%0 Journal Article
%T HBV Perinatal Transmission
%A Muhammad Umar
%A Hamama-tul-Bushra
%A Shifa Umar
%A Haider Ali Khan
%J International Journal of Hepatology
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/875791
%X Hepatitis B is a serious public health problem all around the world. It is a blood-borne and sexually transmitted DNA virus in adults, but mother to child transmission of hepatitis B virus also occurs in infants born to hepatitis B surface antigen positive mothers. 1. Epidemiology About 350 million individuals have chronic HBV infection worldwide, and half of them acquired the infection either through perinatal route or in early childhood [1, 2], the latter being mostly asymptomatic, frequently goes unrecognized, yet 30每90% of them will develop chronic infection, which will not be diagnosed until adulthood [3每7]. 2. Modes of HBV Transmission in Infants and Children The modes of HBV transmission at an early age are (i) perinatal transmission, (ii) vertical transmission from an infected mother to her infant, or (iii) horizontal transmission from an infected household contact to the child [8]. 3. Risk Factors for Mother to Child Transmission (MTCT) The presence of HBeAg in serum is an indicator of viral replication. It is often used as a marker of ability to spread the virus to other people. HBeAg can filter through the placenta and can infect the fetus. Mother to child transmission rate is about 70每90% for HBeAg-positive mothers, 25% for HBeAg-negative/HBeAb-negative mothers, and 12% for HBeAg-negative/anti-HBe-positive mothers [9每13]. While there is only 6.6% transient infection in infants born to HBeAg-positive mothers, no persistent infection has been documented. High level of HBV DNA is the main risk factor for perinatal transmission in pregnant women. HBV can infect the placental tissue and vascular endothelium. HBV DNA is also present in sperms of HBV-infected males, and homology between the father and child＊s viral sequences has been found [12, 14]. HBV can infect the follicular fluid and ovary, and studies have suggested that high levels of maternal HBV DNA enhance HBV transmission to embryos. Nie et al. demonstrated HBV replication in 50% embryos from mothers with HBV viremia versus 7% in mothers with undetectable levels of HBV DNA [15每17]. As regards the HBV genotype, some Japanese studies showed association between genotype C and MTCT when compared with other genotypes which were refuted by some later Chinese studies. Similarly the role of precore mutant (HBeAg-negative) and basal core mutation is also not very well documented in MTCT. Therefore, no conclusive evidence can be drawn regarding association of HBV genotypes (A, B, C, and D) and perinatal transmission [16每19]. 4. Routes for Mother to Child Transmission (MTCT) Intrauterine
%U http://www.hindawi.com/journals/ijh/2013/875791/