[The duration of preservation of anamnestic antibodies to hepatitis E virus.]

The purpose of the study was to determine the duration of antibody response against hepatitis E virus (anti-HEV). Veterans of the war in Afghanistan who were in this endemic region in the late 1970s and early 1980s were tested for anti-HEV. On average, 20 years after the end of military service in Afghanistan, the rate of seropositivity was 30.0% (95/317), which was significantly higher compared to positivity rates in males who were at military service in the territory of Russia during the same period (3.9%, 8/208). At an average of 29.5 years after the visit to Afghanistan anti-HEV prevalence in veterans dropped to 20.0% (21/105), but still significantly exceeded the seroprevalence in general population (3.8%). Serum samples from elderly individuals (>60 years) without known risk factors of infection were also tested for anti-HEV IgG and IgM (n = 896). Anti-HEV IgG detection rates in the elderly from two regions of Russia exceeded those observed of primary blood donors (18.0-27.8% vs. 4.5-10.0%, p<0.01). The detection of anti-HEV IgM in individuals above 60 years (2.7-6.9%) indicates a current or recent infection. Thus, anti-HEV IgG can persist several decades after the infection. This might account for the wide anti-HEV prevalence among the elderly. At the same time, a significant proportion of individuals exposed to HEV lose detectable anti-HEV IgG within 20-30 years. The detection of anti-HEV IgM among the elderly indicates the viral circulation in older age groups, suggesting the need for testing for hepatitis E markers in elderly patients with liver diseases.

[The panels of serums, containing various subtypes and mutant forms of HBsAg, to evaluate the diagnostics sensitivity of kits oa reagents detecting HBsAg]

The detection of HBsAg in blood serum using immune-enzyme analysis techniques decisively matters both for diagnostics of acute and chronic hepatitis B and screening of donor's blood and its components, controls of persons from risk groups of hepatitis B injection. The making of panels containing wide specter of samples of blood serums with sero-variants and mutant forms of surface antigen of hepatitis B virus widespread on the territory of the Russian Federation is necessary to control analytic and diagnostic sensitivity of test systems for detecting HBsAg. The testing of reagents kits to detect HBsAg using twi panels containing recombinant and native variants of HBsAg, demonstrated that these kits enable to detect various sero-vatriants of HBsAg (ayw2, adw2, ayw3varA, ayw3varB, adrq-) in concentration 0.1-0.01 IU/l and the so called elusive mutant forms of HBsAg of recombinant and native origin (G145R, Q129R, Q129H, Q129L, T143K, T126N, T126S, D144A, M133L, K141E and P142S). At that, the sensitivity can differ during the detection of native and recombinant mutant forms. The results testify the importance of using the panels both with recombinant and native samples containing the mutant forms of HBsAg in evaluation of sensitivity of reagents kits.

[Evaluation of the effect of mass vaccination against hepatitis B in the Russian Federation]

AIM

Evaluate the effect of mass vaccination against hepatitis B implemented within the framework of national project Health on the rate of development of unfavorable outcomes of infection and on average lifetime of the population of Russia.

MATERIALS AND METHODS

Hepatitis B markers (HBsAg, anti-HBc, HBeAg, anti-HBe) were determined by enzyme immunoassayin 6211 blood serum samples from conditionally healthy population of 6 regions of the Russian Federation. Analysis of damage to health of the population caused by hepatitis B and favorable effect of mass vaccination against hepatitis B was performed by using mathematical model by Goldstein S.T. et al. (2005), that used results of detection of hepatitis B markers in discrete groups (women of childbearing age, children up to 5 years of age, adults aged 30 years and older). A formula developed by us was used to evaluate the effect of vaccination on the average lifespan of the population of the Russian Federation.

RESULTS

The rate of HBsAg detection in the conditionally healthy population of the Tuva Republic was significantly higher (8.1%) than in other studied regions of the Russian Federation (p < 0.05): in Moscow Region--1.6%, in Rostov Region--1.6%, in Sverdlovsk Region--1.2%, Khabarosvk Region--2.0%, in Sakha (Yakutia) Republic--2.5%. The rate of detection of anti-HBc was significantly higher in the Tuva Republic and Sakha (Yakutia) Republic (46.2% and 42.3%, respectively); in other regions: Moscow Region--13.6%, Rostov Region--18.9%, Sverdlovsk Region--17.5%, Khabarovsk Region--21.0%. HBeAg in women of childbearing age was detected only in the Tuva Republic (0.4%). The mathematical analysis performed demonstrated that the level of coverage of vaccination of newborn children that in the studied regions is 96.1-99.6% may lead to the reduction of morbidity and mortality from hepatitis B and its outcomes by 91-95% that exceeds the similar parameter obtained by using our model, described in the literature for Africa, Asia and Europe. The calculated level of decrease of morbidity and mortality from hepatitis B and its outcomes may lead to the increase of average lifespan of the population of the Russian Federation by 1.44 - 4.08 months.

CONCLUSION

The strategy of vaccination of newborn children against hepatitis B employed in the Russian Federation significantly reduces the risk of this disease and development of unfavorable outcomes of the disease especially in hyper endemic regions and promotes the increase of average lifespan of the population of Russia.

[Epidemiological and molecular biological analysis of causes of rise of hepatitis A incidence in Republic of Tuva in 2008]

AIM

Analysis of hepatitis A (HA) incidence in Tyva Republic in 2008 exploiting traditional epidemiological and molecular methods.

MATERIALS AND METHODS

Epidemiological analysis of HA cases and contact persons in Erzinsky and Kyzyl regions of Tyva Republic was performed. Class M and G antibodies to HAV were determined in serum samples (n = 28), and HAV RNA--in stool samples (n = 16). Phylogenetic analysis of HAV RNA sequence was performed for VP1/2A region of the HAV genome with length 394 nucleotides.

RESULTS

Cases of HA were registered during 3.5 months. Water supply sources did not have deviations from established standards. According to results of interviews, common food factor, which was able to cause the rise of HA incidence, was not determined. Signs of fecal contamination were revealed on environmental objects in preschool institutions and schools that demonstrate the low level of hygienic behaviour. It was shown that all cases of HA are related with different variants of the virus belonged to genotype IA that points to the absence of common source of infection.

CONCLUSION

Results of epidemiological and genetic analysis of HAV demonstrate that observed rise in HA incidence in Tyva Republic are connected with phase of seasonal rise of HA incidence, which is characteristic for its perennial dynamics with active realization of contact route of virus transmission.

[GBV-C infection in HIV-infected patients in the Russian Federation]

The spread and genotypical variability of GBV-C virus were determined among the HIV-positive patients in the Russian Federation. More than a fourth (26.2%) of the HIV-infected patients were shown to have GBV-C coinfection; all virus isolates belonged to genotype 2 with a predominance of subtype 2a. Analysis of the impact of GBV-C coinfection on HIV burden and CD4 lymphocyte levels showed no significant impact on these basic characteristics of HIV infection. However, coinfection with GBV-C and HIV was associated with the higher frequency of undetectably low ( < 400 copies/ml) of HIV burden, which enables GBV-C infection to be regarded as a potentially favorable factor in HIV infection.