diversity of B19 strains circulating in distinct outbreaks.

Molecular diversity of human parvovirus B19 during two outbreaks of erythema infectiosum in Brazil

Abstract This study was conducted to provide information on the genetic diversity of human parvovirus B19 (B19V) circulating in the municipality of Niterói, Rio de Janeiro, Southeast Brazil during 1996-2006, a period with two distinct outbreaks of B19V infection: 1999-2000 and 2004-2005. A total of 27 sera from patients with erythema infectiosum and five sera from HIV-infected patients that tested positive for B19V DNA during the study period were analyzed. To genotype B19V strains, a semi-nested PCR for partial amplification of the capsid gene was performed and sequence analysis revealed that 31 sequences belonged to subgenotype 1a (G1a) of the main genotype 1 and one sequence was characterized as subgenotype 3b (G3b). The phylogenetic tree supported the division of the G1a into two well-defined clades with 1.3% of divergence. The low diversity of the G1a strains may be explained by the fact that all patients had acute B19V infection and 30/32 sera were collected during two distinct outbreaks. The G3b strain was from an HIV-infected patient who seroconverted to anti-B19 IgG antibodies in September/2005. This is the first report of G3b in the state of Rio de Janeiro.

Molecular diversity of human parvovirus B19 during two outbreaks of erythema infectiosum in Brazil.

This study was conducted to provide information on the genetic diversity of human parvovirus B19 (B19V) circulating in the municipality of Niterói, Rio de Janeiro, Southeast Brazil during 1996-2006, a period with two distinct outbreaks of B19V infection: 1999-2000 and 2004-2005. A total of 27 sera from patients with erythema infectiosum and five sera from HIV-infected patients that tested positive for B19V DNA during the study period were analyzed. To genotype B19V strains, a semi-nested PCR for partial amplification of the capsid gene was performed and sequence analysis revealed that 31 sequences belonged to subgenotype 1a (G1a) of the main genotype 1 and one sequence was characterized as subgenotype 3b (G3b). The phylogenetic tree supported the division of the G1a into two well-defined clades with 1.3% of divergence. The low diversity of the G1a strains may be explained by the fact that all patients had acute B19V infection and 30/32 sera were collected during two distinct outbreaks. The G3b strain was from an HIV-infected patient who seroconverted to anti-B19 IgG antibodies in September/2005. This is the first report of G3b in the state of Rio de Janeiro.

Eritema infeccioso: un exantema infantil a considerar en la práctica diaria / Fifth disease or infectious erythema: a childhood rash to consider in the daily medical practice

Se presenta el caso de un escolar con febrícula y leve ataque del estado general, quien desarrolla una erupción maculosa en mejillas, pocos días después un exantema en "encaje" o reticulado en tronco posterior y parte proximal de extremidades inferiores, compatible con la quinta enfermedad y confirmado por la morfología lesional característica y la inmuno-serología (IgM).

We present a five years old child with a mild fever and malaise, a maculoedematous eruption on cheeks and a "lace" exanthema located on posterior aspect of the trunk and lower limbs, developed after a few days. A fifth disease was diagnosticated based on characteristic morphological presentation and immunoserological studies.

Eritema infeccioso: un exantema infantil a considerar en la práctica diaria / Fifth disease or infectious erythema: a childhood rash to consider in the daily medical practice

Se presenta el caso de un escolar con febrícula y leve ataque del estado general, quien desarrolla una erupción maculosa en mejillas, pocos días después un exantema en "encaje" o reticulado en tronco posterior y parte proximal de extremidades inferiores, compatible con la quinta enfermedad y confirmado por la morfología lesional característica y la inmuno-serología (IgM).(AU)

We present a five years old child with a mild fever and malaise, a maculoedematous eruption on cheeks and a "lace" exanthema located on posterior aspect of the trunk and lower limbs, developed after a few days. A fifth disease was diagnosticated based on characteristic morphological presentation and immunoserological studies.(AU)

Freqüência de sarampo, rubéola, dengue e eritema infeccioso entre casos suspeitos de sarampo e rubéola no estado de Pernambuco, no período de 2001 a 2004 / Frequency of measles, rubella, dengue and erythema infectiosum among suspected cases of measles and rubella in the State of Pernambuco between 2001 and 2004

O estudo teve como objetivo verificar a freqüência de sarampo, rubéola, dengue e eritema infeccioso entre casos suspeitos de sarampo e rubéola, no estado de Pernambuco, Brasil. Foram testadas 1.161 amostras de soro coletadas no período de 2001 a 2004, para as quatro viroses, utilizando-se ensaios imunoenzimáticos para detecção de anticorpos IgM. Desse total, 276 (23,8 por cento) amostras foram positivas para uma das quatro viroses analisadas. Foram detectados 196 (16,9 por cento) casos positivos para dengue, 38 (3,3 por cento) para eritema infeccioso (parvovírus B19), 32 (2,8 por cento) para rubéola e 10 (0,9 por cento) para sarampo. Entre os casos suspeitos de sarampo e rubéola, a infecção pelo vírus dengue foi a mais freqüente, seguida pelo parvovírus B19. A semelhança de manifestações clínicas entre as doenças exantemáticas contribui para dificultar o diagnóstico de sarampo, rubéola, dengue e eritema infeccioso, quando observados apenas os critérios clínicos. Deve-se salientar que os quatro testes utilizados foram insuficientes para diagnosticar 76,2 por cento das doenças febris exantemáticas notificadas. Este é o primeiro estudo que evidencia a circulação de parvovírus B19 humano em Pernambuco.

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 percent) samples were positive for one of the four viral diseases analyzed. There were 196 positive cases (16.9 percent) for dengue, 38 (3.3 percent) for erythema infectiosum (parvovirus B19), 32 (2.8 percent) for rubella and 10 (0.9 percent) 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 percent of the febrile and rash diseases notified. This is the first study bringing evidence of human parvovirus B19 circulation in Pernambuco.

Surveillance epidemiological: parvovirus B19 genotype 1 / Vigilância epidemiológica: parvovirus B19 genótipo 1

Human parvovirus B19 was identified and characterized in sample collected from a patient who was infected in Japan, and the symptoms as fever and rash appeared after arriving to Brazil. The occurrence of virus infection was confirmed by both assays: Elisa parvovirus B19-specific IgM antibody detection and polymerase chain reaction (PCR). A fragment of NS1-VP1 region was directly submitted to nucleotide sequencing. Partial phylogenetic analysis of B19 sequences, including several sequences available in GenBank, indicated that the isolated HPV B19 corresponded to genotype 1.

O parvovirus humano B19 foi isolado e caracterizado de amostra clínica de um paciente, infectado no Japão, e que apresentou os sintomas de febre e erupção cutânea após sua chegada ao Brasil. A infecção por parvovírus foi confirmada por meio de seguintes ensaios: Elisa para detecção de anticorpos IgM antiparvovirus B19 e técnica de polymerase chain reaction (PCR). Um fragmento da região NS1-VP1 foi diretamente submetido ao seqüenciamento do nucleotídeo. A análise filogenética parcial do B19, frente às várias seqüências disponíveis no GenBank, indicou que PV B19 isolado correspondeu ao genótipo 1.