Standardization of measles, mumps and rubella assays to enable comparisons of seroprevalence data across 21 European countries and Australia.

The aim of the European Sero-Epidemiology Network is to establish comparability of the serological surveillance of vaccine-preventable diseases in Europe. The designated reference laboratory (RL) for measles, mumps, rubella (MMR) prepared and tested a panel of 151 sera by the reference enzyme immunoassay (rEIA). Laboratories in 21 countries tested the panel for antibodies against MMR using their usual assay (a total of 16 different EIAs) and the results were plotted against the reference results in order to obtain equations for the standardization of national serum surveys. The RL also tested the panel by the plaque neutralization test (PNT). Large differences in qualitative results were found compared to the RL. Well-fitting standardization equations with R2> or =0.8 were obtained for almost all laboratories through regression of the quantitative results against those of the RL. When compared to PNT, the rEIA had a sensitivity of 95.3%, 92.8% and 100% and a specificity of 100%, 87.1% and 92.8% for measles, mumps and rubella, respectively. The need for standardization was highlighted by substantial inter-country differences. Standardization was successful and the selected standardization equations allowed the conversion of local serological results into common units and enabled direct comparison of seroprevalence data of the participating countries.

The 2001 serological survey in the Czech Republic--measles.

In total, 3,013 sera from a representative population sample of the Czech Republic aged from 1 to 64 years were tested according to the requirements of the ESEN 2 project using a commercial kit Measles IgG (II) EIA manufactured by Denka Seiken, Japan. The highest seropositivity rate and GMT values were found in the population group aged over 35 years coming into natural contact with the causative agent. Among the vaccinee population, the best outcomes were achieved in 2-9-year-olds (seropositivity rate: 94-100%, GMT: 2500-4000 EIA) and 10-14-year-olds (seropositivity rate: 93-97.1%, GMT almost 2000 EIA). The lowest seropositivity rate was found in the age group 20 to 24 years, more precisely in the 20-year-olds (78.4%), vaccinated with only one dose before the end of the first year of life. The seropositivity rates and GMT values vary with the vaccination strategies adopted in different years. The morbidity trend is supportive of the appropriateness of the vaccination strategy selected.

The 2001 serological survey in the Czech Republic--rubella.

In total, 3,009 sera from a representative population sample of the Czech Republic, 1508 females and 1,501 males, were tested by EIA using a commercial kit ETI-RUBEK-G Plus manufactured by Dia Sorin, Italy. The vaccination strategy was as follows: vaccination of 12-year-old girls since 1982 and all 2-year-olds vaccinated since 1986. Currently, all women under 31 years of age and all men under 17 years of age have been vaccinated. The results of the serological survey confirmed lower seropositivity rates in young men compared to vaccinated women of the same age as expected. An epidemic outbreak of rubeola among young men is another evidence of that The seropositivity rate of 2- 9-year-old vaccinee children reaches almost 95%. The long-term morbidity trend in the Czech Republic is downward sloping, with a marked differentiation between the male and female populations.

The 2001 serological survey in the Czech Republic--mumps.

In total, 3,010 sera from a representative population sample of the Czech Republic aged from 1 to 64 years were tested according to the requirements of the ESEN 2 project using a commercial kit Mumps IgG (II) EIA manufactured by Denka Seiken, Japan. To date, the regular programme of vaccination against mumps has covered the population of children under 15 years of age. The vaccination coverage achieved (97-100%) does not correspond to the antibody prevalence rates of 70.2 to 86.4% as found. After implementation of regular vaccination in 1987, the morbidity rates have fallen dramatically. Nevertheless, the collective immunity achieved is not sufficient to prevent epidemics of mumps.

[Parvovirus B19 in the Czech Republic. Seroepidemiologic study]. / Parvovirus B 19 v Ceské republice. Séroepidemiologická studie.

Erythema infectiosum which is caused by parvovirus B 19 is notified in the Czech Republic similarly as some other viral exanthemas under the diagnosis "Other viral infections affecting the skin and mucosae, not listed elsewhere" (B08). Analysis of the epidemiological position in the Czech Republic in 1993-1995 was based on EPIDAT data, documentation of epidemic of 1993 in the Liberec district and serologically confirmed minor epidemics (1994, 1995). An increased number of cases (in particular in late winter and early spring) is observed in several years' (cca four-year) cycles and only in some districts. Children aged 3-10 years (88.2%) are affected predominantly. All the year round however sporadic cases affecting people of all age groups are notified. Concurrent illness of several family members (usually two) was confirmed by laboratory tests only in 9 of cca 200 investigated cases. The source of infection is usually not identified. The increase in the number of cases in a given locality rose rapidly after brief time intervals. The longest interval between two cases was 24 days. In families all affected members contracted the disease with 24 hours. According to the seroprevalence of the IgG parvovirus B 19 in different age groups the majority of cases in subadult and adult subjects is not diagnosed and notified. Seroprevalence of IgG antibodies of the parvovirus B 19 in subjects with arthropathies was 72.4%, in subjects with suspect borreliosis 69.9% an in the normal population cca 50%.

[Parvovirus B 19 in pregnancy]. / Parvovirus B 19 v tehotenství.

The human parvovirus B 19 was discovered in 1975 by Cossart but its etiological association with erythema infectiosum and hydrops of the foetus was proved only in 1984-1985. The objective of the submitted prospective study was to assemble basic findings on the herd immunity of the female population and the risk of infection with this agent during pregnancy. Seropositivity of women of fertile age before the epidemic of parvovirus B 19 in 1993 and 1994 was cca 50%, after the epidemic 70%. Erythema infectiosum is a childhood disease (96% of the cases are children under 14 years of age), but seroprevalence of parvovirus IgG in these age groups is only 11%. Thus the infection in adults is frequent but not diagnosed. A parvovirus etiology of possible loss of the foetus on the basis of serological examination is encountered only exceptionally. The Czech commercial preparation gammaglobulin can be used for prevention and treatment of a non-immune foetal hydrops.

[Seroprevalence of IgG antibodies against parvovirus B19 in the population of the Czech Republic]. / Séroprevalence protilátek trídy IgG proti parvoviru B 19 v populaci Ceské republiky.

The human parvovirus B 19 was discovered in 1975 by Cossart in England. Later (1984) evidence was provided that this virus is the etiological agent of erythema infectiosum and hydrops foetalis, and in 1985 it was provided that it is also the etiological agent of some types of arthritis or arthropaties and vasculitis. The diagnosis of the disease caused by this agent is most frequently based on evidence of specific immunoglobulins. The epidemiological and clinical impact of parvoviral infections in the Czech Republic was not known so far. Examination of sera from 562 subjects aged 0-60 years assembled in 1992 in three Czech regions revealed in children, age 0 - 4 years 9.8%, during preschool and school age 27 - 35.7% and in age groups above 15 years a 53.3 - 57.7% seroprevalence of IgG parvovirus B 19, roughly equally distributed among both sexes. The more frequent prevalence of specific immunoglobulins was proved in small groups of female workers in nurseries (66.7%), nursery schools (91.7%) and in blood transfusion stations (77.8%). The seropositivity of the general female population of matched age groups, with the exception of women aged 20 - 24 years, was 53.86%.

[Immunoglobulin specific and conventional methods in the serodiagnosis of measles]. / Immunoglobulinspezifische und konventionelle Methoden in der Masernserodiagnostik.

The serological diagnostics of suspicions of measles is of ever growing importance with adequately decreasing morbidity. The utilization of the complement binding reaction is compared with results of the haemagglutination test, the IgG enzyme immunoassay, the IgG and IgM immunofluorescence technique and the haemadsorption immunosorbent test for IgM prove of measles. The virus-specific methods of evidence prove to be favourable ones. The present possibilities of the decentralized routine diagnostics in district laboratories make the complement binding reaction a reliable method.

[Serological evidence of persistent elimination of measles in Czechoslovakia]. / Sérologický prukaz o perzistující eliminaci spalnicek v CSR.

The authors report on the elimination surveillance programme initiated in 1969 with the introduction of mass vaccination. In 1982 the elimination of measles was achieved. It included serological surveillance or/and annual serological reports, which considerably contributed to the optimum effect of vaccination and re-vaccination strategies. Within the frame work of this programme, from 1971 to 1987, approximately 40,000 probands from all regions of the Czech Socialist Republic were examined. Proof was supplied as regards low vaccination and high post-vaccination seropositivity in children. Since the elimination of measles, seropositivity in children's and adult age has been in the range of approximately 95%. The paper gives an illustration of the vaccination history in children born in the Czech Socialist Republic in 1960-1986. It also analyzes the average levels of HI antibodies in non-vaccinated persons (1:54.9) with measles infection, in vaccinated and non-vaccinated newborns (1:20.4) and in persons after a single-dose vaccination (1:12.0). From 1982, when measles was eliminated, up to 1987, 126 sporadically occurring cases with measles were reported. In some of these cases, the exact diagnosis of measles was made with the aid of serological tests (HI test, CF reaction, EIA, IF IgM tests and SPIT-HI test).