Rubella epidemic in Vietnam: Characteristic of rubella virus genes from pregnant women and their fetuses/newborns with congenital rubella syndrome

• Published in: Journal of clinical virology Vol. 57; no. 2; pp. 152 - 156
• Main Authors: Pham, Van Hung, Nguyen, Thong Van, Nguyen, Truc Thanh Thi, Dang, Linh Duy, Hoang, Ngoc Hieu, Nguyen, Truong Van, Abe, Kenji
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2013
• Subjects: Aborted Fetus - virology; Adolescent; Adult; Allergy and Immunology; Antibodies, Viral - blood; Congenital rubella syndrome; Epidemics; Female; Genotype; Humans; Infant, Newborn; Infectious Disease; Molecular Epidemiology; Polymerase Chain Reaction - methods; Pregnancy; Pregnancy Complications, Infectious - epidemiology; Pregnancy Complications, Infectious - virology; Rubella; Rubella - epidemiology; Rubella - virology; Rubella Syndrome, Congenital - epidemiology; Rubella Syndrome, Congenital - virology; Rubella virus; Rubella virus - classification; Rubella virus - genetics; Rubella virus - immunology; Sequence Analysis, DNA; Southeast Asia; Vietnam; Vietnam - epidemiology; Virus genotype; Young Adult; Vietnam; Rubella; Vietnam; Southeast Asia; Rubella virus; Virus genotype; Congenital rubella syndrome
• ISSN: 1386-6532; 1873-5967
• DOI: 10.1016/j.jcv.2013.02.008

Abstract Background Rubella remains poorly controlled in Southeast Asia, including Vietnam. Objectives The aim of this study was to characterize rubella virus spread in Vietnam during 2011–2012. Study design Amniotic fluid, throat swab and placenta samples were collected from 130 patients (110 cases from pregnant women with suspected rubella and 20 cases from fetuses/newborns). Viral RNA was obtained directly from clinical specimens, amplified by PCR, and then the E1 gene containing 739 nucleotides recommended by the WHO to identify the viral genotypes was sequenced. Results By screening with real-time PCR, viral RNA was detectable in amniotic fluids from 103 out of 110 (93.6%) pregnant women with suspected rubella and in the throat swabs from all of 20 (100%) fetuses/newborns. In addition, viral RNA was also detected in the placenta from all cases of fetuses/newborns. All of 20 fetuses/newborns presented with congenital cataract. Twenty-four strains with the E1 gene were obtained by PCR. Using phylogenetic analysis with rubella reference sequences, all of the strains were found to be genotype 2B. Interestingly, 94% (30/32) of Vietnamese strains, including 9 strains from the database, formed an independent cluster within the genotype 2B suggesting that indigenous viruses are prevalent in this region. Conclusions Rubella virus identified in Vietnam belonged to the genotype 2B. Importantly, the infection rate of rubella virus in fetuses/newborns was 100% and all of them had congenital cataract. Our results indicate an establishment of rubella prevention in this area is an urgent task in order to improve maternal and child health.