Colonization factor different from K88, K99, F41 and 987P in enterotoxigenic Escherichia coli strains isolated from postweaning diarrhoea in pigs.

A novel common colonization factor was detected in enterotoxigenic strains of Escherichia coli isolated from intestinal contents of piglets affected with postweaning diarrhoea. This factor was antigenically distinct from the previously described K88, K99, F41, 987P, CFAI, CFAII and Att25 fimbrial antigens. E. coli strains possessing this factor adhered to the pig intestinal brush borders and one strain, used in experimental infection in weanlings, colonized the intestinal epithelium and induced diarrhoea. Examination of 212 toxigenic strains of E. coli isolated from weanlings revealed the presence of the novel common colonization factor in 83 strains, belonging to serogroups O25, O108, O138, O141, O147 and O157. The antigen K88 was detected in 47 strains belonging to serogroups O8, O141, O147 and O149.

[Diagnosis of infectious pancreatic necrosis (IPN) of trout using immunofluorescence]. / Diagnostika infekcní nekrózy pankreatu (IPN) pstruhu pomocí imunofluorescence.

Until recently, demonstration of infectious pancreatic necrosis was conditioned by the isolation of virus. By means of the immunofluorescence method it is possible to make a rapid and accurate diagnosis, as well as to determine the development of infection. In acute cases, the virus in fry was demonstrated mainly in the cytoplasm of epithelial cells of guts; in Pd1-2 trout, the virus was proved in the cytoplasm of epithelial cells of primary kidney tubules and in the cytoplasm of epithelial cells of pancreatic acini. In all cases the virus occurrence demonstrated by immunofluorescence was in correlation with the results achieved by cultivation methods.

[Necrotic processes in the gill tissue of carp caused by changes in the aquatic environment]. / Nekrotické procesy zaberní tkáne kapra, zpusobené zmenami vodního prostredí.

Histological findings show that various pathogenic processes are involved in the cases of clinically detected branchionecrosis. The changes in gills occurring at toxic branchionecrosis are a necrobiotic process in their nature; in gill lamellae this process manifests itself as a swelling of the respiratory epithelium and as dilation of lamellar sinuses, and in stratified epithelium of gill arch and filaments it takes on the form of the hypertrophy and hyperplasia of epithelial cells. In severe cases the swollen epithelium forms deposits filling up also the interlamellar space. Toxic branchionecrosis is a term referring to a disease when the pathological processes are caused by ammonia intoxication and autointoxication, the main role being played by pH value. At experimental ammonia intoxication the changes in gills are about the same as in toxic branchionecrosis but the symptoms are not so pronounced. Changes characteristic of spherosporosis involve severe necrotic processes in the respiratory epithelium as well as in the stratified epithelium of gills, and the epithelium harbours different developmental stages of spherospores. The spherospores are easily detected when stained with alcian blue at pH 2.5. The changes in the gills of carp naturally invaded by spherospores with additional ammonia intoxication correspond to findings characteristic of toxic branchionecrosis: degeneration of stratified and respiratory epithelium of gills combined with necrotic changes caused by the developmental stages of spherospores. When water is highly oxygenated with chlorinated lime, large cells with eosinophilic granules severely multiply mainly in the stratified epithelium of gills; this process is considered as an inflammatory process. Parasitic invasions by Trichodina and Chilodonella induce local inflammatory reactions with the swelling of the respiratory epithelium.

[Gill structure in healthy carp]. / Stavba zaber zdravého kapra.

When the gills of carp are studied, this organ should be evaluated from there planes of projection: sagittal, transversal and horizontal. Lamellae, the functional base of the gills, provide the exchange of oxygen between blood and water. Lamellae consist of a network of sinuses with a skeleton formed by columnar cells and with walls constituted by the cytoplasmic processes of these cells. On the outer side the sinuses are covered with one or two layers of flat epithelial cells. The gill filaments and gill arches, the structure and mobility of which enable the perfect function of lamellae are covered with stratified epithelium. Cylindrical cells (germ cells) of this epithelium are borne by a basal membrane; during maturation they flatten and differentiate towards the surface. Besides the already flat epithelial cells, the surface of epithelium also carries mucous cells and gustatory buds. Separate large irregular cells with excentric nucleus and small eosinophilically staining granules are also found in the epithelial layers of healthy fish.

[Regional ileitis - a diarrheal disease of pigs]. / Regionální ileitida - proújmové onemocnení prasat.

Morphological and histological changes were described in regional ileitis of pigs, which constitutes one of the forms of the complex of diseases referred to as intestinal adenomatosis of pigs. The most pronounced changes were concentrated on the ileum and were characterized, from the morphological point of view, by a distention of the intestinal wall and from the histological point of view, by proliferation of the epithelial cells of ileum, proliferation of the lymphatic tissue of tunica mucosae and submucosae, and hypertrophy of tunica muscularis. This disease has not been described in Czechoslovakia up to now.

[The redox potential of the large intestine in swine in relation to swine dysentery]. / Redox potenciál tlustého streva prasete ve vztahu k dyzentérii prasat.

The redox potential of (Eh) +111 +/- 25 mV was measured in the large intestine of newly born piglets. In the post-weaning period the Eh values decreased significantly to -173 +/- 27 mV and remained at this level also in the healthy sows (-214 +/- 55 mV). The Eh value recorded in dysenteric pigs was -188 +/- 5 mV, and this was not statistically significant in relation to the healthy weaned piglets. The Eh level measured in the blood agar prepared with cysteine and covered by a thick growth of the strain Treponema hyodysenteriae, which had been incubated in an anaerobic medium for five days, was -218 +/- 18 mV. The Eh of piglets after weaning was not the decisive condition for the development of dysentery. However, it can be assumed that the impossibility of eliciting dysentery in microbe-free and gnotobiotic pigs is associated with a relatively high redox potential of a microbially unpopulated or insufficiently populated intestine.

[Etiology of porcine dysentery]. / Etiologie dyzentérie prasat.

The etiological agent of swine dysentery is an anaerobic spiralshaped microorganism of the Treponema genus. Examination of a scraping from the mucous membrane of the large intestine or the examination of faeces in a native preparation by phase contrast are the fastest diagnostical methods of determining swine dysentery. Large treponemas, as predominating microflora, 6--9 micrometer long, 0.3--0.4 micrometer in diameter, spiralshaped and moving in a serpentine way are found in faeces and the mucous membrane in the case of acute swine dysentery. These large treponemas were identified in 14% of clinically healthy pigs but in very small numbers. Treponemas are sensitive to their habitat. Treponemas survive for up to five days only in faeces which are suitably reduced. This finding is important both for subduing the infection and for diagnosis.

[Isolation of Treponemas from the colon of pigs with clinical dysentery]. / Izolace treponem z tlustého streva prasat s klinickou dyzentérií.

Optimal culture conditions in artificial nutritive media were determined for a defined avirulent strain of Treponema hyodysenteriae and for four field strains of treponemas in pigs with clinical dysentery. The treponemas were isolated with the use of milliporous filters with pores of 0.3 micrometer in diameter, which were located on the surface of blood agar. No significant difference in the influence of equine, bovine or sheep blood on the growth of treponemas was determined. The commercial amount of glucose in the used media, 2.0 to 2.5 g per 1,000 ml, was quite sufficient for the growth of the treponemas and it was not necessary to increase the amount. After reaching the optimal rate of growth the oxidoreduction potential was diminished by adding cystein or cystein hydrochloride and placing the Petri dishes with the media, prior to inoculation, into an anaerobic medium filled with hydrogen. The suitable composition of the culture atmosphere created in a special anaerostat comprised 0.4 to 1.0% carbon dioxide and the rest being hydrogen. Treponemas grew on the blood agar in zones with very slight hemolysis without forming separated colonies.

[Comparison of the suitability of phase-contrast and immunofluorescence technics in the laboratory diagnosis of porcine dysentery]. / Porovnání vhodnosti metody fázového kontrastu a imunofluorescencní techniky pro laboratorní diagnostiku dyzentérie prasat.

Immunofluorescence technique, compared with the method of phase contrast, does not appear to be better for laboratory diagnostics of swine dysentery because neither of these methods can be used for distinguishing between pathogenic and nonpathogenic strains of treponemas. The number of treponemas contained in faeces should still be considered to be the main criterion in laboratory diagnostics. In clinically healthy pigs from stocks which never suffered from dysentery treponemas were found only in few cases and always in small numbers. The numbers of treponemas contained in the faeces of dysenteric pigs were several times higher. Antigenic relationship of one nonpathogenic and three pathogenic strains of Treponema hyodysenteriae was proved by the agglutination and fluoresence methods.

Experimental infection of white mouse with Chrysosporium and Paecilomyces.

SPF white mice were inoculated intraperitoneally with 5 strains of saprophytic fungi of the mycelial genera Chrysosporium (C. keratinophilum, C. tropicum) and Paecilomyces (P. lilacinus, P. marquandii, P. victoriae). The fungi caused granulomatous lesions in the peritoneal cavity and they were recultured (except P. lilacinus and P. marquandii) two months after inoculation. Spores, short hyphae and budding cells of all the fungi were observed in the granulomas stained by periodic-acid Schiff (PAS) and methenamine-silver nitrate (Grocott) techniques.