Sarwar J. Zuberi ( PMRC Research Centre, Jinnah Postgraduate Medical Centre, Karachi. )
The last decade was the period of a rapid evolution in the understanding of the new delta antigen/antibody system discovered by Rizzetto et al1. Delta is a 35-37 nm defective RNA Viral agent which requires helper function from the HBV or other hepadna viruses for its replication and expression. Delta agent can superinfect HBs positive host and results in a reduction of circulating and intrahepatic levels of HBV antigens.2
Delta coinfection can occur in patients with acute hepatitis B, fulminant hepatitis and superinfection in HBV carriers resulting in chronic active hepatitis and cirrhosis.
Acute HBV/delta infection occurs as self limited, disease or fulminant hepatitis. In simultaneous infection of both viruses the features may be of HBV infection alone or two aminotrans. ferase peaks may indicate HBV and delta infections respectively. Delta antigen is briefly detec. table, 1gM antidelta is transient and IgG antidelta is undetectable in the absence of HBsAg. This makes retrospective diagnosis of dual infection in acute self limited disease rather difficult2. Govindarajan et al3 reported delta coinfection in 33.8% cases of fulminant and 42% of nonfulminant hepatitis. In nonfulminant hepatitis in Pakistan antidelta was found in 1.1% of cases4.
Delta epidemics have also been reported from areas like Venezuala where HBV is endemic in Yucpa Indians with a mortality due to ful. minant hepatitis in 17%, active progressive fatal disease in 23% and chronic outcome in 68% of cases.
Duration of HBV infection determines the duration of Delta infection therefore patients with chronic HBV positive disease develop delta infection more frequently. Recurrent acute exacerbations in chronic hepatitis indicate delta infection. 2
Cirrhosis is more frequent in patients with antidelta. Four of seven anti delta positive British carriers had histologically proven cirrhosis6. Sixtytwo percent of HBsAg positive cirrhotics in Karachi (Zuberi, S.J. et a!. unpublished data) and 62% in Kuwait7 were anti delta positive.
Association of Delta with hepatocellular carcinoma has also been reported in some populations8 and not in others. 9-10 Rizzetto et a18 have found delta markers in cases of hepatoma in Italy and 41% cases in Karachi were anti.delta positive (Zuberi, SJ. et a!. unpublished data). None of the liver cancer patients reported from Taiwan8 and South Africa showed serological evidencó of delta infection. No relationship has been observed between the HBsAg carriage rates and the frequency of delta infection in these countries.
Delta carriage rate varies from 4.8% in Pakistan4 to 40 — in Italy11 and 40% in Kuwait. 7 Delta infection is preventable by immunizing the non HBV immune individuals against hepatitis B.
1. Rizzetto, M., Canese, M.G., Arico, S., Crivelli. Trepo, C., Bonino, F. and Verme, G. Immunofluorescence detection of a new antigen-antibody system (delta/anti-delta) associated to hepatitis B virus in liver and in serum of HBsAg carriers. Gut, 1977; 18:997.
2. Jacobson, LM. and Dienstag, J.L. The delta hepatitis agent; “viral hepatitis, Type D”. Gastroenterology, 1984; 86:1614.
3. Govindarajan, S., Chin, K.P., Redeker, A.G. and Peters, R.L. Fulminant B viral hepatitis; role of delta agent. Gastroenterology, 1984; 86: 1417.
4. Malik, LA., Ahmad, A.,Iqbal, M., Legters, Li., Luqman, M. and Akhtai, M.A. Infection with Delta agent in Pakistan: Introduction of a new hepatitis agent. JPMA., 1988; 38:126.
5. Hadler, S.C., De Monzon, M., Ponzetto, A., Anzola, E., Rivero, D., Mondolfi, A., Bracho, A., Francis, D.P., Gerber, MA., Thung, S., et a!. Deltavirus infection and severe hepatitis. An epidemic of severe hepatitis due to delta virus infection in Yucpa Indians in Venezuala. Ann. Intern. Med., 1984; 100: 339.
6. Weller, I.V., Karayiannis, P., Lok, A.S., Montano, L., Bamber, M., Thomas, B.C. and Sherlock, S. Significance of delta agent infection in chronic hepatitis B virus infection; a study in British carriers. Gut, 1983; 24:1061.
7. Nordenfelt, E., Hanson, B.G., Al-Nakib, B., Al-Kandari, S. and Al-Nakib, W. Frequency of delta agent infections in Kuwait. J. Infect. Dis., 1983; 148:768.
8. Rizzetto, M., Shih, J.W., Gocke, D,j Purcell, R.H., Venue, G. and Gerin J.L. Incidence and significance of antibodies to delta antigen In
9. Chen, D.S., Lal, M.Y. and Sung, J.L. Delta agent infection, in patients with chronic liver diseasesnd hepatocellular carcinoma — an infrequent Taiwan. Hepatology, 1984; 4:502.
10. M.C., Dusheiko, G.M., Hadziyannis, SJ.and Patterson, A. Does delta infection play a pathogenesis of hepatitis B virusrelated hepatocellular carcinoma? Br. Med. j, (Clin. Res.), 1984; 288: 1727.
11. Rizzetto, M. Biology and characterization of the delta agent, in Proceedings of the Third International Symposium on Viral Hepatitis. Edited by Samuness, W., Witer, Hi., Maynard, J.E.Philadelphia, Franklin Institute Press, 1982; /p. 355.