[The health impact of stray and wild cats in the human environment]. / Zdravotnický význam toulavých a zdivocelých kocek v zivotním prostredí cloveka.

The population of stray cats in towns expands due to irresponsible behaviour of humans who allow them to enter cellars, hot water canals, store rooms etc. As a result of frequent feeding some specimens become tame, lose their shyness and on contact with humans and domestic animals they can become the source of some infectious agents. The most important of thus transmitted diseases is rabies. Cats become infected from foxes on rubbish heaps on the periphery of communities. More than 60% of cases of rabies of domestic animals are found in cats. Toxoplasmosis--cats excrete the infectious stage of the causal agent in their excreta. In the same manner also the agent causing intestinal salmonelloses is excreted. More than 5% cats are infected. Via excreta also the causal agents of toxocariasis are spread--the larvae of cat thread worms settle in the internal organs of humans (larva migrans). The assumed incidence in cats is as high as 50%, as suggested also by the high positivity of specimens from children playgrounds. Stray cats may be the source of agents causing various dermatomycoses and of ectoparasites.

Induction of copulatory behavior in castrated female and male Arctic foxes.

The aim of the study was to test if it is possible to induce complete copulatory behavior in castrated Arctic foxes (Alopex lagopus) of both sexes for the purpose of other experiments. Two groups of castrated, sexually experienced Arctic foxes, four pairs in Experiment 1 (a pilot study) and eight pairs in Experiment 2, were treated with different regimes of hormone (estrogens and progesterone in females, testosterone in males). The animals were than tested for copulatory behavior. Nine out of 12 castrated bitches and 10 out of 12 castrated males displayed copulatory behavior during the season of reproductive quiescence for intact Arctic foxes. All the treatments induced complete copulatory behavior (i.e., copulation leading to locking) at least in some animals of both sexes. Examination of results for individual animals suggested that copulatory performance was influenced by preference for specific partners. Also the occurrence of copulation in an early test facilitated its reoccurrence on a later test in the same day with a different partner.

Experimental infection of the squirrel (Sciurus vulgaris) and the muskrat (Ondatra zibethica) with Tahyna virus (California group, Bunyaviridae).

Two squirrels aged 16 weeks and three muskrats aged 24 weeks were subcutaneously infected with a dose of 400 SMicLD50 of the extraneurally passaged "236" strain of Tahyna virus. Viremia was detected in one squirrel (48 and 96 hours post infection) and in two muskrats (24 and 48 hours p.i.). Seroconversion was demonstrated by plaque-reduction neutralization test (PRNT) 21 days p.i. in all animals.

Some features of the ecology of fleas inhabiting the nests of the suslik (Citellus citellus (L.)). I: Population dynamics, sex ratio, feeding, reproduction.

While studying the suslik fleas in artificial nests planted in free nature, significant changes in the population dynamics of N. setosa, C. simplex and C. orientalis (from the spring build up to the autumnal peak and the decrease of flea number until the next spring) were noted. The predominance of females in the spring period was recorded in N. setosa. Significant seasonal changes in the number of engorged females of N. setosa and C. simplex and of C. orientalis males (the increase of engorged specimens in the spring and summer) were demonstrated. A significant predominance of females with mature eggs in the spring and summer and their negligible number in the autumn were found in N. setosa and C. simplex.

Possible role of birds and ticks in the dissemination of Bhanja virus.

Several wild birds (4 Fringilla coelebs, 1 Coccothraustes coccothraustes and 2 Erithacus rubecula) were inoculated subcutaneously with Bhanja virus (BHAV). No clinical symptoms of infection were observed in any of the birds; a low viremia was demonstrated only in C. coccothraustes (2 and 4 days p.i.), seroconversion in all birds. BHAV was not isolated from organs 32 days p.i. Consequently, the tested birds do not seem to serve as "amplifying hosts" of BHAV. The paper includes a survey of geographic distribution of Bhanja virus and a list of its vectors. A hypothesis on the indirect dissemination of BHAV by birds by means of infected ticks is discussed. According to this hypothesis the European birds could be divided into 3 categories: 1. birds of the Palaearctic-African migration system in which African vectors of BHAV were detected and which could introduce into southern parts of the Palaearctic Region infected ticks from tropical savannahs of Africa (i.e., the biome of main BHAV distribution), 2. migratory birds, hosts of BHAV vectors occurring in southern Europe, which could transfer viruliferous ticks from South to Central Europe, 3. sedentary or migratory birds of steppe or forest--steppe biotopes, hosts of BHAV vectors, which could increase the virus circulation in natural foci either by dispersion of infected ticks to short distances or by a support of their life cycles.

Experimental infection of rabbit with Bhanja virus.

Two young female rabbits (Oryctolagus cuniculus var. edulis) were inoculated subcutaneously with Bhanja virus (BHA) in a dose of 85 intracerebral LD50 for suckling mice (SMicLD50) and 8500 SMicLD50 (rabbit A and B, resp.). In rabbit A no clinical symptoms, nor viremia were observed, only seroconversion was revealed on day 7 p.i. On the other hand, in the rabbit B hypothermy on days 7--11 p.i., a mild adynamia on day 11 p.i. and a slight paresis on one hind leg on days 23--30 p.i. were observed; traces of BHA virus in the blood were detected on day 9 p.i. and seroconversion on day 7 p.i. The virus was not isolated from the interior organs (brain, liver, spleen, kidneys, lungs and heart) of the two rabbits dissected 38 days p.i.

Experimental transmission of Tahyna virus (California group) to wild rabbits (Oryctolagus cuniculus) by mosquitoes.

Two wild rabbits (Oryctolagus cuniculus) were subcutaneously infected with a dose of 2.6 dex. i.c. LD50/0.02 ml of extraneurally passaged Tahyna virus strain "236". During the 24-72 hours interval p.i. viremia was demonstrated in both animals ranging from 1.0 to 3.42 dex. i.e. LD50/0.02. Mosquitoes Aedes vexans, which had fed on them, transmitted the virus to one of three other rabbits. During 24-96 hours interval after terminated feeding of infectious mosquitoes viremia was detected in this animal ranging from 0.49 to 4.08 dex i.c. LD50/0.02 ml. Seroconversion was revealed by means of plaque reduction neutralization test 11 days after infection.

Investigation on the transfer of fleas among small mammals using radioactive phosphorus.

The transfer of fleas Megabothris turbidus, Ctenophthalmus agyrtes, Nosopsyllus fasciatus etc. was investigated by labelling the bank vole (Clethrionomys glareolus Schreb.) with radioactive phosphorus. On the one hand, the process of flea transfer was traced among different individuals of the same host species, and on the other, among different host species (C. glareolus, Apodemus flavicollis Melch.). The investigations revealed that the flea transfer in a rodent nest visited by another host depended partly on the number of fleas present in the nest, partly on the period spent by the new-comer in it. Conversely, the number of fleas transferred in the nest by the newly arrived host depended on the temperature of nest bedding and on the initial nest occupation by other host.

Experimental infection of Putorius eversmanni polecats and Martes foina martens with Tahyna virus.

Three Putorius eversmanni pole-cats and two Martes foina martens aged about 9 months were subcutaneously infected with about 260 suckling mouse LD50 of the extraneurally passaged "236" strain of Tahyna virus (California group, genus Bunyavirus). Viraemia with maximal titres of 1.32 (pole-cats) and 1.28 (martens) dex intraperitoneal (i.p.) mouse LD50/0.02 ml was demonstrated from 48 to 96 hr after inoculation (p.i.). By the plaque-reduction neutralization test, seroconversion was demonstrated 15 days p.i. (from less than 4 to titres of 8192 in pole-cats and 4096 in martens).

Accurate determination of volumes injected intracerebrally into suckling mice.

Inoculum with 125I added as a marker was used to determine the volume actually administered to suckling mice on intracerebral (i.c.) inoculation. In 1-2 days old animals, this volume corresponded to approximately 75% of a 20 microliter dose.

Experimental infection of foxes with Tahyna virus.

Three foxes about 18 weeks old were each subcutaneously inoculated with approximately 200 LD50 dose of extraneurally passaged strain of the Tahyna virus "236". Viremia was demonstrated in all animals during the 48-96 hours interval after infection. The maximum value was 1.31 dex LD50/0.02 ml. Three weeks after infection a seroconversion was revealed by means of hemagglutination-inhibition test (from titre less than 1 : 10 to 1 : 320) and plaque-reduction neutralization test (from titre less than 1 : 4 to titre 1 : 4096 or 1 : 8192).