Interference among viruses circulating and administered in Hungary from 1931 to 2008

Viral interference was discovered about 60 years ago. Molecular epidemiology revealed that this phenomenon possesses important biological implications, it can reduce the epidemic spread of certain viruses from time to time (influenza and enteroviruses) and the efficiency of live vaccination can be impaired, too. Phenomena observed during the last 80 years in Hungary are analyzed. It is suggested to concentrate the distribution of MMR vaccines to seasons of limited influenza and enterovirus circulation. Interference seems to impair the progress of wild poliovirus eradication in the endemic tropical countries. It is recommended to enhance enterovirus surveillance in the region of European countries, since the exchange of the oral poliovirus vaccine to the enhanced inactivated polio vaccine might result in enhanced circulation of non-polio enteroviruses leading to the increase in the number of type I (juvenile) diabetes patients

Co-infections with Hepatitis G and TT Virus in Patients with Chronic Hepatitis C in Hungary

The significance of co-infections with novel hepatitis viruses Hepatitis G (GBV-C, HGV) and TT virus (TTV) in chronic hepatitis C is not clear. We determined the prevalence of HGV RNA and TTV DNA in chronic hepatitis C patients and in asymptomatic hepatitis C virus (HCV) carriers, and assessed the influence of these agents on the course of HCV infection.  Seventy-seven patients with chronic hepatitis C - 50 of them treated with interferon (IFN) - and 33 HCV carriers with normal alanine aminotransferase have been investigated. Previous HBV infection was detected by testing serum HBsAg and aHBc. HGV RNA and TTV DNA were detected by PCR. In the healthy population, the prevalence of anti-HCV was 0.3%, HGV RNA 8.0% and TTV DNA 18.5%. In chronic hepatitis C HGV RNA occurred in 9.09% and TTV DNA in 40.25% of cases. In IFN-treated patients with sustained remission, the frequency of TTV was 20% vs. 45.7% found in non-responders. Among asymptomatic HCV-carriers, the prevalence of HGV RNA was 9.09% and TTV DNA 75.7%. Neither HGV RNA nor TTV DNA had apparent effect on the HCV infection. TTV was detected with the lowest frequency in persons with sustained remission due to IFN, suggesting antiviral effect of IFN on TTV