Excretion into Bile of a Novel Unenveloped DNA Virus (TT Virus) Associated with Acute and Chronic Non‐A–G Hepatitis

Abstract

Recently, an unenveloped, single-stranded DNA virus named TT virus (TTV) has been reported in association with hepatitis of non-A-G etiology. Five patients with TTV viremia, who received bile drainage or cholecystectomy, were tested for TTV DNA in bile by polymerase chain reaction with heminested primers. TTV DNA was detected in bile from all patients; titers were 10-100 times higher than in serum in 4 and at a comparable level in the remaining 1 patient. TTV DNA was detected in feces, also, in 1 of the 2 patients tested. The buoyant density of TTV in bile from 1 tested patient (1.33-1.35 g/cm3) was the same as that in feces (1.32-1.35 g/cm3). TTV may be secreted via bile into feces in a transmissible form and would spread by a fecal-oral route for deep and wide penetration into the general population.

Prevalence and genetic variants of hepatitis GB-C/HG and TT viruses in Gabon, equatorial Africa.

“…Previous reports have suggested a fecal-oral route of transmission for TTV. 25,26 It is unclear whether TTV is efficiently transmitted by sexual intercourse but recent data obtained in France suggest that this is the case. 42 Most studies on TTV in North America and Europe have shown no significant impact of TTV on liver disease.…”

“…The route of TTV transmission is also unclear, although there is strong evidence for blood transmission and some studies have suggested a fecal-oral route. 25,26 A few studies have reported a high prevalence of GBV-C/HGV [27][28][29] and TTV infection 30 in sub-Saharan Africa. The prevalence of both types of viral infection within a single African geographical area has not been considered, and the modes of transmission of these viruses in Africa have remained elusive.…”

Global impact of Torque teno virus infection in wild and domesticated animals

“…The buoyant density in cesium chloride was found to be 1.31-1.33 g/cm 3 for TTV in serum and 1.33-1.35 g/cm 3 for TTV in feces [2]. Resistance to treatment with detergents, solvents, and dry heat confirmed the absence of a lipid envelope [37,38]. TTV proteins have not been well characterized yet; however, similar to CAV, it is believed that the capsid is made up of a single structural protein.…”

Clinicopathological study on TTV infection in hepatitis of unknown etiology

“…Meanwhile, different studies suggested that TTV genotypes were so much and could vary frequently [4][5][6][7][8] . It is believed that TTV belongs to hepadnavirus and replicates chiefly in the liver [9][10][11] , however, some researchers think that the replication site is in the bone marrows rather than in the livers [12] . At present, epidemiological studies suggest that TTV is mainly transmitted by blood [13][14][15] ; blood products [16] and body fluid routes [13,17] , it can also be transmitted by mother-to-child vertical [18] and horizontal [19,20] route , fecal-oral route [9,15,21] and sexual route [22] .…”

“…It is believed that TTV belongs to hepadnavirus and replicates chiefly in the liver [9][10][11] , however, some researchers think that the replication site is in the bone marrows rather than in the livers [12] . At present, epidemiological studies suggest that TTV is mainly transmitted by blood [13][14][15] ; blood products [16] and body fluid routes [13,17] , it can also be transmitted by mother-to-child vertical [18] and horizontal [19,20] route , fecal-oral route [9,15,21] and sexual route [22] . The infection rate of TTV DNA varies largely in healthy population and patients with liver diseases, but generally, it is higher in patients than in healthy donors [7,[23][24][25][26] .…”