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Biomedical subjects

V Danielová

Publications and source records attributed to V Danielová.

13 recordsLinked to original sources

Arbovirus isolations from mosquitoes in South Slovakia.

In the years 1973 and 1975 mosquitoes and some other Diptera (Tabanidae, Simuliidae, Hippoboscidae) were tested for virus. 13,924 mosquitoes, 75 horseflies and 60 blackflies were processed in 1973. Five strains of Tahyna virus were isolated from mosquito species Aedes vexans. 3,378 mosquitoes and 12 sheep keds were tested for virus in 1975. Twelve strains of Calovo virus were isolated from Anopheles maculipennis and one strain of Tahyna virus was obtained from Aedes vexans mosquitoes.

Aedes

The isolation of Central European encephalitis (tick-borne encephalitis) virus from Ixodes ricinus (L.) ticks in southern-Germany.

During the years 1972--1976 a total of 14.692 ticks of the species Ixodes ricinus (L.), (2.738 adults and 11.954 nymphs) was collected. They were taken from five areas where human Central European encephalitis virus (CEE) infections had occurred. By means of, intracerebral (IC) and subcutaneous (SC) isolation experiments with suckling mice 19 agents, exhibiting the pathogenic characteristics of CEE virus, were isolated from these ticks. In neutralization tests with suckling mice these isolates could be identified as CEE virus strains. From the 14.692 ticks at least 1.29% were virus carriers as evidenced by the number of isolated virus strains. By the same reasoning at least 3.6% of the adults and 0.76% of the nymphs must have contained virus. We were successful in each of the five areas, rather distant from each other, to isolate the virus. The favorable ecological conditions for the main vector Ixodes ricinus in the Federal Republic of Germany give rise to the assumption that this medically important tick-borne disease might be permanently present in many areas.

Animals

Experimental infection of pheasants with Lednice (Yaba 1) virus.

Young pheasants (24-hour- and 7-day-old) are capable of producing viraemia and antibodies after experimental infection with Lednice virus even after low doses of virus (0.7-0.9 log mouse LD50/g). Viraemia lasts approximately 3 days, but the titres of virus in the blood are low. The possible role of young pheasants in the circulation of virus in nature is discussed.

Animals

Two more mosquito species proved as vectors of Tahyna virus in Czechoslovakia.

Two strains of Tahyna virus were isolated during mosquito virological testing in summer 1975 in the littoral zone of large fishponds in South Moravia. The first of them was isolated from Culex modestus mosquito, the other one from Aedes sticticus. Virus isolation from these species proved them to be vectors of Tahyna virus, as it was found already experimentally that Tahyăn virus multiplies in these mosquitoes. This virus was isolated from the two species for the first time in Central Europe and from Aedes sticticus for the first time in general.

Aedes

Dynamics of the natural focus of Tahyna virus in southern Moravia and species succession of its vectors, the mosquitoes of the genus Aedes.

The paper deals with the occurrence of Aedes mosquitoes in southern Moravia and with Tahyna virus infection rates for them in 1972; a comparison of the data from previous years reveals the dynamics of the natural focus under long-term study. A total of 13,204 mosquitoes of the genus Aedes was processed in 122 tests, resulting in 17 Tahyna virus strains isolates. As concerns the valence of the natural focus, the most important was the inundated forest in the Drnholec locality. Infection rates for the mosquitoes were also determined in various microbiotopes of the said locality. A. cinereus, from which Tahyna virus was first isolated in the summer of 1972, was much more numerous than in the preceding seasons studied, indicating its important role as vector of Tahyna virus. The cell line of Aedes albopictus was demonstrated to be susceptible enough for virus detection from mosquitoes collected in the field.

Aedes

Cultivation of Lednice (Yaba 1) virus in goose, duck, and chick embryo cells.

Lednice (Yaba 1) virus was found to multiply in primary cultures of goose, duck and chick embryo cells. The size of inoculum and age of embryos used for preparation of primary cultures was decisive for the amount of multiplied virus. One strain (110) of Lednice virus showed reduced ability to induce a cytopathic effect in the first passage in chick embryo cells. Virus multiplication in all three kinds of cells was confirmed by immunofluorescence.

Animals

Studies on viremia and antibody formation in ducklings and goslings after experimental infection with Lednice (Yaba 1) virus.

A very low virus level was found for a short time in the blood of ducklings and goslings after experimental Lednice (Yaba 1) virus infection by subcutaneous (scut) and intranasal (inas) route and in blood of ducklings also after infection by intracerebral (icer) route. Subsequently virus neutralizing antibody formation was examined. Antibody formation was found in most of animals. In goslings onset of antibody formation seems to be slower than in ducklings after the same virus infection dose; vice versa, in ducklings antibody titer decreased after 6 weeks. Using low infection virus dose, neutralizing antibody level in ducklings was lower than in the former case. On examining the blood and the organs, the virus was detected in a very low amount and for a very short time in blood and spleen of goslings and only in blood of ducklings.

Animals

Experimental infection of Macaca mulatta monkeys with Lednice (Yaba 1) virus.

Macaca mulatta monkeys were inoculated with Lednice (Yaba 1) virus strain 6118. The animals developed no clinical signs and the body temperature and values of complete haematological examination remained within normal limits. In spite of positive immunofluorescence in regional lymph nodes, no virus could be recovered from them by passages in mice. Viraemia was not demonstrated. The antibody response was directly proportional to the amount of virus inoculated, i.e. it was significant after a higher virus dose or after repeated inoculation. The results obtained are discussed in respect of and in comparison with serological findings in man.

Animals

Growth of Tahyna virus at low temperatures.

Replication of two Tahyna virus strains in the Aedes albopictus mosquito cell line was studied in the temperature range from 6 to 28 degrees C. The virus grew in this temperature range; its replication rate was related to the temperature of incubation. At lower temperatures the virus titres increased more slowly and did not reach as high maximum values as at higher temperatures. Short increase in incubation temperature resulted in a short increase in the titre of virus previously incubated at 10 degrees C, but not of virus previously incubated at 15 degrees C. At 10 and 15 degrees C, the released virus was demonstrated for more than 300 days past infection (p.i.).

Arboviruses