[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.

[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 tonsillitis epidemic caused by adenoviruses]. / Epidemie angín vyvolaná adenoviry.

An epidemic of lacunar angina which affected, in relatively close common life, mostly only one of nine military units living in the same area. The failure of penicillin and negative finding of streptococci resulted in a retrospective establishment of the agent, which with all probability was adenovirus type 4. It has become obvious that the typical picture of lacunar or even pseudomembranous angina is not a reliable sign indicating streptococcal etiological even in a mass infection. The authors draw attention to the importance of continuous bacteriological surveillance even if only several cases of pharnygotonsillitis occur in a community. Uncertainties of the use of penicillin are then unnecessary in the therapy and even prophylaxis of the whole group, even if the first view may suggest its use. Some epidemiological features of the mass adenovirus angina are discussed.

Use of hyperimmune mouse ascitic fluids for arbovirus differentiation by indirect immunofluorescence and conventional serology.

The cross-reactivity of 22 arbovirus species (alphaviruses; tick- and mosquito-borne flaviviruses; and selected bunyaviruses) was tested with monovalent immune mouse ascitic fluids by indirect immunofluorescence (IIF) in comparison with classical serological reactions (virus neutralization -- VN; haemagglutination inhibition -- HI; and complement fixation -- CF -- reactions). Known relationships within the virus groups studied were confirmed. As to the differentiation limits, the VN test was followed by IIF. Evaluation of the ratio of heterologous to homologous antibody activities showed that with the exception of antigenically closely related arboviruses (Western equine encephalomyelitis -- Sindbis; Japanese encephalitis -- Murray Valley encephalitis; dengue viruses; California -- Tahyna), most arboviruses within the antigenic complexes tested could be relatively reliably differentiated by IIF.

CV-1 monkey kidney cell line -- a highly susceptible substrate for diagnosis and study of arboviruses.

The CV-1 cell line, derived from Cercopithecus aethiops monkey kidneys, acquired in the course of serial passaging an epitheloid morphology and heteroploid karyotype. As compared with Vero and GMK cell lines, the CV-1 line proved to be more susceptible to a broad spectrum of arboviruses belonging to the families Togaviridae and Bunyaviridae. Most of them reached high titres and were markedly cytopathic in CV-1 cells so that all tests based on the cytopathic effect could be carried out. The CV-1 cell line can thus be recommended as an extra-ordinarily suitable substrate for the diagnosis and study of arboviruses.

Cultivation of Tuleniy virus (strain Murman) in vitro.

In vitro culturability of Murman strain of Tuleniy flavivirus isolated recently in the northern regions of the USSR was studied. Stable PS pig kidney line was found suitable as a primary sensitive cell substrate for the isolation, proliferation and serial propagation of the virus. The pronounced pathogenicity of the virus to PS cells permits the testing of its infective activity comparable with i.c. titrations on mice, VNT in vitro and the plaquing technique. PS line is suitable for the demonstration and identification of the virus antigen and/or for the study of reproduction of the virus on cellular level using the technique of immunofluorescence.

Experiences with the adaptation of crimean hemorrhagic fever virus to the CV-1 monkey cell line.

Of several cell lines tested, the CV-1 monkey cell line proved to be the most suitable system for propagation of Crimean hemorrhagic fever (CHF) virus. Two CHF strains could be adapted to this cell line by serial passaging. The viral progeny from these passages was specifically cytocidal and produced plaques in CV-1 cells, which could be used in serological diagnosis of CHF. After adaptation of CHF virus to CV-1 cells, the rate of virus synthesis was more rapid, but the yield of virus produced by these cells did not substantially increase. Data reported on cultivation of CHF-Congo viruses are discussed in comparison with the present findings.

A modified plaque method for arboviruses on plastic panels.

Autoclavable culture media containing an increased (10---15-fold)concentration of succinate buffer permit a comparitively long-term cultivation of cells in free gas exchange with the atmosphere. Based on them, an economical technique of plaque titration of arboviruses on plastic panels with methylcellulose overlay was developed. With seven arboviruses of three different groups and three cell lines (CV-1, PS and PK), the method proved sufficiently sensitive as compared with titrations in mice or tube cell cultures and suitable for plaque reduction tests.