| dc.description.abstract | Abstract
Background
Porcine respiratory disease complex (PRDC) is now regularly used to describe multifactorial clinical porcine respiratory disease caused by individual infections or coinfections of viruses and bacteria. As one of the most prevalent health issues in domestic pigs, respiratory disease shows impacts on pig production performance like average daily gain (ADG), mortality and feed conversion rate (FCR). Impacts of different pathogen infections were previously studied separately on individual cases, did not map the difference between (co-)infections, different pathogens, epidemic or endemic scenarios and geographic locations. Results from different studies are heterogeneous, making it challenging to accurately assess the true impacts of disease and develop effective pathogen prevention strategies. Therefore, the aim of this systematic review was to identify studies carried out on the impact of infectious respiratory disease on the production performance of nursery and fattening pigs, to identify impacts of single pathogen infection and co-existing PRDC pathogens, to identify variations across continents, genotypes and disease scenarios.
Results
By following PRISMA method, a total of 38 studies were considered as eligible for this systematic review. The main findings in this review were: 1) The studies were conducted in 17 different countries, including European, North American, Asian countries and Brazil; 2) M. hyopneumoniae and PRRSV were the most studied pathogens, while SIV, PCV2 and A. pleuropneumoniae were mostly studied in coinfection cases; 3) Comparability of impacts on production performance was limited due to the lack of evidence regarding the baseline production parameters, inadequate information on disease history, and the absence of genotype and other pathogens detection; 4) It is difficult to attribute the change of production parameters to specific pathogen single infection or coinfection; 5) Epidemic infections seem to induce higher mortality in pig herds than endemic infections; 6) Coinfections did not show significantly different impacts on production parameters compared to single pathogen infections.
Discussion
This systematic review gives insight into the distribution and focus of respiratory disease research in pigs across different regions and highlights the need for more studies with detailed baseline production performance, pathogen genotype detection and investigation of coinfection scenarios. Further research can be conducted in the potential differences in impacts on performance between international production systems. | |
