No abstract

Campylobacter fetus is a gram-negative motile bacterium, with two subspecies relevant for cattle health: C. fetus subsp. venerealis (Cfv) and C. fetus subsp. fetus (Cff). Both subspecies are associated with reproductive losses in cattle. Herein, the C. fetus infection of three Angus bulls naturally challenged with Cfv, Cfv biovar intermedius (Cfvi) or Cff were assessed through conventional and molecular diagnosis of preputial smegma (PS) samples collected with different devices. The Cfv-and Cfvi-bulls were positive until at least 9 months. Although Cff is not considered a venereal strain, this study demonstrated its transmission to bull from heifers experimentally infected, with evidence of colonization and persistence in the preputial cavity for 5 to 6 months. This nding suggests a potential risk of dissemination of the bacteria within herds. The results obtained by bacteriological culture or direct immuno uorescence (DIF) showed no signi cant differences, regardless the sampling device used (aspiration with Cassou pipette, metal and plastic scraper). On the other hand, the qPCR for C. fetus detection yielded better results with an in-house DNA extraction method than with a commercial kit (75% vs 66.6%). Furthermore, the molecular diagnosis by qPCR was more e cient than culture (66.6%) or DIF (56%). Bacteremia in whole blood samples was negative by qPCR and bacteriological culture in all samples. PCR-based methods are promising for the diagnosis of Bovine Genital Campylobacteriosis from clinical samples of PS. This study demonstrated the transmission of Cff from heifers to bull.

Campylobacter fetus is a gram-negative motile bacterium, with two subspecies relevant for cattle health: C. fetus subsp. venerealis (Cfv) and C. fetus subsp. fetus (Cff). Both subspecies are associated with reproductive losses in cattle. Herein, the C. fetus infection of three Angus bulls naturally challenged with Cfv, Cfv biovar intermedius (Cfvi) or Cff were assessed through conventional and molecular diagnosis of preputial smegma (PS) samples collected with different devices. The Cfv- and Cfvi-bulls were positive until at least 9 months. Although Cff is not considered a venereal strain, this study demonstrated its transmission to bull from heifers experimentally infected, with evidence of colonization and persistence in the preputial cavity for 5 to 6 months. This finding suggests a potential risk of dissemination of the bacteria within herds. The results obtained by bacteriological culture or direct immunofluorescence (DIF) showed no significant differences, regardless the sampling device used (aspiration with Cassou pipette, metal and plastic scraper). On the other hand, the qPCR for C. fetus detection yielded better results with an in-house DNA extraction method than with a commercial kit (75% vs 66.6%). Furthermore, the molecular diagnosis by qPCR was more efficient than culture (66.6%) or DIF (56%). Bacteremia in whole blood samples was negative by qPCR and bacteriological culture in all samples. PCR-based methods are promising for the diagnosis of Bovine Genital Campylobacteriosis from clinical samples of PS. This study demonstrated the transmission of Cff from heifers to bull.