Antibodies to the hepatitis A virus in the healthy population of Moscow

Serum specimens collected from 1002 persons in Moscow were tested for the presence of antibodies to hepatitis A virus (anti-HAV antibodies) by solid-phase enzyme immunoassay. The prevalence of these antibodies increased progressively with age from 10% in children aged 5-9 years to over 90% in the age groups of 40-49 years and over, the 50% immunity level being established at the age of 18 years. 79% of infants under 1 year were found to be immune, which was obviously due to the placental transfer of antibodies from mother to child. In a considerable part of seropositive persons over 30 years high or medium antibody titers were detected. These age groups showed a stable proportion of the low, medium and high level of anti-HAV antibodies. The prevalence of such antibodies was not related to sex. The presence of an ample amount of anti-HAV antibodies was determined in all of 18 tested lots of commercial serum immunoglobulin obtained from 3 different manufacturers.     

A trial of using immunoglobulins of known specificity for preventing hepatitis A in regions with high epidemic activity

The economic effectiveness of immunoglobulin prophylaxis (IGP), carried out among children aged 1-3 at the beginning of a seasonal rise in hepatitis A (HA) morbidity with high coefficients of protection (80-85%), was directly related to the activity of the epidemic process. Preparations with sufficiently high content of antibodies to HA virus sharply decreased the manifestation of this infection. The detection rate of the manifest forms of the infection among children covered by prophylactic measures in the foci of HA was considerably lower than among children who had not received the preparation. IGP exerted no essential influence on the dynamics of the formation of population immunity. A high share of children aged 3-4 years, seropositive to HA virus (up to 90%), validates the inadvisability of carrying out IGP in older groups of children.     

Retrospective epidemiologic diagnosis of viral non-A, non-B hepatitis with a fecal-oral mechanism of transmission of the causative agent

The possibility of the retrospective epidemiological diagnosis of viral hepatitis non A, non B with the fecal-oral mechanism of the transfer of infection in three cities of Central Asia on the basis of the analysis of the dynamics of registered hepatitis A morbidity is shown. With the irregularity of morbidity levels among the total population being characteristic of all three cities, in Andizhan one rise in morbidity within a period of 3 years (1975-1978) and in Tashauz one rise within a period of 5 years (1975-1980) were registered. The analysis of the dynamics of morbidity observed in individual age and social groups showed that these rises, especially those registered in 1976 in Andizhan and in 1977 in Tashauz, were determined by morbidity levels among school children and adults. This is also true for a rise in morbidity rate registered in Tashauz in 1985. In Andizhan the highest morbidity rates among adults were registered in districts insufficiently equipped with modern amenities. Cases of infection registered as hepatitis A (HA) among persons immune to HA at territories with high intensity of the epidemic process of HA at the above-mentioned periods seem to be due to viral hepatitis non A, non B with the fecal-oral mechanism of the transmission of the infective agent.     

Emergency measures to control the spread of diseases caused by the human immunodeficiency virus

Since the middle of 1996 the growth of HIV-infected persons and AIDS morbidity are registered in Russia. In 1997 4,300 new cases of HIV infection were registered, which exceeded 1.6 times the total number of cases for the period of 1987-1996. The highest morbidity rate was observed in the cities of the European part of Russia: Kaliningrad (west), Krasnodar and Rostov-on-Don (south), Nizhny Novgorod and Moscow (center). AIDS patients and HIV-infected persons were registered in 73 out of 89 regions of the country. 90% of HIV-infected persons were drug users in 1997. In 1992-1997 the number of drug addicts increased 3.5 fold and young women in 1987-1997, 6.5 fold. 71 HIV-infected children were registered were born from HIV-infected mothers at present time. The article deals with the main provisions of the federal laws aimed at the prevention of the spread of HIV infection in Russia and characterizes scientific research on AIDS. Evidence is presented that the early detection of HIV-infected persons, as well as rendering timely medical and social assistance to such persons, makes it possible to increase their mean survival time and check the spread of human immunodeficiency virus.     

The vaccinal prophylaxis of hepatitis B in Russia--the achievements, problems and outlook

Certain specific features of the present epidemic situation with hepatitis B (HB) in Russia were established: significant growth of HB morbidity, starting from 1995; the prevalence of persons aged 15-29 years among HB patients, which was linked with the sharp activation of the sexual route of the transmission of HB virus in recent years; an essential increase in the number of patients having contacted this virus in the process of the intravenous use of drugs. The results of the use of vaccine "Engerix B" among persons belonging to different risk groups were considered (a decrease in HB morbidity among them by 8-19 times was noted), the study demonstrated high immunogenicity anti-HBs antibodies on protective titers were determined in 92.3-95.7% of the vaccinees) and low reactogenicity of the vaccine, as well as stable postvaccinal immunity (5 years after the course of vaccination was completed anti-HBs antibodies were retained in 70.6-74% of the vaccinees). The study showed that only the vaccination of adolescents in combination, in the presence of opportunity, with the immunization of newborn infants and young children in the first year of their life made it possible to produce an essential effect on the activity of the epidemic process. Already in 2 years such organization of work on the prophylaxis of HB in one of the cities of the Sverdlovsk region led to a decrease in HB morbidity by 2.9 times, and among adolescents 9 times.     

Declining prevalence of hepatitis A virus antibodies among children from low socioeconomic groups reinforces the need for the implementation of hepatitis A vaccination in Brazil

Age-related seroprevalence studies that have been conducted in Brazil have indicated a transition from a high to a medium endemicity of hepatitis A virus (HAV) infection in the population. However, most of these studies have focused on urban populations that experience lower incidence rates of HAV infection. In the current study, the prevalence of anti-HAV antibodies was investigated in children with a low socioeconomic status (SES) that live on the periphery of three capital cities in Brazil. A total of 1,162 dried blood spot samples were collected from individuals whose ages ranged from one-18 years and tested for anti-HAV antibodies. A large number of children under five years old (74.1-90%) were identified to be susceptible to HAV infection. The anti-HAV antibody prevalence reached ≥ 50% among those that were 10-14 years of age or older. The anti-HAV prevalence rates observed were characteristics of regions with intermediate level of hepatitis A endemicity. These data indicated that a large proportion of children with a low SES that live at the periphery of urban cities might be at risk of contracting an HAV infection. The hepatitis A vaccine that is currently offered in Brazil is only available for high-risk groups or at private clinics and is unaffordable for individuals with a lower SES. The results from this study suggest that the hepatitis A vaccine should be included in the Brazilian National Program for Immunisation.     

Humoral immunity indices of chronic alcoholism patients

Sera obtained from 642 patients with chronic alcoholism and 400 sera from healthy donors, collected in different regions of the USSR (Moscow, the Kirghiz SSR, Transcarpathian Province, the northern Caucasus), were studied. Out of all patients with chronic alcoholism whose blood sera were examined, persons aged 20-30 years constituted 22%, 31-40 years, 41.8%, 41-50 years, 27.5%, above 50 years, 8.7%. The results of the study of the immune structure of these patients with respect to the causative agents of respiratory diseases revealed a large proportion of persons seropositive to influenza virus B Leningrad/369/75 (92-93%) and coronavirus OC-43 (78-93%). Patients with chronic alcoholism were shown to belong to a high risk group with respect to Legionella pneumophila infection. The proportion of persons with antibodies to L. pneumophila among such patients (up to 21.1%) was considerably higher than among healthy donors (not more than 6%). In different regions of the USSR large risk groups with respect to diphtheria (42-56%) and tetanus (12-45%) were detected among patients with chronic alcoholism. These patients also showed considerably higher levels of anti-tissue antibodies in comparison with the healthy population.     

Immune structure of the pediatric population in relation to the mumps virus and the morbidity of serous meningitis of mumps etiology in Sverdlovsk

The work presents the results of the longterm study of regularities in the formation of herd immunity to mumps virus in children in Sverdlovsk with due regard to vaccination carried out in this city and morbidity level in serous meningitis of mumps etiology. The inverse correlation between the number of seropositive persons in the total child population and the level of morbidity in the nervous form of mumps has been established. No differences in the size of the immune stratum and the intensity of immunity to mumps virus among boys and girls have been revealed. Vaccination against mumps, carried out at the period of a natural drop in mumps morbidity, has produced no essential effect on the level of herd immunity, though it has led to a considerable decrease in the incidence of serous meningitis of mumps etiology.     

Quantitative evaluation of the content of antibodies to hepatitis of A virus in serial immunoglobulin preparations

A total of 156 samples of several lots of immune serum globulin (ISG) were tested for antibodies to hepatitis A virus (anti-HAV). In this study the blocking variant of the solid-phase enzymoimmunological method was used. The samples under test were the production of 12 manufacturing enterprises in the USSR and I enterprise in Czechoslovakia. All the samples under test were found to contain anti-HAV within the limits from 2500-5000 to 20000-40000. The samples produced by different manufacturing enterprises showing no essential differences in the content of anti-HAV. Most preparations (93.6%) contained antibodies at levels of 5000-20000. The ISG proposed as the international standard preparation had a titer of 8000-10000. No differences in the content of anti-HAV were detected in comparing ISG whose shelf life expired 4 years before the test with ISG whose shelf life was to expire 3 years later. The results obtained in this study are discussed in connection with the immunoprophylaxis of viral hepatitis A.     

The verification of the results of screening antibodies to hepatitis C virus in blood donors

6,744 persons were examined for the presence of antibodies to hepatitis C virus (HCV) before blood donation (4,219 persons in Moscow and 2,525 persons in St. Petersburg). The serum samples found to contain antibodies to HCV were additionally studied by the immunoblot techniques. The positive results of antibody screening were registered in 78 persons: 26 persons in Moscow (0.62%) and 52 in St. Petersburg (2.05%). In both cities the positive results of screening were confirmed in 62% of cases. Different occurrence of the profile with the presence of antibodies to all fragments of the virus: 52% in Moscow, 12% in St. Petersburg (chi2 = 12.11; p < 0.001). Considerable differences were also registered in the spread of individual antibodies.     

Total immunization of children against influenza decreases morbidity in a number of diseases among elderly persons during influenza epidemic

Immunization of children aged 3-6 years in kindergartens and school children aged 7-17 years against influenza with inactivated influenza vaccine was carried out in two districts of the Moscow region. The comparison of morbidity in influenza-like diseases among the immunized children with that among nonimmunized children in control districts revealed that the effectiveness of immunization was 60.9% in kindergartens and 68.8% in schools. The analysis of morbidity in a number of diseases among 158,451 elderly persons not immunized against influenza demonstrated that, in comparison with the control districts, in those districts where mass immunization of children was carried out morbidity in influenza-like diseases among elderly persons was 3.4 times lower and, out of other 10 diseases under study, morbidity in 8 diseases was 1.5-2.6 times lower. As indicated by the data obtained in this study, total anti-influenza immunization of children in organized groups not only essentially decreased influenza morbidity among children, but also greatly decreased morbidity in influenza and a number of diseases, appearing as complications of influenza infection, among nonimmunized elderly persons during influenza epidemic.     

Epidemiological characteristics of meningococcal infection in a number of territories of the RSFSR (1969-1984)

In this work the dynamics and morbidity level in respect of meningococcal infection at 11 territories of the RSFSR at the period of 1969-1984 are analyzed. The study covered altogether 16 cities and 211 districts. The role of big cities as the sources of infection spreading into rural areas and further "fixation" of this infection mainly in regions with a population of 60,000 and more had been established. The data on meningococcal morbidity and carriership among different age groups are presented. The study has shown a pronounced increase in the incidence rate of meningococcal infection among children aged up to 2 years, as well as an increase in the proportion of these children among patients with meningococcal infection in recent years.     

Characteristics of the distribution of the markers of hepatitis B vir us infection among the healthy population of the Tadzhik SSR and Azerbaijan SSR

A total of 708 healthy persons in Tajikistan and 576 healthy persons in Azerbaijan, these groups comprising persons of both sexes and different age groups, were examined by the method of double gel immunodiffusion (the gel precipitation test) and by the passive hemagglutination test for the presence of the markers of hepatitis B virus (HBV) infection (HBsAg and HBeAg) and antibodies to them. This investigation showed that, in accordance with the level of hepatitis B morbidity, HBsAg was significantly more often detected among the population in Tajikistan (7.2%) than in Azerbaijan (2.8%). In both republics HBV carriers occurred most frequently among children aged 1-4 years (4.0% in Azerbaijan and 13.9% in Tajikistan), and among men more frequently than among women. In accordance with different intensity of the spread of HBV infection in the territories under comparison, differences in the age structure of the immune population were noted: in Tajikistan the formation of the immune layer occurred most frequently among younger age groups and in Azerbaijan, among senior adult age groups. The presence of a considerable percentage of persons with HBe-antigenemia (14.3-14.9% as determined by the gel precipitation test) among HBV carriers, observed in Tajikistan and in Azerbaijan, indicates that some of them have undetected chronic hepatitis B.     

Seroepidemiological characterization of virus hepatitis in the Republic of Armenia

The survey of the population immunological structure with respect to parenteral hepatitis showed awide circulation of hepatitis B (HB) and hepatitis C (HC) viruses among the adult population of Armenia. During the 5 year period of observation the number of persons having antibodies to HC virus increased 2.7-fold. High occurrence of antibodies to HBsAg of HB virus among the healthy population in 2002 (12.0%) in comparison with 1997 (5.4%) reflected a decreased infection rate with HB virus as well. Antibodies to hepatitis A (HA) virus were isolated, on the average, in 64 % of persons. Simultaneously with a decrease in the proportion of HA cases an increased number of HC patients was registered. No circulation of hepatitis E virus was detected. A high percentage of hepatitis cases of mixed etiology was established, as well as an increased number of combined parenteral hepatitis cases was registered (57.1%).     

Prevalence of hepatitis-B surface antigen among blood donors and human immunodeficiency virus-infected patients in Jos, Nigeria

Information is very scarce on the prevalence of hepatitis-B virus (HBV) infection among blood donors and patients with human immunodeficiency virus (HIV) infection in Nigeria. Hepatitis-B surface antigen (HBsAg) ELISA was used to determined the prevalence of HBsAg among 175 blood donors (aged 20-40 years) and 490 HIV-infected patients (aged 17-60 years) in Jos, Nigeria. Twenty-five (14.3%) of the blood donors and 127 (25.9%) of the HIV-infected individuals were HBsAg seropositive, indicating a higher HBV infection among HIV-infected persons than among healthy blood donors. A slightly higher HBsAg seroprevalence was recorded in the males (14.6%) than females (12.9%) of the blood donors. Among the HIV-infected patients, the males had considerably higher HBsAg seroprevalence than the females (31.8 vs 22.1%) with the highest prevalence of HBsAg occurring in the 51-60 years age group (44%), followed by those of 31-40 years (28.2%). Results confirmed the high endemicity of HBV infection in Jos, Nigeria and the significantly greater prevalence of HBV infection among HIV-infected patients than among blood donors.     

Experimental inoculation of three arboviruses in black-bellied whistling ducks (Dendrocygna autumnalis).

Wild-caught, immature black-bellied whistling ducks (Dendrocygna autumnalis) were inoculated with eastern equine encephalitis (EEE), St. Louis encephalitis (SLE), or western equine encephalitis (WEE) virus. Susceptibility, duration and titer of viremia, and antibody response to these arboviruses were determined. Birds from all inoculated groups became viremic. Higher virus titers occurred in the EEE group but overall mean titers were not significantly different among experimental groups. All birds inoculated with EEE and SLE viruses developed antibodies, and six of seven ducks receiving WEE virus were seropositive. All seropositive ducks had antibodies for at least 59 days, when the study was terminated. The EEE group had significantly more seropositive ducks during more days than the WEE and SLE groups. Geometric mean antibody titers were significantly smaller in the WEE group when compared to the EEE and SLE groups. Control ducks did not develop viremia or antibodies. Gross and histopathologic lesions compatible with viral encephalitis were absent in all of nine ducks necropsied. Black-bellied whistling ducks can develop low and short-term levels of viremia sufficient to infect mosquitoes, but probably cannot contribute significantly to the transmission of EEE and SLE. They may serve as good indicators of virus activity.     

The etiological structure of acute bacterial meningitis in different regions]

In 1985-1989 the etiological structure of acute bacterial meningitides (ABM) in children was studied in 4 largest industrial cities in different regions of the European part of the former USSR, as well as in 2 industrial cities of western Siberia. Due to the common methodological approach used in all investigations, comparable data were obtained in all cities. These investigations revealed that meningococci caused 53.0-86.7% of all cases of ABM in children, which corresponded to moderately increased morbidity rate in meningococcal infection (3.9-11.0 cases per 100,000 of the population, mostly 5.0-7.0 cases) in these cities with its progressive decrease during 3-4 years of observation. The gradual change of meningococci from group A, prevailing in the '70s and early '80s, to group B and in some cases the appearance of group C meningococci, accompanied by a decrease in morbidity rate, were noted. In St. Petersburg the indices of ABM morbidity in children aged up to 5 years for 1987 and 1988, caused by Haemophilus influenzae (0.74 and 4.13) and pneumococci (3.23 and 4.86), could be calculated. A great number of ABM cases of unclear etiology (15.9-33.3%) suggests that the number of ABM cases caused by these two infective agents was underestimated.     

Shifting seroepidemiology of hepatitis A in Japan, 1973-2003

BACKGROUND: Hepatitis A infection is caused by hepatitis A virus (HAV) contracted through fecal-oral transmission. Life-long immunity is conferred after infection. Improved sanitary conditions have generally resulted in a significant decline in the incidence of hepatitis A. However, a low incidence of infection results in increased HAV susceptibility. The present study investigates the prevalence of anti-HAV antibody and clarifies the current HAV status and HAV susceptibility in Japan at 2003. METHODS: A total of 2,430 serum specimens collected during 2003 from Japanese individuals ranging in age from 0-92 years, were tested for anti-HAV antibody using an inhibition enzyme linked immunosorbent assay. All specimens were obtained from the WHO and the National Serum Reference Bank/National Institute of Infectious Diseases, Tokyo, Japan. RESULTS: The overall seroprevalence was 12.2%. Anti-HAV antibodies were rarely detected in individuals between 0-44 years of age. Starting from the age of 45-49 years, seropositivity gradually increased through age 65 years and above. Seroprevalence was not affected by gender, and geographic distribution did not affect age-specific seroprevalence until the age of 60 years. CONCLUSIONS: HAV susceptibility in Japan is increasing annually. Particularly, the prevalence of anti-HAV antibody in individuals older than 50 years in 2003 was 50.3%, which is significantly lower than that of corresponding studies in 1994 (74.3%), 1984 (96.9%) and 1973 (96.9%). The growing susceptible population of advanced age results in more frequent HAV infection among them. The surveillance of anti-HAV antibody prevalence is useful for implementing preventive measures and for controlling the spread of HAV.     

Serum antibodies to the hepatitis A virus in persons following a history of the infection

Enzyme immunoassay was used for titration of serum antibodies in subjects with a history of clinically pronounced or asymptomatic hepatitis A infection. Titers of hepatitis A virus antibodies (anti-HAV) essentially decreased during 3-4 years after the disease, then the rate of this decrease slowed down and antibody titers stabilized at low levels. After clinically pronounced hepatitis A anti-HAV levels were considerably higher than after the asymptomatic form of this infection.     

The results of multiyear observations on the duration of the maintenance of immunity in those vaccinated and revaccinated against and recovered from measles

The results of 5-year observations on the duration of immunity to measles virus in persons vaccinated and revaccinated against measles, as well as in persons having had this infection, are presented. The intensity of immunity was determined in the same persons with the use of the passive hemagglutination test. The study revealed differences in the formation, intensity and duration of postvaccinal immunity. A significant decrease in the concentration of antibodies over the period of 5 years was established in 50.0-52.3% of vaccines. Revaccination with live measles vaccine is an effective measure for enhancing immunity to measles virus in persons with initial antibody titers less than 1:10-1:20, but revaccination made in a single injection is not sufficient for the stable maintenance of measles morbidity at the sporadic level. Postinfectious immunity is characterized by stability and has no tendency towards decrease. Persons having had measles have no need in additional measures irrespective of the time elapsed after the disease.