No evidence of Mycobacterium avium subsp. paratuberculosis in in vitro produced cryopreserved embryos derived from subclinically infected cows

Decontamination of Bovine Fecal and Environmental Samples Aimed to Culture Mycobacterium Paratuberculosis in Liquid Media: A Narrative Review

“…The centrifugal concentration of bovine fecal specimens has been shown to shorten the incubation time required. However, centrifugation did not increase the isolation rate of MAP from fecal specimens when compared to the standard sedimentation method [16].…”

“…In addition, incubation temperature has an impact on decontamination results, concluding that double incubation at 42 °C was more selective and sensitive than the standard procedure at 37 °C on this matrix (fecal slurry) [15]. Double centrifugation-based protocols increase the chances of detecting animals shedding small numbers of organisms [16]. Recent approaches concluded that the most successful method for bovine fecal sample processing involves double centrifugation, and then the culture in two stages-culture systems (liquid, then solid).…”

“…According to the author, this can be due to the centrifugation process and to the longer storage of the samples [17]. Nevertheless, other authors have reported a significant increase in contamination (60 vs. 26%) in fecal samples prepared for culture by the centrifugation method compared to those processed by the sedimentation method in HEYM cultures, with overall detection rates being similar between methods [16]. Other authors have described an alternate centrifugation/ double incubation method, with lower centrifugation speeds than the Cornell method, to reduce contamination problems.…”

Detection of Mycobacterium avium subsp. paratuberculosis in reproductive tissue and semen of naturally infected rams

“…However, although the mycobacteria from the semen samples used in this study did not show the capability of replication in culture, the identification of MAP in semen through nPCR does reveal the potential risk of horizontal transmission to the female via semen, which has already been considered in bovines (Larsen et al, 1981;Ayele et al, 2004). To test the risk of horizontal transmission, cows have been inseminated with doses of 5×10 8 CFU of MAP, twenty four hours after artificial insemination or after natural mounting; then this mycobacterium was isolated in uterus and in uterine horns during the first week, in utero and pelvic lymph nodes in the second week (Perry et al, 2006). For the area of animal reproduction, the identification of MAP in reproductive tissue and semen is of great relevance, since this study confirms the presence of MAP in tissues and organs that are not considered target organs, in addition to the fact that infected rams can be a source of infection.…”

Sanitary control in bovine embryo transfer How far should we go? A review

“…In 2000, the true herd prevalence of M. paratuberculosis infection in Belgium was estimated at 6%, but due to the relatively low test specificity, this figure must be considered with caution (9). Cows with subclinical Johne's disease however do not seem to transmit the disease by embryo transfer when the embryos have been washed as recommended by the International Embryo Transfer Society (IETS) (4,49 and not necessarily in the same animals (57).…”