Chlamydial infection in a colony of captive koalas

Forty three koalas in a captive colony were investigated for the presence of Chlamydia psittaci infection and associated disease. Swabs were taken from conjunctivae and urogenital sites for cell culture isolation of C psittaci and for cytological examination (direct smears) for chlamydial inclusions and evidence of inflammation. On the basis of cell culture isolation, 28 samples from 25 koalas were positive for C psittaci (that is, infected). Three koalas were positive from both sites, 5 from conjunctivae alone and 17 from urogenital sites alone. Seven of the 8 koalas with positive conjunctival swabs had overt signs of conjunctivitis, but only 3 of the 20 koalas with positive urogenital swabs had overt signs of 'wet bottom' (continual urine soiling due to cystitis) or purulent discharge. However, 5 of the 20 with positive urogenital swabs had past episodes of 'wet bottom'. Moreover, examination of direct cytological smears showed evidence of inflammation (neutrophils) in 7 of 8 koalas with positive conjunctival swabs and 17 of 20 with positive urogenital swabs. Chlamydial inclusions were rarely identified with surety on direct cytological smears. In the 18 koalas without chlamydia, one had overt conjunctivitis while 2 had past episodes of conjunctivitis. The koala with conjunctivitis at the time of sampling had a prior history of 'wet bottom'. Examination of direct cytological smears revealed 2 of the chlamydial negative koalas had high numbers of neutrophils in urogenital smears. It was concluded that C psittaci infection may cause overt or sub-clinical disease, with the former developing when the koalas were stressed through management procedures or concomitant disease.     

Evaluation of an enzyme immunoassay for detection of Chlamydia psittaci in vaginal secretions, placentas, and fetal tissues from aborting ewes

A commercially available enzyme immunoassay (EIA) for the detection of Chlamydia trachomatis in human urogenital and conjunctival specimens was compared with isolation in cell culture for the detection of Chlamydia psittaci in vaginal and placental swabs from aborting ewes and swabs of aborted fetal tissues. The EIA on vaginal swabs collected from 10 ewes experimentally infected with C. psittaci had a sensitivity of 85.7% and a specificity of 85.7%. Vaginal swabs collected at the time of abortion or within 3 days were the best samples for detection of chlamydial infection. The 29 vaginal swabs collected during this period from experimentally infected ewes were all strongly EIA-positive, and chlamydia were isolated from 28. The EIA on vaginal swabs from 78 field cases of abortion had a sensitivity of 78.0% and a specificity of 76.8%. The EIA on swabs of cotyledons from 65 placentas had a sensitivity of 100% and a specificity of 75.0% compared with isolation in cell culture. The EIA on 57 swabs of fetal tissues or body fluids from 10 aborted fetuses or weak lambs from experimentally infected ewes had a sensitivity of 26.6% and a specificity of 88.1% compared with isolation in cell culture. Limitations of the EIA are discussed.     

Diagnosis of avian chlamydiosis: specificity of the modified Giménez staining on smears and comparison of the sensitivity of isolation in eggs and three different cell cultures.

For the diagnosis of chlamydiosis in dead and live birds different methods were compared for their sensitivity and specificity. The specificity of the modified Giménez staining and the direct immunofluorescence (DIF) test for direct demonstration of Chlamydia psittaci in organ, cloacal and/or conjunctival smears was examined. The sensitivity of the isolation of Chlamydia psittaci in 6 days embryonated specific pathogen free (SPF) chicken eggs, Buffalo Green Monkey (BGM) cell line, McCoy cell line and Vero cell line was compared. On smears, the direct immunofluorescence test was more specific than the modified Giménez staining. The concordance between the results of both detection methods was 80%. The BGM cell culture was the most sensitive artificial host for isolation of Chlamydia psittaci, followed by the embryonated eggs, the Vero cell line and the McCoy cell line. The concordance between the results of isolation in BGM cell culture and eggs was 96.5%, while it was 86% between the results of isolation in BGM cell culture and Vero cell culture and only 65.5% between the results of isolation in BGM cell culture and McCoy cell culture. For dead bird species, chlamydiosis could be diagnosed more often using DIF on smears than with isolation. The concordance between the results of the DIF on smears and isolation followed by DIF was 91%.     

Comparison of results of three commercial heartworm antigen test kits in dogs with low heartworm burdens

OBJECTIVE: To compare results of 3 commercial heartworm antigen test kits performed on serum samples from dogs infected with low numbers of adult female heartworms. DESIGN: Blinded laboratory evaluation. Sample Population-Serum samples from dogs (n = 208) proven at necropsy to be infected with 1 to 4 adult female heartworms and from dogs (32) without heartworms. PROCEDURE: Samples were sequentially tested with each test kit, following the manufacturers' instructions, by licensed veterinary technicians in private practice who were not aware of infection status of the dogs. The order of test kit evaluations was randomly chosen. For each test kit, sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were evaluated. RESULTS: All tests yielded some false-negative results, and there were significant differences among tests in regard to ability to detect low heartworm burdens. Sensitivity of the test kits ranged from 78 to 84%. For all test kits, sensitivity increased as number of female heartworms increased. All 3 test kits had high specificity (97%). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that sensitivity of the 3 commercially available heartworm antigen test kits ranged from 78 to 84% when used to test serum samples from dogs with low heartworm burdens, and that sensitivity varied among test kits. For all 3 test kits, specificity was 97%. All 3 test kits yielded false-positive and false-negative results for some dogs with low heartworm burdens.     

ACCURACY OF INCREASED THYROID ACTIVITY DURING PERTECHNETATE SCINTIGRAPHY BY SUBCUTANEOUS INJECTION FOR DIAGNOSING HYPERTHYROIDISM IN CATS

Our purpose was to determine the accuracy of increased thyroid activity for diagnosing hyperthyroidism in cats suspected of having that disease during pertechnetate scintigraphy using subcutaneous rather than intravenous radioisotope administration. Increased thyroid activity was determined by two methods: the thyroid:salivary ratio (T:S) and visual inspection. These assessments were made on the ventral scintigram of the head and neck. Scintigraphy was performed by injecting sodium pertechnetate (111 MBq, SQ) in the right-dorsal-lumbar region; static-acquisition images were obtained 20 min after injection. We used 49 cats; 34 (69%) had hyperthyroidism based on serum-chemistry analysis. Using a Wilcoxon's rank-sum test, a significant difference (P < 0.0001) was detected in the T:S between cats with and without hyperthyroidism. Using a decision criterion of 2.0 for the T:S, the test accurately predicted hyperthyroidism in 32/34 cats (sensitivity, 94%; 95% confidence interval (CI), 85-100%) and correctly predicted that hyperthyroidism was absent in 15/15 cats (specificity, 100%; CI, 97-100%). Using visual inspection, the test accurately predicted hyperthyroidism in 34/34 cats (sensitivity, 100%; CI, 99-100%) and correctly predicted that hyperthyroidism was absent in 12/15 cats (specificity, 80%; CI, 56-100%). The positive and negative predictive values were high for a wide range of prevalence of hyperthyroidism. And, the test had excellent agreement within and between examiners. Therefore, detecting increased thyroid activity during pertechnetate scintigraphy by subcutaneous injection is an accurate and reproducible test for feline hyperthyroidism.     

Evaluation of an enzyme-linked immunosorbent assay kit to detect Babesia bovis antibodies in cattle

The sensitivity and specificity of an enzyme-linked immunosorbent assay (ELISA) to detect antibodies; to Babesia bovis was evaluated in 1000 sera from Holstein heifers. Five hundred of them were from cattle naturally or experimentally infected with B. bovis and 500 from uninfected heifers born and raised in a region free of the vector of cattle babesiosis. Additionally, the ELISA was evaluated and compared with an indirect immunofluorescent antibody (IFA) test in 374 heifers inoculated with different kinds of B. bovis antigens in four trials. The cross-reaction was also evaluated in 50 heifers infected with Babesia bigemina and 50 heifers infected with Anaplasma marginale. The mean percentage positivity of negative sera in relation to the ELISA strong positive sera was 8%. The seropositive/seronegative cutoff point was set as twice the mean percentage positivity of negative cattle sera ( = 16%). The sensitivity of the ELISA was 98% with a 95% confidence interval (CI) of 96–99%. The specificity was 95% (CI 93–97%). The agreement was 97% and the kappa value was 0.93. The predictive values of positive and negative results were 95% and 98% respectively. ELISA showed a similar sensitivity to that of the IFA test to detect antibodies to different B. bovis antigens. Its sensitivity ranged from 97.1% to 100% (CI 89–100%), while the sensitivity of the IFA test ranged from 92.8% to 100% (CI 83–100%). ELISA cross-reacted in 8% and 6% of the sera carrying B. bigemina and A. marginale antibodies, respectively, while the IFA showed 4% cross-reaction in each situation. The ELISA evaluated has the advantages of a proper sensitivity, objectivity and capacity to be adapted to test large number of samples in a short period of time. The results indicate that the ELISA is a suitable replacement for the IFA test to detect B. bovis antibodies in cattle sera, especially in epidemiological studies.     

Histofarcin test for the diagnosis of epizootic lymphangitis in Ethiopia: development, optimisation, and validation in the field

Histofarcin, a skin test antigen for the diagnosis of epizootic lymphangitis, was locally produced from the mycelial form of Histoplasma capsulatum var. farciminosum (HCF) in disease-endemic districts of Ethiopia and tested for its application in the field between April 2002 and May 2003. The test was evaluated using 108 mules, 84 in endemic and 24 in disease-free districts. Microscopic and mycological examinations of clinical lesions were used as the "gold standard" for the validation of the test. The concentration of histofarcin that caused an optimum reaction was 0.2-0.4 mg/mL in a 0.1 mL dose and this was attained 24-48 h post-injection. The sensitivity and specificity of the histofarcin test were 90.3% (CI = 73.1, 97.5) and 69% (95%, CI = 48.1, 84.9%) in disease-endemic districts. On the other hand, specificity was 100% (CI=94.8, 100) in disease-free districts. Positive and negative predictive values of the histofarcin test were 77.78% (95% CI = 60.4, 89.3) and 85.71% (95% CI = 62.6, 96.2), respectively. A marginal substantial agreement (kappa = 0.61, P = 0.0000) was observed between the clinical status and the result of the histofarcin test. A large proportion (31%) of 'false positives' was recorded in endemic districts, which could be due to the pre-clinical stage of the disease. The latter ended in lower specificity and positive predictive value of the test since the true infection status of a 'false positive' could not be known on the basis of clinical features. Therefore, standard test validation procedures including slaughtering and isolation of HCF is required. After proper validation, we conclude that the histofarcin test could play a significant role in detecting early infection, and differentiating of EL from glanders, ulcerative lymphangitis, and sporotrichosis.     

A Bayesian evaluation of six diagnostic tests for foot-and-mouth disease for vaccinated and non-vaccinated cattle

The sensitivity and specificity of six ELISA tests for foot-and-mouth disease (FMD) to discriminate between sero-converted (for non-structural FMD virus proteins) and non-sero-converted cattle were evaluated for vaccinated and unvaccinated cattle. Since none of the tests could be considered as a proper reference test and for about half of the tested sera the true status (sero-converted or not for non-structural proteins, i.e. presence of antibodies) of the animals was unknown, a Bayesian analysis employing a latent class model was used that did not rely on the use of a reference test or gold standard. Prior information about prevalence for subsets of the data and specificity of the tests was incorporated into the analysis. The specificity of the six tests for vaccinated and non-vaccinated cattle ranged from 96 to 99%. For vaccinated cattle, one test stood out with an estimated sensitivity of 94% (95% CI from 89.8 to 98.1%). Second best for vaccinated cattle were two tests with estimated sensitivities of 85% (95% CI from 78.9 to 89.7%) and 92% (95% CI from 86.2 to 95.6%). For non-vaccinated cattle, the sensitivities of these three tests were around 97%. The remaining three tests showed lower estimated sensitivity for vaccinated cattle, ranging from 57 to 79%.     

Evaluation of an immunochromatography strip assay for the detection of Salmonella sp. from poultry.

The present study was conducted to evaluate the sensitivity and specificity of an immunochromatography-based diagnostic kit for Salmonella. The analytical sensitivity of the test when using pure colonies of different Salmonella species was in the range of 1 X 10(4) to 1 x 10(5) colony-forming units per milliliter. The strip detected 19 of 22 strains of Salmonella spp. but failed to detect S. worthington, S. choleraesuis var. kunzendorf and S. johannesburg. The strip did not detect 27 different enteric bacteria, including Escherichia coli O157:H7, Campylobacter jejuni, Shigella sonnei, and Vibrio parahaemolyticus. In direct testing of feces (n = 66) from chickens infected with Salmonella typhimurium, the strip had a sensitivity of 12.3% and a specificity of 100%. Evaluation of the strip assay (n = 510) after sample pre-enrichment in 2% buffered peptone water (BPW) yielded a sensitivity of 93.8% and specificity of 89% when compared to isolation and identification with xylose-lysine-tergitol 4 (XLT4) selective plating media. Subsequent enrichment in Hajna tetrathionate (TT) broth yielded a higher sensitivity (94.7%) and specificity (96.8%). The agreement (kappa) between the strip test and isolation was 0.004 in direct fecal testing, 0.82 in BPW, and 0.89 in TT broth. The assay could detect Salmonella sp. as early as 18-48 hours during pre-enrichment and enrichment compared to isolation on XLT4, which required an overnight incubation step for the presumptive isolation and identification of Salmonella.     

Comparison of polyacrylamide gel electrophoresis, an enzyme-linked-immunosorbent assay, and an agglutination test for the direct identification of bovine rotavirus from feces and coelectrophoresis of viral RNAs

The dsRNA concentrated polyacrylamide gel electrophoresis (CPAGE) detected rotavirus directly from 19% of 77 stool specimens from diarrheic calves. A commercial enzyme-linked immunosorbent assay (ELISA) detected 25%, latex agglutination test, 23%, and polyacrylamide gel electrophoresis (PAGE), 19%. Establishing CPAGE as the "standard," the commercial ELISA and the latex agglutination test both had higher sensitivity (84%) than PAGE (79%). However, PAGE produced the highest specificity (100%), followed by agglutination (88%) and ELISA (84%). The commercial ELISA had a slightly higher sensitivity than agglutination, PAGE, and CPAGE, but the ELISA specificity was generally lower. The latex agglutination test had a lower sensitivity than ELISA, but specificity was higher. Agglutination had similar negative predictive values (94%), compared with agglutination and PAGe, but had the lowest positive predictive value (a measure of accuracy) (70%). Agreement with CPAGE was highest for PAGE (94.8%), followed by agglutination (87%) and ELISA (84.4%). The calculated percentages of total disagreement with all other tests indicated that ELISA differed from the other rotavirus detection assays in 10.4% of the cases, agglutination in 7.8%, PAGE in 2.6%, and CPAGE in 1.3%. The 2 PAGE assays allowed the detection of atypical rotaviruses from feces based on the characteristic "super-short" migration pattern of the 11 genomic segments of rotaviruses and of other members of the Reoviridae.     

Urine sulfated and nonsulfated bile acids as a diagnostic test for liver disease in cats

Urine bile acid (UBA) tests reflecting "average" serum bile acid (SBA) concentrations may have greater practical utility than paired SBA samples in cats. This study evaluated whether urine sulfated bile acids (USBAs), urine nousulfated bile acids (UNSBAs), or a combined approach had a clinical utility equivalent to SBAs. Routine serum biochemistry tests, SBA concentrations, and urine samples were collected from 54 cats with hepatobiliary disease, 17 cats with nonhepatic disorders, and 8 healthy cats. UBAs were measured by a quantitative enzymatic colorimetric method, and results were normalized with urine creatinine (UCr) concentrations. Significantly higher values occurred in cats with liver disease than in cats without liver disease for USBA : UCr, UNSBA:UCr, and (USBA and UNSBA) : UCr, P < .05 each. UBA tests with diagnostic performance (sensitivity [SS], specificity [SP], and positive and negative predictive values [PV+ and PV-]) equivalent to SBAs were the UNSBA : UCr and the combined test (SS: 87, 87 versus 85; SP: 88, 88 versus 88; PV+: 96, 96 versus 96; PV-: 68, 65 versus 68; UNSBA : UCr, [USBA, and UNSBA]: UCr versus SBA, respectively). Clinical applications of the UNSBA : UCr or the combined (USBA and UNSBA) : UCr test should be useful as convenient diagnostic tests for identifying cats with liver disease and high SEA concentrations.     

Detection of equine herpesvirus-1 in nasal swabs of horses by quantitative real-time PCR

Background: Early identification of inhalation-transmitted equine herpesvirus type 1 (EHV-1) infections has been facilitated by the availability of a number of real-time quantitative PCR (qPCR) tests. A direct comparison between nasal swab qPCR and traditional virus isolation (VI) requires a method for normalizing the qPCR samples and controlling for PCR inhibitors present in some clinical samples.
Objectives: To quantify EHV-1 shedding in viral swabs using an internal control and to compare fast qPCR to VI for the detection of EHV-1 in nasal swabs from horses.
Animals: Fifteen horses experimentally infected with EHV-1.
Methods: Experimental study : Nasal swab samples were collected daily after experimental infection for up to 21 days. VI was performed by conventional methods. The DNA was prepared for qPCR with the addition of a known quantity DNA of Marek's disease virus as an internal control. qPCR was performed.
Results: The qPCR method detected virus up to day 21 after challenge, whereas VI detected virus only to day 5. The median Kaplan-Meier estimates for EHV-1 detection were 12 days for qPCR and 2 days for VI ( P < .0001). When compared with VI, the sensitivity and specificity of qPCR were 97 (95% CI: 86–100) and 27% (95% CI: 20–35).
Conclusions and Clinical Importance: We conclude that fast qPCR of nasal swab samples should be chosen for diagnosis and monitoring of herpesvirus-induced disease in horses. Recommended reference ranges of C _T values are provided as well as justification of a minimum 10-day quarantine period.     

Comparison of antigen detection and quantitative PCR in the detection of chlamydial infection in koalas (Phascolarctos cinereus)

The gold standard method for detecting chlamydial infection in domestic and wild animals is PCR, but the technique is not suited to testing animals in the field when a rapid diagnosis is frequently required. The objective of this study was to compare the results of a commercially available enzyme immunoassay test for Chlamydia against a quantitative Chlamydia pecorum-specific PCR performed on swabs collected from the conjunctival sac, nasal cavity and urogenital sinuses of naturally infected koalas (Phascolarctos cinereus).The level of agreement for positive results between the two assays was low (43.2%). The immunoassay detection cut-off was determined as approximately 400 C. pecorum copies, indicating that the test was sufficiently sensitive to be used for the rapid diagnosis of active chlamydial infections.     

The detection of pigs carrying Streptococcus suis type 2

An indirect fluorescent antibody test (I.F.A.T.) was performed on tonsillar swabs collected at slaughter and on nasal swabs from electrically stunned pigs prior to exsanguination. The identification of carriers of Streptococcus suis type 2 using the I.F.A.T. was compared with bacteriological isolation. If it is assumed that 100% of pigs were carrying the bacterium, 76% of 89 carriers were detected when the I.F.A.T. was performed on the bacterial growth from blood agar cultures of tonsillar swabs, compared with only 15% detected using cultural techniques. Similarly, I.F.A.T. on nasal swabs increased the sensitivity of the detection of carriers. Nasal swabbing, although of lower sensitivity than tonsillar swabbing, allows for the detection of S. suis type 2 carriers in the live animal.     

Abnormalities of serum electrolyte concentrations in dogs with hypoadrenocorticism

BACKGROUND: The sensitivity and specificity of the sodium to potassium ratio (Na:K ratio) as a cutoff for recommendation of an adrenocorticotropic hormone (ACTH) stimulation test in dogs suspected of having hypoadrenocorticism (HA) is unknown. Additionally, abnormalities in plasma ionized calcium (iCa2+) and ionized magnesium (iMg2+) concentrations and venous pH of dogs with HA are incompletely documented. OBJECTIVES: To define the sensitivity and specificity of the Na:K ratio as a diagnostic aid for HA in dogs and to examine for associations between venous pH and the Na:K ratio, iCa2+ concentration, or iMg2+ concentration in dogs with HA. ANIMALS: Seventy-six dogs with HA and 200 dogs randomly selected from the general hospital population. METHODS: Retrospective study. Dogs were included in the study if results of an ACTH stimulation test confirmed a diagnosis of HA, the dog had a serum sodium concentration below the reference range or a serum potassium concentration above the reference range, and the dog was treated with mineralocorticoids. Receiver operating curve analysis was used to determine optimal cutoffs of sensitivity and specificity for the Na:K ratio in diagnosing HA. RESULTS: Use of Na:K ratios of 27 or 28 classified 95% of dogs correctly as diseased or not diseased. The sensitivity of a Na:K ratio of 28 was 93% (CI, 85-98%) and that of 27 was 89% (CI, 80-95%). The specificity of a Na:K ratio of 28 was 96% (CI, 92-98%) and that of 27 was 97% (CI, 93- 99%). The sensitivity and specificity of a Na:K ratio of 24 were 79% (95% CI, 67-86%) and 100% (98%, CI, 97%-100%), respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Na:K ratios of 27 or 28 identify the highest percentage of dogs with suspected mineralocorticoid and glucocorticoid deficiency correctly. In dogs with a Na:K ratio of 24 or less, the likelihood of confirming a diagnosis of HA with an ACTH stimulation test is high.     

A rapid monoclonal immunofluorescence assay for Chlamydia psittaci in fecal smears from psittacine birds

One hundred two fecal specimens from psittacine birds submitted to Veterinary Laboratory Services of the California Department of Food and Agriculture at Petaluma were screened for Chlamydia psittaci by a direct immunofluorescence assay using a fluorescein-labeled monoclonal antibody conjugate specific for Chlamydia sp. Results were compared with those obtained by isolation of chlamydia in cultures of McCoy mouse cells. The relative specificity of the direct fluorescent antibody test on fecal smears was 98.9% and the relative sensitivity was 62.5%. The results of this study suggested that the direct fluorescent antibody test was highly specific, and it proved to be a useful same-day antemortem diagnostic test for birds with symptomatic chlamydial infection. The use of centrifugation in the cell culture assay was found to significantly enhance the level of chlamydial infection in cell culture.     

Plasma concentrations of chloramphenicol after subcutaneous administration to koalas (Phascolarctos cinereus) with chlamydiosis

Nine mature koalas with chlamydiosis, typically keratoconjunctivitis and/or urogenital tract infection, were treated with daily subcutaneous injections of chloramphenicol at 60 mg/kg for 45 days (five koalas), or for a shorter duration (four koalas). All koalas were initially positive for Chlamydia pecorum as determined by real-time polymerase chain reaction (qPCR). Plasma chloramphenicol concentrations were determined at t = 0, 1, 2, 4, 8, and 24 h after the day 1 injection (nine koalas) and after the day 15 injection (seven koalas). Chloramphenicol reached a median (and range) maximum plasma concentration of 3.03 (1.32-5.03 μg/mL) at 4 (1-8 h) after the day 1 injection and 4.82 (1.97-27.55 μg/mL) at 1 (1-2 h) after day 15. The median (and range) of AUC(0-24) on day 1 and day 15 were 48.14 (22.37-81.14 μg·h/mL) and 50.83 (28.43-123.99 μg·h/mL), respectively. The area under the moment curve (AUMC)(0-24) median (and range) for day 1 and day 15 were 530.03 (233.05-798.97 h) and 458.15 (291.72-1093.58 h), respectively. Swabs were positive for chlamydial DNA pretreatment, and all koalas except one, produced swabs negative for chlamydial DNA during treatment and which remained so, for 2-63 days after treatment, however whether chloramphenicol treatment prevented long-term recrudescence of infection was not established. At this dose and dosing frequency, chloramphenicol appeared to control mild chlamydial infection and prevent shedding, but severe urogenital disease did not appear to respond to chloramphenicol at this dosage regime. For koalas affected by severe chlamydiosis, antibiotics alone are not sufficient to effect a cure, possibly because of structural or metabolic changes associated with chronic disease and inflammation.     

A comparison of gross pathology,histopathology, and mycobacterial culture for the diagnosis of tuberculosis in elk (Cervus elaphus).

Using the isolation of Mycobacterium bovis as the reference standard, this study evaluated the sensitivity, specificity and kappa statistic of gross pathology (abattoir postmortem inspection), histopathology, and parallel or series combinations of the two for the diagnosis of tuberculosis in 430 elk and red deer. Two histopathology interpretations were evaluated: histopathology I, where the presence of lesions compatible with tuberculosis was considered positive, and histopathology II, where lesions compatible with tuberculosis or a select group of additional possible diagnoses were considered positive. In the 73 animals from which M. bovis was isolated, gross lesions of tuberculosis were most often in the lung (48), the retropharyngeal lymph nodes (36), the mesenteric lymph node (35), and the mediastinal lymph nodes (16). Other mycobacterial isolates included: 11 M. paratuberculosis, 11 M. avium, and 28 rapidly growing species or M. terrae complex. The sensitivity estimates of gross pathology and histopathology I were 93% (95% confidence limits [CL] 84.97%) and 88% [CL 77.94%], respectively, and the specificity of both was 89% [CL 85.92%]). The sensitivity and specificity of histopathology II were 89% (CL 79.95%) and 77% (CL 72.81%), respectively. The highest sensitivity estimates (93-95% [CL 84.98%]) were obtained by interpreting gross pathology and histopathology in parallel (where an animal had to be positive on at least one of the two, to be classified as combination positive). The highest specificity estimates (94-95% [CL 91-97%] were generated when the two tests were interpreted in series (an animal had to be positive on both tests to be classified as combination positive). The presence of gross or microscopic lesions showed moderate to good agreement with the isolation of M. bovis (Kappa = 65-69%). The results showed that post-mortem inspection, histopathology and culture do not necessarily recognize the same infected animals and that the spectra of animals identified by the tests overlaps.