Pathogenicity study of Mycoplasma hyorhinis and M. flocculare in specific-pathogen-free pigs pre-infected with M. hyopneumoniae

Publication date: Available online 6 April 2019Source: Veterinary MicrobiologyAuthor(s): Sarah Fourour, Véronique Tocqueville, Frédéric Paboeuf, Gérald Lediguerher, Nadège Morin, Isabelle Kempf, Corinne Marois-CrehanAbstractMycoplasma (M.) hyopneumoniae is the initiator agent of the porcine respiratory disease complex (PRDC) and the etiological agent of enzootic pneumonia. M. hyorhinis and M. flocculare are also found in extensive gross pneumonia-like lesions, but their role is not known. We investigated the pathogenicity of M. hyorhinis and M. flocculare in specific-pathogen-free pigs pre-infected or not with M. hyopneumoniae. Mono-inoculated pigs with M. flocculare showed no clinical signs, hematological changes or macroscopic lesions upon necropsy. Mono-inoculated pigs with M. hyorhinis showed, overall seven days after inoculation, an increase in mean temperature with increases in white blood cell (monocyte) counts and in concentrations of pig major acute phase protein, whereas the average daily weight gain (ADWG) decreased compared with non-infected animals. M. hyorhinis was detected in serous membranes (polyserositis) but not in bronchi. Co-infected pigs with M. hyopneumoniae and M. hyorhinis or M. flocculare showed lower ADWG during the third week of the experiment and higher haptoglobin concentrations in contrast to pigs only mono-infected with M. hyopneumoniae. In pigs co-infected with M. hyopneumoniae and M. hyorhinis, it was interesting to observe that (i) M. h...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research