Hepatitis B: Causes

Pathogenesis (development of disease)

Increasingly, hepatitis B virus is transmitted sexually. Other modes of infection include parenteral transmission – via the bloodstream – and perinatal infection – during birth from infected mother to child.

Hepatitis B is very contagious. Because the virus can be detected in virtually all body fluids, transmission of the pathogen without sexual or blood contact is also possible, for example, through sharing dishes or kissing.

The virus reaches the liver via the bloodstream and infects the hepatocytes (liver cells). Severe tissue damage occurs as a result of the ensuing immune system response.

Etiology (causes)

Biographic causes

  • Genetic burden
    • Genetic diseases
      • Trisomy 21 (Down syndrome) – special genomic mutation in humans in which the entire 21st chromosome or parts of it are present in triplicate (trisomy). In addition to physical characteristics considered typical for this syndrome, the cognitive abilities of the affected person are usually impaired; furthermore, there is an increased risk of leukemia.
  • Occupations – medical and emergency service workers.
  • Socioeconomic factors – low socioeconomic status.
  • Geographic factors – high prevalence countries (Far East, tropical countries).

Behavioral causes

  • Consumption of stimulants
    • Alcohol (woman: > 40 g/day; man: > 60 g/day).
  • Drug use (intravenous, i.e., through the vein).
  • Shared use of everyday objects such as nail scissors or razor.
  • Pierce ear hole
  • Piercings
  • Tattoos
  • Sexual transmission
    • Promiscuity (sexual contact with relatively frequently changing different partners or with parallel multiple partners).
    • Prostitution
    • Men who have sex with men (MSM).
    • Sexual contacts in the vacation country
    • Unprotected coitus (sexual intercourse)

Causes related to disease

  • Alcohol dependence
  • Dialysis patients – individuals who require dialysis (blood washing) as renal replacement therapy due to kidney disease.
  • Hepatitis C (liver inflammation)
  • HIV infection
  • Hodgkin’s lymphoma – malignant disease of the lymphatic system.
  • Leprosy – chronic tropical infectious disease.
  • Leukemia (blood cancer)
  • Polyarteritis nodosa (PAN) – autoimmune disease leading to vasculitis (inflammation of blood vessels) with narrowing of the vessel lumen.
  • Tuberculosis (consumption) – infectious disease that affects mainly the lungs.

Medication

  • Blood products

Other causes

  • Horizontal infection (non-sexual) – pathogen transmission from host to host of the same generation:
    • Health care workers
    • Residents and employees of care facilities
    • Inmates

    The risk of infection from a needle stick injury with virus positive blood is up to 30%.

  • Vertical infection – pathogen transmission from a host (here. the mother) to its offspring (here: the child):
    • Transmission of infection during birth from mother to child (perinatal) [risk of transmission: 90%].
    • Transmission through breast milk (postnatal infection).
  • Iatrogenic transmission