Control strategies against Campylobacter at the poultry production level: biosecurity measures, feed additives and vaccination.

Campylobacteriosis is the most prevalent bacterial foodborne gastroenteritis affecting humans in the European Union, and ranks second in the United States only behind salmonellosis. In Europe, there are about nine million cases of campylobacteriosis every year, making the disease a major public health issue. Human cases are mainly caused by the zoonotic pathogen Campylobacter jejuni. The main source of contamination is handling or consumption of poultry meat. Poultry constitutes the main reservoir of Campylobacter, substantial quantities of which are found in the intestines following rapid, intense colonization. Reducing Campylobacter levels in the poultry chain would decrease the incidence of human campylobacteriosis. As primary production is a crucial step in Campylobacter poultry contamination, controlling the infection at this level could impact the following links along the food chain (slaughter, retail and consumption). This review describes the control strategies implemented during the past few decades in primary poultry production, including the most recent studies. In fact, the implementation of biosecurity and hygiene measures is described, as well as the immune strategy with passive immunization and vaccination trials and the nutritional strategy with the administration of organic and fatty acids, essential oil and plant-derived compound, probiotics, bacteriocins and bacteriophages.

Development of a quantitative Real-Time TaqMan PCR assay for determination of the minimal dose of Mycoplasma hyopneumoniae strain 116 required to induce pneumonia in SPF pigs.

AIMS: A triplex real-time PCR assay to quantify Mycoplasma hyopneumoniae in specimens from live and dead pigs was developed and validated. The minimal dose of Myc. hyopneumoniae required to induce pneumonia in specific pathogen-free pigs was determined. METHODS AND RESULTS: This TaqMan test simultaneously detected three genes encoding the proteins P46, P97 and P102. All Myc. hyopneumoniae strains analysed were detected, including strains isolated in three countries (France, England and Switzerland) and from several pig farms (n = 33), and the test was specific. The estimated detection thresholds were 1.3 genome equivalents (microl(-1)) for the targets defined in p97 and p102 genes and 13 genome equivalents (microl(-1)) for the segment defined in the p46 gene. This test was used to quantify Myc. hyopneumoniae in specimens sampled from experimentally infected pigs. In live pigs, c. 10(7), 10(8) and 10(10) genome equivalents (ml(-1)) of Myc. hyopneumoniae were detected in the nasal cavities, tonsils and trachea samples, respectively. In dead pigs, 10(8)-10(10) genome equivalents (ml(-1)) of Myc. hyopneumoniae were detected in the lung tissue with pneumonia. The estimated minimal dose of Myc. hyopneumoniae required to induce pneumonia was 10(5) colour-changing units (CCU) per pig (corresponding to 10(8) mycoplasmas). CONCLUSION: The triplex RT-PCR test was validated and can be used for testing samples taken on the pig farms. SIGNIFICANCE AND IMPACT OF THE STUDY: This test should be a very useful tool in pig herds to control enzootic pneumonia or healthy carrier pigs and to study the dynamics of Myc. hyopneumoniae infections.

Immune and protective abilities of ubiquitinated and non-ubiquitinated pseudorabies virus glycoproteins.

Plasmids encoding ubiquitinated (ubi-) or non-ubiquitinated (non-ubi-) glycoproteins of Pseudorabies virus (PRV) were used for vaccination of pigs. We found that the fusion of ubiquitin to viral glycoproteins increased their degradation in proteasomes in vitro, in which ubiquitin plays a key role. In the animals immunized with the plasmids encoding PRV ubi-glycoproteins and then challenged with PRV, we detected a slightly decreased cellular immune response on days 13 and 19 after immunization and a reduced nasal excretion of infectious virus on day 2 after the challenge. Afterwards, no effect of the ubiquitination of the glycoproteins on humoral or cellular immunity and on excretion of infectious virus was observed. Similarly, no effect of the ubiquitination on protective abilities of PRV glycoproteins was found.

Risk assessment in new and conventional vaccines.

New technology, and in particular new molecular biology tools, have opened up access to new generations of vaccines or control tests. DNA vaccines are of particular interest since only the gene is injected and, as a consequence, specific risks are associated with this kind of vaccination. Some strategies are presented here to improve DNA vaccine efficacy, which can in some cases result in the reduction of the quantity of plasmid needed and therefore limits the risk. Specific tools to study the distribution of plasmids inside the body as well as tools to detect plasmid insertion inside the host genome have been developed. A final part of this paper will present briefly the new tools which have been or can be developed to detect contaminants in vaccines.

Purification of a 41 kDa cod-allergenic protein.

Cod fish is one of the foods most frequently involved in allergy. Only the cod allergen Gad c I, a 12.3 kDa parvalbumin, has been purified and characterized. Recently, we have detected allergen bands which have not previously been described, in particular a 41 kDa protein, by Western-blot. In the present work, this protein has been purified from a crude cod extract by ammonium sulfate fractionation, hydroxyapatite chromatography and preparative electrophoresis; a single band with an Mr of 41 x 10(3) was found in silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The amino acid composition and the isoelectric point of the protein were determined. The purified protein (p41) was shown to bind specifically to reaginic IgE from sera of cod-allergic individuals and to a monoclonal anti-parvalbumin which recognizes specifically the first calcium binding site of parvalbumins. p41 may therefore contain a calcium binding site corresponding to an IgE-epitope similar to that of Gad c I.

Recognition of an extensive range of IgE-reactive proteins in cod extract.

Allergy to fish is one of the most common food allergies. Gad c 1 is the only fish allergen which has been purified and characterized. Other allergens have been detected by Western blot in cod extracts. We have now improved the Western-blot procedure in order to characterize fish IgE-reactive proteins from extracts prepared under different conditions: pre-rigor mortis and post-rigor mortis, EDTA addition or not, and DEAE ion-exchange chromatography. Several IgE-reactive protein bands have been identified over a wide molecular-weight range. In particular, the 104- and 130-kDa IgE-reactive protein bands were detected. These new bands may correspond to aggregates, as EDTA increased the relative amount of the 60-, 67-, 104-, and 130-kDa IgE-reactive protein bands in Western blot. All these bands were also detected by antiparvalbumin monoclonal antibody, specific to the first calcium-binding site. The longer period of storage increased the relative amounts of the 41-, 80-, 104-, and 130-kDa IgE-reactive protein bands. The 18-kDa band was detected only in fish stored for several days. In conclusion, we have described IgE-reactive protein bands over a wide molecular-weight range (12-130 kDa) in Western blot of cod extract, and shown that EDTA and storage conditions may influence the relative distribution of IgE-reactive protein bands.

Modified rapid deployment hemostat bandage reduces blood loss and mortality in coagulopathic pigs with severe liver injury.

BACKGROUND: Hemostasis can be difficult to achieve after blunt abdominal trauma, especially if the patient is coagulopathic. The U.S. Food and Drug Administration has recently approved a hemostatic dressing for treating bleeding after extremity trauma (RDH bandage; Marine Polymer Technologies, Cambridge, MA). It has not been evaluated for internal bleeding after trauma. We redesigned this dressing for internal use, and then tested whether this modified bandage (Miami-modified Rapid Deployment Hemostat) could achieve hemostasis when used as an adjunct to standard laparotomy pad packing in a pig model of severe liver injury with coagulopathy. METHODS: Anesthetized swine (35-45 kg) received an isovolemic 45% blood volume replacement with refrigerated Hextend (6% hetastarch). Core body temperature was maintained at 33-34 degrees C with intra-abdominal ice packs. A coagulopathic condition was documented by thromboelastography. At this point a severe liver injury was induced by the avulsion of the left lateral hepatic lobe, then the pigs were randomized to treatment with either standard abdominal packing (control) or packing plus Miami-modified Rapid Deployment Hemostat. Two series of experiments were conducted. In series one (n = 14), the abdomen was closed and the animals were observed with no resuscitation. After one hour, the abdomen was opened, the packing was removed and the presence of bleeding was noted. In series two (n = 10), the abdomen was closed and the animal resuscitated with one unit of blood plus as much lactated Ringers intravenous fluid (IVF) as required to maintain a mean arterial pressure (MAP) > 70 mm Hg. After one hour, the packing was removed, the abdomen closed, and data were collected for an additional two hours. RESULTS: Series one: 6/7 animals in the control group had continued bleeding at one hour; 1/7 animals in the treatment group had active bleeding (p = 0.0291). Series two: With control vs. Miami-modified Rapid Deployment Hemostat, the three-hour survival was zero vs. 80% (p = 0.0476). The total blood loss was 1.2 +/- 0.1 vs. 0.3 +/- 0.1 mL/kg/min (p = 0.001) and the IVF requirement was 1.6 +/- 0.3 vs. 0.6 +/- 0.3 mL/kg/min (p = 0.026). CONCLUSIONS: The Miami-modified Rapid Deployment Hemostat bandage significantly reduced mortality, blood loss, and fluid requirements when used as an adjunct to standard abdominal packing following severe liver injury in coagulopathic pigs [corrected].