- 2 minutes, 12 seconds
- Expertise article
- Kraft C., Dürlinger S., Balka G., Rathkjen PH., Morgenstern R., Ladinig A.
INTRODUCTION
Porcine reproductive and respiratory syndrome (PRRS) is one of the most widespread, and economically devastating disease in swine production. lt is characterized by reproductive losses in breeding herds, increased mortality in newborns and respiratory disorders in growing pigs. Vaccination of piglets with modified life virus (MLV) vaccines has been shown to be an effective measure to aid in the effects of wildtype virus infection and general health of the animals (Balka et al., 2016).
STUDY DESIGN
The aim of the study was to investigate the induction of cough after challenge with a highly pathogenic PRRSV-1 strain (AUT15-33) in vaccinated and non-vaccinated piglets. Vaccination was performed at three weeks of age and challenge was administered three weeks post vaccination. Coughing was monitored from the day of vaccination until two weeks post challenge either by the study investigator or a 24/7 continuously monitoring system (SoundTalks NV, Belgium) METHODS The experiment consisted of a total of 25 piglets that were assigned into three groups. One group of 10 animals was vaccinated with Ingelvac PRRSFLEX® EU, while the second group of 10 animals was not vaccinated (challenge control), the third group of five animals served as strict negative control. Animals were kept under the same conditions, but in separate rooms.
Three weeks after vaccination groups 1 and 2 were intranasally challenged with the highly pathogenic PRRSV-1 strain AUT15-33 (‘ACRO’ strain).
Separate cough monitor systems were installed in each of the rooms. Collected digital data were uploaded to the SoundTalks database and analyzed (see Fig. 1).
Figure 1. Cough index per day
RESULTS
The investigator visited each animal room once per day at around the same time. No respiratory clinical signs were recorded in the vaccinated group and only one animal was recorded with dyspnoe in the challenge control group from 10 to 14 days post challenge.
The cough monitor recorded a low amount of cough until time of challenge (cough index: 0 – 6). After challenge the cough index remained the same for the vaccinated group, however, in the non-vaccinated challenge group the cough index started to rise above the previous background one week after challenge and was markedly higher (up to cough index 19) for the following seven days (see Fig. 1).
The cough monitor recorded cough mainly during night and early morning hours (see Fig. 2), when the monitoring investigator was not present.
Figure 2. Cough index per hour
CONCLUSIONS
The continuous recording of cough revealed a distinct difference between vaccinated and non-vaccinated animals after challenge that was not adequately observed with the punctual recording. Therefore, the cough monitoring system offers more accurate information on the situation in a herd than what can be achieved by human staff.
REFERENCES
Balka G, et al. Porcine Health Management 2016 2:24