Comparison of ante-mortem assays to assess progression/regression of paratuberculosis in individual dairy animals

Abstract

Johne's disease, caused by Mycobacterium avium, subspecies paratuberculosis (MAP) is becoming increasingly widespread on dairy farms worldwide, due in part, to the absence of vaccine/drug or curative modalities. This spread is of concern since MAP is at the center of a controversy as to its role in Crohn's disease. None of the methods presently available to define paratuberculosis in cattle have been examined for their ability to assess progression/regression of any treatment or intervention of this disease The research presented herein, therefore was designed to assess the reliability and accuracy of available ante-mortem assays to predict disease change of individual animals undergoing a probiotic, potentially therapeutic, treatment. Paratuberculosis positive (n = 75) and negative (n = 10) animals were longitudinally monitored over their natural lifetimes with specific serum antibody and fecal shedding assays, and for development of end-stage clinical disease. Longitudinal, increasing/decreasing serum ELISA values were associated with, and predictive of, progression/regression of disease. Changes in fecal shedding and serum AGID were of value at only specific stages. Documentation that ELISA-positive animals were positive for paratuberculosis was done by a compilation of ELISA-independent assays--succumbing with end-stage clinical disease, autopsy, AGID, and MAP fecal shedding.

A 60-day probiotic protocol withDietziasubsp.C79793-74prevents development of Johne's disease parameters after in utero and/or neonatalMAPinfection

“…Evidence supporting positivity of the three ELISA-only-positive dams (dams of calves 1-2, 3-3 and 4-1) is that 2 (calves 1-2 and 4-1) of these 3 calves tested both ELISA-and fecal-positive-both calves were born prior to initiating a Dietzia treatment that cured the dams-prevented development of fecal shedding. [13][14][15] Therefore, based on the predictive accuracy of the Allied Monitor ELISA found with the previous 75 adults, 37 plus similar accuracy found for the dams in the present study, the probability that all animals (dams and calves) that were only ELISA testpositive as adults, irrespective of their age, are not paratuberculosis-positive is extremely remote.…”

“…Stage III animals had signs of early clinical disease (change in fecal consistency, loss of appetite and reduced milk production, all noted by the author) and were either ELISA-and/ or fecal-positive, whereas, Stage IV animals had severe, end-stage clinical disease, irrespective of whether they were ELISA-and/ or fecal-negative/positive (almost all were fecal shedding). The magnitude of ELISA values and fecal shedding cfu were not used to define these stages, since previous longitudinal assessment 37 showed that there was no correlation. All dams were tested three to four times per year over their lifetime and maintained in the herd until local veterinarians humanely euthanized recumbent, emaciated and/or cachectic animals that could not rise and stand on their own by intravenous injection of a sodium pentobarbital solution (Fatal Plus, 6 g/ml) at a dose of 1 ml per 4.5 kg body weight.…”

“…Since animals that continually tested negative skew these values higher, perhaps a more informative way to coming from a report that MAP growth in vitro was inhibited by Dietzia under specific culture conditions 34 in a similar way to that achieved in vitro by antimicrobial drugs. 35,36 The results of these previous investigations [13][14][15] indicated that (a) longevity of late-stage, diseased cows was significantly extended by an extensive Dietzia treatment (high daily dose of >5 x 10 11 cfu for months) and (b) 40% of cows in the early stages of Johne's disease were "cured" by a similar extensive treatment; i.e., those cured became negative for all parameters used to define paratuberculosis, 37 lived a normal uneventful life and succumbed to nonparatuberculosis insults. More importantly, the Dietzia cures were long-lasting post-treatment and were therefore unlike the palliative benefits of anti-mycobacterials described for paratuberculosis goats and cattle.…”

The Johne paradigm: From detection to management to treatment

“…By testing a combination of Allied's MAP ELISA, bacterial fecal growth and serum agar gel immunodiffusion (AGID), Click has determined that ELISA analysis is the most accurate and reliable testing method for changes in the disease status of an individual by best-fit longitudinal increases/decreases in serum ELISA values with a sensitivity of 100%. 26 Click was able to determine that Allied's ELISA detected MAP antigens at a much earlier time point in the progression of disease, as compared with other leading ELISA methods, leading to its very high sensitivity. These ELISA values did not directly correlate with the fecal shedding of MAP, which as it turns out, is advantageous since serum ELISA values were detectable before fecal shedding was detected.…”

“…17,18,23 Reports of variability in the sensitivity of the ELISA for the diagnosis of MAP-positive sera for isolates derived from different host species is not surprising since antigen preparation is not standardized. [24][25][26] Although the current challenges discussed here have been plaguing Johne disease researchers for some time, recent events in research conducted by Click et al [26][27][28][29] shed a sense of optimism on a somewhat overwhelming subject. 29 This data shows a direct impact of Dietzia not only on the shedding of MAP bacteria in the feces but also on the disease status of the individual.…”