Delta hepatitis is most prevalent in groups at high risk of hepatitis B. Injection drug users are those at greatest risk in the western parts of the world, and as many as 50% of such individuals may have IgG antibody to the delta virus antigen. Other risks include dialysis. Nonparenteral and vertical transmission can also occur.
DELTA HEPATITIS DISEASE : CLINICAL ASPECTS
Two major types of delta infection have been noted: simultaneous delta and hepatitis B infection or delta superinfection in those with chronic hepatitis B. Simultaneous infection with both delta and hepatitis B results in clinical hepatitis that is indistinguishable from acute hepatitis A or B; however, fulminant hepatitis is much more common than with hepatitis B virus alone. Persons with chronic hepatitis B who acquire infection with hep-atitis D suffer relapses of jaundice and have a high likelihood of developing chronic cirrhosis. Epidemics of delta infection have occurred in populations with a high incidence of chronic hepatitis B and have resulted in rapidly progressive liver disease, causing death in up to 20% of infected persons.
Diagnosis is made most commonly by demonstrating IgM or IgG antibodies, or both, to the delta antigen in serum. IgM antibodies appear within 3 weeks of infection and persist for several weeks. IgG antibodies persist for years.
Response to treatment with interferon alpha in patients with delta hepatitis (and hepatitis B) is less than in those with hepatitis B alone. Recommended doses are higher and may produce sustained improvement in only 15–25% of patients.
Because the capsid of delta hepatitis is HBsAg, measures aimed at limiting the transmission of hepatitis B (eg, vaccination, blood screening) prevent the transmission of delta hepatitis. Individuals infected with hepatitis B or D should not donate blood, or-gan, tissues, or semen. Safe sex should be practiced unless there is only a single sex part-ner who is already infected. Methods of reducing transmission include decreased use of contaminated needles and syringes by injection drug users and use of needle safety de-vices by health care workers.