[The epidemic process in infections before and after active immunization. I. Comparison of long-term monitoring of the disease with a simple mathematical model]. / Epidemický proces u nekterých infekcí pred aktivní imunizací a po jejím zavedení. I. Konfrontace dlouhodobého sledování nemocnosti s jednoduchým matematickým modelem.

In the first part of this paper the authors used for demographic data and morbidity data concerning measles, parotitis, rubella and chickenpox in the Sokolov district a model of exponential distribution, in particular its distribution function. The authors introduced the concept of mean population year. They tested the theoretical assumption that in different infections in long-term average the annual number of infected subjects is equal and equals the mean population year. They found that the delta parameter which determines the shape of the exponential regression curve and is the measure of the rate of spread of a given infection, expressed at the same time numerically by the number of mean population years the mean number of susceptibles which remain permanently in a given population.

[The epidemic process in infections before and after active immunization. II. Changes in the number of susceptible individuals in the population during a natural epidemic and its control by active immunization]. / Epidemický proces u nekterých infekcí pred aktivní imunizací a po jejím zavedení. II. Zmeny v poctech vnímavých v populaci pri prirozeném epidemickém procesu a jejich ovlivnení aktivní imunizací.

Based on the long-term follow-up of the incidence of some infectious diseases in the district and calculations of the actual number of infected subjects, the authors present an estimate of the ratio of susceptible and immune subjects during the unimpaired epidemic process. The epidemic process develops from the lowest range of immune subjects and stops at the highest range. The highest range thus gives the ratio of immune subjects which must be achieved or maintained by active immunization to achieve elimination of a given infection. The authors demonstrate on the model infection the mechanism by which after immunization the shift of infections to higher age groups occurs, and during introduction of the infection not only contact infections occur, but epidemic incidence develops. The restoration of some infections after years of elimination is to a restricted extent a natural phenomenon and does not imply failure of active immunization.

[Nosocomial infections in surgical intensive care of multiple injuries]. / Nozokomiální infekce u polytraumat v chirurgické intenzívní péci.

The authors present an abridged version of the final report of a State research programme. By introduction of a series of provisions and expedient use of funds available for research it proved possible to reduce the incidence of nosocomial infections in surgical patients from 14% to 12% and in a group with multiple injuries in the surgical intensive care unit from 18% to 10%.

[The contribution of the virology laboratory to the diagnosis of neuroinfections]. / Príspevek virologické laboratore k diagnostice neuroinfekcí.

The authors summarizes the results of a virological examination in 1231 patients with neuroinfections hospitalized in 1973-1984 at the Infectious Diseases Clinic in Plzen. The virological diagnosis contributed towards the elucidation of the aetiology in 62.4% of the patients. In the aetiology participated the virus of tick-borne encephalitis in 28.2%, the virus of epidemic parotidis in 15.8% and a group of enteroviruses in 14.9%. The participation of other viral agents was small.

[Incidence of zoonoses with their natural foci in the West Bohemia Region. II. Antibodies to the Tahyna and Tribec tick-borne encephalitis viruses]. / K výskytu nekterých zoonóz s prírodní ohniskovostí v Západoceském kraji. II. Protilátky k viru klíst'ové encefalitidy, Tahyna a Tribec u obyvatel kraje.

The authors examined serum samples from 475 men from different districts of the West Bohemian region for the presence of antibodies against viruses of tick-borne encephalitis, Tahyna and Tribec, strain Lipovník. Antibodies against the virus of tick-borne encephalitis were found in 1.1% and antibodies against the Tahyna virus in 4.4% of the examined sera. Antibodies against the Tribec virus were not detected. In the prevalence of antibodies against both viruses no geographical differences were revealed. The ratio of subjects with antibodies against the virus of tick-borne encephalitis was consistent with the long-term follow-up of morbidity and the reported clinical manifestation of the infection.

[Occurrence of zoonoses in a natural reservoir in the West Bohemian Region. I. Tick-borne encephalitis--basic epidemiologic characteristics]. / K výskytu nekterých zoonóz s prírodní ohniskovostí v Západoceském kraji. I. Klíst'ová encefalitis--základní epidemiologické charakteristiky.

In 1960-1987 in the population of the West Bohemian region by means of various serological methods 621 cases of tick-borne encephalitis were diagnose. The disease was not present in the northern districts (Cheb, Sokolov, Karlovy Vary) and in the mountainous zone along the western frontier of the country. In other areas it is ubiquitary with the highest mean morbidity for the entire period - 5.1 cases per 100,000/year in the district Plzen-South. The morbidity of the population of the regional town was only slightly lower. The patients were most frequently from the age group of 20-29 years. In younger age groups there were twice as many men than women, in children and older age groups the differences were not significant. The incidence was highest in July and August. Only 5.5% cases had the character of an occupational infection. Tick-borne encephalitis is a leisure time disease in the West Bohemian region.

A contribution to the interpretation of immunological survey records.

In certain infection types the use of official immunological survey figures expressed mathematically by means of exponential distribution or its distributional function may help assess the epidemiological trends in herd immunity levels. This approach to the evaluation of immunological survey records is primarily well applicable to infections that are uniform in exposure pattern, affect the entire population, and result in life-long immunity. The parameters characterizing the rise in the level of herd immunity can be determined by means of negative exponential regression. Applied to selected immunological survey data this essentially simple catalytic model of investigation may provide reliable information on the actual state of immunity in the general population, and may also help estimate its dynamics in the retrospect.

[Analysis of deaths of patients in a pediatric clinic--the role of infection]. / Rozbor úmrtí u nemocných detské kliniky--podíl infekce.

At the Paediatric Clinic in Plzen in 1982-1984 257 hospitalized children died; 175 were infants under 7 days of age, their deaths were not analyzed. At the age under one year 54 infants died, 25 children were older than one year. Infections of different aetiology and localization were revealed on necropsy as the immediate cause of death in half the children who died. On necropsy no infection was detected in 17 infants under one year and in 8 of the older children. Among the infants who died there were none, with one exception who were born healthy by a normal delivery, were admitted later on account of disease not threatening life and died subsequently from a nosocomial infection. The older children were admitted with malignant or irreversible chronic disease and the infections were associated with the breakdown of the defence of the organism.

Small wild rodents rabies in Czechoslovakia.

During a period of 1969-1979 a total of 3174 small wild rodents of the genus Muridae and Microtinae (predominantly Microtus arvalis) were examined. The animals were trapped in five localities differing both in type of ecological conditions and epizootologic situation. Fox-rabies occurred here either enzootically, or epizootologically, or had been completely absent for many years in one of the localities investigated. Of the 71 isolated strains of RV 18 strains were isolated from brain, 25 from brown fat and 28 from salivary glands. Simultaneous isolation positivity in more than one tissue was sporadic. Virus isolations from deep-frozen material were mostly unsuccessful. Basic biological characteristics were determined in each isolate. The isolated strains differed in the rate of adaptation on albino mice and in intracerebral virulence. All isolates exhibited extraneural pathogenicity for common laboratory animals, dogs and foxes, showed distinct viscerotropism, stimulated formation of interferon and produced various forms of non-lethal infection. Incidence of "murine" rabies did not show any locality-specific differences and in longitudinally studied areas was enzootic. In a number of Czech districts there was observed a distinct relationship between fox-rabies incidence and the density of small game animal populations. Role of small wild rodents in the epizootology and epidemiology of rabies is discussed.