Detection of antibodies to polyomavirus SV40 in two central European countries.

Simian virus 40 (SV40) is significantly associated with some human cancers. However, the frequency of tumor-associated virus detection differs by geographic regions, so it is important to understand the status of SV40 infections in different populations. Poliovaccines potentially containing live SV40 were used in well-documented nationwide vaccination programs in Hungary and the Czech Republic that are reported here. We analyzed serum samples from periodic surveillance programs in those two countries for antibodies to SV40 using a specific plaque reduction neutralization assay. The prevalence of antibodies was between 1.3 and 8.7% in Hungary and from 1.0 to 4.0% in the Czech Republic. Females had a higher rate of antibodies than males, reaching in certain age groups 15.6% in Hungary and 8.3% in the Czech Republic. Antibodies to SV40 were found in similar proportions in both countries among persons not directly exposed to poliovaccines and subjects vaccinated in the era of SV40-free vaccines. Complexities and limitations of current serological approaches to epidemiological studies of SV40 in humans are discussed. These data suggest that SV40 may be present in these populations and emphasize the importance of follow-up studies to determine the pathogenesis of infections by this emerging human agent.

Factors and facts in Hungarian HIV/AIDS epidemic, 1985-2000.

In Hungary among others there were some special factors, which shaped the outcome of HIV/AIDS epidemic. (1) In the early period of pandemic the "iron curtain" delayed and limited the importation of HIV to Hungary. (2) In 1985, at the time of detection of first HIV infected persons the etiological diagnostic tools were already commercially available and laboratory facilities have been created immediately for HIV antibody tests in networks of blood banks, public health and venereological services. (3) Laboratory facilities together with introduced health regulations resulted in (a) elimination of possibility of nosocomial HIV transmission by blood, blood products and organ transplantation; (b) efficient case finding and contact tracing in population groups potentially playing a significant role in spreading of infection; (c) opportunities for voluntary HIV testing free of charge. (4) Broad scale education and information activities have been developed from the beginning by governmental and non-governmental organizations alike. (5) Parenteral drug abuse did not play a role in spreading of HIV, so far. The above factors resulted in a slowly developing moderate epidemic. The facts are as follows. By the end of 2000 altogether 879 HIV positive (666 male, 100 female and 113 anonymous) persons have been notified, 377 (344 male and 33 female) of whom showed already the characteristic features of AIDS and 229 died. 29% of registered HIV positive persons have been foreigners originating from 56 countries. The cumulative incidence rate of AIDS was 38 per million population. 73% of Hungarian HIV positive persons and 72% of patients with AIDS belonged to transmission group of men having sex with men. The age of HIV positive persons at the time of detection was between 20 and 49 years in 81% and 72% of them resided in or around Budapest.

The 1988-1989 measles epidemic in Hungary: assessment of vaccine failure.

Hungary has had a successful measles vaccination programme, achieving over 93% coverage in targeted groups. However, from September 1988 until December 1989, 17,938 measles cases were reported among the civilian population (attack rate [AR] = 169 per 100,000 population) with the majority of cases occurring in vaccinated people. National surveillance data were analysed to determine reasons for the outbreak and risk factors for vaccine failure. People born during 1971 and 1972 had been targeted for vaccination during campaigns in April and September of 1973 and had the highest AR (1332 and 1632 per 100,000, respectively). Epidemiological studies of vaccine efficacy conducted among secondary school students corroborated these findings. Among 754 secondary school students, those vaccinated during the April 1973 campaign were at highest risk compared with those vaccinated at routine health care after 1974 (relative risk = 10.9, 95% confidence interval [Cl]: 2.5-47.9). Among 341 primary school students, one-dose recipients were at higher risk compared with two-dose recipients controlling for age at and time elapsed since vaccination (P = 0.04).

[Transfusion-associated non-A, non-B, non-C hepatitis caused by flaviviruses]. / A non-A, non-B, non-C flavivírus által okozott inokulációs hepatitis.

Hepatitis C virus was shown to be a member of the flavivirus family. Tick-borne encephalitis virus and West Nile virus, members of the same family occur in Hungary, too. Serum samples from patients suffering from transfusion associated hepatitis were tested with yellow fever virus antigens for specific IgG, and IgM using immunofluorescence test. Eight hundred serum samples were tested. Yellow fever virus related IgG antibodies were found in 232 sera. In the case of 72 patients specific IgM antibodies could also be detected. The majority of the IgM positive patients underwent surgical operation and/or blood transfusion 1 to 2 months before the onset of the disease. Fifty-four sera positive for yellow fever virus-related antibodies were tested with HCV reagents, but only 13 were found to be positive, or cross-reacting. The 20 patients with yellow fever related antibodies were controlled with tick-borne encephalitis antigens, too. Nevertheless, no measurable cross-reaction could be detected. No measurable cross-reaction could be detected with the West Nile virus. The hepatitis B markers also were tested in 44 sera positive for yellow fever antibodies. There was only one, which contained HBsAg, and 10 of them proved to be positive for anti-HBcAg. The results indicate, that a non-A, non-B, non-C flavivirus is also present in the Hungarian population, which can be detected on the basis of the antigenic cross-reactivity with the attenuated yellow fever virus. This virus seems to be responsible for every 11th transfusion associated hepatitis examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Experiences associated with the use of live poliovirus vaccine in Hungary, 1959-1982.

Live Sabin poliomyelitis vaccine has been given in Hungary since December 1959. Generally, monovalent vaccines--administered in the sequence type 1, 3, and 2--have been used in annually repeated nationwide campaigns. Each type was administered within a week all over the country, with an interval of five to eight weeks between administrations. In the initial campaigns, children younger than 14 years of age were vaccinated. Since 1962, children between two and 38 months of age have been vaccinated annually. As a result of the vaccination program, the mean annual incidence of poliomyelitis declined to 0.03 per 100,000 population between 1961 and 1982 from a level of 12 per 100,000 observed over the previous five years. Epidemiologic and virologic evidence indicated that 47 (82%) of 57 cases registered since 1961 were vaccine-associated. Circumstances connected with the special vaccination practice in Hungary gave an opportunity to estimate the risk of vaccine-associated poliomyelitis. For recipients receiving the vaccine for the first time, the estimated risks for each type of vaccine were type 1, 0.99; type 2, 0.65; and type 3, 8.91 per million and for susceptible contacts, type 1, 0; type 2, 3.62; and type 3, 4.97 per million. The author's opinion is that these rates of risk are acceptable in view of the benefits provided by the live vaccine, especially under circumstances when importation of wild polioviruses that circulate widely in extended regions of the world may commonly occur.

Lymphocytic choriomeningitis (LCM) virus carrier cell cultures in Hungarian laboratories.

One of the HEp-2 sublines maintained in the authors' laboratory was found to carry LCM virus. The virus proved to be identical with the prototype strain LCM-Am except that its multiplication rate in cell cultures and its mouse pathogenicity were limited. Forty-six cell cultures maintained in 10 Hungarian laboratories were examined for LCM carriership. Sixteen cultures including 11 HEp-2 sublines, all originating from a culture brought into Hungary in 1959, proved to carry the virus. Three FL sublines maintained in two laboratories and two sublines, viz. an RK-13 and a HeLa, maintained in a third one, were also contaminated by LCM virus. In these cases, the carrier HEp-2 subline was the probable source of infection and virus transmission is thought to have occurred in the course of manipulation with cell cultures. The necessity of introducing strict preventive measures in tissue culture laboratories is emphasized in the interest of the laboratory workers and for obtaining reliable laboratory results.

Some characteristics of poliovirus strains isolated in Uganda between 1966 and 1971.

Sixty-five poliovirus strains were investigated in genetic marker tests in order to obtain information on the characteristics of polioviruses circulating in Uganda where, owing to the insufficient use of live poliovirus vaccine, poliomyelitis remained a serious public health problem. Of the type 1 strains predominant in both epidemic and non-epidemic years, 29 were studied for their antigenic fine structure. Based on their intratypic character, these strains proved to represent six different antigenic variants. Three of these variants were predominant during certain periods; the first variant was present in 1966 and 1968, the second in 1967, and the third from 1969 to the end of observation period. Four strains from Kuwait and three from Ghana isolated in 1969 and 1970 showed an antigenic structure identical to that of the strains predominant in Uganda in these years. Some strains proved to be of vaccine origin. Twenty-nine type 1 and 24 type 2 strains showed a great variety of characteristics when studied in d, od, and rct/40 marker tests. There was no indication that the distribution of strains according to their in vitro markers would have been different in epidemic and non-epidemic years, or that any particular combination of markers would have been more common among strains isolated from paralytic patients than among those from non-paralytic patients. Nine of 12 type 3 strains had the rct/40(+) marker.

Factors affecting the efficacy of live poliovirus vaccine in warm climates. Efficacy of type 1 Sabin vaccine administered together with antihuman gamma-globulin horse serum to breast-fed and artificially fed infants in Uganda.

A virologically controlled field trial was conducted with live monovalent type 1 poliovirus vaccine in children aged 3-30 months living in a rural area of Uganda, in an attempt to find out the reason for the poor efficacy of such vaccine often observed in countries with a warm climate. Groups of breast-fed and of artificially fed infants received the vaccine orally, either alone or mixed with horse serum prepared against partly purified human gamma-globulin. Irrespective of the diet, the "take rate"-measured by the rates of vaccine virus excretion and of antibody conversion-was found to be poor when the vaccine was given alone but satisfactory when it was given together with the horse antiserum. However, the extent and duration of vaccine virus multiplication in the intestinal tract proved to be limited and the mean antibody level elicited by the vaccination, irrespective of the schedule of vaccine administration, was low. These results, besides indicating that breast-feeding does not influence the efficacy of vaccination in the age groups studied, revealed the presence of an inhibitor in the alimentary tract. This inhibitor acts against the multiplication of vaccine virus, which may be blocked by antibodies in the horse antiserum for a limited period at the time of vaccination. Interference between the enteroviruses and the vaccine strain was also found to be responsible for decreasing the efficacy of vaccination, though its role was secondary to that of the inhibitor. Revaccination experiments showed that the effects of both inhibitor and interference may be overcome by repeated administration of the vaccine.

WHO collaborative studies on poliovirus type 3 strains isolated during the 1968 poliomyelitis epidemic in Poland.

In 1968 in Poland an extensive outbreak of poliomyelitis, caused by type 3 poliovirus, began about four months after small vaccine trials with the Leon 12a(1)b (Sabin) and USOL-D bac vaccine strains had been carried out. Because of the temporal association, and because the first cases appeared in the province in which the USOL-D vaccine trial was carried out, a detailed investigation of the strains isolated from cases in the epidemic was made in four laboratories in an attempt to determine whether they were related to the two vaccine strains or to a "wild" strain. All the studies were made under code. The rct marker was of no help in determining the relationship of the epidemic strains to the vaccine strains. The McBride test and the elution marker test clearly separated the Leon 12a(1)b strains from those from the cases, but were incapable of detecting whether the epidemic strains were related to the USOL-D bac strain or to wild type 3 strains. Thus the studies did not provide valid information on the origin of the epidemic.