Infectious bovine bacteria detected in porcine lung infections in Quebec.

Ureaplasma diversum (U. diversum) is a bacterium considered infectious and that can cause abortions and respiratory diseases in cattle. This bacterium is found in many countries on all continents, mostly in cattle. However, in Quebec, Dr. Dominique Fournier and his MAPAQ colleagues have noticed a significant increase in Quebec in cattle abortion cases associated with U. diversum since 2015.

The old diagnostic techniques based on the culture of this bacterium are long, laborious and insensitive with frequent failures, which led MAPAQ to wish to use a faster and more sensitive molecular diagnostic test, a PCR test. The Diagnostic Service of the Faculté de médecine vétérinaire (FMV) of the Université de Montréal therefore developed such a PCR test and started to check its validity by analyzing several samples of animal secretions and tissues (organs) of various animal species (pets, wildlife, breeding). This validation went well confirming the sensitivity of the FMV test on tissues and secretions of cattle. Nonetheless, it also allowed identifying two samples of pigs positive for this bacterium, with respiratory lesions. This result aroused curiosity of the FMV team.

The study of scientific literature highlighted a single detection, in Cuba in 2013, of pigs carrying this bacteria. Dr. Fournier and Dr. Gagnon then analyzed the clinical data of these two Quebec swine cases from different farms. Both cases had respiratory lesions compatible with the presence of mycoplasma. For one of the two pigs, only Ureaplasma diversum, which is of the same family as mycoplasmas, was identified following sequencing of the mycoplasma present. This suggested that this bacterium was involved in some of the respiratory lesions present. However, other respiratory pathogens were present in these two pigs and U. diversum might cause respiratory lesions only in the presence of other pathogens and not primarily. Then the role of U. diversum as a causal agent of the infection remains a hypothesis at this point. A team from another diagnostic service, the Prairie Diagnostic Services (PDS) in Saskatoon, corroborated FMV's PCR results, confirming that this bovine bacteria, ie. U. diversum was present in both swine cases.

In Cuba, 6.6% of pigs carry this bacterium, whereas the prevalence of U. diversum in Canadian hog is still unknown. Nevertheless, preliminary results suggest a prevalence of 2.59% - 3.85% from the Faculty’s collection of clinical specimens submitted in the past to confirm the presence of other infectious diseases.

In conclusion, Quebec now has a rapid test to monitor cattle infections with U. diversum, the incidence of which appears to be increasing. Following the discovery of this bacterium, which has a virulent power in cattle also in the Canadian hog; it has now become essential to confirm the role of the latter in respiratory diseases of pork.

Source: First report of Ureaplasma diversum, a bovine pathogen, in the respiratory tract of swine in Canada. Yaima Burgher, Marika Koszegi, Valérie Grenier St-Sauveur, Dominique Fournier, Cynthia Lafond-Lambert, Chantale Provost, Carl A. Gagnon. CVJ / VOL 59 / DECEMBER 2018