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.

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.

Presença de parvovírus B19 em Manaus, AM / Occurrence of parvovirus B19 in Manaus, AM

A investigação de 1.107 casos de doenças exantemáticas em Manaus permitiu a identificação dos primeiros 47 casos de parvovírus humano B19 na cidade. O parvovírus B19 foi caracterizado por uma combinação de sinais e sintomas como febre, cefaléia, artralgia, mialgia e exantema. A freqüência de exantema foi maior em indivíduos menores de quinze anos e, no adulto, prevaleceram a febre e artropatias. O maior número de casos foi registrado em 1999. Quanto à faixa etária, nos menores de 15 anos, predominou o sexo masculino e, entre os adultos, o feminino. Este estudo, portanto, ressalta a necessidade de se elucidar a causa de doenças exantemáticas que ocorrem no Estado do Amazonas e indica que estudos são necessários, no que concerne à atividade viral.

A pilot study on the seroprevalence of parvovirus B19 infection.

BACKGROUND & OBJECTIVES: Human parvovirus B 19 (PVB 19) causes aplastic crisis in children with congenital haemolytic anaemia, erythema infectiosum, abortion and stillbirth. Since data on PVB 19 prevalence is lacking in India, a pilot study was undertaken to estimate the prevalence of IgG antibody in children and adults. METHODS: The samples were obtained from children attending our hospital and from volunteer blood donors, majority of whom were from south India. They included 45 children aged 1-5 yr, 39 aged 6-10 yr, 42 aged 11-15 yr and 100 healthy blood donors > 15 yr of age. Sera were tested for the presence of antibody to PVB 19 using a commercial enzyme immuno assay (EIA). RESULTS: Of 226 samples tested, 113 (50%) were positive for PVB 19 IgG. The prevalence of antibody increased from 8.9 per cent at 1-5 yr to 70 per cent in those > 15 yr: the median age of infection was between 6 and 15 yr. Sex and domiciliary status did not have significant effect on the prevalence of antibody. The IgG antibody index increased significantly with age, suggesting repeated exposure to the virus. INTERPRETATION & CONCLUSION: This seroprevalence study indicates that large numbers of individuals show exposure to PVB 19 virus. The exposure as indicated by IgG positivity is seen to increase with age. The IgG negative individuals may be considered to be at risk of developing infections due to PVB 19.