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Background Children with congenital CMV infection (cCMV) shed virus in urine and saliva for prolonged periods of time. Outcome of cCMV varies from asymptomatic infection with no sequelae in most cases, to severe longterm morbidity. The factors associated with asymptomatic cCMV are not well defined. We evaluated the viral shedding in a cohort of infants with cCMV identified on newborn screening. In addition, we describe the distribution of viral genotypes in our cohort of asymptomatic infants and previous cohorts of cCMV children in the literature. Methods Study population consisted of 40 children with cCMV identified in screening of 19,868 infants, a prevalence of 2/1000. The viral shedding was evaluated at 3 and 18 months of age by real-time CMV-PCR of saliva and plasma, and CMV culture of urine. CMV positive saliva samples were analyzed for genotypes for CMV envelope glycoproteins gB (UL55), and gH (UL75) by genotype specific real-time PCR, and gN (UL73) by cloning and sequencing Results At 3 months age 40/40 saliva and urine samples, and 19/40 plasma samples were positive for CMV. At 18 months age all urine samples tested (33/33), 9/37 of saliva samples, and 2/34 plasma samples were positive for CMV. The genotype distribution did not differ from the published data Conclusions The urinary virus shedding is more persistent than salivary shedding in children with cCMV. The genotype distribution was similar to previous literature and does not explain the low disease burden of cCMV in our population.

A prospective analysis of active Human Cytomegalovirus infection (HCMV) was conducted on 33 pediatric renal or hematopoietic stem cell post-transplant patients. The HCMV-DNA positive samples were evaluated for the prevalence of different gB subtypes and their subsequent correlation with clinical signs. The surveillance of HCMV active infection was based on the monitoring of antigenemia (AGM) and on a nested polymerase chain reaction (N-PCR) for the detection of HCMV in the patients studied. Using restriction analysis of the gB gene sequence by PCR-RFLP (Restriction Fragment Length Polymorphism), different HCMV strains could be detected and classified in at least four HCMV genotypes. Thirty-three pediatric recipients of renal or bone marrow transplantation were monitored. Twenty out of thirty-three (60.6%) patients demonstrated active HCMV infection. gB1 and gB2 genotypes were more frequent in this population. In this study, we observed that gB2 had correlation with reactivation of HCMV infection and that patients with mixture of genotypes did not show any symptoms of HCMV disease. Future studies has been made to confirm this.

Human cytomegalovirus (HCMV) displays genetic variability in several regions, supposed to be related with strain-specific tissue tropism and immunopathogenesis. Based on sequence variation in the UL55 gene that encodes gB glycoprotein, HCMV strains can be assigned to one of four genotypes. Previous studies have addressed gB genotyping mostly by investigating strains derived from immunosuppressed patients, sometimes without previous knowledge about genotype distribution in a geographic area. The present study verified the distribution of HCMV gB genotypes of strains obtained from immunocompetent women at Vitória City, Espírito Santo State, Southeastern, Brazil. The HCMV genome was extracted from their cervical secretion, fetal and maternal placenta tissues (chorionic villous and decidua) from abortion cases and from white blood cells (WBCs). HCMV genotyping was performed by restriction fragment length polymorphism analyses of amplified product from the high variability site of the UL55 gene. All four genotypes were observed in both cervical secretion and placenta, whereas in WBCs a single gB1 genotype was detected. HCMV gB1 and gB2 genotypes were detected, respectively, in nine and in six of the 23 studied samples, while gB3 and gB4 were each found in four separate samples of the total. The differences in genotype frequency were not considered statistically significant. No mixed genotype infection was observed. The results indicated that the four gB HCMV genotypes had no particular tropism for placenta tissues and that all genotypes circulated within immunocompetent women at the time and in the region of study. O citomegalovírus humano (HCMV) apresenta variabilidade em diversas regiões do genoma, supostamente relacionada ao tropismo tecidual e imunopatogênese viral. Baseando-se na variação de seqüência do gene UL55 que codifica a glicoproteína gB, o HCMV pode ser classificado em um dos quatro genótipos. Estudos prévios têm investigado a associação destes genótipos a partir de cepas obtidas de pacientes imunossuprimidos. O presente estudo determinou os genótipos gB de cepas de HCMV obtidas de mulheres imunocompetentes em Vitória, Espírito Santo, Sudeste do Brasil. O genoma do HCMV foi extraído de secreção cervical, tecidos placentários fetais e maternos (vilosidade coriônica e decídua) obtidos de casos de aborto e de leucócitos do sangue periférico. A genotipagem foi realizada através da análise de polimorfismo de fragmentos de restrição do produto amplificado da região de alta variabilidade do gene UL55. Todos os quatro genótipos foram detectados na secreção cervical e na placenta, enquanto que somente o genótipo gB1 foi detectado em leucócitos. Genótipos gB1 e gB2 foram detectados em nove e seis das 23 cepas estudadas, respectivamente, enquanto gB3 e gB4 foram encontrados cada um em quatro casos. A diferença na freqüência de genótipos não foi estatisticamente significante. Infecção mista não foi detectada. Estes resultados indicam que os quarto genótipos de HCMV apresentam tropismo para os tecidos placentários e que todos eles circularam nas mulheres imunocompetentes no período e região geográfica do estudo.