Rangelova D.,Technical University of Denmark |
Nielsen J.,Technical University of Denmark |
Strandbygaard B.,Technical University of Denmark |
Koenen F.,CODA CERVA |
And 2 more authors.
Vaccine | Year: 2012
Marker vaccines offer the possibility to differentiate classical swine fever (CSF) infected from CSF vaccinated animals based on serology and their implementation will ensure free trade with pigs. Therefore, new generations of promising marker vaccines have been developed, among them the chimeric vaccine CP7_E2alf. However, in populations previously vaccinated with live attenuated vaccines like the C-strain, passive immunity through maternal antibodies can interfere with efficacy of CP7_E2alf vaccination. Therefore, the efficacy of CP7_E2alf was examined in piglets from sows vaccinated once intramuscularly with C-strain vaccine 4. weeks before farrowing. Thus, these piglets were vaccinated intramuscularly with CP7_E2alf at the age of 5 or 8. weeks. Subsequently, the piglets and their mock-vaccinated littermate controls were challenged 2. weeks post vaccination with highly virulent Classical swine fever virus (CSFV) strain "Koslov"CP7_E2alf provided clinical protection upon challenge as no severe clinical signs or mortality was observed in the vaccinated piglets. Post mortem examination revealed pathological changes associated to CSFV only in the mock-vaccinated piglets. No infectious CSFV could be isolated from the tonsils of the vaccinated piglets. Two weeks after vaccination at the time of challenge, the vaccinated piglets only, had an increase in the ELISA antibody titer. Interestingly, the maternally derived immunity in the mock-vaccinated control piglets seems to neutralize the challenge virus. Thus, the previously observed 100% mortality in naïve (negative for antibodies to CSFV) piglets infected with CSFV Koslov was reduced in the control piglets of this study to 30% for challenge at the age of 7. weeks and 50% at the age of 10. weeks, respectively. In conclusion, CP7_E2alf proved to be effective in preventing mortality, severe clinical signs and pathological lesions in 5 or 8. weeks old piglets positive for maternal antibodies derived from sows vaccinated intramuscularly 4. weeks before farrowing with one dose of C-strain vaccine. © 2012 Elsevier Ltd.
Guardabassi L.,Copenhagen University |
Larsen J.,Statens Serum Institute |
Weese J.S.,University of Guelph |
Butaye P.,CODA CERVA |
And 6 more authors.
Journal of Global Antimicrobial Resistance | Year: 2013
Whilst meticillin-resistant Staphylococcus aureus (MRSA) infections reported sporadically in companion animals and cattle in the 1970s were probably of human origin, the recently emerged livestock-associated MRSA (LA-MRSA) and meticillin-resistant Staphylococcus pseudintermedius (MRSP) strains clearly have animal origins and their isolation from humans is usually associated with exposure to livestock and companion animals, respectively. LA-MRSA is primarily an occupational health risk to farm workers and veterinarians. The risk that this zoonotic agent may spread in the community is particularly acute in countries with high livestock production and low MRSA prevalence in the human population.MRSP is primarily a threat to animal health, and cases of human infection are rare butmay be overlooked in diagnostic laboratories. There is no conclusive evidence of antimicrobial selection associated with the sudden emergence of LA-MRSA and MRSP. However, the rapid global spread of these bacteria has presumably been favoured by antimicrobial selective pressure. Tetracyclines, zinc and extended-spectrum cephalosporins (including extra-label use) are the most likely selective drivers implicated in the spread of LA-MRSA,whilst increased use of broad-spectrumblactams and fluoroquinolones, partly enhanced by extra-label use and the introduction of cheap generics, may have played an important role in the rapid dissemination of MRSP. Control of LA-MRSA and MRSP requires a dual approach aimed at reducing antimicrobial consumption and preventing transmission between animals and from animals to humans or vice versa. Restricted use of fluoroquinolones and cephalosporins in livestock, and national practice guidelines for rational antimicrobial use both in food and companion animals are warranted. © 2013 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.
Paton D.J.,The Pirbright Institute |
Fussel A.-E.,DG SANCO G2 |
Vosloo W.,Australian Animal Health Laboratory |
Dekker A.,Central Veterinary Institute |
De Clercq K.,CODA CERVA
Vaccine | Year: 2014
To eliminate incursions of foot-and-mouth disease (FMD) quickly, a combination of measures, including emergency vaccination, can help block the spread of infection. For the earliest recovery of the FMD-free status for trade, without the slaughter of uninfected vaccinated animals, a serosurvey for antibodies to FMD virus non-structural proteins (NSP) must be used to substantiate absence of occult virus infections. Areas of doubt over requirements for post-vaccination serosurveillance and its feasibility include the required and achievable confidence, the amount of sampling necessary, and the appropriate responses to and consequences of different seropositive findings. This derives largely from uncertainty over the extent of localised pockets of virus infection that may remain within vaccinated populations and the circumstances that permit this. The question therefore remains whether tests are sufficiently sensitive and specific to detect and eliminate infected animals, without excessive culling of uninfected animals, before vaccinated animals mix with non-vaccinated livestock when movement restrictions are lifted. It is recommended to change the rationale for serosurveillance after emergency vaccination. Only when emergency vaccination is used in limited outbreaks is it possible to test and cull comprehensively, an approach compatible with a three-month minimum period to recover the FMD-free status. In other situations, where emergency vaccination is used, such as dealing with large outbreaks in animal-dense regions and where the onset of vaccination has been delayed, post-vaccination serosurveys should be targeted and focus on providing an assurance to detect higher levels of infection, in case of inadequate control measures. As this provides less assurance of absence of infection, the approach would be compatible with a six-month waiting period for free-status recovery and should be complemented by other methods to provide evidence that vaccination and control measures have been effectively implemented, as these are the best guarantee against continuing virus transmission. © 2014 The Authors.
Nauwynck H.J.,Ghent University |
Sanchez R.,University of the Philippines at Los Banos |
Meerts P.,Ablynx |
Lefebvre D.J.,CODA CERVA |
And 3 more authors.
Virus Research | Year: 2012
Porcine circovirus 2 (PCV2) may induce reproductive failure (return to oestrus, embryonic death, mummification, weak- and stillborn piglets) and postweaning multisystemic wasting syndrome (PMWS). Furthermore, it may modulate the immunity in such a way that it aggravates the outcome of many bacterial and viral infections. In the present paper, the cellular tropism and entry of PCV2 are described and linked with the pathological and clinical consequences. © 2011 Elsevier B.V.
Tsonos J.,Vrije Universiteit Brussel |
Tsonos J.,Catholic University of Leuven |
Oosterik L.H.,Catholic University of Leuven |
Tuntufye H.N.,Catholic University of Leuven |
And 9 more authors.
Veterinary Microbiology | Year: 2014
Avian pathogenic Escherichia coli (APEC) causes colibacillosis in poultry, leading to important economic losses worldwide. To cure APEC-infected chickens, a cocktail of four different APEC-specific bacteriophages (phages) was composed and tested. Specific phages were selected from a collection of phages isolated in Belgium. The selection was based on their obligate lytic infection cycle, a broad host range, low cross-resistance and low frequency of development of resistant APEC mutants. Genome analysis of the phages indicated they were close relatives of T4 and N4, considered to be safe in vivo. Chickens were intratracheally infected with APEC strain CH2 (serogroup O78), causing a mortality of about 50% during the seven days following the infection. The phage cocktail was administered 2. h after the infection, via three different ways: intratracheally, intra-esophageally or via the drinking water. Treated groups did not show a significant decrease in mortality, lesion scores or weight loss compared to untreated groups, although the APEC-specific phages could be re-isolated from the lung and heart of chickens that were euthanized. Moreover, the re-isolated bacteria from infected chickens had remained sensitive to the phage cocktail. Our results indicate that the efficiency of the phage cocktail used in treating CH2-infected chickens in vivo is negligible, even though in vitro, the phages in the cocktail were able to efficiently lyse the APEC strain CH2. Our results emphasize that the 'traditional' pathway of isolation, followed by phenotypical and genotypical characterization of phages composing the cocktail, does not lead to success in phage therapy in all cases. © 2013 Elsevier B.V.