Stimulation of cell defense mechanism of bovine endometrium by temporal colonization with selected strains of lactobacilli.

The aim of the experiments was to assess the response to topical administration of selected live strains of lactobacilli of the cells responsible for the resistance of bovine endometrium. Experimental cows (n = 8) at 8 to 12 days of the estrous received one intrauterine dose of 20 ml of a suspension of lactobacilli in 1% glucose solution. Group I (n = 4) was treated with the strain Lactobacillus spp. G 013 (5.5 x 10(8) CFU/ml) and Group II (n = 4) with the strain Lactobacillus casei CCM 1753 (1.2 x 10(8) CFU/ml). Control cows (n = 4) received 20 ml of 1% glucose solution. Samples of endometrial tissue were obtained by biopsy or from slaughtered cows on post-treatment days 5 or 6 and/or 10 or 12. Colonization of the uterine cavity with lactobacilli for up to 12 days was confirmed by bacteriological examination and scanning electron microscopy. Highly significant increases (P < 0.01) were found in numbers of all cell types under study. The pronounced cellular infiltration of endometrium was mostly due to the accumulation of mononuclear cells, particularly lymphocytes forming often indistinctly demarcated lymphoid nodules. Also marked was the infiltration of mast cells and macrophages. The cellular infiltration of endometrium persisted still on post-treatment day 12. No signs of alteration of epithelial cells were observed. No principal differences in the effects on endometrium were found between the two lactobacilli strains. The proved stimulatory effect of lactobacilli on endometrial cell defense mechanisms demonstrated in our experiments and inhibitory effects of the former on the growth of pathogenic microorganisms are promising for practical application in the prevention and alternative therapy of bovine endometritis.

[An epizootiologic study of an outbreak of equine influenza in the Czech Republic in the fall of 1995]. / Epizootologická studie vzplanutí chripky koní v Ceské republice na podzim roku 1995.

A mild outbreak of acute respiratory infection was reported in racing horses in the fall of 1995. Four studs were investigated for the sources and routes of infection. In five horses from two herds, virus isolates were obtained which, in preliminary typing experiments, were identified as the influenza A/equi 2 virus. The presence of this illness in all the examined herds was confirmed by a rise in specific antibody titres. The affected animals included both older vaccinated horses and young horses not yet vaccinated. Epidemiological studies suggested that the spread of infection occurred in situations where infected and non-infected horses were together, most frequently at races. Newly infected horses brought the infection back to their studs where further animals became infected. Some of them, still being in the incubation period without any clinical signs, may have taken part in another race and passed the infection onto healthy animals from other studs. Since the races usually took place in 7-day intervals, the epidemiological chain remained continuous. The causes of the outbreak of infection in vaccinated horses are analysed. The length of post-vaccination immunity, the antigenic composition of vaccines and their completion with new strains of the influenza virus are discussed.

Development of a disease control programme based on the use of an inactivated vaccine against infectious bovine rhinotracheitis.

Studies to investigate the efficacy of an inactivated vaccine against infectious bovine rhinotracheitis (IBR) suggest that this vaccine can prevent the in utero infection of calves from experimentally infected dams. In an experimental herd the inactivated vaccine induced a humoral immune response in both seropositive and seronegative cattle and, after subsequent intratracheal infection with IBR (BHV-1) virus, prevented development of symptoms in the cows and protected their fetuses against infection. The calves were all healthy and were born at term. The non-vaccinated, seronegative cows responded to the experimental infection with mild respiratory disease and abortion of 4 out of 10 fetuses. All organs from the aborted fetuses were found to have IBR virus. Through the use of this vaccine, the nucleus of a seronegative, virus-free breeding herd can be established. Thus, valuable genetic material can be preserved and the eradication of IBR becomes a realistic prospect. From our initially strictly controlled experiments producing 234 healthy calves, our programme was expanded into farm practice where 1001 calves were reared free from IBR virus.

[Detection of herpesvirus serum antibodies in red deer (Cervus elaphus) imported into the Czech Republic]. / Prukaz protilátek proti herpesvirum v sérech jelena evropského (Cervus elaphus) importovaného do Ceské republiky.

Antibodies reacting in the virus-neutralisation test with bovine herpesvirus (BHV-1), the causative agent of infectious bovine rhinotracheitis (IBR), were demonstrated in a herd of red deer (Cervus elaphus) imported into the Czech Republic. Sera from the same collection were later tested against a homologous virus, termed herpesvirus cervidae 1 (HVC-1), isolated from red deer in Scotland. Out of 165 imported animals, antibodies to BHV-1 were found in 68% and to HVC-1 in 71% of the animals. Titres of antibodies to the two viruses ranged from 1 : 2 to 1 : 4 or were occasionally greater. As documented by several experimental studies carried out abroad, the HVC-1 virus, though antigenically closely related to BHV-1 virus, is not pathogenic to cattle under natural conditions. Antibodies which reacted with both BHV-1 and HVC-1 were also demonstrated in 3 out of 7 roebucks randomly shot in this territory.

The efficacy of an inactivated IBR vaccine in the prevention of intra-uterine infection and its use in a disease-control programme.

The effects of administration of an established, inactivated IBR vaccine were studied in 30 cows from two herds (one seropositive and one seronegative). All acquired immunity which, after subsequent intratracheal infection with IBR virus, prevented development of symptoms in the cows and protected their foetuses against viral infection in utero. The calves were all healthy and were born at normal term. Ten non-vaccinated cows from the seronegative herd responded to the experimental infection with mild respiratory disease and abortion of four out of 10 foetuses. Organs from the aborted foetuses were found to have IBR virus. In a breeding herd, without clinical signs of disease but with 40% of cows tested as seropositive, a 2-year disease-control programme was initiated. A total of 234 newborn calves were examined and it was shown that immunization of their dams with an inactivated vaccine conferred full in utero protection against IBR-virus infection. When such calves are reared in isolation they can be used as the nucleus for a seronegative breeding herd.

Differentiation of Salmonella enteritidis and S. typhimurium by plasmid profile analysis and restriction endonuclease analysis of chromosomal DNA.

Infections with Salmonella enteritidis and S. typhimurium are frequent causes of food-borne diseases in man and are responsible for considerable economic losses in the poultry industry (Fantasia et al., 1991; Pohl et al., 1991). Methods for the more careful differentiation and typing of these two serotypes are necessary for the investigation of the spread and transmission of the infection. Conventional methods of Salmonella differentiation (bioassays, phage-typing, resistance to antibiotics) often lack the necessary resolution potential (Wray et al., 1987). Plasmid profile analysis and restriction analysis of chromosomal DNA, based on restriction fragment length polymorphism (RFLP) have been used for the differentiation of Salmonellae (Wray et al., 1987; Nastasi et al., 1988; Franklin et al., 1990; Helmuth von et al., 1990; Martinetti and Altwegg, 1990). Rapid and unsophisticated analysis of the content of plasmid DNA tends to be preferred. However, some strains lack plasmids or may lose them during laboratory passages (Nastasi et al., 1988; Hartstein et al., 1991). On the other hand, restriction analysis of chromosomal DNA yields more constant and reliable information on bacterial strains (Tveten et al., 1991). The aim of this study was to compare 18 field strains of S. enteritis and 12 strains of S. typhimurium on the basis of plasmid profile analysis and restriction endonuclease analysis of chromosomal DNA. Plasmid DNA content was determined and chromosomal DNA, isolated from bacterial cells immobilized in low-melting agarose, was digested with restriction endonuclease Pst I in 18 and 12 field strains of S. enteritidis and S. typhimurium, respectively. The resulting fragments were separated by pulse-field electrophoresis in agarose gel.(ABSTRACT TRUNCATED AT 250 WORDS)