Early Mycoplasma hyopneumoniae infections in European suckling pigs in herds with respiratory problems: detection rate and risk factors

The present study aimed at estimating the detection rate of M. hyopneumoniae in 3-week-old pigs in different European countries and to identify possible risk factors. Nasal swabs from suckling pigs in 52 farms were collected for nested PCR analysis. Potential risk factors for respiratory disease were analysed with a multi - variable logistic regression model. The average percentage of positive piglets was 10.7% (95% confidence interval, CI 7.4-14.2); at least one pig tested positive in 68% of herds. In 32% of the herds, more than 10% of piglets tested positive. Herds that vaccinated sows against swine influenza virus (SIV) had a significantly higher risk of a piglet being positive for M. hyopneumoniae (OR 3.12; 95% CI 1.43-6.83). The higher risk in case of SIV vaccination is difficult to explain, but may be due to the fact that pig herds with respiratory symptoms are more likely to be vac - cinated against SIV, overlooking the possible influence of other respiratory pathogens such as M. hyopneumoniae. The present findings show that M. hyopneumoniae is widespread in 3-week-old piglets across different European countries.