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Efficacy of a live attenuated vaccine in classical swine fever virus postnatally persistently infected pigs.

Muñoz-González S, Perez-Simó M, Muñoz M, Bohorquez JA, Rosell R, Summerfield A, Domingo M, Ruggli N, Ganges L - Vet. Res. (2015)

Bottom Line: The humoral and interferon gamma responses as well as the CSFV RNA loads were monitored for 21 days post-vaccination.Furthermore, no E2-specific antibody response or neutralising antibody titres were shown in CSFV persistently infected vaccinated animals.Likewise, no of IFN-gamma producing cell response against CSFV or PHA was observed.

View Article: PubMed Central - PubMed

Affiliation: Centre de Recerca en Sanitat Animal (CReSA)-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. sara.munoz@cresa.uab.es.

ABSTRACT
Classical swine fever (CSF) causes major losses in pig farming, with various degrees of disease severity. Efficient live attenuated vaccines against classical swine fever virus (CSFV) are used routinely in endemic countries. However, despite intensive vaccination programs in these areas for more than 20 years, CSF has not been eradicated. Molecular epidemiology studies in these regions suggests that the virus circulating in the field has evolved under the positive selection pressure exerted by the immune response to the vaccine, leading to new attenuated viral variants. Recent work by our group demonstrated that a high proportion of persistently infected piglets can be generated by early postnatal infection with low and moderately virulent CSFV strains. Here, we studied the immune response to a hog cholera lapinised virus vaccine (HCLV), C-strain, in six-week-old persistently infected pigs following post-natal infection. CSFV-negative pigs were vaccinated as controls. The humoral and interferon gamma responses as well as the CSFV RNA loads were monitored for 21 days post-vaccination. No vaccine viral RNA was detected in the serum samples and tonsils from CSFV postnatally persistently infected pigs for 21 days post-vaccination. Furthermore, no E2-specific antibody response or neutralising antibody titres were shown in CSFV persistently infected vaccinated animals. Likewise, no of IFN-gamma producing cell response against CSFV or PHA was observed. To our knowledge, this is the first report demonstrating the absence of a response to vaccination in CSFV persistently infected pigs.

No MeSH data available.


Related in: MedlinePlus

Clinical score values in CSFV persistently infected-vaccinated pigs. The individual clinical signs were recorded daily after vaccination until 21 days post-vaccination. The scores are defined in Section 2. † The pig was euthanized at 16 dpv.
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Fig2: Clinical score values in CSFV persistently infected-vaccinated pigs. The individual clinical signs were recorded daily after vaccination until 21 days post-vaccination. The scores are defined in Section 2. † The pig was euthanized at 16 dpv.

Mentions: After 21 dpv, no clinical signs were detected in vaccinated pigs from Group 2, and rectal temperatures remained within the established normal range until the end of the experiment, (Figure 1). Conversely, the vaccinated CSFV persistently infected pigs showed varying rectal temperature values; one of the pigs showed fever from day 2 until day 15 post-vaccination (pig #4), and had to be euthanized at 16 dpv after developing hypothermia, as well as severe clinical signs (diarrhoea, mild tremors, polyarthritis). Two pigs (#2 and #3) developed fevers starting at day 17 and 21 post-vaccination, respectively, in the absence of other clinical signs. Finally, pig #1 did not have an increase in rectal temperature at any point in the study with a healthy clinical status during the trial (Figures 1 and 2).Figure 1


Efficacy of a live attenuated vaccine in classical swine fever virus postnatally persistently infected pigs.

Muñoz-González S, Perez-Simó M, Muñoz M, Bohorquez JA, Rosell R, Summerfield A, Domingo M, Ruggli N, Ganges L - Vet. Res. (2015)

Clinical score values in CSFV persistently infected-vaccinated pigs. The individual clinical signs were recorded daily after vaccination until 21 days post-vaccination. The scores are defined in Section 2. † The pig was euthanized at 16 dpv.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4496848&req=5

Fig2: Clinical score values in CSFV persistently infected-vaccinated pigs. The individual clinical signs were recorded daily after vaccination until 21 days post-vaccination. The scores are defined in Section 2. † The pig was euthanized at 16 dpv.
Mentions: After 21 dpv, no clinical signs were detected in vaccinated pigs from Group 2, and rectal temperatures remained within the established normal range until the end of the experiment, (Figure 1). Conversely, the vaccinated CSFV persistently infected pigs showed varying rectal temperature values; one of the pigs showed fever from day 2 until day 15 post-vaccination (pig #4), and had to be euthanized at 16 dpv after developing hypothermia, as well as severe clinical signs (diarrhoea, mild tremors, polyarthritis). Two pigs (#2 and #3) developed fevers starting at day 17 and 21 post-vaccination, respectively, in the absence of other clinical signs. Finally, pig #1 did not have an increase in rectal temperature at any point in the study with a healthy clinical status during the trial (Figures 1 and 2).Figure 1

Bottom Line: The humoral and interferon gamma responses as well as the CSFV RNA loads were monitored for 21 days post-vaccination.Furthermore, no E2-specific antibody response or neutralising antibody titres were shown in CSFV persistently infected vaccinated animals.Likewise, no of IFN-gamma producing cell response against CSFV or PHA was observed.

View Article: PubMed Central - PubMed

Affiliation: Centre de Recerca en Sanitat Animal (CReSA)-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. sara.munoz@cresa.uab.es.

ABSTRACT
Classical swine fever (CSF) causes major losses in pig farming, with various degrees of disease severity. Efficient live attenuated vaccines against classical swine fever virus (CSFV) are used routinely in endemic countries. However, despite intensive vaccination programs in these areas for more than 20 years, CSF has not been eradicated. Molecular epidemiology studies in these regions suggests that the virus circulating in the field has evolved under the positive selection pressure exerted by the immune response to the vaccine, leading to new attenuated viral variants. Recent work by our group demonstrated that a high proportion of persistently infected piglets can be generated by early postnatal infection with low and moderately virulent CSFV strains. Here, we studied the immune response to a hog cholera lapinised virus vaccine (HCLV), C-strain, in six-week-old persistently infected pigs following post-natal infection. CSFV-negative pigs were vaccinated as controls. The humoral and interferon gamma responses as well as the CSFV RNA loads were monitored for 21 days post-vaccination. No vaccine viral RNA was detected in the serum samples and tonsils from CSFV postnatally persistently infected pigs for 21 days post-vaccination. Furthermore, no E2-specific antibody response or neutralising antibody titres were shown in CSFV persistently infected vaccinated animals. Likewise, no of IFN-gamma producing cell response against CSFV or PHA was observed. To our knowledge, this is the first report demonstrating the absence of a response to vaccination in CSFV persistently infected pigs.

No MeSH data available.


Related in: MedlinePlus