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PubMed2025

The Results After One Year of an Experimental Protocol Aimed at Reducing Paratuberculosis in an Intensive Dairy Herd.

Paratuberculosis or Johne's disease is caused by Mycobacterium avium subsp. paratuberculosis (MAP). The disease is characterized by a chronic and incurable enteritis in ruminants and it is responsible for significant economic losses, also raising concerns about food safety and animal welfare. Effective control is hindered by diagnostic limitations, long incubation periods, and the environmental resistance of the pathogen. This study aimed to reduce the apparent prevalence of paratuberculosis in a single intensive dairy herd through an integrated approach that combines diagnostics and management strategies. All cows over 24 months of age were tested using both fecal PCR and ELISA serology. Digital PCR (dPCR) was used to quantify MAP shedding in fecal-positive animals, enabling prioritization for removal based on environmental contamination risk. Integrating diagnostic tools allowed the precise identification and quantification of high-risk animals. Meanwhile, structural improvements and biosecurity measures were implemented on the farm. Preliminary outcomes suggest a marked reduction in herd-level MAP prevalence, lowering the seroprevalence from 7.6% to 4.5% and the fecal PCR prevalence from 6.5% to 2.8%. This case highlights the effectiveness of combining laboratory testing (serology and molecular diagnostics) and targeted changes in farm management to control paratuberculosis in high-density dairy systems.

MAP↗
PubMed1979

Paratuberculosis (Johne's disease) in bighorn sheep and a Rocky Mountain goat in Colorado.

Between May, 1972 and February, 1978, six cases of paratuberculosis (Johne's Disease) caused by Mycobacterium paratuberculosis were diagnosed in free-ranging Rocky Mountain bighorn sheep (Ovis canadensis) and one Rocky Mountain goat (Oreamnos americanus) on or near Mt. Evans in Colorado. Diagnosis of paratuberculosis was based on gross and histopathologic examination of the animals and by isolation of M. paratuberculosis from three sheep and the goat. The clinical signs and pathologic changes seen in the bighorn sheep resembled those described in cattle, while the lesions in the goat were similar to those described for domestic sheep and goats.

Animals↗
PubMed1975

Effect of aflatoxin on susceptibility of hamsters to Mycobacterium paratuberculosis.

After oral administration of Mycobacterium paratuberculosis to hamsters, the organism passed the epithelial barrier of the intestine, and infection was established in the small intestine and mesenteric lymph nodes. The addition of aflatoxin to the ration of hamsters did not increase their susceptibility to M paratuberculosis but, rather, seemed to decrease susceptibility to the bacillus. Hamsters not treated with aflatoxin and infected with M paratuberculosis had higher bacterial counts in intestinal tract and mesenteric lymph node on necropsy than did infected hamsters that had been treated with aflatoxin. Aflatoxin-treated hamsters grew slowly, had an unthrifty appearance, and developed lesions of megalocytosis regardless of whether they were infected with M paratuberculosis.

Administration, Oral↗
PubMed2002

Diagnosis of paratuberculosis in naturally infected goats.

A survey was carried out to verify if an immunohistochemical method associated with agar gel immunodiffusion (AGID) will establish a firm diagnosis of caprine paratuberculosis. One hundred and thirty-six goats were tested by AGID for antibodies against Mycobacterium avium subsp. paratuberculosis at two different times: the first time 22 (19.1%) were positive and the second time 25 (18%). One seronegative goat with severe diarrhea and 5 seropositive goats, two of which showing similar clinical signs, were sacrificed and necropsied. Samples were taken from small intestine, liver, spleen, mesenteric lymph nodes for bacteriological, histological and immunohistochemical examinations. M.a. paratuberculosis was isolated from intestine samples of 4 seropositive goats and from mesenteric lymph nodes of one seropositive goat; the microorganism was not isolated from samples of one seropositive and the seronegative animals. Ziehl Neelsen staining showed acid-fast bacilli in macrophages of the 5 seropositive animals and the immunohistochemical method for M. a. paratuberculosis detected bacterial antigen in the same samples.

Animals↗
PubMed1991

Serodiagnosis of bovine paratuberculosis by use of a dot enzyme-linked immunosorbent assay.

A dot ELISA was developed for detection of antibodies to Mycobacterium paratuberculosis. The assay was evaluated by testing sera from cattle that were determined, by bacteriologic culturing of feces, to be infected with M paratuberculosis and were suspected of having clinical disease. Further evaluation involved testing sera from cattle in which M paratuberculosis had not been isolated from feces on several attempts. Results of the dot ELISA were positive for sera from 86 of 101 infected cattle, and results were negative for sera from 64 of 64 noninfected cattle. Results of conventional ELISA and agar gel immunodiffusion (AGID) tests were positive for 79 of 99 and for 51 of 101 infected cattle, respectively. The dot ELISA also was evaluated by comparing results of testing 708 sera with results of bacteriologic culturing of matched fecal samples from 262 cattle in 3 central Ohio dairy herds known to include cattle infected with M paratuberculosis. Results of the dot ELISA were positive for 25 of 39 sera from cattle with positive results on culturing of concurrently obtained fecal specimens. The dot ELISA results were negative for 661 of 669 sera from cattle with negative results to culturing of concurrently obtained fecal specimens. The 39 sera from cattle with positive results on bacteriologic culturing of matched fecal specimens had positive results for ELISA and the AGID test 25 and 14 times, respectively. The 669 sera from cattle with concurrently negative results on bacteriologic culturing of feces had negative results to ELISA and the AGID test 559 and 668 times, respectively.

Animals↗
PubMed1990

Probable paratuberculosis in a Sicilian ass.

A presumptive diagnosis of paratuberculosis was made in a Sicilian ass on the basis of a history of chronic diarrhea and weight loss, pasture exposure to a heifer with paratuberculosis confirmed by bacterial culture of feces, postmortem identification of granulomatous inflammation of the intestine containing acid-fast organisms, the absence of acid-fast organisms in extraenteric tissues, and the absence of exposure to tuberculosis. The literature on paratuberculosis in equids is reviewed. The potential for cross-species transmission is emphasized. Justification for consideration of Mycobacterium paratuberculosis infection in the differential diagnoses of equine granulomatous enteritis is discussed.

Animals↗
PubMed1990

Granulomatous enteritis following oral inoculation of newborn rabbits with Mycobacterium paratuberculosis of bovine origin.

To assess the rabbit as a model for the study of paratuberculosis infection, two groups of newborn rabbits were orally inoculated at one to two days of age with Mycobacterium paratuberculosis (ATCC 19698 or field strain 22206) and compared to uninoculated controls. Nine of thirteen rabbits (69%) inoculated with ATCC 19698, and all three rabbits inoculated with 22206, experienced episodes of intermittent diarrhea starting four months after inoculation. Multifocal granulomas containing acid-fast organisms were observed in the sacculus rotundus and vermiform appendix of the cecum in three of nine rabbits (all with diarrhea) that had been inoculated with ATCC 19698. Although M. paratuberculosis was not recovered from inoculated rabbits when fecal cultures were incubated three months in vitro, a slow-growing mycobactin-dependent form of Mycobacterium was recovered from feces and ileal tissue after incubation for 11-15 months. Reduced feed intake, body weight loss and reduced abdominal fat at necropsy, were not observed. Epithelial transport function across the distal ileum in vitro was not altered nine months subsequent to inoculation. Diarrhea and the histological lesions indicate that the rabbit may be a useful model for the study of paratuberculosis infection.

Animals↗
PubMed1989

Comparison of dot immunobinding assay, enzyme-linked immunosorbent assay and immunodiffusion for serodiagnosis of paratuberculosis.

A rapid, simple and inexpensive dot immunobinding assay (DIA) was evaluated for the serodiagnosis of paratuberculosis in cattle. The assay was performed on nitrocellulose strips which were dotted with purified protoplasmic antigen of Mycobacterium paratuberculosis. After incubation with test serum samples, the bound antibodies were detected using an enzyme-amplified immunostaining procedure. The efficacy of DIA as a screening test for paratuberculosis was compared to that of an enzyme-linked immunosorbent assay (ELISA), a modified agar gel immunodiffusion (mAGID) test, and an AGID test using 329 serum samples from cattle which were examined for M. paratuberculosis infection by a sensitive fecal culture technique. The DIA and ELISA had comparable results and both of the enzyme immunoassays had higher sensitivity than tests based on AGID. The sensitivity of all four tests was influenced by the intensity of fecal bacterial shedding. Preabsorption of sera with Mycobacterium phlei increased the sensitivity of both enzyme immunoassays. the specificity but reduced the sensitivity of both enzyme immunoassays.

Animals↗
PubMed1986

Restriction endonuclease analysis of various strains of Mycobacterium paratuberculosis isolated from cattle.

Deoxyribonucleic acid (DNA) preparations from 3 reference strains of Mycobacterium paratuberculosis and from 23 isolates of M paratuberculosis obtained from cattle in New Zealand were characterized by restriction endonuclease analysis, using the enzymes BstE II, Pvu II, and Bcl I. Patterns of DNA fragments for strain 18 (one of the reference strains) differed markedly from patterns of other strains, indicating genetic differences between strain 18 and the other strains of M paratuberculosis evaluated. The other 2 reference strains (TMC 1613 and Weybridge strain 316) and all but 1 of the isolates from cattle had identical patterns with the 3 enzymes. These 2 reference strains differed from each other in their dependence on exogenous mycobactin, but this was not reflected in their restriction patterns. The single variant isolate from cattle had patterns identical to those of the other isolates, using Pvu II and Bcl I, and had only 1 fragment line difference with BstE II. Although close genetic homogeneity of cattle strains of M paratuberculosis prevented development of a typing system on the basis of restriction endonuclease analysis, the results provided a basis for genomic comparison with other closely related organisms.

Animals↗
PubMed1986

Evidence of paratuberculosis in Ohio's white-tailed deer, as determined by an enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was developed and used to detect antibodies to Mycobacterium paratuberculosis in serum samples obtained in December of 1983 from 954 hunter-killed white-tailed deer (Odocoileus virginianus) in 13 Ohio counties. Positive or negative status was determined by calculating a signal-to-noise ratio, a ratio between the optical density of the test serum and negative reference sera; a ratio of greater than or equal to 3.0 was considered positive. Twenty-four samples (2.5%) were found to be assay positive, using this method. A statistically significant difference among age groups was found, with those less than or equal to 6 months of age having a lower proportion of positives. Differences by sex were not observed. To determine the validity of the ELISA in deer, serum samples from 46 fallow (Dama dama) and axis deer (Axis axis) harvested from a known infected population were tested by ELISA and agar-gel immunodiffusion. The agar-gel immunodiffusion test showed evidence of exposure of the deer to M paratuberculosis or a related antigen. The ELISA closely approximated the prevalence of paratuberculosis infection as previously determined by fecal culture in this population. As a result of these tests, it was concluded that free-ranging Ohio deer have been infected with M paratuberculosis or exposed to a closely related antigen.

Animals↗
PubMed1987

Analysis by ELISA and Western blotting of antibody reactivities in cattle infected with Mycobacterium paratuberculosis after absorption of serum with M phlei.

Preabsorption of cattle serum with Mycobacterium phlei was of value in eliminating falsely positive reactions in an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against M paratuberculosis. Specific antibody titres from 16 animals naturally infected with M paratuberculosis were unaffected by absorption. Analysis by Western blotting indicated that a different set of antigens of M paratuberculosis were recognised by serum from falsely positive reactors compared with that from animals with established infection. After experimental infection the time required for seroconversion in the ELISA in nine calves lay between 10 and 28 months, although one animal had not seroconverted after 30 months when the experiment ended. All animals shed M paratuberculosis in their faeces before seroconversion.

Animals↗
PubMed1988

Relationship between Mycobacterium avium, Mycobacterium paratuberculosis and "wood pigeon mycobacteria". Determinations by DNA-DNA hybridization.

The DNA-DNA homology percentages obtained in this study indicate that M. avium and M. paratuberculosis belong to one species. Consequently, M. paratuberculosis ought to be considered a variant of M. avium, and the following designations are proposed: Mycobacterium avium, subsp. avium. Mycobacterium avium, subsp. paratuberculosis. Identification and classification of "wood pigeon mycobacteria" occurring in wild animals have been problematic due to their dysgonic and mycobactin-dependent growth. DNA-DNA homology percentages indicate that these bacteria are closely related to reference strains both of M. avium and of M. paratuberculosis. "Wood pigeon mycobacteria" should therefore be classified as atypical strains of M. avium, and the following designation is proposed: Mycobacterium avium subsp. columbae.

Animals↗
PubMed1988

Characterization of clinical isolates of Mycobacterium paratuberculosis by DNA-DNA hybridization and cellular fatty acid analysis.

The DNA-DNA homologies obtained were more than 90 per cent for all strains examined, including the reference strains of Mycobacterium paratuberculosis and Mycobacterium avium. Consequently, in a genetic sense, M. paratuberculosis with its variants belong to a single species which should be considered a subspecies of M. avium. The same reference strains of M. paratuberculosis and M. avium showed small but distinct differences in the cellular fatty acid patterns. The Norwegian goat isolate proved to be M. paratuberculosis, while the three sheep isolates from Iceland and the Faroe Islands showed a typical M. avium pattern.

Animals↗
PubMed1987

Disseminated Mycobacterium paratuberculosis infection in a cow.

A cow with chronic diarrhea and weight loss caused by localization of Mycobacterium paratuberculosis in the intestinal tract (Johne's disease) had gross and microscopic changes indicative of a disseminated infection. A direct association between the remote lesions and the intestinal infection was shown by isolation of M paratuberculosis from renal tissue, detection of intracellular M paratuberculosis antigen(s), using an indirect immunoperoxidase method, and by the characteristic granulomatous nature of the lesions. This case illustrates the potential for extra-intestinal lesions in M paratuberculosis infection of cattle and should cause veterinarians to consider mycobacterial disease when confronted with multinodular lesions of the bovine kidney. The immunoperoxidase method was useful in determining the cause of the inflammatory lesion in which intact organisms were not evident.

Animals↗
PubMed1985

[Economic losses to farms due to paratuberculosis in cattle].

The results of a study on economic losses to farms caused by paratuberculosis in dairy cattle are reported. Quantification of the decrease in production and determination of standard losses due to premature disposal using calculations based on a model were stressed. A decrease in production of 19.5 per cent compared with the last lactation but two was recorded in animals showing clinical symptoms of paratuberculosis. The decrease in production was 5 per cent during the last lactation but one compared with the previous lactation. The decrease in production during lactation on disposal was 16 per cent and 6 per cent during the last lactation but one compared with the last lactation but two in animals with non-clinical forms of paratuberculosis. The average cow showing clinical symptoms of paratuberculosis, which was disposed of, caused a total loss of 2,250 guilders, whereas the average cow with a non-clinical form of Johne's disease was estimated to cause a loss of 1,800 guilders.

Animal Husbandry↗
PubMed1979

Susceptibility of the lemming (Dicrostonyx rubricatus) to Mycobacterium paratuberculosis.

The susceptibility of the lemming (Dicrostonyx rubricatus) to Mycobacterium paratuberculosis was studied. Twelve lemmings were exposed to cultural material of M paratuberculosis and were necropsied at 40- to 260-day intervals after exposure. Selected tissues were examined bacteriologically and histologically. Mycobacterium paratuberculosis was recovered from all exposed lemmings except the one necropsied 40 days after exposure. Pathologic changes typical of paratuberculosis were seen in a few lemmings. Clinical signs of disease were not seen. Rate of growth and general appearance of the exposed lemmings and the normal controls did not differ. The extent of infection in this species of lemming was similar to that seen in exposed hamsters.

Animals↗
PubMed1982

Intrauterine inoculation of Mycobacterium paratuberculosis into guinea pigs and cattle.

Mycobacterium paratuberculosis was inoculated intrauterinely into guinea pigs and cattle near the time of insemination to assess the effect and subsequent distribution of the organisms. Guinea pigs inoculated intrauterinely with 1 of 3 concentrations of M paratuberculosis or not inoculated were caged with male guinea pigs for 10 days. Guinea pigs given the largest dose had the lowest rate of pregnancy when examined. At necropsy, tissues were cultured to determine extent of infection. Abortion followed hypersensitivity reactions to johnin in some highly infected animals. Mycobacterium paratuberculosis was recovered in culture from the body and horns of the uterus of cows necropsied 1, 2, 3, and 7 days after inoculation and from 1 of 3 cows necropsied 2 weeks after inoculation. The organisms were not detected in extrauterine organs of any cattle or in uterine specimens taken at 3 or 4 weeks after inoculation. The evidence indicates that the small numbers of M paratuberculosis sometimes found in semen from paratuberculous bulls probably would be destroyed, rather than leading to systemic infection of the dam or to persistent hypersensitivity.

Animals↗
PubMed1993

Serologic reactivity against Mycobacterium paratuberculosis antigens in patients with sarcoidosis.

Although sarcoidosis has clinical and histopathologic similarities to some forms of tuberculosis and other mycobacterial infections, attempts to establish a mycobacterial etiology have not been successful. Using cytoplasmic antigens derived from a wild strain of Mycobacterium paratuberculosis in an enzyme-linked immunosorbent assay, patients with sarcoidosis were found to have immunoglobulin levels significantly higher than those found in a control population in the IgG, but not in IgA or IgM antibody classes. Results were comparable to those reported from patients with Crohn's disease, where M. paratuberculosis has been intensively studied as a possible etiologic agent. To elucidate these relationships, examination of DNA from sarcoid tissues for possible homology with DNA from M. paratuberculosis and closely related organisms, as well as cultural attempts with techniques and media appropriate for M. paratuberculosis may be warranted.

Adult↗