Pathology of Gastrointestinal Tuberculosis in Cattle.

We describe the pathology of gastrointestinal tuberculosis in three cows. Gross lesions were found in the jejunum and ileum in all cases, and were characterized by button-shaped ulcers in the mucosa overlying Peyer's patches and adjacent mucosa. One case had similar changes in the pyloric region of the abomasum. In the affected intestinal segments, marked granulomatous inflammation effaced the lymphoid follicles of Peyer's patches and often extended transmurally. Transmural granulomatous inflammation was also found in the abomasum of one cow. Acid-fast bacilli were identified by the Ziehl-Neelsen method and the lesions were immunolabelled by an anti-Mycobacterium tuberculosis complex antibody. M. tuberculosis var. bovis was isolated in one case. Disseminated tuberculosis and marked lung lesions in all cows suggested that the gastrointestinal lesions were most likely secondary to pulmonary infection.

Genomic Polymorphism Associated with the Emergence of Virulent Isolates of Mycobacterium bovis in the Nile Delta.

Mycobacterium bovis is responsible for bovine tuberculosis in both animals and humans. Despite being one of the most important global zoonotic disease, data related to the ecology and pathogenicity of bovine tuberculosis is scarce, especially in developing countries. In this report, we examined the dynamics of M. bovis transmission among dairy cattle in the Nile Delta of Egypt. Animals belonging to 27 herds from 7 governorates were tested by the Single Intradermal Comparative Skin Tuberculin (SICST), as a preliminary screen for the presence of bovine tuberculosis. Positive SICST reactors were identified in 3% of the animals spread among 40% of the examined herds. Post-mortem examination of slaughtered reactors confirmed the presence of both pulmonary and/or digestive forms of tuberculosis in > 50% of the examined animals. Targeted and whole-genome analysis of M. bovis isolates indicated the emergences of a predominant spoligotype (SB0268) between 2013-2015, suggesting a recent clonal spread of this isolate within the Nile Delta. Surprisingly, 2 isolates belonged to M. bovis BCG group, which are not allowed for animal vaccination in Egypt, while the rest of isolates belonged to the virulent M. bovis clonal complex European 2 present in Latin America and several European countries. Analysis of strain virulence in the murine model of tuberculosis indicated the emergence of a more virulent strain (MBE4) with a specific genotype. More analysis is needed to understand the molecular basis for successful spread of virulent isolates of bovine tuberculosis among animals and to establish genotype/phenotype association.

Real time detection of farm-level swine mycobacteriosis outbreak using time series modeling of the number of condemned intestines in abattoirs.

Mycobacteriosis in swine is a common zoonosis found in abattoirs during meat inspections, and the veterinary authority is expected to inform the producer for corrective actions when an outbreak is detected. The expected value of the number of condemned carcasses due to mycobacteriosis therefore would be a useful threshold to detect an outbreak, and the present study aims to develop such an expected value through time series modeling. The model was developed using eight years of inspection data (2003 to 2010) obtained at 2 abattoirs of the Higashi-Mokoto Meat Inspection Center, Japan. The resulting model was validated by comparing the predicted time-dependent values for the subsequent 2 years with the actual data for 2 years between 2011 and 2012. For the modeling, at first, periodicities were checked using Fast Fourier Transformation, and the ensemble average profiles for weekly periodicities were calculated. An Auto-Regressive Integrated Moving Average (ARIMA) model was fitted to the residual of the ensemble average on the basis of minimum Akaike's information criterion (AIC). The sum of the ARIMA model and the weekly ensemble average was regarded as the time-dependent expected value. During 2011 and 2012, the number of whole or partial condemned carcasses exceeded the 95% confidence interval of the predicted values 20 times. All of these events were associated with the slaughtering of pigs from three producers with the highest rate of condemnation due to mycobacteriosis.

Mycobacterium avium Subsp. avium infection in four veal calves: differentiation from intestinal tuberculosis.

Mycobacterium avium subsp. avium (Maa) is an intracellular pathogen belonging to the Mycobacterium avium-intracellulare complex (MAC). Reservoirs of MAC are the natural environment, wildlife and domestic animals. In adult bovine, MAC infections are typically caused by Mycobacterium avium subsp. paratuberculosis (Map). Maa infections in bovine are rarely reported but may cause clinical disease and pathological lesions similar to those observed in paratuberculosis or those induced by members of the Mycobacterium tuberculosis complex (MTBC). Therefore, differentiation of MAC from MTBC infection should be attempted, especially if unusual mycobacterial lesions are encountered. Four veal calves from a fattening farm dying with clinical signs of otitis media, fever, and weight loss were submitted for necropsy. Samples from affected organs were taken for histologic investigation, bacteriologic culture, and bacterial specification using PCR. Macroscopic thickening of the intestinal mucosa was induced by granulomatous enteritis and colitis. Intracytoplasmic acid-fast bacteria were detected by Ziehl-Neelsen stains and PCR revealed positive results for Mycobacterium avium subsp. avium. Clinical and pathological changes of Maa infection in veal calves had features of Mycobacterium avium subsp. paratuberculosis and the MTBC. Therefore, Mycobacterium tuberculosis complex infection should be considered in cases of granulomatous enteritis in calves.

Milk containing Mycobacterium bovis as a source of infection for white-tailed deer fawns (Odocoileus virginianus).

SETTING: White-tailed deer represent the first wildlife reservoir of Mycobacterium bovis in the United States. The behavior of does with nursing fawns provides several potential mechanisms for disease transmission. Little information exists concerning transmission between doe and fawn, specifically transmammary transmission. OBJECTIVE: Determine if fawns can become infected by ingestion of milk replacer containing M. bovis, thus simulating transmission from doe to fawn through contaminated milk. DESIGN: Seventeen, 21-day-old white-tailed deer fawns were inoculated orally with 2 x 10(8) CFU (high dose, n=5), 2.5 x 10(5) to 2.5 x 10(6) CFU (medium dose, n=5), and 1 x 10(4) CFU (low dose, n=5) of M. bovis in milk replacer. Dosages were divided equally and fed daily over a 5-day period. Positive control fawns (n=2) received 1 x 10(5) CFU of M. bovis instilled in the tonsillar crypts. Fawns were euthanized and examined 35-115 days after inoculation and various tissues collected for bacteriologic and microscopic analysis. RESULTS: All fawns in the tonsillar, high oral and medium oral dose groups developed generalized tuberculosis involving numerous organs and tissues by 35-84 days after inoculation. Three of five fawns in the low-dose oral group had tuberculous lesions in the mandibular lymph node, and one of five had lesions in the medial retropharyngeal lymph node when examined 115 days after inoculation. CONCLUSION: White-tailed deer fawns can become infected through oral exposure to M. bovis. Therefore, the potential exists for fawns to acquire M. bovis while nursing tuberculous does.

Mycobacterium bovis infection in a captive herd of Sika deer.

Infection with Mycobacterium bovis was diagnosed in a small privately owned herd of Sika deer. After postmortem examination of a deer with progressive pulmonary disease, diagnosis of infection with M bovis was confirmed by bacteriologic culture. The 2 remaining deer in this herd were euthanatized, necropsied, and confirmed to be infected with M bovis. Three cats in contact with the deer were also euthanatized and necropsied. One of these cats had lesions suggestive of mycobacterial infection in the colon and mesenteric lymph nodes. Infection of this cat with M bovis was not confirmed by bacterial culture. Mycobacteriosis, infrequently encountered in clinical veterinary practice, may be confused with disease caused by other infective agents or neoplasia. The zoonotic potential of these bacteria and a recent increase in human tuberculosis warrants continued surveillance of companion and food animal populations for mycobacterial infection.

Mycobacterium avium infection through the alimentary tract in mice.

Intestinal infection by Mycobacterium avium was investigated in C57BL/6 and BALB/c mouse strains. Single intragastric administration of a massive dose (10(8] or multiple administration of a lower dose (10(7), 10 times) established infection principally in the mesenteric lymph-node (MLN); a continuous or intermittent fecal excretion of the bacilli was detected by 6-8 weeks after the administration. Based on three criteria--isolation of the organisms from the MLN and from feces, and detection of acid-fast bacilli in sections of the MLN--germ-free (GF) BALB/c mice exhibited clearer dose-effect relations than the flora-bearing (FB) counterparts. After intragastric administration, the organisms were probably trapped in the Peyer's patch and then transferred to the MLN at an early period (by 4-7 days), persistent infection thus being established in the MLN. Systemic involvement evolved both in athymic and euthymic mice after a prolonged period of time (more than 40 weeks) showing far more severe involvement in the former regardless of the presence of floral organisms.