[Occurrence and control of the Clostridium perfringens type A associated diarrhea of the suckling pigs with special consideration of the immunoprophylaxis]. / Vorkommen und Bekämpfung des Clostridium-perfringens -Typ-A-assoziierten Durchfalls der Saugferkel unter besonderer Berücksichtigung der Immunprophylaxe.

OBJECTIVE: Clostridium (C.) perfringens type A is often associated with diarrhoea in suckling piglets. The impact of the alpha (α) and beta (ß)2 toxins on the pathogenesis of the disease has not been conclusively answered. Previously, autologous vaccines were used to control this disease. The aim of our investigation was the classification of C. perfringens strains and the quantitative determination of the α and ß2 toxins during the production of autologous vaccines. The efficacy of a commercial vaccine against the C. perfringens type A associated diarrhoea was tested using an animal intoxication model. MATERIAL AND METHODS: A total of 1,434 C. perfringens strains from piglets with diarrhoea were classified using a multiplex PCR in the first part of the examination. In parallel, the α and ß2 toxin content was determined quantitatively using ELISA tests. In the second part of the study 18 gilts were vaccinated twice in the last third of gestation to evaluate the α and ß2 toxoid containing C.perfringens type A vaccine (Clostriporc A, IDT Biologika GmbH). RESULTS: Of the C. perfringens strains which were found, 87.9% were type A ( cpa , cpb2 ), 6.3% type A ( cpa ), and 5.8% type C ( cpa , cpb , cpb2 ). Low to middle a toxin-producing strains often strongly expressed the ß2 toxin. The vaccination led to the production of antibodies against the α and ß2 toxins, which were transferred to the offspring by colostrum. Piglets were significantly protected (p<0.05) by the antibodies after having been challenged with an α and ß2-containing supernatant of a heterologous C. perfringens type A strain. CONCLUSION AND CLINICAL RELEVANCE: These results underline the importance of α and ß2 toxin producing C.perfringens type A strains in diarrhoea in suckling piglets. Using the intoxication model, this vaccine showed significant protective effects against the α and ß2 toxins.

Vaccination against porcine parvovirus protects against disease, but does not prevent infection and virus shedding after challenge infection with a heterologous virus strain.

The demonstration of field isolates of porcine parvovirus (PPV) that differ genetically and antigenically from vaccine strains of PPV raises the question of whether the broadly used inactivated vaccines can still protect sows against the novel viruses. Ten specific-pathogen-free primiparous sows were assigned to three groups and were vaccinated with one of two vaccines based on the old vaccine strains, or served as non-vaccinated controls. After insemination, all sows were challenged with the prototype genotype 2 virus, PPV-27a, on gestation day 41; fetuses were delivered on gestation day 90 and examined for virus infection. The fetuses of the vaccinated sows were protected against disease, but both the vaccinated and the non-vaccinated sows showed a marked increase in antibody titres after challenge infection, indicating replication of the challenge virus. All sows (vaccinated and non-vaccinated) shed the challenge virus for at least 10 days after infection, with no difference in the pattern or duration of virus shedding.

Study of the virulence and cross-neutralization capability of recent porcine parvovirus field isolates and vaccine viruses in experimentally infected pregnant gilts.

The pathogenicity of two recent German field isolates of Porcine parvovirus (PPV-27a and PPV-143a) and two vaccine viruses [PPV-NADL-2 and PPV-IDT (MSV)], which are used for the production of inactivated vaccines, was investigated by inoculation of pregnant sows at day 40 of gestation. Post-infection sera of these sows as well as antisera prepared in rabbits by immunization with the four above-mentioned PPV isolates and with the virulent strain PPV-Challenge (Engl.) were tested for their homologous and heterologous neutralization activities. All antisera had high neutralization activity against the vaccine viruses, the PPV-Challenge (Engl.) virus and PPV-143a, but much lower activity against PPV-27a. These results suggest that PPV-27a represents a new antigenic variant or type of PPV and vaccines based on the established vaccine viruses may not be fully protective against this field isolate. PPV-27a has been characterized based on the amino acid sequences of the capsid protein as a member of a new and distinct PPV cluster (Zimmermann et al., 2006). Interestingly, the homologous neutralizing antibody titres of the sera of all three pigs and both rabbits inoculated or immunized with PPV-27a were 100- to 1000-fold lower than the heterologous titres against any of the other viruses. The low homologous neutralizing antibody titres suggest a possible, yet undefined, immune escape mechanism of this PPV isolate.

VP1 sequences of German porcine parvovirus isolates define two genetic lineages.

In order to evaluate the genetic variability of Porcine parvovirus (PPV), the complete capsid protein sequences (VP1/VP2) from seven recent field isolates from Germany, one isolate from the UK and one German vaccine strain were sequenced and analysed, along with two American (NADL-2 and Kresse), three Asian and 22 Brazilian partial PPV sequences retrieved from GenBank. The analysis revealed a high degree of diversity: 1.2-2.6% at the nucleotide level and 1.2-6.8% at the amino acid level. Phylogenetic analysis defined two German clusters: one formed by four German isolates and the English, Asian and American sequences; and the second, distinct cluster formed by the other three of the seven German isolates examined. The latter cluster was still observed when the 22 partial sequences (853 nt of the 3' terminus of the VP2 gene) from the Brazilian isolates were included in the analyses, indicating that the VP2 sequence determines the phylogeny.

Tissue distribution of two field isolates and two vaccine strains of porcine parvovirus in foetal organs after experimental infection of pregnant sows as determined by real-time PCR.

The aim of this study was to investigate the tissue distribution of two different field isolates and two vaccine strains of porcine parvoviruses (PPV) in infected piglets after transplacental infection. The viral load in 10 different foetal organs was determined by real-time polymerase chain reaction assays with SYBR Green targeting the viral VP2 gene and the genomic c-myc gene in 12 foetuses. The viral load in foetal tissues differed greatly among the different parvoviruses. Between one virulent field isolate compared with the other field isolate and the vaccine strains, the detected viral copy number differed in an order of magnitude of 10(9). The virulent isolate contained PPV in all 10 organs with viral loads varying between 10(11) and 10(15) per 10(6) cells. Concerning the other field isolate and the two vaccine strains, if PPV was detected, in most of the cases the highest viral load was found in foetal kidneys with a maximum viral load of 10(3) per 10(6) cells. Additionally, PPV was found in the heart of one foetus, in the liver and duodenum of one foetus and in the thymus of one foetus with viral loads varying between 10(2.1) and 10(3.5) per 10(6) cells. In completely mummified foetuses with no discriminable organs of foetuses infected with the vaccine strains and the less virulent isolate, PPV was present in very low amounts or even below the detection limit.

[Prevalence and association of porcine circovirus type 2 (PCV2), porcine parvovirus (PPV) and porcine reproductive and respiratory syndrome virus (PRRSV) in aborted fetuses, mummified fetuses, stillborn and nonviable neonatal piglets]. / Prävalenz sowie Assoziation von porzinem Circovirus Typ 2 (PCV2), porzinem Parvovirus (PPV) und porzinem reproductive and respiratory syndrome virus (PRRSV) in abortierten Feten, mumifizierten Feten, totgebore- nen und lebensschwach geborenen Ferkeln.

Porcine circovirus type 2 (PCV2) seems to cause reproductive failure in sows not only in experimental studies. A retrospective study was made with a total of 252 aborted fetuses, mummified fetuses, stillborn and nonviable neonatal piglets to determine the presence of PCV2, porcine parvovirus (PPV) and porcine respiratory and reproductive syndrome virus (PRRSV) by PCR. PCV2 was found in all stages of gestation in 27.1 percent of samples examined. A statistically significant association could be shown between the detection of PCV2 and PRRSV. However, no significant association was seen between the detection of PCV2 and PPV and between PPV and PRRSV.

Investigation of the efficacy of a genetically-stabile live Salmonella typhimurium vaccine for use in swine.

Hybrid swine (Landrace x Pietrain) aged 3-4 weeks were immunized twice at an interval of 3 weeks solely by the oral route and by the oral/parenteral route to evaluate the efficacy of a live S. Typhimurium vaccine. In each experiment a control group was run without vaccination. The animals were challenged at the age of 8-10 weeks by oral test infection with a labelled S. Typhimurium DT 104 strain. An ELISA was used to establish the presence of antibodies to S. Typhimurium in serum samples, coupled with clinical investigation. The presence of the challenge strain in the ileal and caecal mucosa and in the ileocolic lymph nodes was investigated quantitatively using the Koch plating method to determine the degree of colonization of those organs at the time of slaughter. The clinical course of disease was used to assess the success of vaccination. However, it was not possible to trigger, in a reproducible manner, clinical signs of disease in unvaccinated animals through infection. The vaccinated animals had a significantly lower (p < 0.05) colonization of the ileal and caecal mucosa than the unvaccinated animals. This was also seen to a lesser degree for the ileocolic lymph nodes.

[Fundamental safety requirements in the use of live vaccine in food animals]. / Grundsätzliche Sicherheitsanforderungen beim Einsatz von Lebendimpfstoffen bei lebensmittelliefernden Tieren.

Live vaccines have a number of advantages over inactivated ones--above all in respect of the stimulation of cell-mediated immune reactions. Various live vaccines, based on viruses, bacteria, fungi or parasites, have been approved for use in Germany in animals used as a source of food. Safety requirements obviously play a more important role for live vaccines, both in vaccine development and in batch testing, than with inactivated vaccines. Vaccine strains isolated from tissue samples must be clearly distinguishable from field strains. The safety of overdoses and the spread of the vaccine strain in the immunized animals have to be investigated, as well as shedding of the vaccine strain and its safety in non-target species. Any impact of a live vaccine strain on humans and the environment must be assessed. Live vaccines will remain an important research field in the long term, with efforts focused on developing deletion mutants and vector vaccines.

[A new live Salmonella enteritidis vaccine for chickens--experimental evidence of its safety and efficacy]. / Ein neuer Salmonella Enteritidis-Lebendimpfstoff für Hühner--experimenteller Nachweis der Sicherheit und Wirksamkeit.

Within the works for the registration of a new live Salmonella Enteritidis vaccine for layers, safety and efficacy of the vaccine strain were tested by experimental studies. After oral administration of the single and the tenfold dose, no incompatibility reactions were seen in day-old chicks. The laying performance and the egg weight were not affected by the vaccination of the chickens during the laying period. There was only a limited period in which the excretion of the vaccine strain and its persistency in organs were seen. Even after the threefold oral vaccination the vaccine strain could not be isolated from eggs and internal organs of slaughtered chickens. Moreover, a high safety for non-target animals (cattle, pigs) could be established. Studies with BALB/c mice proved that a cell-mediated immunity and the development of complement-fixing antibodies is induced by the vaccine. Efficacy studies in target animals were carried out by a proved dependable oral challenge system that reproduces a latent infection with marked S. Enteritidis strains and by means of the seeder-bird method. The test results demonstrate that the vaccination is capable to avert or to reduce an infection significantly.

The control of necrotic enteritis in sucking piglets by means of a Clostridium perfringens toxoid vaccine.

Necrotic enteritis in sucking piglets constitutes a serious problem in piglet rearing units because of the high morbidity and mortality associated with the disease. The primary causal agent is Clostridium perfringens type C. The beta-toxin plays a decisive role in the pathogenesis of this disease. A toxoid vaccine for use in sows has been developed and studied in field trials. The European Pharmacopoeia Monograph on vaccines for use in animals lays down a method of the efficacy testing based on the immunization of rabbits, the collection of pooled sera and the subsequent assay of anti-toxin antibodies in mice using an appropriate test toxin. The vaccine is regarded as effective if it induces a minimum of 10 IU of beta-anti-toxin per ml of rabbit serum. We have established a range of 17.14-98.23 IU beta-anti-toxin per ml rabbit serum induced by a sample of C. perfringens toxoid vaccine. The vaccine has been used under field conditions in different rearing units at the same time, mostly in the form of emergency vaccinations following the outbreak of disease. The outcome of vaccination was evaluated by recording the total numbers of piglets born alive and the piglet losses. Use of the vaccine, coupled with other measures, resulted in an approximately 30% reduction in the number of losses.

[Vaccination of pigeons against Salmonella infections]. / Zur Schutzimpfung gegen die Taubensalmonellose.

The efficiency of the live vaccine Zoosal T with a double marker mutant of Salmonella Typhimurium was tested on conditioned pigeons. For challenge infection we used a pigeon specific variation copenhagen strain in a defined state of virulence. The reduction of mortality and the persistence of Salmonella in organs were evaluated. An oral booster enhances the protection due to vaccination.

[Bacterial infections in felines in zoological gardens]. / Bakterielle Infektionen bei Feliden in Zoologischen Gärten.

The significance of selected bacterial infections of felines in zoological gardens is discussed. Anthrax and malleus are in Germany of historical interest only, tuberculosis went down very strongly. Isolated cases of pseudotuberculosis must be expected in future. Infections with bacteria of the genera Chlamydia, Pasteurella and of the family Enterobacteriaceae are also considered. The significance of Clostridium perfringens in the so called tiger disease is discussed.

[Detection of enterotoxin production in bovine Salmonella isolates]. / Nachweis der Enterotoxinbildung bei bovinen Salmonella-Isolaten.

54 Salmonella-strains (7 serovars) of bovine origin isolated from faecal samples, rectal swabs as well as from organs of emergency-slaughtered or dead animals were tested for enterotoxin production (heat-labile and heat-stable) in rabbit-ileal-loop-assay (RILT), skin-permeability-factor-test (HPT), CHO- and Y1-cell-culture-assay and in baby-mouse-test (BMT). The cell-free supernatants (CFS) were used in the tests. The Y1-cells did not respond to the Salmonella toxins. While the RILT was suitable, the CHO-cell-assay proved to be the most sensitive and easy-to-handle system. The results confirm the frequent occurrence of the biological property of enterotoxin production within the species Salmonella enterica. Therefore, this property is in our opinion not useful as an epizootological marker for salmonellae.

[The occurrence of cytotonic and cytotoxic enterotoxins in Salmonella]. / Das Vorkommen von zytotonischen und zytotoxischen Enterotoxinen bei Salmonellen.

A survey is given on the presence and the detection of entero- and cytotoxin production of Salmonella. Their role in the pathogenesis of Salmonellosis has not yet been clarified completely. The standardization of the terms of toxins according place and modus of action is proposed. Cytotonic and cytotoxic enterotoxins were demonstrated in Salmonella strains. Toxins, like the Verotoxin of E. coli, acting in enterocytes as well as in other cells of organisms have not been detected in Salmonella strains. For detection cell culture assays are preferred, DNA-hybridization will be of importance in the near future.

[Detection and characterization of Salmonella strains from laughing gulls (Larus ridibundus)]. / Nachweis und Charakterisierung von Salmonella-Stämmen bei Lachmöwen (Larus ridibundus).

25 and 17 Salmonella strains could be isolated from 429 and 423 blackheaded gulls (Larus ridibundus), respectively, during two years of examination. S. typhimurium was the most frequent serovar. All strains of S. typhimurium belonged to the biochemovar c (inosite and rhamnose negative), nearly a third of isolates caused a mannose-sensitive hemagglutination of guinea pig erythrocytes. This result is in contradiction to the literature. Furthermore the phagovars, the plasmid profiles and the resistance against chemotherapeutics were tested. The Salmonella carriage by gulls presumably reflects the contamination of the environment.

[Possibilities of clinico-cytological diagnosis in contagious equine metritis (CEM)]. / Möglichkeiten der klinisch-zytologischen Diagnostik bei der contagiösen equinen Metritis (CEM).

Clinical, bacteriological and serological examinations on a 6 years old pony mare were performed. Cytological alterations in the genital tract were also recorded. A cellular reaction was seen after infection with T. equigenitalis. This reaction is an evidence for infection but it is not specific for this organism. Cytological studies should be performed on mares especially in cases of latent infections to complete bacteriological examination and to prevent false positive or negative results.

[Preliminary results of the determination of plasmid profiles of veterinary Salmonella isolates]. / Erste Ergebnisse der Bestimmung von Plasmidprofilen veterinär-medizinischer Salmonella-Isolate.

A plasmid of 60 Md magnitude was recorded from 40 in 41 Salmonella (S.) typhimurium strains, including the Copenhagen minus variant. A plasmid of that kind had been described in the international literature as serovar-specific of S. typhimurium. One S. typhimurium strain was without plasmid. Five contained the 60-Md and other plasmids. No relationship was found to exist between the 60-Md plasmid and biovar as well as chemotherapeutic resistance. Further studies will be necessary for consistent information on virulence association of this plasmid and its serovar specificity. Plasmid profiles were also checked in four S. enteritidis strain and additional serovars.

[Epizootiology of salmonellosis in wild and zoo animals]. / Die Epizootiologie der Salmonellosen bei Wild- und Zootieren.

To demonstrate a few characteristic features of zoo animals caused by infections, bacterial examination of material collected in Leipzig Zoo Garden was carried out with respect to the presence of Salmonella. Examination of 7022 organ and faeces samples revealed that 350 salmonella isolates could be cultivated. This established 5% presence of salmonella. Among the 3 most important classes of animals exists quite a reasonable difference: 9.9% of all samples taken from animals of reptile-origin revealed the presence of Salmonella, only 6.0% and 4.1% was registered among birds and mammals respectively. 65.4% of all the Salmonella isolates were of serovar typhimurium whereby a clear difference between the animal classes was noted. Among birds 84.2% of the isolates were S. typhimurium, among mammals 62.6%, among reptiles only 26.8%.

[Development, position and trends in the taxonomy of the genus Salmonella]. / Entwicklung, Stand und Tendenzen der Taxonomie der Gattung Salmonella.

The development of taxonomy of Salmonella genus interpretation was outlined in 1900 by Lignieres. The idea that any Salmonella defined by the Kauffmann-White scheme should be rated as a species in its own right has become under criticism for some time. It was suggested that S. cholerae suis should be seen as the only valid species name in the early 80's. This was ever misunderstood because this name had long ago been attributed to a pig-adapted serovar. Le Minor and Popoff (1987) suggested that S. enterica should be used as the species name. Confusion will thus be ruled out, since enterica has not been associated with any serovar. All salmonella names contained in Kauffmann-White scheme are serovars. It was suggested that all interpretations after consultation with human and veterinary medicine should be accepted in order to avoid the misunderstanding of the terminology and to achieve rational interpretation of results.

[Virulence factors of animal pathogenic Salmonellae with reference to plasmid typing]. / Virulenzfaktoren tierpathogener Salmonellen unter Berücksichtigung der Plasmidtypisierung.

All the representatives of the genus Salmonella belong to one pathogenic species S. enterica. The virulence intensification of Salmonella are due mainly to endo-, entero- and cytotoxins, fimbria, cilia, the invasion capacity and the serum resistance. The plasmid code is among a series of virulence factors. Studies about the plasmid profile of the salmonella strains is of great importance to the characterisation of the isolates from the epidemiological point of view as well as for research purposes.