Viral hepatitis G: epidemiology and course
The source of infection in hepatitis G includes patients with acute or chronic forms, as well as asymptomatic virus carriers.
Routes of transmission:
- Parenteral — the leading route. The disease threatens recipients of blood products, organ transplant patients, and intravenous drug users.
- Vertical — the possibility of virus transmission from an infected mother to the fetus has been proven.
An independent course of hepatitis G is extremely rare. Usually, HGV is detected as a mixed infection against the background of viral hepatitis C (HCV). It is important to note that the addition of HGV does not significantly affect the severity and progression of the underlying pathological process.
Diagnostics:
- ELISA: IgM antibodies (markers of replication) appear on days 10–12 and circulate for 1–2 months. IgG antibodies (markers of past infection) emerge a month after the disease resolves.
- PCR: aimed at detecting viral RNA. The feature of pathogenesis is that RNA is detected in the first days, but during the icteric period (peak period) it is impossible to identify it.
Hepatitis "non-A, non-G": TTV and SEN viruses
According to ICD-10, these conditions are coded as B19.0. The causative agents belong to the family Circoviridae. These are small non-enveloped virions (TTV size is 30–50 nm). Unlike HGV, their genome is represented by single-stranded circular DNA. Viruses are prone to frequent mutations: 16 genotypes are distinguished for TTV, and several variants for SEN.
Epidemiology: The infection is distributed ubiquitously. The reservoir of infection includes not only the human population, but also domestic and farm animals (pigs, cows, sheep, poultry). The main proven route of transmission is parenteral (historically these are post-transfusion hepatitis cases). However, epidemiological data do not exclude fecal-oral and contact mechanisms of transmission.
Clinical presentation of TTV and SEN
The exact mechanisms of hepatocyte damage by these viruses have not yet been studied. The disease is characterized predominantly by a latent (asymptomatic) course. A high rate of healthy virus carriage is recorded in the population.
- TTV virus is often detected in patients with severe forms of liver pathology, including fulminant hepatitis and cryptogenic cirrhosis.
- SEN virus is at the research stage. No unequivocal link between it and the development of cirrhosis, hepatocellular carcinoma, or acute/chronic hepatitis has been established yet.
Specific treatment protocols and vaccines for these infections do not exist.
Syndromic presentation of acute viral hepatitis
Using the classic course of acute hepatitis in adolescents as an example, characteristic stages of the pathological process that require differential diagnosis can be identified.
- Preicteric period: lasts several days. It manifests with asthenovegetative and intoxication syndromes (low-grade fever, weakness, sleep disturbances) and dyspepsia (anorexia, nausea, vomiting, loose stools). Because of this, the disease is often mistaken for dietary indiscretion.
- Icteric period: the condition becomes moderately severe, arthralgia appears. Icterus is primarily noticeable on the sclera and oral mucosa. Hepatomegaly is characteristic (the liver protrudes from under the costal margin, palpation is painful, the parenchyma is denser, the surface is smooth).
With pronounced cytolysis syndrome (high ALT and AST) and hyperbilirubinemia, testing for viral hepatitis markers serves as the gold standard for verifying the diagnosis.
TTV stands for Transfusion Transmitted Virus — this directly indicates its main (parenteral) route of transmission through blood.
Class and exam questions
Does hepatitis G virus worsen the course of hepatitis C?
No, clinical practice shows that the addition of HGV as a mixed infection does not significantly affect the severity and progression of hepatitis C.
What is the difficulty of PCR diagnostics for hepatitis G?
HGV RNA can be detected in the blood from the first days of infection, but during the peak (icteric) period it cannot be detected by PCR.
How does the genome of TTV and SEN differ from other hepatitis viruses?
Unlike most other hepatitis viruses (including HGV), the genome of TTV and SEN is represented by single-stranded circular DNA.
What else to study on this topic
- Mechanisms of viral hepatitis co-infection
- Differential diagnosis of jaundice of various origins
- Interpretation of cytolysis markers (ALT, AST) in liver lesions
- Markers of post-vaccination immunity (using anti-HBs in hepatitis B as an example)
- Molecular genetic diagnostic methods (PCR and hybridization)
Master the entire topic in the Pediatrics course
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- Complete study guide on "Viral Hepatitis G, TTV, and SEN" and 3,738 more pages of the subject
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Other topics from the section «Chapter 12. Infectious and parasitic diseases»
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