Bendiocarbamate toxicity in the chick embryo.

Carbamate pesticides generally possess low toxicity for warm-blooded vertebrates, but developmental data are scarce. We have therefore evaluated embryotoxicity of choline esterase inhibitor bendiocarbamate in the chick embryo. The pesticide was dissolved in 5% acetone in distilled water and a volume of 200 microl was administered over the embryo through membrana papyracea on embryonic days 2, 3, 4, 5, and 10. Sampling was performed on embryonic day 10, while the embryos treated on embryonic day 10 were sampled on embryonic day 17. The toxicity of bendiocarbamate was fairly low, and LD50 decreased with advancing development from 1 mg/ embryo on embryonic day 2 to 29 mg on embryonic day 5. Malformations in surviving embryos were observed rarely (< 3 %) and occurred in both control and experimental groups. There was a mild but statistically significant dose-dependent reduction in body weight, most pronounced in the treatment on embryonic days 5 and 10, but the maximum difference from controls was below 15 %. A small but not significant increase in the number of positive cells was observed in the eye, limb buds, and the central nervous system of embryos treated on embryonic days 3 and 4 and examined after supravital whole-mount staining with Lysotracker Red for apoptosis. In agreement with previously published studies in other vertebrate animals, we conclude that bendiocarbamate does not possess significant toxicity in the avian embryo.

[Host immune response in mammals to Encephalitozoon cuniculi infection]. / Imunitná odpoved' cicavcov na infekciu Encephalitozoon cuniculi.

The immunity system status of an individual plays the key role in regulation of opportune infection. In the fight against the intracellular parasites several non-specific as well as specific immunity mechanisms are applied. The dominant role in response to infection caused by the representatives of genus Encephalitozoon plays the cell-mediated immune response. Encephalitozoon cuniculi, as the most explored representative of this genus is able to survive in the host organism despite his active immunity response. Latent asymptomatic infection goes on only as long as the parasite multiplication and immune response are balanced.

Immune response in mice infected by Encephalitozoon cuniculi and suppressed by dexamethasone.

Several indicators of immune response were observed in immunocompetent mice of the ICR line and those suppressed by dexamethasone upon their experimental infection with the microsporidia of Encephalitozoon cuniculi. The mice were infected by one-shot intraperitoneal administration of 5 x 10(7) pathogenic spores. On Days 7, 14, 28 and 42 after infection, peripheral blood leukocyte phagocytic activity was determined and compared, including phagocytic index and the blastogenic response in spleen cells to mitogenic activation by concanavalin A and phytohaemagglutinin. The results point to the fact that E. cuniculi itself can cause a significant decrease in phagocytic activity of phagocytic leukocytes in the early stages of infection as well as a remarkable decrease in the proliferative response of spleen cells to T-cellular mitogens.

An unusual manifestation of encephalitozoonosis in chinchilla rabbits.

This disease occurred in 6 rabbits in which leukemic changes after infection with the bovine leukemia virus were being studied.

Bovine leukemia virus-induced clinical signs and morphological changes of encephalitozoonosis in rabbits.

Fourteen three-month-old rabbits spontaneously-infected with the microsporidium Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 were inoculated intravenously with lymphocytes (Ly) from seropositive bovine leukemia virus infected cattle (Ly/BLV) or with fetal lamb kidney cells infected with bovine fetal leukemia (FLK/BLV). Thirteen rabbits were seropositive to BLV at least for a period of three months. Six rabbits died of pulmonary lesions. Chronic inflammatory lesions of encephalitozoonosis were found in six rabbits killed between 454 and 548 days of the observation period. Five animals bore subcutaneous granulomas. Immunohistochemically, E. cuniculi was demonstrated in the inflammatory lesions of rabbits studied. Control animals also spontaneously infected with E. cuniculi did not show clinical signs of encephalitozoonosis. Morphological changes were found incidentally in the form of small glial foci and focal interstitial nephritis in these animals. The combined action of BLV-E. cuniculi on the bodies of rabbits is proposed as a suitable model for the study of encephalitozoonosis in man with human immunodeficiency virus (HIV) infection.

[The recovery and rearing of gnotobiotic lambs and their use in veterinary medicine]. / Získavanie a odchov gnotobiotických jahniat a ich vyuzitie vo veterinárnej medicíne.

Our own innovated method of the hysterectomy recovery of gnotobiotic lambs, modified equipment for gnotobiote rearing, management and tending techniques were tested in this study. A hysterectomy hood (Fig. 1) was made from plexiglass and it fully met the requirements for simple and rapid handling. Our own modified isolator for gnotobiotic lamb rearing (Fig. 2) made out of glass-reinforced plastic with plexiglass sight holes was used for group rearing. It was more resistant to mechanical damage in comparison with the isolators equipped with PVC sheet pouches. The use of an isolator for feed and material (Fig. 3) and of an isolator for waste material storage with a PVC sheet pouch was found to be very practical; these isolators were connected to the rearing isolator through piping. The ventilation system was sufficient enough. An emasculator was used for hysterectomy. The method is simple and rapid, reliable and it enabled to preserve lambing ewes for other experimental purposes. Gnotobiotic lambs were successfully fed a milk replacer for calves. Samples of biological material (blood, rumen fluid, droppings) were taken from lambs kept in the isolator. The isolators were sterilized with 2% solution of peracetic acid sprayed as aerosol. Milk, materials made of glass and metal were autoclaved at a temperature of 121 degrees C, pressure 1.2 atm, for 30 minutes, and the concentrate mixture was sterilized with an X-ray dose of 2.5 Mrad. All the used methods of sterilization were fully efficient. A modified method reliably detecting lamb and isolator contamination was used for microbiological monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)

[Occurrence of viral particles of avian sarcoma viruses in sarcoma tissue]. / Výskyt vírusových castíc vtácieho sarkómového vírusu v sarkómovom tkanive.

An electron-microscopic examination was performed of chicken fibrosarcoma caused by avian sarcoma virus (ASV), strain B 77, to investigate virus budding and release through the cytoplasmic membrane. The virus particles of type C- were 90-100 nm in size, the electron-optically denser nucleoids being clearly differentiated from the outer membrane.

[Testing the susceptibility of cultured cells to infection with bovine leukemia virus]. / Testovanie vnímavosti bunkových kultúr k infekcii vírusom bovinnej leukózy.

Different cell cultures were studied for their susceptibility to bovine leucosis virus infection. Syncytial assay was used for this study. The FLS/BLV+ cell line served as virus source. Cell lines BHK-21 and ZP-1/58 were found to be susceptible to syncytium formation. Large cells with one to three large nuclei, and loose nuclei reaching the size of syncytium were observed to occur in the BHK-21 and ZP-1/58 cell lines, apart from the syncytial formations. The virus specificity of the syncytia arising in these two cell lines was confirmed by the immunofluorescence assay. In the case of the immunoperoxidase assay, a positive result was obtained only in the BHK-21 cell line. The occurrence of syncytia and large nuclei was observed even in the cases when the BHK-21 cells were infected with the lymphocytes of leucotic cows.

[Induction of cysts in adult rats by means of sodium nitrite after infection with avian sarcoma virus]. / Indukcia cýst pri dospelých krysách dusitanom sodným po infekcii vtácím sarkómovým vírusom.

Trials were conducted to study the possible effect of sodium nitrite administered in drinking water as exerted upon carcinogenesis induced by the sarcoma virus in the organisms of adult rats during a five-month period of observation. No clinical changes were observed in these rats during the test period. On the 125th day of age the rats were subjected to post-mortem examination. Cysts were found in seven of twenty rats (36.8%), as compared with the zero induction in the control groups. The cysts occurred in the renal region and in thymus. They were as large as a pea up to the size of an egg and contained serous or slightly haemorrhagic liquid. There is a description of the macroscopic structure of the studied cysts. Interstitial pneumonia was observed in three cases, including the control group. The results show that sodium nitrite may act as a promoter in the carcinogenesis of rats induced by avian sarcoma virus.

[The effect of sodium nitrite on rats infected with avian sarcoma virus]. / Vplyv Dusitanu sodného na krysy infikované vtácím sarkómovým vírusom.

A potential effect of sodium nitrite was studied as exerted on carcinogenesis elicited by the avian sarcoma virus in the body of rats. In the case of the infection of the rats with indefective avian sarcoma virus B77 (Bratislava strain; ID50 10-25/0.1 ml) and i. p. inoculation of sodium nitrite, great mortality occurred already on the 20th day p. i. On the 125th day p. i. the cumulative mortality in this group was 76.92%; on the other hand, in the control groups (rats inoculated with sodium nitrite or avian sarcoma virus) no deaths occurred before this period. The rats infected with a double dose of the virus were not observed to show pronounced changes in mortality. It was only on the 125th day that cumulative mortality in the group of rats infected with the avian sarcoma virus and rats inoculated s. c. with sodium nitrite was 87.5% and in the group of animals which had only been infected with the virus the mortality was 64.26%. The patho-morphological changes were in keeping with the hitherto described changes in rats infected with the avian sarcoma virus. In the trial no effect of sodium nitrite on the patho-morphological changes induced by the avian sarcoma virus was observed.

[Transmission of Marek's disease to wild feathered game]. / Prenos Markovej choroby na vol'ne zijúcu pernatú zver.

The following wild feathered game were tested from 6 to 12 months of age: common pheasant (Phasianus colchicus), common gray partridge (Perdix perdix), European quail (Coturnix coturnix), and Greek partridge (Alectoris graeca). Only pheasant was found to be susceptible to infection with a virulent virus of Marek's disease. In this bird the first clinical symptoms of the disease (nervous changes) were observed in 28 days from infection. Immunoprecipitation antibodies to the Marek's disease virus occurred in the serum on the 75th day from infection, and patho-morphological changes, typical of acute Marek's disease, were observed on the 75th to 85th day from infection. The remaining species of wild feathered game appeared not to be susceptible to infection with the Marek's disease virus. In these birds, like in pheasants, immunoprecipitation antigens of the Marek's disease virus were not found to be present in the epithelial cells of feather follicles. In the infected Greek partridge, common gray partridge and quail, serum was not found to contain any antibodies. Laying quail had no antibodies in the yolk of the eggs they laid. The results indicate a different oncogenesis of Marek's disease in the domestic fowl and pheasant. It is concluded that wild feathered game play no important role in the epizootology of Marek's disease.

[Testing of poultry for susceptibility to sarcoma viruses in the C subgroup]. / Testovanie hydiny na vnímavost k sarkómovému vírusu z podskupiny C.

Experiments were performed to test the conventional chickens of the Ross I and Tetra-B broiler hybrid and the Shaver Starcross 288 and Slovgal laying hybrid for their susceptibility to the poultry sarcoma virus of subgroup C (B77). The chickens were inoculated six days from hatching and the first sarcomata began to appear at the inoculation spot on the fourth day. The first deaths were observed on the eighth day from inoculation, and the necropsy revealed frequent metastases. Regressive fluid was also found to develop in some cases. On the basis of the haematological examination of all hybrids, significant lymphocytopenia and heterophilia were determined; in addition to this, a significant drop in the basophile count was ascertained in the Tetra-B hybrid and a significant rise in the monocyte count was found in the Slovgal hybrids. Also, a frequent occurrence of a high number of large lymphocytes, a random occurrence of large thrombocytes, and individual myelocytes and metamyelocytes were also observed. The results suggest that the tested poultry represent progressive (highly susceptible) types of poultry, in relation to sarcoma virus of subgroup C.

[Immunological aspects of Marek's disease in chickens with maternal antibodies]. / Immunologické aspekty Markovej choroby u kurciat s materskými protilátkami.

The dynamics of the production of immunoprecipitation antibodies to Marek's disease virus was studied in the serum of chickens with maternal antibodies in relation to the occurrence of the immunoprecipitation antigens of Marek's disease virus in feather follicles. One-day-old chickens were infected by the contact method with Marek's disease virus. The first occurrence of immunoprecipitation antigen was detected on the 14th day after infection and this occurrence persisted throughout the experiment, i. e. until the 112th day after infection. The antibodies were first detected the 28th day after infection and their titre kept rising until the 98th day after infection. Immunoprecipitation antibodies and antigens of Marek's disease virus were detected in some tumorously changed kidneys. Immunoelectrophoretic examination revealed in the same kidneys immunoglobulins of the class IgY, IgA and beta-globulin. The slowest-migrating fraction of IgY, together with IgA, beta-globulin and C-reactive protein were detected in the skin extracts from infected poultry. Indirect haemagglutination enabled the detection of the presence of haemagglutination antibodies in rabbit immunoglobulin to the skin antigen of Marek's disease virus, and in avian immunoglobulin to the same virus. Haemagglutination antigen was revealed in the extract from tumorously changed kidneys.

[Testing the immunogenicity of the dermal antigen in Marek's disease virus]. / Overovanie imunogenicity kozného antigénu vírusu Markovej choroby.

An experiment was performed to study the immunogenicity of the dermal antigen of Marek's disease virus, extracted from the skin of 30-day-old chickens, infected with Marek's disease virus on the first day of life. Three kinds of samples were tested: (1) dermal antigen centrifuged at 10 000 g per 0.5 h, (2) dermal antigen centrifugated at 10 000 g per 0.5 h and 100 000 g per 1 h, (3) dermal antigen treated like sample (2) and partly purified by DEAE-cellulose chromatography. Samples (1) and (2) were inoculated to two-day-old chickens and the vaccination was repeated, using complete Freund's adjuvant, 21 days later. Sample (3) was inoculated to two-day-old chickens with DEAE-dextran. All the three groups were challenged together with the controls (non-vaccinated chickens) on the seventh day after the first vaccination. A reduction of mortality was observed in the chickens vaccinated with and re-vaccinated with sample (1) (23.07%) and in the chickens vaccinated with sample (3) (30.76%). The chickens of the latter group were the last to start dying from Marek's disease--only after the 10th week of life. In the chickens which had been vaccinated and revaccinated with sample (2) the mortality was not reduced. The study is continued, with particular emphasis on the relationship of DEAE-dextran to protection against Marek's disease.

Pathogenesis of Marek's disease in chickens with maternal antibody.

Histopathological lesions were studied in chickens with maternal antibody against MD virus at 14-day intervals after their exposure by contact to HPRS-16 of MD virus in the first-day of life. The first lesions occured 14 days after infection in the liver, kidney, heart, brain and the sciatic nerves. Relatively, the most expressive changes were observed between 56th and 70th day after infection. Lesions were characterized as light to heavy infiltrations formed by immature and mature pleomorphic mononuclear cells. Among these cells myeloid type cells occured too. In some cases expressive tumorous lesions with intensive mitosis were observed mainly in the liver. Intranuclear inclusion bodies were also observed mainly among the proliferating epithelial cells of the proventriculus. 14-days after infection changes in the brain were classified as nonpurulenta encephalitis. Gross lesions characteristic of MD occured the most frequently in the gonads, liver and the kidney. In one case 56 days after infection herpesvirus-like particles were observed by electron microscopy in the tumorous gonads and liver. They measured about 200 to 260 nm in diameter. Degraded and/or aberrant incompleted virus-like particles occured the most often and completed (enveloped) ones with electrondense nucleoids were observed occasionally. It was concluded that MD in chickens with materanal antibody against MD virus shows monophasis progress.

Immunization against Marek's disease using Marek's disease virus-specific antigens free from infectious virus.

Immunity against Marek's disease was conferred by the use of non-infectious materials extracted with non-ionic detergents from cells infected with the attenuated strain of Marek's disease virus (MDV). Antibody-free Rhode Island Red chicks were inoculated at 1 week of age with cell extracts emulsified in Freund's complete adjuvant and were given a second inoculation 1 week later without adjuvant. Protection against natural infection was obtained in groups inoculated with both soluble (not sedimented at 100,000 times g/2h) and insoluble antigens present in Nonidet P40 (NP40) extract, but only with the insoluble fraction of deoxycholate extract. The results suggest that the immunizing antigens can be partially solubilized with 0.5% NP40 and that the growth and spread of MDV are reduced in immunized chickens.