To date, the routes of mother-to-infant transmission of TT virus (TTV) have not been fully elucidated. The present study examines the detection rates of TTV DNA in the serum of pregnant Japanese women and in cord blood at the time of delivery, as well as in the saliva and breast milk of mothers one-month postpartum. Primers derived from the well-known translated region N22 (N22 system), as well as the untranslated region (UTR system) were used. The prevalence of TTV DNA in the serum of pregnant women was found to be 11.9% (19/160) using the N22 system and 72.4% (55/76) using the UTR system. No TTV DNA was detected in the cord blood samples (0/160) when the N22 system was used for detection but TTV DNA was detected in 11.8% (7/76) of samples studied with the UTR system. Using the N22 system, TTV DNA was not detected in breast milk, but was detected in saliva. However using the UTR system, TTV DNA was detected in both specimens. These results imply that some babies are vertically infected with TTV via cord blood at the time of delivery or via breast milk or saliva. However, further research is necessary to confirm this hypothesis. polymerase chain reaction; pregnant women; horizontal route of transmission
Absence or presence of bile salt export protein gene mutations was confirmed as representing a useful prognostic marker for clinical course after liver transplantation.
TT virus (TTV) is a novel viral agent, detected recently in non-A to E hepatitis cases. Little is known about its natural history or routes of transmission in childhood. For the detection of serum TTV DNA, semi-nested polymerase chain reaction (PCR) was carried out using TTV-specific primers and TTV nucleotide sequences were determined by the dideoxy chain-mediated termination method. Five of the 70 children studied (including 20 hepatitis B virus [HBV] carriers, 40 children born to HBV carrier mothers and 10 children born to hepatitis C virus [HCV] carrier mothers) had serum TTV DNA. Three of the 5 children had siblings (4 in total), so that a total of 9 children were studied to determine the time of initial serum TTV DNA detection. In the 8 seropositive children, the time of serum TTV DNA detection ranged from 6 to 14 months after birth, and TTV DNA persisted thereafter throughout the follow-up period. The TTV DNA-negative child was assessed most recently at 6 months of age. TTV DNA was detected in only 2 of the 4 mothers tested (families 2 and 3). When 271-bp TTV DNA fragments from each of the 8 children were sequenced, the degree of homology between siblings in families 1-3 was 100%, 99.5%, and 92.3%, respectively. The degree of homology between child-mother pairs of families 2 and 3 was 99.5-100% and 62. 6-63.9%, respectively. The distribution of different TTV strains was consistent within families, except for family 3. None of the TTV-infected children had elevated levels of alanine aminotransferase or clinical signs of liver disease.
The prevalence rates of serum TT virus (TTV) DNA among children with or without a history of transfusion or liver disease were studied by polymerase chain reaction (PCR) using either the Okamoto primer set or the Takahashi primer set developed more recently. Using Okamoto and Takahashi primer sets, the prevalence rates were 31.6% (12/38) and 78.9% (30/38), respectively, for children with a history of blood transfusion (including malignant and non-malignant groups) and 6.7% (2/30) and 60% (18/30), respectively, for children without a history of blood transfusion. Among pregnant women, these rates were 12.9% (4/31) and 61.3% (19/31), respectively. On the other hand, the prevalence rates were 0% (0/16) and 50% (8/16), respectively, in hepatitis B patients, 21.4% (3/14) and 71.4% (10/14), respectively, for hepatitis C patients, and 20.0% (9/45) and 57.8% (26/45), respectively, for non-A to C hepatitis patients (including 27 acute hepatitis patients, 5 fulminant patients and 13 chronic hepatitis patients). In this study, the prevalence rates determined by the Takahashi primer set tended to be 2-9 times higher than those determined using the Okamoto primer set. These results suggest that TTV infection is widespread among Japanese children. Furthermore, blood transfusion does not appear to be the major route of infection. The similar prevalence rates between control children and children with various types of hepatitis using the Takahashi primer system suggest that TTV infection does not play a direct causative role in the development of liver disease in children.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.