Intradermal Tuberculin Test Research Articles

Prevalence of bovine tuberculosis in a dairy cattle farm and a research farm in Ghana

The aim of the study was to estimate the prevalence of bovine tuberculosis (BTB) and to identify the mycobacterial species causing BTB in a dairy farm and research farm. Six hundred and eighty-five cattle were screened for BTB by using the Comparative intradermal tuberculin test (CTT). Positive reactors were slaughtered and carcasses were taken for isolation of mycobacterial species. This was followed by speciation of isolates using both standard conventional and molecular assays. Seventeen of the cattle were positive by CTT, giving a crude BTB prevalence of 2.48% among cattle from the two farms. Six of the 17 samples (35.30%) yielded positive acid-fast bacilli cultures and three of the isolates were identified as Mycobacterium tuberculosis complex (MTBC), which were sub-divided into two Mycobacterium tuberculosis sensu scrito (Mtb) and one Mycobacterium africanum; the remaining three were Mycobacterium other than tuberculoisis (MOTT). Spoligotyping further characterised the two Mtb isolates as Ghana (spoligotype Data Base 4 number 53) and Latin American Mediterranean (LAM), whilst spoligotyping and Single Nucleotide Polymorphism (SNP) analysis typed the M. africanum as West African 1. Microseq 500 analysis identified two of the MOTT as Mycobacterium flavescens and Mycobacterium Moriokaense respectively, whilst the remaining one could not be identified. This study observed the prevalence of bovine TB among cattle from two farms in Ghana as 2.48% and confirms the public health importance of M. africanum as a pathogen in Ghana.

Agreement between assays of cell-mediated immunity utilizing Mycobacterium bovis-specific antigens for the diagnosis of tuberculosis in African buffaloes (Syncerus caffer)

We assessed the use of Mycobacterium bovis-specific peptides for the diagnosis of tuberculosis in African buffaloes (Syncerus caffer) by evaluating the agreement between the single intradermal comparative tuberculin test (SICTT), the Bovigam® EC (BEC) assay, the Bovigam® HP (BHP) assay and two assays utilizing the QuantiFERON® TB-Gold (in tube) system employing 20h (mQFT20 assay) and 30h (mQFT30 assay) whole blood incubation periods. Of 84 buffaloes, 45% were SICTT-positive, 48% were BEC-positive, 50% were BHP-positive, 37% were mQFT20-positive and 43% were mQFT30-positive. Agreement between the BEC and BHP Bovigam® assays was high (κ=0.86, 95% CI 0.75–0.97) and these detected the most test-positive animals suggesting that they were the most sensitive assays. Interferon-gamma release was significantly greater in buffaloes that were test-positive for all tests than in animals with discordant but positive Bovigam® results. Agreement between the mQFT assays was equally high (κ=0.88, 95% CI 0.77–0.98); however, all buffaloes with discordant mQFT results (n=6) were mQFT30-positive/mQFT20-negative, including three confirmed M. bovis-infected animals, suggesting that the mQFT30 assay is the more sensitive of the two. Agreements between the two Bovigam® and two mQFT assays were moderate, suggesting that in its current format the mQFT assay is less sensitive than either the BEC or the BHP assays.

Evaluation of the single cervical skin test and interferon gamma responses to detect Mycobacterium bovis infected cattle in a herd co-infected with Mycobacterium avium subsp. paratuberculosis

This study reports the performance of the single intradermal tuberculin (SIT) test and the interferon-gamma (IFN-γ) assay for Mycobacterium bovis in a cattle herd with high prevalence of paratuberculosis (PTB). A total of 58/350 animals were selected for necropsy based on one or more of the following criteria: positive to SIT, IFN-γ, a breeding cow that seroconverted to PTB and showed signs compatible with a wasting disease. Infection status was determined by post mortem diagnostic tests that included histopathology examination, mycobacterial cultures and PCR identification for M. bovis and Mycobacterium avium subsp. paratuberculosis (MAP). In 7/58 animals primary tuberculosis (TB) lesions, affecting only the retropharyngeal and/or mediastinal lymph nodes, were found; 3/7 animals were found SIT positive. PTB was confirmed in 35/58 animals, of which 30 had seroconverted and 14 had typical clinical signs. 45/58 animals were IFN-γ+ using the most stringent criterion (cut-off point≥0.05); however, IFN-γ test was only positive in 33 animals when using a higher threshold (cut-off point≥0.1). Three animals co-infected also showed extensive TB and diffuse PTB lesions. These results show that the combined use of SIT and IFN-γ, as interpreted using official guidelines, detected all confirmed cases of TB. Individually, the sensitivity of the SIT was inadequate to diagnose TB-positive animals with an advanced stage of PTB. The large number of IFN-γ+ animals with no visible TB lesion could be due, in part, to some protection conferred by prior infection with MAP.

Prevalence of Bovine Tuberculosis and Risk Factor Assessment in Cattle in Rural Livestock Areas of Govuro District in the Southeast of Mozambique

BackgroundBovine tuberculosis (bTB), caused by Mycobacterium bovis, is an infectious disease of cattle that also affects other domestic animals, free-ranging and farmed wildlife, and also humans. In Mozambique, scattered surveys have reported a wide variation of bTB prevalence rates in cattle from different regions. Due to direct economic repercussions on livestock and indirect consequences for human health and wildlife, knowing the prevalence rates of the disease is essential to define an effective control strategy.Methodology/Principal findingsA cross-sectional study was conducted in Govuro district to determine bTB prevalence in cattle and identify associated risk factors. A representative sample of the cattle population was defined, stratified by livestock areas (n = 14). A total of 1136 cattle from 289 farmers were tested using the single comparative intradermal tuberculin test. The overall apparent prevalence was estimated at 39.6% (95% CI 36.8–42.5) using a diagnostic threshold cut-off according to the World Organization for Animal Health. bTB reactors were found in 13 livestock areas, with prevalence rates ranging from 8.1 to 65.8%. Age was the main risk factor; animals older than 4 years were more likely to be positive reactors (OR = 3.2, 95% CI: 2.2–4.7). Landim local breed showed a lower prevalence than crossbred animals (Landim × Brahman) (OR = 0.6, 95% CI: 0.4–0.8).Conclusions/SignificanceThe findings reveal an urgent need for intervention with effective, area-based, control measures in order to reduce bTB prevalence and prevent its spread to the human population. In addition to the high prevalence, population habits in Govuro, particularly the consumption of raw milk, clearly may potentiate the transmission to humans. Thus, further studies on human tuberculosis and the molecular characterization of the predominant strain lineages that cause bTB in cattle and humans are urgently required to evaluate the impact on human health in the region.

Detection of Mycobacterium bovis in Bovine and Bubaline Tissues Using Nested-PCR for TbD1

In the present study, a nested-PCR system, targeting the TbD1 region, involving the performance of conventional PCR followed by real-time PCR, was developed to detect Mycobacterium bovis in bovine/bubaline tissue homogenates. The sensitivity and specificity of the reactions were assessed with DNA samples extracted from tuberculous and non-tuberculous mycobacteria, as well as other actinomycetales species and DNA samples extracted directly from bovine and bubaline tissue homogenates. In terms of analytical sensitivity, the DNA of M. bovis AN5 was detected up to 1.56 ng with conventional PCR, 97.6 pg with real-time PCR, and 1.53 pg with nested-PCR in the reaction mixture. The nested-PCR exhibited 100% analytical specificity for M. bovis when tested with the DNA of reference strains of environmental mycobacteria and closely-related Actinomycetales. A clinical sensitivity value of 76.0% was detected with tissue samples from animals that exhibited positive results in the comparative intradermal tuberculin test (CITT), as well as from those with lesions compatible with tuberculosis (LCT) that rendered positive cultures. A clinical specificity value of 100% was detected with tissue samples from animals with CITT- results, with no visible lesions (NVL) and negative cultures. No significant differences were found between the nested-PCR and culture in terms of detecting CITT+ animals with LCT or with NVL. No significant differences were recorded in the detection of CITT- animals with NVL. However, nested-PCR detected a significantly higher number of positive animals than the culture in the group of animals exhibiting LCT with no previous records of CITT. The use of the nested-PCR assay to detect M. bovis in tissue homogenates provided a rapid diagnosis of bovine and bubaline tuberculosis.

Detection of specific antibodies in cows after injection of PPD

The diagnosis of bovine tuberculosis aims to identify the immune response against mycobacterial antigens. Although Single Intradermal Comparative Cervical Tuberculin test (SICCT) is broadly used for first identification of the disease, the performance of ELISAs has been investigated for diagnosis improvement. The present study expected to find out the influence of intradermal skin tests on the results of ELISAs using the recombinant proteins MPB70 and MPB83 as antigens on cows from a naturally infected herd. Results were analyzed by the F-test, Mann-Whitney and Friedman tests Although comparable to both proteins, results showed that positive animals presented a tendency of augment reactivity to MPB70, representing a tendency for a booster effect, but not to MPB83.

Assessment of the sensitivity of the gamma-interferon test and the single intradermal comparative cervical test for the diagnosis of bovine tuberculosis under field conditions

In some French départements, the eradication of bovine tuberculosis is incomplete and usual skin tests [single intradermal tuberculin test (SIT) and single intradermal comparative cervical test (SICCT)] have poor specificity due to cross-reactions with non-pathogenic mycobacteria, causing economic losses. In Côte d'Or (Burgundy, France), an experimental serial testing scheme based on the combination of SICCT and gamma-interferon (IFN-γ) tests has been initiated in order to shorten the interval between suspicion and its invalidation in herds with false-positive results to skin tests. Our aim was to assess the scheme's sensitivity and to compare it to the sensitivity of the screening scheme recommended by the European Commission. Our study included 1768 animals from Côte d'Or. The sensitivities of both schemes were estimated using a Bayesian approach. The individual sensitivity of the IFN-γ test [88·1%, 95% credibility interval (CrI) 72·8-97·5] was not significantly different from individual SICCT sensitivity (80·3%, 95% CrI 61·6-98·0) and individual SIT sensitivity (84·2%, 95% CrI 59·0-98·2). The individual specificity of the IFN-γ test was 62·3% (95% CrI 60·2-64·5). No significant difference could be demonstrated between the sensitivities of the serial testing scheme used in Côte d'Or (73·1%, 95% CrI 41·1-100) and the European Union serial testing scheme (70·1%, 95% CrI 31·5-100·0).

Bovine Tuberculosis and Brucellosis in Cattle and African Buffalo in the Limpopo National Park, Mozambique

Bovine tuberculosis (BTB) and brucellosis are prevalent in buffaloes of the Kruger National Park (KNP, South Africa). Both diseases were considered to have no or a very low prevalence in wildlife and livestock in and around the Limpopo National Park (LNP, Mozambique). The same applies for tuberculosis in Gonarezhou National Park (GNP, Zimbabwe), but just recently, BTB was detected in buffaloes in the GNP and fears arose that the disease might also spread to the LNP as a result of the partial removal of the fences between the three parks to form the Great Limpopo Transfrontier Park. To assess the status of both diseases in and around LNP, 62 buffaloes were tested for bovine tuberculosis (BTB) and bovine brucellosis. The percentage of positive BTB reactors in buffalo was 8.06% using BovidTB Stat-Pak® and 0% with BOVIGAM® IFN-γ test and IDEXX ELISA. The brucellosis seroprevalence in buffalo was found to be 17.72% and 27.42% using Rose Bengal Test (RBT) and ELISA, respectively. In addition, 2445 cattle in and around the LNP were examined for BTB using the single intradermal cervical comparative tuberculin test (SICCT), and an apparent prevalence of 0.98% was found with no significant difference inside (0.5%) and outside (1.3%) the park. This is the first published report on the presence of positive reactors to BTB and bovine brucellosis in buffalo and cattle in and outside the LNP. Monitoring the wildlife-livestock-human interface of zoonotic high-impact diseases such as BTB and brucellosis is of outmost importance for the successful implementation and management of any transfrontier park that aims to improve the livelihoods of the local communities.

Risk factors associated with negative in-vivodiagnostic results in bovine tuberculosis-infected cattle in Spain

BackgroundDespite great effort and investment incurred over decades to control bovine tuberculosis (bTB), it is still one of the most important zoonotic diseases in many areas of the world. Test-and-slaughter strategies, the basis of most bTB eradication programs carried out worldwide, have demonstrated its usefulness in the control of the disease. However, in certain countries, eradication has not been achieved due in part to limitations of currently available diagnostic tests. In this study, results of in-vivo and post-mortem diagnostic tests performed on 3,614 animals from 152 bTB-infected cattle herds (beef, dairy, and bullfighting) detected in 2007–2010 in the region of Castilla y León, Spain, were analyzed to identify factors associated with positive bacteriological results in cattle that were non-reactors to the single intradermal tuberculin test, to the interferon-gamma (IFN-γ) assay, or to both tests applied in parallel (Test negative/Culture + animals, T-/C+). The association of individual factors (age, productive type, and number of herd-tests performed since the disclosure of the outbreak) with the bacteriology outcome (positive/negative) was analyzed using a mixed multivariate logistic regression model.ResultsThe proportion of non-reactors with a positive post-mortem result ranged from 24.3% in the case of the SIT test to 12.9% (IFN-γ with 0.05 threshold) and 11.9% (95% CI 9.9-11.4%) using both tests in parallel. Older (>4.5 years) and bullfighting cattle were associated with increased odds of confirmed bTB infection by bacteriology, whereas dairy cattle showed a significantly lower risk. Ancillary use of IFN-γ assay reduced the proportion of T-/C + animals in high risk groups.ConclusionsThese results demonstrate the likelihood of positive bacteriological results in non-reactor cattle is influenced by individual epidemiological factors of tested animals. Increased surveillance on non-reactors with an increased probability of being false negative could be helpful to avoid bTB persistence, particularly in chronically infected herds. These findings may aid in the development of effective strategies for eradication of bTB in Spain.

A polymerase chain reaction and enzyme linked immunosorbent assay based approach for diagnosis and differentiation between vaccinated and infected cattle with Mycobacterium bovis.

Background:In most African and Arabic countries tuberculosis (TB) causes great economic losses in bovine species and constitutes serious zoonotic problem. As the traditional diagnostic method delay the research because of low sensitivity and specificity, a rapid method of diagnosis is of outmost importance.Aim:The study was designed to evaluate the two rapid diagnostic methods of TB in cattle, further to differentiate between infected and bacillus Calmette-Guerin (BCG) vaccinated animals.Materials and Methods:Intradermal tuberculin test was applied to 300 cattle. Of these cattle, 15 cattle were vaccinated from cattle negative to tuberculin test with BCG. Blood samples were taken for lymphocyte separation to apply polymerase chain reaction (PCR) upon and for serum preparation for the enzyme-linked immunosorbent assay (ELISA) application, this blood collected from 65 cattle classified into three groups, viz. positive tuberculin test (35 animals), negative tuberculin test (15 animals), and vaccinated cow with BCG (15 animals). From blood samples lymphocytes were separated and the isolated lymphocytes were subjected to PCR and serum for ELISA application. Blood samples, specimens from lymph nodes and specific tissues were taken for PCR and for cultivation and isolation of Mycobacterium bovis.Results and Conclusions:The results of this study revealed that PCR can be used as rapid efficient and accurate diagnostic test in detection of ruminant TB. Moreover, cattle's ELISA reading showed higher sensitivity in positive tuberculin animals. However, the differentiations between vaccinated and infected animals not clear by using a single antigen only.

Prevalence of tuberculosis in slaughter camels (Camelus dromedarius) at kano abattoir, nigeria based on lateral-flow technology

In Nigeria and indeed Africa, camels are increasingly gaining economic importance due to their increasing value as source of meat, milk, hide and as draught animals. This study aimed at determining the prevalence of tuberculosis, based on lateral-flow technology in slaughter camels. Diagnosis of TB in camels faces many difficulties, with none of the standard available tests being able to detect the disease with some certainity. The intradermal tuberculin test, which is the traditional diagnostic tool in cattle, is not reliable in camels as it is in cattle but the serology-based test is showing potentials in various environments. A total of five hundred (500) camels, consisting of 188 males and 312 females, in Sahel part of northern Nigeria brought for slaughter at Kano abattoir were tested for TB infection using lateral-flow technology. The overall positive samples were one hundred and thirteen (113) with a prevalence rate of 22.6%. Out of these, 45 were males with a prevalence rate of 23.9% while 68 were females with a prevalence rate of 21.8%. The chi-square (×2) test of significance based on sex was not statistically significant (P>0.05). This study highlights the importance of tuberculosis in camels and its public health implications. Measures for control are also been suggested.

Assessment of Bovine Tuberculosis and Its Risk Factors in Cattle and Humans, at and around Dilla Town, Southern Ethiopia

A cross-sectional study was carried out from February, 2012 to June, 2013 using comparative intradermal tuberculin (CIDT) test on 440 individual live cattle kept in 118 housholds/farms to determine the prevalence of, and to identify the risk factors associated with, bovine tuberculosis (BTB) infection in cattle and to assess the public awareness on its zoonotic importance through structured questionnaires at and around Dilla town, southern Ethiopia. The herd and individual cattle prevalence of bovine tuberculin positivity were 15.3% (95%, Confidence interval (CI): 8.7 to 21.8) and 4.3% (95%, CI: 2.4 to 6.2), respectively at cut-off greater than 4 mm. The herd prevalence of BTB varied significantly among herd size (P=0.019) and management conditions (P=0.031). Herds which had 5-9 and more than 9 cattle were six (Odds ratio (OR) = 6.4) and twelve (OR=12.0) times more reactive to bovine tuberculin testing than herds that had less than or equals to four cattle in their farms. Among the animal related risk factors only breed (P=0.020) had a significant association with the prevalence of bovine tuberculin positivity with the highest odds ratio in Holstein breeds (OR= 6.1) as compared to Zebu and cross (Holstein X Zebu) breeds. Less than one third (29.7%; 35 of 118) of the respondents recognized BTB, and only 22.9% (27/118) of the respondents had understanding of its zoonotic implication. Awareness rising of cattle owners about BTB and its transmission, and the zoonotic implication of BTB is of extreme importance for effective implementation of TB control measures.

Extent ofMycobacterium bovisinfection in dairy cattle herds subject to partial culling as determined by an interferon-gamma assay

The interferon-gamma (IFN-γ) assay is employed as a complementary diagnostic test for bovine tuberculosis (BTB) in many countries. To simplify this assay, we established a 96-well plate format using the ESAT-6 and CFP-10 antigens and then employed it to determine the extent of Mycobacterium (M.) bovis infection in dairy herds with a history of BTB outbreaks in a country where only selective culling is practiced. The sensitivity and specificity of this IFN-γ assay were 85.9% and 100%, respectively, based on comparison with the conventional single intradermal tuberculin test (SIDT). The IFN-γ assay was also positive in 30.4% and 36.8% of SIDT-negative animals from herds with recent and remote BTB outbreaks, respectively. Of 14 SIDT-negative, IFN-γ positive cattle, five (35.7%) were culture positive and an additional six were positive based on a polymerase chain reaction-based test for M. bovis. Therefore, the IFN-γ assay has the potential to serve as a specific and sensitive test for M. bovis infection in dairy cattle. Further, the results indicated that a substantial portion of SIDT-negative animals in herds with previous BTB outbreaks were actually infected with M. bovis. Accordingly, the present selective-culling strategy may require modifications to include this more sensitive assay.

Polymerase chain reaction based detection ofMycobacterium tuberculosisIS6110 in cattle faeces

PCR amplification of insertion element IS6110 of Mycobacterium tuberculosis in fecal samples was evaluated in the diagnosis of intestinal tuberculosis (ITB). Single intradermal tuberculin test was carried in 125 cattle from organized dairy farms, off which, 36 animals gave a positive reaction. Blood and faecal samples were collected from all the tuberculin positive (36) animals. Demonstration of acid fast bacilli was done in the faecal samples by using the Ziehl - Neelsen staining. DNA was extracted and PCR was carried out in the blood and faecal samples by using IS6110 insertion sequence. Acid fast bacilli were observed in 10 (27.77%) faecal smears whereas, 18 (50%) faecal samples and 4 (11.11%) blood samples were found positive for the insertion sequence IS6110 of Mycobacterium tuberculosis complex. This result shows that IS6110 insertion sequence-PCR assay may be applied to detect tuberculous bacilli directly from faecal sample of dairy cows and therefore could be a valuable diagnostic or screening test for herds.

Prevalence of tuberculosis among southern Zambian cattle and isolation of Mycobacterium bovis in raw milk obtained from tuberculin positive cows

Aim: To determine the prevalence of tuberculosis among traditional milking cows in southern Zambia and isolation of Mycobacterium spp from the tuberculin positive cow's milk. Materials and Methods: A total of 1,025 cows originating from traditional cattle sector, in Mapepe, Magoye, Monze, Batoka, GART- Batoka, Kalomo areas of Zambia, supplying major quantity of milk to milk processors, were tested for bovine tuberculosis using single comparative intra-dermal tuberculin test during 2011 and 2012. Milk samples obtained from 16 bovine tuberculin reactor cows were cultured for isolation of Mycobacterium spp and those showing growth of Mycobacterium spp. were identified through biochemical tests of the culture. Further confirmation and species differentiation of the Mycobacterium spp. isolates was done using the loop-mediated isothermal amplification system and multiplexpolymerase chain reaction Results: 27 (2.6%) of the cows tested were found tuberculin reactors, 9 cows (0.87 %) gave inconclusive reaction and 989 (96.48%) were non-reactors. Three milk samples (18.7%) out of the 16 tuberculin reactor cow's milk when cultured and upon molecular analysis, were found positive for presence of M. bovis indicating these positive cows were shedding M. bovis in their milk. Conclusion: The isolation of M. bovis in freshly drawn milk from the tuberculin positive reactor cows is being reported for the first time in Zambia. Bovine tuberculosis is an animal and human health risk in the traditional dairy herds supplying milk to the Zambian population especially in the informal market and needs attention of the public health and veterinary authorities.

Paratuberculosis Vaccination Causes Only Limited Cross-Reactivity in the Skin Test for Diagnosis of Bovine Tuberculosis

Although there is a wide consensus on the efficacy of paratuberculosis vaccination to limit economic losses, its use has been restricted because of its interference in the diagnosis of tuberculosis. Data from a vaccine clinical trial in the Basque Country (Spain) has been evaluated in relationship with bovine tuberculosis intradermal test results. The trial included two herds applying a Test and Culling strategy and five applying an inactivated vaccine. The vaccine was applied to animals of all ages present in each vaccinated herd when joining the trial, and then to all the replacers within their first three months of life. Yearly testing done with the comparative intradermal test (CIT) was applied to all animals older than 6 weeks. Between 2005 and 2011, the study generated 2,033 records from Vaccinated Herds (VH) and 2,252 from Test and Cull herds (TC). Pre-vaccination positive results rate was 2.40% among the 7 herds in the single bovine intradermal tuberculin test (BSIT). Two years later it rose to 20.42% in the VH and remained below at 0.75% in the TC. Applying the CIT reduced these rates to only 0.58% in the VH and to 0.25% in the TC ons. Regarding time since each animal joined the program, the proportion of positives to BSIT was variable and, in some cases, significantly different between time points. With regard to the age of vaccination, no significant differences were found between vaccination within the first year of life and afterwards. Vaccinated animals showed seventeen times more reactions than the non-vaccinated in the BSIT, but only four times more in the CIT. In conclusion, comparative intradermal test can be a useful tool to differentiate paratuberculosis vaccine cross-reactions from specific bovine tuberculosis reactions according to the European and Spanish legislation.

Evaluation of single and comparative intradermal tuberculin tests for tuberculosis eradication in caprine flocks in Castilla y León (Spain)

Goats can act as reservoirs for tuberculosis (TB) infection. The main etiological agents of TB in goats are Mycobacterium caprae and Mycobacterium bovis and they infect also a wide range of domestic and wild animals and humans. Control programmes based mainly on the application of single and comparative intradermal tuberculin (SIT and SCIT respectively) tests are being implemented in certain regions of Spain with a high density of caprine flocks as Castilla y León, including goats with epidemiological relationship with cattle. The aim of this study was to evaluate the performance of the intradermal tests in naturally TB-infected caprine flocks from this region. The study was performed using data from 17,450 goats in 54 different flocks that were classified as TB-infected in the control programmes executed in 2010 and 2011. Data from 1237 goats from 7 dairy flocks depopulated after the first intradermal testing were used to estimate the sensitivity (Se) using bacteriology as the gold-standard. Overall Se of the SIT test using the severe interpretation was 43.9% (CI 95%, 40.4–47.4) and decreased to 38.8% (CI 95%, 35.5–42.3) using the standard interpretation. Overall Se of the SCIT test ranged between 21.3% (CI 95%, 17.6–25.4) and 7% (CI 95%, 4.9–9.8) depending of the interpretation criteria. A significant weak positive correlation was found between age and skin fold thickness (Spearman’s test p<0.05). Results from this study yielded, in general, low Se values probably due the systematic detection and slaughter of reactors as a consequence of the eradication programme in previous years or the presence of factors that may interfere in the diagnosis. Therefore, these results suggest the necessity of including ancillary diagnostic tools and/or strict interpretation criteria to maximize detection of positive animals in infected settings.

Preliminary study on prevalence of bovine tuberculosis in cattle owned by tuberculosis positive and negative farmers and assessment of zoonotic awareness in Ambo and Toke Kutaye districts, Ethiopia

A cross sectional study was conducted from April to September, 2012 on cattle owned by tuberculosis positive and negative farmers and households to assess prevalence of bovine tuberculosis and zoonotic awareness of the households in Ambo and Guder districts, Ethiopia. A total of 398 cattle were tested using single comparative intradermal tuberculin test. The result was interpreted at >4 and >2 mm. An overall 1 and 4.02% prevalence of bovine tuberculosis at individual cattle and 7.02 and 24.56% at herd level were recorded at cut off >4 and >2 mm, respectively. Bovine tuberculosis was more prevalent in cattle owned by tuberculosis positive farmers (1.36 and 5% at individual cattle, 12 and 36% herd level) than in cattle owned by tuberculosis negative farmers (0.56 and 2.81% at individual cattle, 3.13 and 15.63% at herd level) at >4 and >2 mm cut off, respectively. Lack of awareness of the community about the zoonotic importance of the disease was observed. In conclusion, the present study indicated more prevalence of the disease in cattle owned by tuberculosis positive farmers than tuberculosis negative farmers and lack of zoonotic awareness of the households. Therefore, further study, collaboration between physician and veterinarians, and creation of awareness about zoonotic diseases were recommended. Key words: Bovine tuberculosis, cattle, prevalence, tuberculosis positive and negative farmers.

Transmission of Mycobacterium tuberculosis between Farmers and Cattle in Central Ethiopia

BackgroundTransmission of Mycobacterium tuberculosis (M. tuberculosis) complex could be possible between farmers and their cattle in Ethiopia.Methodology/Principal FindingsA study was conducted in mixed type multi-purposes cattle raising region of Ethiopia on 287 households (146 households with case of pulmonary tuberculosis (TB) and 141 free of TB) and 287 herds consisting of 2,033 cattle belonging to these households to evaluate transmission of TB between cattle and farmers. Interview, bacteriological examinations and molecular typing were used for human subjects while comparative intradermal tuberculin (CIDT) test, post mortem and bacteriological examinations, and molecular typing were used for animal studies. Herd prevalence of CIDT reactors was 9.4% and was higher (p<0.01) in herds owned by households with TB than in herds owned by TB free households. Animal prevalence was 1.8% and also higher (p<0.01) in cattle owned by households with TB case than in those owned by TB free households. All mycobacteria (141) isolated from farmers were M. tuberculosis, while only five of the 16 isolates from cattle were members of the M. tuberculosis complex (MTC) while the remaining 11 were members of non-tuberculosis mycobacteria (NTM). Further speciation of the five MTC isolates showed that three of the isolates were M. bovis (strain SB1176), while the remaining two were M. tuberculosis strains (SIT149 and SIT53). Pathology scoring method described by “Vordermeier et al. (2002)” was applied and the average severity of pathology in two cattle infected with M. bovis, in 11 infected with NTM and two infected with M. tuberculosis were 5.5, 2.1 and 0.5, respectively.Conclusions/SignificanceThe results showed that transmission of TB from farmers to cattle by the airborne route sensitizes the cows but rarely leads to TB. Similarly, low transmission of M. bovis between farmers and their cattle was found, suggesting requirement of ingestion of contaminated milk from cows with tuberculous mastitis.

1H-NMR Spectroscopy Revealed Mycobacterium tuberculosis Caused Abnormal Serum Metabolic Profile of Cattle

To re-evaluate virulence of Mycobacterium tuberculosis (M. tb) in cattle, we experimentally infected calves with M. tb andMycobacterium bovisvia intratracheal injection at a dose of 2.0×107 CFU and observed the animals for 33 weeks. The intradermal tuberculin test and IFN-γin vitro release assay showed that both M. tb and M. bovis induced similar responses. Immunohistochemical staining of pulmonary lymph nodes indicated that the antigen MPB83 of both M. tb and M. bovis were similarly distributed in the tissue samples. Histological examinations showed all of the infected groups exhibited neutrophil infiltration to similar extents. Although the infected cattle did not develop granulomatous inflammation, the metabolic profiles changed significantly, which were characterized by a change in energy production pathways and increased concentrations of N-acetyl glycoproteins. Glycolysis was induced in the infected cattle by decreased glucose and increased lactate content, and enhanced fatty acid β-oxidation was induced by decreased TG content, and decreased gluconeogenesis indicated by the decreased concentration of glucogenic and ketogenic amino acids promoted utilization of substances other than glucose as energy sources. In addition, an increase in acute phase reactive serum glycoproteins, together with neutrophil infiltration and increased of IL-1β production indicated an early inflammatory response before granuloma formation. In conclusion, this study indicated that both M. tb and M.bovis were virulent to cattle. Therefore, it is likely that cattle with M. tb infections would be critical to tuberculosis transmission from cattle to humans. Nuclear magnetic resonance was demonstrated to be an efficient method to systematically evaluate M. tb and M. bovi sinfection in cattle.