Persistence of Mycoplasma hyopneumoniae sequence types in spite of a control program for enzootic pneumonia in pigs

Publication date: Available online 26 June 2017 Source:Preventive Veterinary Medicine Author(s): Gudrun Overesch, Peter Kuhnert Enzootic pneumonia (EP) in pigs caused by Mycoplasma (M.) hyopneumoniae has successfully been combatted in Switzerland. A control program was fully implemented in 2004 which is based on total depopulation strategies of affected fattening farms as well as partial depopulation on breeding farms. Thereby, the number of cases has dropped drastically from more than 200 in 2003 to two cases in 2013. Currently monitoring is done based on clinical observation and subsequent diagnostic of coughing pigs. Moreover, in case of more than 10% gross pathological lesions per slaughter batch laboratory confirmation for EP is compulsory. Despite these strict measures it was not possible to eliminate M. hyopneumoniae from Swiss pig production. In fact, during the last few years the number of EP cases has slightly increased. Therefore, genotyping of the involved M. hyopneumoniae strains was conducted in order to elucidate possible sources and routes of infection. All available and typeable samples from totally 22 cases during the period 2014–2016 were investigated by extended multilocus sequence typing (MLST). A total of 16 cases, including eight from 2014, five from 2015 and three from 2016 could thereby be included in the study. MLST revealed that the majority of cases in 2014/2015 were due to two major spread scenarios, i.e. two M. hyopneumoniae sequence types,...
Source: Preventive Veterinary Medicine - Category: Veterinary Research Source Type: research