Serological investigations regarding the effect of infection with swine influenza virus H1N1 on the evolution of enzootic pneumonia in fattened pigs from western romanian farms

It is well-kown that to minimize the impact of respiratory diseases in pig farms, modern production systems have been developed. Despite these trends toward high health levels, Mycoplasma hyopneumoniae and swine influenza virus (SIV) remain significant pathogens in the pig industry. Therefore, in recent years, the occurrence and the relevance of these pathogens in growing and fattening pigs has been examined in several studies. However, none of these studies included a detailed analysis regarding the effect of infection with swine influenza virus H1N1 on the evolution of enzootic pneumonia in fattened pigs. For this reason, the aim of the present study was to compare the seroprevalence of infection caused by Mycoplasma hyopneumoniae in fattened pigs with that determined by swine influenza virus subtype H1N. To achieve this goal, detection of antibodies against Mycoplasma hyopneumoniae and swine influenza virus H1N1 was performed by ELISA technique in pig fattening farms located in Western Romania. The value of seroprevalence of infection with Mycoplasma hyopneumoniae within the infected farms ranged between 5.88% and 92.85%. Mixed infections of swine influenza virus subtype H1N1 and Mycoplasma hyopneumoniae had been identified in four out of the six farms studied for both types of infection. By comparing the seroprevalence of infection caused by swine influenza virus subtype H1N1 with that determined by Mycoplasma hyopneumoniae, it was concluded that in farms (AR2, AR3, TM3 and TM4), where the value of seroprevalence of swine influenza virus subtype H1N1 ranged between 5.88% and 25%, the seroprevalence of infection caused by Mycoplasma hyopneumoniae had increased from 5.88% (in farm TM4) to 92.85% (in farm AR3). From a statistical point of view, no correlation between the two infections was found in this study. Knowing and understanding this aspect is important for both the pig industry and a public health point of view. Taking into account the multifactorial character of enzootic pneumonia and swine influenza virus infection, the results of this study emphasize that a comprehensive herd specific prevention program is a prerequisite to reduce transmission of both diseases in pig fattening farms