SUBFOVEAL CHOROIDAL TUBERCULOMA IN A HEALTHY YOUNG WOMAN CAUSED BY MYCOBACTERIUM BOVIS

PURPOSE

To describe a case of a macular tuberculoma in a young and healthy woman after developing a tuberculous lymphadenitis caused by Mycobacterium bovis .

METHODS

Retrospective case report.

RESULTS

Tuberculous lymphadenitis caused by M. bovis was detected after biopsy and histological examination as well as polymerase chain reaction test testing of cervical lymph nodes in a 20-year-old patient. An interferon gamma was positive. Shortly starting antitubercular therapy, the patient developed visual deterioration caused by a single yellowish subretinal structure in the macula of the right eye. Optical coherence tomography showed a dome-shaped, hyperreflective, subfoveal choroidal lesion with subtle subretinal fluid. Antitubercular therapy with isoniazid, rifampicin, ethambutol, and pyrazinamide was performed, and the deescalation therapy with isoniazid and rifampicin was extended to 7 months. Further examinations showed regression of choroidal tuberculoma to a scar.

CONCLUSION

This is the first reported case of choroidal tuberculoma after tuberculous lymphadenitis caused by M. bovis .

Evaluation of the discriminatory power of spoligotyping and 19-locus mycobacterial interspersed repetitive unit-variable number of tandem repeat analysis (MIRU-VNTR) of Mycobacterium bovis strains isolated from cattle in Algeria

Bovine tuberculosis (bTB) caused by Mycobacterium (M.) bovis and M. caprae is a transmissible disease of livestock, notifiable to the World Organization for Animal Health (OIE). BTB particularly affects cattle and small ruminants and can be transmitted to humans thereby posing a significant threat to veterinary and public health worldwide. M. bovis is the principal cause of bTB in Algeria. In order to better understand the route of spreading and elaborate an eradication program, isolation and characterization of mycobacteria from Algerian cattle was performed. Sixty strains belonging to the M. tuberculosis complex were analyzed by spoligotyping, thereof 42 by 19-locus-MIRU-VNTR-typing. Spoligotyping revealed 16 distinguishable patterns (Hunter-Gaston discriminatory index [HGDI] of 0.8294), with types SB0120 (n = 20) and SB0121 (n = 13) being the most frequent patterns, representing 55% of the strains. Analyses based on 19-locus-MIRU-VNTR yielded 32 different profiles, five clusters and one orphan pattern, showing higher discriminatory power (HGDI = 0.9779) than spoligotyping. Seven VNTR-loci [VNTR 577 (alias ETR C), 2163b (QU11b), 2165 (ETR A), 2461 (ETR B), 3007 (MIRU 27), 2163a (QUB11a) and 3232 (QUB 3232)] were the most discriminative loci (HGDI ˃ 0.50). In conclusion, 19-locus-MIRU-VNTR yielded more information than spoligotyping concerning molecular differentiation of strains and better supports the elucidation of transmission routes of M. bovis between Algerian cattle herds.

Inferring Mycobacterium bovis transmission between cattle and badgers using isolates from the Randomised Badger Culling Trial

Mycobacterium bovis (M. bovis) is a causative agent of bovine tuberculosis, a significant source of morbidity and mortality in the global cattle industry. The Randomised Badger Culling Trial was a field experiment carried out between 1998 and 2005 in the South West of England. As part of this trial, M. bovis isolates were collected from contemporaneous and overlapping populations of badgers and cattle within ten defined trial areas. We combined whole genome sequences from 1,442 isolates with location and cattle movement data, identifying transmission clusters and inferred rates and routes of transmission of M. bovis. Most trial areas contained a single transmission cluster that had been established shortly before sampling, often contemporaneous with the expansion of bovine tuberculosis in the 1980s. The estimated rate of transmission from badger to cattle was approximately two times higher than from cattle to badger, and the rate of within-species transmission considerably exceeded these for both species. We identified long distance transmission events linked to cattle movement, recurrence of herd breakdown by infection within the same transmission clusters and superspreader events driven by cattle but not badgers. Overall, our data suggests that the transmission clusters in different parts of South West England that are still evident today were established by long-distance seeding events involving cattle movement, not by recrudescence from a long-established wildlife reservoir. Clusters are maintained primarily by within-species transmission, with less frequent spill-over both from badger to cattle and cattle to badger.

Prevalence of bovine tuberculosis in dairy cattle in China during 2010-2019: A systematic review and meta-analysis

BACKGROUND

Bovine tuberculosis (bTB), caused by members of the Mycobacterium tuberculosis complex bacteria, mainly Mycobacterium bovis (M. bovis), is a major threat to public health and economic development. There has been no systematic epidemiological assessment concerning bTB in dairy cattle in China.

METHODOLOGY/PRINCIPAL FINDINGS

Literature related to bTB in China was retrieved from China National Knowledge Infrastructure (CNKI), PubMed, ScienceDirect, VIP Chinese Journals Database, and Wan Fang Database to build the first meta-analysis for estimating the prevalence and infection moderators of bTB in dairy cattle in China. A total of 100 relevant studies published from 2010 to 2019 were included. We estimated the overall prevalence of bTB was 2.4% (95% CI: 2.1-2.8) during this decade. In the sampling year subgroup, the prevalence was lowest in 2017 or later at 0.8% (95% CI: 0.3-1.5). The lowest prevalence was 0.7% (95% CI: 0.5-1.0) in Northwestern China. The lowest prevalence was 2.1% (95% CI: 1.8-2.5) using SIT test. Heifer cows had the highest prevalence, which was 27.1% (95% CI: 9.7-49.2). The prevalence in scale farming was 3.7% (95% CI: 3.1-4.3), significantly higher than that in free-range farming (1.7%, 95% CI: 1.1-2.4). The prevalence of bTB was highest in summer at 4.0% (95% CI: 1.7-7.0). In addition, the influence of different geographical factors (altitude, longitude, latitude, precipitation, temperature, humidity) on the prevalence was analyzed.

CONCLUSIONS/SIGNIFICANCE

The results showed that bTB was widespread in China but has been gradually reduced through concerted national intervention. It is suggested that different countries should formulate corresponding prevention and control measures according to the epidemic situation in its cattle industry. Enhanced monitoring of warm and humid areas may play an important role in reducing the incidence of bTB. In addition, when large-scale breeding is promoted, attention should be paid to standardizing breeding management and improving animal welfare to reduce the prevalence of bTB in cattle.

A new phylodynamic model of Mycobacterium bovis transmission in a multi-host system uncovers the role of the unobserved reservoir

Multi-host pathogens are particularly difficult to control, especially when at least one of the hosts acts as a hidden reservoir. Deep sequencing of densely sampled pathogens has the potential to transform this understanding, but requires analytical approaches that jointly consider epidemiological and genetic data to best address this problem. While there has been considerable success in analyses of single species systems, the hidden reservoir problem is relatively under-studied. A well-known exemplar of this problem is bovine Tuberculosis, a disease found in British and Irish cattle caused by Mycobacterium bovis, where the Eurasian badger has long been believed to act as a reservoir but remains of poorly quantified importance except in very specific locations. As a result, the effort that should be directed at controlling disease in badgers is unclear. Here, we analyse densely collected epidemiological and genetic data from a cattle population but do not explicitly consider any data from badgers. We use a simulation modelling approach to show that, in our system, a model that exploits available cattle demographic and herd-to-herd movement data, but only considers the ability of a hidden reservoir to generate pathogen diversity, can be used to choose between different epidemiological scenarios. In our analysis, a model where the reservoir does not generate any diversity but contributes to new infections at a local farm scale are significantly preferred over models which generate diversity and/or spread disease at broader spatial scales. While we cannot directly attribute the role of the reservoir to badgers based on this analysis alone, the result supports the hypothesis that under current cattle control regimes, infected cattle alone cannot sustain M. bovis circulation. Given the observed close phylogenetic relationship for the bacteria taken from cattle and badgers sampled near to each other, the most parsimonious hypothesis is that the reservoir is the infected badger population. More broadly, our approach demonstrates that carefully constructed bespoke models can exploit the combination of genetic and epidemiological data to overcome issues of extreme data bias, and uncover important general characteristics of transmission in multi-host pathogen systems.

Population structure and transmission of Mycobacterium bovis in Ethiopia

Bovine tuberculosis (bTB) is endemic in cattle in Ethiopia, a country that hosts the largest national cattle herd in Africa. The intensive dairy sector, most of which is peri-urban, has the highest prevalence of disease. Previous studies in Ethiopia have demonstrated that the main cause is Mycobacterium bovis, which has been investigated using conventional molecular tools including deletion typing, spoligotyping and Mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR). Here we use whole-genome sequencing to examine the population structure of M. bovis in Ethiopia. A total of 134 M. bovis isolates were sequenced including 128 genomes from 85 mainly dairy cattle and six genomes isolated from humans, originating from 12 study sites across Ethiopia. These genomes provided a good representation of the previously described population structure of M. bovis, based on spoligotyping and demonstrated that the population is dominated by the clonal complexes African 2 (Af2) and European 3 (Eu3). A range of within-host diversity was observed amongst the isolates and evidence was found for both short- and long-distance transmission. Detailed analysis of available genomes from the Eu3 clonal complex combined with previously published genomes revealed two distinct introductions of this clonal complex into Ethiopia between 1950 and 1987, likely from Europe. This work is important to help better understand bTB transmission in cattle in Ethiopia and can potentially inform national strategies for bTB control in Ethiopia and beyond.

Serological test performance for bovine tuberculosis in cattle from herds with evidence of on-going infection in Northern Ireland

The ability to accurately identify infected hosts is the cornerstone of effective disease control and eradication programs. In the case of bovine tuberculosis, accurately identifying infected individual animals has been challenging as all available tests exhibit limited discriminatory ability. Here we assess the utility of two serological tests (IDEXX Mycobacterium bovis Ab test and Enfer multiplex antibody assay) and assess their performance relative to skin test (Single Intradermal Comparative Cervical Tuberculin; SICCT), gamma-interferon (IFNγ) and post-mortem results in a Northern Ireland setting. Furthermore, we describe a case-study where one test was used in conjunction with statutory testing. Serological tests using samples taken prior to SICCT disclosed low proportions of animals as test positive (mean 3% positive), despite the cohort having high proportions with positive SICCT test under standard interpretation (121/921; 13%) or IFNγ (365/922; 40%) results. Furthermore, for animals with a post-mortem record (n = 286), there was a high proportion with TB visible lesions (27%) or with laboratory confirmed infection (25%). As a result, apparent sensitivities within this cohort was very low (≤15%), however the tests succeeded in achieving very high specificities (96–100%). During the case-study, 7/670 (1.04%) samples from SICCT negative animals from a large chronically infected herd were serology positive, with a further 17 animals being borderline positive (17/670; 2.54%). Nine of the borderline animals were voluntarily removed, none of which were found to be infected post-mortem (no lesions/bacteriology negative). One serology test negative animal was subsequently found to have lesions at slaughter with M. bovis confirmed in the laboratory.

Simulating the next steps in badger control for bovine tuberculosis in England

Industry-led culling of badgers has occurred in England to reduce the incidence of bovine tuberculosis in cattle for a number of years. Badger vaccination is also possible, and a move away from culling was "highly desirable" in a recent report to the UK government. Here we used an established simulation model to examine badger control option in a post-cull environment in England. These options included no control, various intermittent culling, badger vaccination and use of a vaccine combined with fertility control. The initial simulated cull led to a dramatic reduction in the number of infected badgers present, which increased slowly if there was no further badger management. All three approaches led to a further reduction in the number of infected badgers, with little to choose between the strategies. We do note that of the management strategies only vaccination on its own leads to a recovery of the badger population, but also an increase in the number of badgers that need to be vaccinated. We conclude that vaccination post-cull, appears to be particularly effective, compared to vaccination when the host population is at carrying capacity.

Development of a loop-mediated isothermal amplification (LAMP) method for specific detection of Mycobacterium bovis

Bovine tuberculosis (TB) caused by Mycobacterium bovis is a significant health threat to cattle and a zoonotic threat for humans in many developing countries. Rapid and accurate detection of M. bovis is fundamental for controlling the disease in animals and humans, and for the proper treatment of patients as one of the first-line anti-TB drug, pyrazinamide, is ineffective against M. bovis. Currently, there are no rapid, simplified and low-cost diagnostic methods that can be easily integrated for use in many developing countries. Here, we report the development of a loop-mediated isothermal amplification (LAMP) assay for specific identification of M. bovis by targeting the region of difference 4 (RD4), a 12.7 kb genomic region that is deleted solely in M. bovis. The assay's specificity was evaluated using 139 isolates comprising 65 M. bovis isolates, 40 M. tuberculosis isolates, seven M. tuberculosis complex reference strains, 22 non-tuberculous mycobacteria and five other bacteria. The established LAMP detected only M. bovis isolates as positive and no false positives were observed using the other mycobacteria and non-mycobacteria tested. Our LAMP assay detected as low as 10 copies of M. bovis genomic DNA within 40 minutes. The procedure of LAMP is simple with an incubation at a constant temperature. Results are observed with the naked eye by a color change, and there is no need for expensive equipment. The established LAMP can be used for the detection of M. bovis infections in cattle and humans in resource-limited areas.

Although bovine tuberculosis in humans has been eliminated in developed countries, the disease remains a challenge in many developing countries. Routine laboratory methods used to identify tuberculosis (TB) in high-burden countries do not distinguish between the two main causes of TB in humans, namely Mycobacterium tuberculosis and M. bovis. In addition, M. bovis is naturally resistant to one of the first-line drugs used to treat TB called pyrazinamide; therefore, accurate diagnosis of M. bovis is important for proper selection of anti TB drugs. In cattle, surveillance for M. bovis infection is important to obtain data on bovine TB burden and hence provide a basis for the establishment and/or improvement of control programs. In this study, a loop-mediated isothermal amplification (LAMP) based method was developed to identify M. bovis. This LAMP method detected M. bovis within 40 minutes following incubation at constant temperature (66°C) in a battery-powered incubator and results could be read with the naked eye following development of a color change. Our results elaborate a rapid and low-cost LAMP based method for detection and surveillance of M. bovis infection in cattle and humans in resource-limited, endemic areas.

The VetMAX™ M. tuberculosis complex PCR kit detects MTBC DNA in antemortem and postmortem samples from white rhinoceros (Ceratotherium simum), African elephants (Loxodonta africana) and African buffaloes (Syncerus caffer)

BACKGROUND

Bovine tuberculosis and tuberculosis are chronic infectious diseases caused by the Mycobacterium tuberculosis complex members, Mycobacterium bovis and Mycobacterium tuberculosis, respectively. Infection with M. bovis and M. tuberculosis have significant implications for wildlife species management, public health, veterinary disease control, and conservation endeavours.

RESULTS

Here we describe the first use of the VetMAX™ Mycobacterium tuberculosis complex (MTBC) DNA quantitative real-time polymerase chain reaction (qPCR) detection kit for African wildlife samples. DNA was extracted from tissues harvested from 48 African buffaloes and MTBC DNA was detected (test-positive) in all 26 M. bovis culture-confirmed animals with an additional 12 PCR-positive results in culture-negative buffaloes (originating from an exposed population). Of six MTBC-infected African rhinoceros tested, MTBC DNA was detected in antemortem and postmortem samples from five animals. The PCR was also able to detect MTBC DNA in samples from two African elephants confirmed to have M. bovis and M. tuberculosis infections (one each). Culture-confirmed uninfected rhinoceros and elephants' samples tested negative in the PCR assay.

CONCLUSIONS

These results suggest this new detection kit is a sensitive screening test for the detection of MTBC-infected African buffaloes, African elephants and white rhinoceros.

Prosthetic joint infection due to Mycobacterium bovis 5-years after BCG-instillations

The Bacillus Calmette-Guerin (BCG) has been used as intravesical immunotherapy for superficial urothelial bladder carcinoma in preventing its recurrence. Prosthetic joint infections due to those instillations are very rare and few practitioners know this side effect. We report the case of a 77-year old male with a medical history of right hip replacement and super- ficial urothelial bladder carcinoma treated with BCG-instillations. He presented with a painful hip joint and extreme difficulty at walking. Because of high suspicion of prosthetic joint infection, a 2-stage arthroplasty was performed. Microbiological culture revealed Mycobacterium bovis so he was kept on antituberculous therapy for twelve months. Remarkable is the delay between the instillations and the acquisition of the prosthetic joint infection. A medical history of BCG instillations should warrant the practitioner for a possible joint infection. There are no current guidelines concerning the therapy.

Test Characteristics of Assays to Detect Mycobacterium bovis Infection in High-Prevalence African Buffalo (Syncerus caffer) Herds

A herd of African buffaloes (Syncerus caffer) was tested for Mycobacterium bovis infection using three cytokine release assays. All animals were subsequently euthanized and mycobacterial culture determined the infection prevalence (52%) and diagnostic characteristics. Sensitivities were lower than previously reported and results provide new insight into the practical utility of these assays.

Evaluating the application of the dual path platform VetTB test for badgers (Meles meles) in the test and vaccinate or remove (TVR) wildlife research intervention project in Northern Ireland

European badgers (Meles meles) are accepted as a wildlife reservoir host for Mycobacterium bovis, which causes bovine tuberculosis (bTB) in the British Isles. The objective of this study was to evaluate the use of Dual Path Platform (DPP) VetTB test (Chembio Diagnostic Systems Inc., Medford, NY, USA) within a Test and Vaccinate or Remove (TVR) wildlife research intervention project. Blood samples were collected from 456 individual badgers, trapped in 2015 and 2016, and tested in the field with DPP VetTB test using whole blood. Additionally, whole blood and serum samples were taken to the laboratory for further DPP VetTB testing and for gamma interferon (IFN-γ) testing. Swabs were taken from the oropharynx and trachea and submitted for bacteriological culture as were swabs from wounds, if present. Field DPP VetTB test positive badgers were euthanised and underwent post-mortem examination and bTB confirmatory testing. The results demonstrated that the test performed as well in the field using whole blood as DPP Vet TB tests in the laboratory using sera or whole blood, and as well as other established tests for M. bovis. Visual assessment of the DPP VetTB test using serum under laboratory conditions showed a high degree of consistency between raters. Using a relative gold standard (parallel interpretation of IFN-γ assay and oropharyngeal/tracheal sample/culture), sensitivity estimates for the DPP VetTB test using sera and whole blood were 0.5 (95%CI 0.34-0.66) and 0.42 (95%CI 0.24-0.66), respectively. Specificity estimates were 0.95 (95%CI 0.93-0.97) for sera and 0.89 (95%CI 0.86-0.92) for whole blood. Parallel interpretation of Band 1 (MPB83) and Band 2 (CFP-10/ESAT-6) of the DPP VetTB test was not superior to interpretation of Band 1 only. The results give confidence in the reliability and reproducibility of the DPP VetTB test for badgers under field conditions and therefore it is considered appropriate for use in a badger bTB control campaign.

Evolutionary analysis of Mycobacterium bovis genotypes across Africa suggests co-evolution with livestock and humans

Mycobacterium bovis is the pathogenic agent responsible for bovine tuberculosis (bTB), a zoonotic disease affecting mostly cattle, but also transmittable to humans and wildlife. Genetic studies on M. bovis allow to detect possible routes of bTB transmission and the identification of genetic reservoirs that may provide an essential framework for public health action.

We used a database with 1235 M. bovis genotypes collected from different regions in Africa with 45 new Mozambican samples. Our analyses, based on phylogeographic and population genetics’ approaches, allowed to identify two clear trends. First, the genetic diversity of M. bovis is geographically clustered across the continent, with the only incidences of long-distance sharing of genotypes, between South Africa and Algeria, likely due to recent European introductions. Second, there is a broad gradient of diversity from Northern to Southern Africa with a diversity focus on the proximity to the Near East, where M. bovis likely emerged with animal domestication in the last 10,000 years.

Diversity indices are higher in Eastern Africa, followed successively by Northern, Central, Southern and Western Africa, roughly correlating with the regional archaeological records of introduction of animal domesticates. Given this scenario M. bovis in Africa was probably established millennia ago following a concomitant spread with cattle, sheep and goat. Such scenario could translate into long-term locally adapted lineages across Africa.

This work describes a novel scenario for the spread of M. bovis in Africa using the available genetic data, opening the field to further studies using higher resolution genomic data.

We describe the genetic diversity distribution in Africa of the pathogen Mycobacterium bovis, the responsible for bovine tuberculosis, mostly present in cattle but also transmittable to other animals including humans. This diversity is geographically clustered within the African continent meaning that the genetic diversity was established through independent evolution within different areas. Higher diversity values of M. bovis are found in Eastern and Northern Africa, followed by Central Africa, with Western and Southern Africa displaying the lowest diversity. These levels of diversity correlate well with the introduction of domesticated livestock in the different regions of Africa, following their domestication in the Near East 10,000 ago. We hypothesize that M. bovis emerged in the Near East and it was carried across Africa together with domesticated animals and people that developed herding practices and biological tolerance for digesting milk in adulthood. Such scenario implies a strong evolution and co-evolution of M. bovis across Africa leading to locally adapted strains that could prove a challenge for public health actions.

Low Prevalence of Mycobacterium bovis in Tuberculosis Patients, Ethiopia

An estimated 17% of all tuberculosis cases in Ethiopia are caused by Mycobacterium bovis. We used M. tuberculosis complex isolates to identify the prevalence of M. bovis as the cause of pulmonary tuberculosis. Our findings indicate that the proportion of pulmonary tuberculosis due to M. bovis is small (0.12%).

A fieldable electrostatic air sampler enabling tuberculosis detection in bioaerosols

Tuberculosis (TB) infects about 25% of the world population and claims more human lives than any other infectious disease. TB is spread by inhalation of aerosols containing viable Mycobacterium tuberculosis expectorated or exhaled by patients with active pulmonary disease. Air-sampling technology could play an important role in TB control by enabling the detection of airborne M. tuberculosis, but tools that are easy to use and scalable in TB hotspots are lacking. We developed an electrostatic air sampler termed the TB Hotspot DetectOR (THOR) and investigated its performance in laboratory aerosol experiments and in a prison hotspot of TB transmission. We show that THOR collects aerosols carrying microspheres, Bacillus globigii spores and M. bovis BCG, concentrating these microparticles onto a collector piece designed for subsequent detection analysis. The unit was also successfully operated in the complex setting of a prison hotspot, enabling detection of a molecular signature for M. tuberculosis in the cough of inmates. Future deployment of this device may lead to a measurable impact on TB case-finding by screening individuals through the aerosols they generate.

Mycobacterium bovis prosthetic joint infection following intravesical instillation of BCG for bladder cancer

A 91-year-old man with a history of intravesicular BCG therapy for recurrent bladder cancer and bilateral total hip arthroplasty (THA) presented with left hip pain. He was noted to have a fluid collection over the left lateral hip and hip X-ray showed loosening of the prosthetic hip stem indicative of a prosthetic joint infection (PJI). He subsequently underwent removal of the THA and insertion of an antibiotic spacer. He was discharged on intravenous ceftriaxone for presumed culture negative PJI. Intraoperative acid fast bacillus culture later grew Mycobacterium tuberculosis complex, which was then differentiated to M. bovis The M. bovis infection was thought to be a complication of the patient's prior BCG therapy. He was initially started on isoniazid, rifampin, pyrazinamide and ethambutol pending cultures and sensitivities; pyrazinamide was discontinued after M. bovis was isolated on culture and susceptibility data confirmed the expected inherent resistance of M. bovis to pyrazinamide. The patient underwent successful THA revision and remains symptom-free at 1 year.

Human as a potential vector of bovine tuberculosis in cattle

INTRODUCTION AND OBJECTIVE

Bovine tuberculosis (bTB, bovine TB) is caused by mycobacteria which are grouped within the MTBC. TB in animals is a highly infectious and progressive disease which can be transmitted to humans. Since 2009, Poland has gained official bTB-free status. Despite the official fact of bTB-free status, a dozen bTB outbreaks are still noted each year. Since 2000 in Poland, every year 1/5 of the national herd is subject to intradermal skin TB testing to control the bTB outbreaks in the cattle population. Application, with 5-year intervals between each government-funded skin test, undoubtedly resulted in financial savings. However it also seems to have caused several adverse and worrying events, e.g. an increase in the number of reactors detected and removed from a single tested herd. The objective of this study was the examination of 898 cattle imputed with bTB infection in Poland between 2008-2012.

MATERIAL AND METHODS

The study concerned a potential epidemic outbreak with suspected bTB transmission. 20 cows came from 3 herds in the same county located in the same province in southern Poland.

RESULTS

134 MTBC strains were identified. In MIRU-VNTR, all isolates showed the same genetic pattern 322532243421232. Based on molecular investigation, the characteristics of M. bovis strains isolated from cattle from 3 different herds confirmed the common source of this zoonotic disease.

CONCLUSIONS

Although not bacteriologically proven, everything points to the fact that humans were the vector of bovine tuberculosis transmission between herds. This finding confirms transmission between 3 cattle herds in the Małopolskie Province in southern Poland (Podhale). The outbreak of tuberculosis in animals finally compromised public health.

A first insight into genetic diversity of Mycobacterium bovis isolated from extrapulmonary tuberculosis patients in South Tunisia assessed by spoligotyping and MIRU VNTR

Introduction

In Tunisia, almost 77% of clinically and bacteriologically diagnosed cases of extrapulmonary tuberculosis (EPTB) are zoonotic TB, caused by M. bovis. Although several studies have analyzed bovine TB in cattle in Tunisia, no study has evaluated the risk of transmission to humans in such an endemic country. We aimed to study the genetic diversity of M. bovis human isolates, to ascertain the causes of human EPTB infection by M. bovis and to investigate the distribution and population structure of this species in Tunisia.

Materials and methods

A total of 110 M. bovis isolates taken from patients with confirmed EPTB were characterized by spoligotyping and MIRU-VNTR typing methods.

Results

Among the 15 spoligotypes detected in our study, 6 (SB0120, SB0121, SB2025, SB1200, SB1003 and SB0134) were the most prevalent (83.5%) of which SB0120, SB0121 and SB2025 were the most prevailing. MIRU-VNTR typing method showed a high genotypic and genetic diversity. The genetic differentiation based on MIRU-VNTR was significant between populations from South East (Tataouine, Medenine) and Central West (Gafsa, Sidi Bouzid, Kasserine) regions. Of note, 13/15 (86.7%) spoligotypes detected in our study were previously identified in cattle in Tunisia with different frequencies suggesting a peculiar ability of some genotypes to infect humans. Using combined spoligotyping and MIRU-VNTR method, a high clustering rate of 43.9% was obtained. Our results underlined that human EPTB due to M. bovis was more commonly found in female gender and in young patients. Most of our patients, 66.4% (73/110) were raw milk or derivatives consumers, whereas 30.9% (34/110) patients would have contracted EPTB through contact with livestock. The findings suggest that the transmission of Zoonotic TB caused by M. bovis to humans mainly occurred by oral route through raw milk or derivatives.

Conclusion

Our study showed the urgent need of a better veterinary control with the implementation of effective and comprehensive strategies in order to reach a good protection of animals as well as human health.

In South Tunisia, the prevalence of bovine TB is high with Mycobacterium bovis as causative agent and cattle as reservoir of the bacteria. However as previously mentioned in several studies, M. bovis is also responsible for human extrapulmonary tuberculosis (EPTB) cases in South Tunisia. Despite the veterinary and medical problems, M. bovis is still little studied. In this context, this work aimed to study the molecular epidemiology of M. bovis in EPTB patients in south Tunisia in order to determine the main risk factors of transmission. Our results underlined that SB0120, SB0121 and SB2025, previously described in cattle in Tunisia, represent the predominant genotypes. The findings highlighted that human EPTB caused by M. bovis mainly occurred through the consumption of raw milk or derivatives. These data demonstrate the urgent need to implement strategies for preventing and controlling zoonotic TB.

Genotype diversity and distribution of Mycobacterium bovis from livestock in a small, high-risk area in northeastern Sicily, Italy

Bovine tuberculosis (bTB) caused by Mycobacterium bovis is an important re-emerging disease affecting livestock, wildlife and humans. Epidemiological studies are crucial to identifying the source of bTB infection, and its transmission dynamics and host preference, and thus to the implementation of effective strategies to contain it. In this study, we typed M. bovis isolates from livestock, and investigated their genetic diversity and distribution. A total of 204 M. bovis isolates were collected from cattle (n = 164) and Sicilian black pigs (n = 40) reared in a limited area of the province of Messina, northeastern Sicily, an area that had previously been identified as having the highest incidence of bTB in livestock on the island. All M. bovis isolates were typed by both spoligotyping and 12-loci MIRU-VNTR analysis. Results from both methods were then combined in order to improve the discriminatory power of M. bovis typing. We identified 73 combined genetic profiles. Thirty-five point six percent of the profiles were common to at least two animals, whereas 64.4% of profiles occurred in only one animal. A number of genetic profiles were predominant in either cattle or black pigs. We identified common genetic patterns in M. bovis isolates originating not only from neighboring districts, but also from non-neighboring districts. Our findings suggest that bTB is widespread in our setting, and is caused by a large number of genetically diverse M. bovis strains. The ecology and farming practices characteristic of the area may explain the substantial M. bovis heterogeneity observed, and could represent obstacles to bTB eradication.

Bovine tuberculosis is a widespread infectious disease affecting both domestic and wild animals, as well as humans. In addition to being of public health concern, the disease, caused mainly by Mycobacterium bovis, has a significant economic impact on the farming industry due to the costs of eradication efforts. In Sicily, the largest of the Italian islands, bovine tuberculosis in livestock is of great concern, and targeted control strategies are needed. Molecular epidemiology is an essential tool for determining the distribution of a disease, so as to control it and minimize its threat to the population. We typed M. bovis isolates isolated from cattle and pigs reared in a limited area of Sicily. An in-depth comparison of the genetic makeup of these isolates allowed us a better understanding of the genetic diversity and distribution of the pathogen in our population of animals. We found that the disease is widespread in the area and caused by a large variety of M. bovis strains, which are in several cases common to different species of livestock. The paper concludes with a discussion of the findings in light of the environmental and ecological setting, and of farming practices in the area. The results are expected to contribute to the improvement of surveillance and control programs of bovine tuberculosis in the region.

Potential efficiency of conventional and advanced approaches used to detect Mycobacterium bovis in cattle

The present study was aimed to assess the prevalence and efficiency of techniques for the diagnosis of bovine tuberculosis (bTB) including enzyme-linked immunosorbent assay (ELISA), Gamma interferon assay (IFN-γ) and polymerase chain reaction (PCR) in comparison to skin tuberculin test and culture technique. A total of 2600 cross-breed dairy cattle in Menoufia and Daqahlia governorates were tested by the single intradermal tuberculin test where the disease prevalence was 1.8%. Serum and whole blood samples were collected from positive tuberculin reactors for ELISA and IFN-γ assay, respectively. After slaughtering of positive tuberculin reactors, the post-mortem examination was carried out and tissue samples were collected for the bacteriological examination and PCR. The percentage of visible lesions of tuberculin reactors was 78.7%, while non-visible lesions were 21.27%. Culture technique revealed that the percentage of bTB was 63.8%. The ELISA and IFN-γ assay using short-term culture filtrate (ST-CF) prepared antigen revealed higher sensitivity (72.3% and 82.9%) than the bovine purified protein derivative (PPD-B) antigen. Although prepared ST-CF antigen has great efficiency and eligibility for the diagnosis of bTB, PCR appeared to have a higher sensitivity (85.1%) than other diagnostic methods when dealing with post-mortem samples. Gamma interferon assay using ST-CF antigen is recommended for antemortem diagnosis of bTB in cattle.

Epidemiology of tuberculous lymphadenitis in Africa: A systematic review and meta-analysis

INTRODUCTION

Tuberculous lymphadenitis is the most frequent form of extra-pulmonary TB (EPTB) and accounts for a considerable proportion of all EPTB cases. We conducted a systematic review of articles that described the epidemiological features of TBLN in Africa.

METHODS

Any article that characterized TBLN cases with respect to demographic, exposure and clinical features were included. Article search was restricted to African countries and those published in English language irrespective of publication year. The articles were retrieved from the electronic database of PubMed, Scopus, Cochrane library and Lens.org. Random effect pooled prevalence with 95% CI was computed based on Dersimonian and Laird method. To stabilize the variance, Freeman-Tukey double arcsine root transformation was done. The data were analyzed using Stata 14.

RESULTS

Of the total 833 articles retrieved, twenty-eight articles from 12 African countries fulfilled the eligibility criteria. A total of 6746 TBLN cases were identified. The majority of the cases, 4762 (70.6%) were from Ethiopia. Over 77% and 88% of identified TBLN were cervical in type and naïve to TB drugs. Among the total number of TBLN cases, 53% were female, 68% were in the age range of 15-44 years, 52% had a history of livestock exposure, 46% had a history of consuming raw milk/meat and 24% had history of BCG vaccination. The proportion of TBLN/HIV co-infection was much lower in Ethiopia (21%) than in other African countries (73%) and the overall African estimate (52%). Fever was recorded in 45%, night sweating in 55%, weight loss in 62% and cough for longer than two weeks in 32% of the TBLN cases.

CONCLUSIONS

TBLN was more common in females than in males. The high prevalence of TBLN in Ethiopia did not show directional correlation with HIV. Population based prospective studies are warranted to better define the risk factors of TBLN in Africa.

Clinical Manifestations, Management, and Outcomes of Osteitis/Osteomyelitis Caused by Mycobacterium bovis Bacillus Calmette-Guérin in Children: Comparison by Site(s) of Affected Bones

OBJECTIVE

To evaluate the clinical manifestations, management, and outcomes of Mycobacterium bovis Bacillus Calmette-Guérin (BCG) osteitis/osteomyelitis.

STUDY DESIGN

We reviewed 71 cases of BCG osteitis/osteomyelitis registered in Taiwan's vaccine injury compensation program (VICP) in 1998-2014. Demographic, clinical, laboratory, treatment, and outcome data were compared according to site(s) of infection.

RESULTS

Involvement of a long bone of the lower extremity was present in 36.6% of the children, followed by foot bone (23.9%), rib or sternum (15.5%), upper extremity long bone (9.9%), hand bone (7%), multiple bones (4.2%), and vertebrae (2.8%). Children with lower extremity long bone involvement had a longer interval from receipt of BCG vaccine to presentation (median, 16.0 months; P = .02), and those with foot bone infection had higher rates of swelling (94.1%; P = .02) and local tenderness (76.5%; P = .004). Surgical intervention was performed in 70 children, with no significant difference in the number of procedures by site (median, 1.0 procedure per patient). Among the 70 children who received antimicrobial therapy, those with vertebral and multifocal infections had a longer duration of treatment (P < .001) and/or second-line antituberculosis medications (P = .002). Three children with vertebral and multifocal infections had major sequelae with kyphosis or leg length discrepancy. Outcomes were good for children with involvement of the ribs, sternum, and peripheral bones without multifocal involvement. The average time for functional recovery was 6.2 ± 3.9 months.

CONCLUSION

Children with BCG osteitis/osteomyelitis in different bones had distinct presentations and outcomes. Pediatricians should consider BCG bone infection in young vaccinated children with insidious onset of signs and symptoms, and consider affected site(s) in the management plan.

A case of bovine tuberculosis in pigs in Poland - a country free from the disease

INTRODUCTION

Bovine tuberculosis is a chronic contagious disease caused by Mycobacterium bovis or Mycobacterium caprae. Before widespread action conducted in Poland between 1959-1975 to combat bovine tuberculosis (BTB), about 40% of all tuberculosis cases in pigs was caused by the bovine bacillus. At the present time, correctly carried out, long-term control of cattle has resulted in cases of bovine tuberculosis in pigs and humans being extremely rare and sporadic. In pigs, tuberculosis is most often caught in a slaughterhouse during slaughter.

MATERIAL AND METHODS

Samples came from pigs kept on the farm. Traditional bacteriological methods on solid media (Stonebrink, LJ with pyruvate) supported by the semi-automatic, liquid indicative culture method (MGIT) and PCR test were applied in targeted studies. The GenoType Mycobacterium MTBC and CM tests (Hain Lifescience, Germany) were used to additionally confirm that isolated strains classification was used.

RESULTS

Strains of mycobacteria were isolated from all examined pigs. Mycobacterium bovis was determined by real time PCR and Hain Genotype methods.

CONCLUSIONS

In order to effectively fight against BTB, all animals on farms should be tested, regardless of species, while the milk of suspected cows should be utilized without being used for feed. It is important to adapt the current legal regulations to the current epidemiological situation.

Molecular epidemiology and whole genome sequencing analysis of clinical Mycobacterium bovis from Ghana

Background

Bovine tuberculosis (bTB) caused by Mycobacterium bovis is a re-emerging problem in both livestock and humans. The association of some M. bovis strains with hyper-virulence, MDR-TB and disseminated disease makes it imperative to understand the biology of the pathogen.

Methods

Mycobacterium bovis (15) among 1755 M. tuberculosis complex (MTBC) isolated between 2012 and 2014 were characterized and analyzed for associated patient demography and other risk factors. Five of the M. bovis isolates were whole-genome sequenced and comparatively analyzed against a global collection of published M. bovis genomes.

Results

Mycobacterium bovis was isolated from 3/560(0.5%) females and 12/1195(1.0%) males with pulmonary TB. The average age of M. bovis infected cases was 46.8 years (7-72years). TB patients from the Northern region of Ghana (1.9%;4/212) had a higher rate of infection with M. bovis (OR = 2.7,p = 0.0968) compared to those from the Greater Accra region (0.7%;11/1543). Among TB patients with available HIV status, the odds of isolating M. bovis from HIV patients (2/119) was 3.3 higher relative to non-HIV patients (4/774). Direct contact with livestock or their unpasteurized products was significantly associated with bTB (p<0.0001, OR = 124.4,95% CI = 30.1–508.3). Two (13.3%) of the M. bovis isolates were INH resistant due to the S315T mutation in katG whereas one (6.7%) was RIF resistant with Q432P and I1491S mutations in rpoB. M. bovis from Ghana resolved as mono-phyletic branch among mostly M. bovis from Africa irrespective of the host and were closest to the root of the global M. bovis phylogeny. M. bovis-specific amino acid mutations were detected among MTBC core genes such as mce1A, mmpL1, pks6, phoT, pstB, glgP and Rv2955c. Additional mutations P6T in chaA, G187E in mgtC, T35A in Rv1979c, S387A in narK1, L400F in fas and A563T in eccA1 were restricted to the 5 clinical M. bovis from Ghana.

Conclusion

Our data indicate potential zoonotic transmission of bTB in Ghana and hence calls for intensified public education on bTB, especially among risk groups.

Osteitis secondary to BCG vaccine in immunocompetent patients: Three case reports

RATIONALE

Osteitis corresponds to a rare but potentially serious complication reported in pediatric population after the application of the Bacillus Calmette-Guerin (BCG) vaccine. In the present study, 3 clinical cases associated with this entity are reported.

PATIENT CONCERNS

The 1st case corresponds to a 1-year-old female patient who presented an increase in the volume of the right pelvic limb after BCG application. The second case is a 2-year-old male who began with an increase in volume, overactive gait and pain at the level of the left knee on walking that began after a trauma in the left low limb. The 3rd case corresponds to a 3-year-old patient who started with intense pain and limitation for ambulation.

DIAGNOSIS

Both the radiographical and histological studies presented data suggestive of infection by Mycobacterium tuberculosis complex, corroborated through biopsy and genotyping analysis with the isolation of Mycobacterium bovis as the causal agent.

INTERVENTIONS

The basic treatment scheme was based on Ethambutol, Rifampicin, Pyrazinamide, and Isoniazid. When M. bovis was typified, clarithromycin was added in the treatment.

OUTCOMES

Osteitis secondary to BCG vaccine usually has a favorable evolution, especially in immunocompetent patients.

LESSONS

It was possible to confirm the association of BCG vaccine with the clinical picture of the patients who presented improvement after the start of antimicrobial management. Osteitis secondary to BCG vaccine usually presents a favorable evolution, especially in immunocompetent patients; however, the involvement of joint, growth discs and vertebrae increases the risk of presenting long-term sequels.

An Overview on Epidemiology of Tuberculosis

Tuberculosis (TB) is a progressive granulomatous infectious disease caused by the gram positive, acid fast bacilli classified under the genus Mycobacterium. Tuberculosis in human is mostly by Mycobacterium tuberculosis and primarily affects lungs causing pulmonary tuberculosis. It can also affect intestine, meninges, bones, joints, lymph nodes, skin and other tissues of the body causing extra-pulmonary tuberculosis. Human TB is transmitted mainly through droplet infection and droplet nuclei. Infection of human with M. avium and M. africanum is very rare. M. microti is not known to cause TB in human, while M. bovis has a wider host range. Human may be infected by M. bovis through milk and milk products or meat of an infected animal. It is estimated that in some developing countries up to 10% of human tuberculosis is due to bovine TB. Tuberculosis causes more than 2 million deaths annually and the death toll is worsened by the emergence of drug resistant Mycobacterium tuberculosis. The South East Asia Region accounts for 39% of global burden of TB in terms of incidence. It is estimated that about 3.4 million new cases of TB continue to occur each year in this region, most of them in India, Bangladesh, Indonesia, Myanmar and Thailand. Tuberculosis is a social disease with medical aspects. It has also been described as a barometer of social welfare. The social factors include poor quality of life, poor housing, overcrowding, population explosion, under-nutrition, smoking, alcohol abuse, lack of education, large families, early marriages, lack of awareness regarding cause and transmission of TB. These factors are interrelated and contribute to the occurrence and transmission of tuberculosis. It is estimated that approximately 10% of total TB is occurred in children. Childhood deaths from TB are usually caused by tuberculous meningitis or disseminated disease. The number of individuals infected with both HIV and TB is increasing worldwide. The HIV affects the body's immune system and enhances the speed at which TB progresses from a innocuous infection to life threatening condition. TB is a major cause of death of HIV positive individuals. Diabetes has been shown to be an independent risk factor for tuberculosis in community based studies from south India and multiple studies globally. It is suggested that diabetes accounts for 14.8% of all tuberculosis and 20.8% of smear positive TB. Understanding of epidemiology of tuberculosis is essential for its effective control. This review tried to summarize the epidemiological aspects of tuberculosis in global, regional and Bangladesh perspectives. For this review article, data available in books and at the official websites of WHO, MBDC, NTP, DGHS, The Ministry of Health and Family Welfare, Government of Bangladesh were consulted through PubMed central and Google scholar search engines. This paper has been written with an aim to offer general education to health professionals, policy makers, patients and the public.

Treatment for active tuberculosis in giraffe (Giraffa camelopardalis) in a Zoo and potential consequences for public health - Case report

INTRODUCTION

Bovine tuberculosis (bTB) is an infectious disease that occurs in many species of both domestic and free-ranging animals, as well as animals kept in zoos. According to the Polish regulations, cattle tuberculosis are slaughtered and microbiological examinations are performed, the rest of animal species can be treated and laboratory diagnostics are not obligatory.

CASE REPORT

The presented case concerns two male giraffes which were purchased by the zoo and united with a third male. After a year, the oldest male died. Post mortem examinations confirmed generalized tuberculosis. After a further six months, the second male was euthanized after suffering great pain. The material for the study of drug resistance was a swab from the nose, obtained ante mortem from the third male. Attempted treatments did not produce the expected results. Genotyping allowed the exclusion of a common source of transmission.

CONCLUSIONS

The final effect of the anti-tuberculosis therapy in the male giraffe raises the question whether the research team should have undertaken the treatment of the animal with active tuberculosis.

A study of tuberculosis in road traffic-killed badgers on the edge of the British bovine TB epidemic area

The role of badgers in the geographic expansion of the bovine tuberculosis (bTB) epidemic in England is unknown: indeed there have been few published studies of bTB in badgers outside of the Southwest of England where the infection is now endemic in cattle. Cheshire is now on the edge of the expanding area of England in which bTB is considered endemic in cattle. Previous studies, over a decade ago when bovine infection was rare in Cheshire, found no or only few infected badgers in the south eastern area of the county. In this study, carried out in 2014, road-killed badgers were collected through a network of local stakeholders (farmers, veterinarians, wildlife groups, government agencies), and Mycobacterium bovis was isolated from 21% (20/94) badger carcasses. Furthermore, there was strong evidence for co-localisation of M. bovis SB0129 (genotype 25) infection in both badgers and cattle herds at a county scale. While these findings suggest that both badgers and cattle are part of the same geographically expanding epidemic, the direction of any cross-species transmission and the drivers of this expansion cannot be determined. The study also demonstrated the utility of using road-killed badgers collected by stakeholders as a means of wildlife TB surveillance.

Badgers as a potential source of bovine tuberculosis - first studies in Poland

Since 2009, Poland has been recognized as a country officially free of bovine tuberculosis (BTB). However, new outbreaks are each year quoted. In many countries it has been shown that badgers (Meles meles) are a vector of Mycobacterium bovis/caprae (M.bovis/caprae) and a source of bovine tuberculosis for many domestical species, mainly for cattle. The aim of the presented study was to determine, for the first time in Poland, the occurrence of tuberculosis in badgers in areas where the disease occurs in cattle. Tissue samples were examined by classical microbiology methods, mycobacteria growth indicator tube (MGIT), and real time PCR. A total of 155 samples from 31 badgers were examined. In any case Mycobacterium bovis/caprae infection has not been diagnosed. This indicates that badgers probably are not a vector of bovine tuberculosis in Poland.

Diagnosis of human bovine tuberculosis aided by PET/CT scanning and EBUS-TBNA

Human bovine tuberculosis is a rare zoonotic infection in developed countries which has been achieved predominantly by effective eradication programmes in cattle. The principal modes of transmission are consumption of unpasteurised dairy products and close contact with infected cattle. The clinical and radiological presentation is indistinguishable from tuberculosis caused by Mycobacterium tuberculosis The diagnosis should be considered in individuals with relevant risk factors who present with intra/extrathoracic pathology. We describe and discuss a case of bovine tuberculosis with a synchronous primary bronchus carcinoma in an immunocompetent individual who presented with a solitary pulmonary nodule and contralateral mediastinal lymphadenopathy on CT imaging. The diagnosis of M. bovis infectionwas aided by 18F-fluorodeoxyglucose positron emission tomography/CT imaging and endobronchial ultrasound-guided mediastinal lymph node sampling.

[Mycotic aorta aneurysm treated with an autologous venous graft]

Systemic side effects, including sepsis, due to bacille Calmette-Guérin treatment for carcinoma in situ in the bladder, are observed in 15% of the patients. In rare cases, patients have developed systemic infections and mycotic aneurysms. In this case report, a 72-year-old man developed a mycotic aortic aneurysm, and the appropriate tuberculostatic drugs had no effect on his systemic infection. He was successfully treated surgically, replacing the affected aortic segment with an autologous venous graft, resulting in complete remission. A follow-up PET-CT three months later showed no sign of ongoing aortic infection.

Detection of mycobacterial small RNA in the bacterial culture supernatant and plasma of patients with active tuberculosis

Bacterial small RNA (sRNA) has been shown to play an important role in control of bacteria virulence, stress response and physiological metabolism by post-transcriptional regulation of gene expression. However, there were few reports about bacterial sRNA as a biomarker of infection. To test the potential role of sRNA in indicating infection of Mycobacterium tuberculosis, total RNA were extracted from the filtrated bacterial cultural supernatant. After synthesis of cDNA by reverse transcription, four Mycobacterial sRNAs including ASdes, ASpks, AS1726, and AS1890, which have been experimentally confirmed by Kristine B in the year of 2009, were detected by real time PCR. The specificity was verified by sequencing of the amplified products. Moreover, we demonstrate that the presence of sRNA Asdes in plasma of 55.56% (15/27) TB patients and 25.00% (6/24) normal controls with BCG vaccination (P < 0.05). Our results suggest that bacterial non-coding sRNA can be detected from either bacterial culture supernatants or patient's plasma. Detecting of Mycobacterial sRNA provides a rapid and relatively noninvasive approach for diagnosing disease and could be developed as a biomarker to identify patients with active tuberculosis to help make informed decisions about proper therapies.¹.

Fluorescence in situ hybridization microscopic detection of Bacilli Calmette Guérin mycobacteria in aortic lesions: A case report

RATIONALE

To improve the diagnosis of life-threatening Bacilli Calmette Guérin (BCG) arterial aneurysm in patients treated by intravesical instillation of BCG vaccine as adjunctive therapy for non-muscular bladder carcinoma, is a life-threatening condition. Its diagnosis remains cumbersome.

PATIENT CONCERNS

One patient with a history of intravesical BCG installation presented with aortic aneurysm with routine microscopic examination after Ziehl-Neelsen staining remaining negative.

DIAGNOSES

We used fluorescence in situ hybridization (FISH) to target the Mycobacterium tuberculosis complex rpob gene in a fresh aortic specimen. FISH yielded fluorescent mycobacteria in aortic lesions; mycobacteria were further confirmed as Mycobacterium bovis BCG mycobacteria by polymerase chain reaction (PCR) sequencing.

INTERVENTIONS

The patient benefited from an antituberculous treatment combining rifampicin, isoniazid, and ethambunol.

OUTCOME

A 9-month follow-up indicated a favorable outcome.

LESSONS

This case report teaches that FISH targeting the M tuberculosis complex rpoB gene should be incorporated in the laboratory investigation of aortic aneurysm in patients with a history of bladder carcinoma.

Comparison of Sputum-Culture Conversion for Mycobacterium bovis and M. tuberculosis

Current US guidelines recommend longer treatment for tuberculosis (TB) caused by pyrazinamide-resistant organisms (e.g., Mycobacterium bovis) than for M. tuberculosis TB. We compared treatment response times for patients with M. bovis TB and M. tuberculosis TB reported in the United States during 2006–2013. We included culture-positive, pulmonary TB patients with genotyping results who received standard 4-drug treatment at the time of diagnosis. Time to sputum-culture conversion was defined as time between treatment start date and date of first consistently culture-negative sputum. We analyzed 297 case-patients with M. bovis TB and 30,848 case-patients with M. tuberculosis TB. After 2 months of treatment, 71% of M. bovis and 65% of M. tuberculosis TB patients showed conversion of sputum cultures to negative. Likelihood of culture conversion was higher for M. bovis than for M. tuberculosis, even after controlling for treatment administration type, sex, and a composite indicator of bacillary burden.

Mycobacterium bovis in a Free-Ranging Black Rhinoceros, Kruger National Park, South Africa, 2016

In 2016, an emaciated black rhinoceros (Diceros bicornis) was found in Kruger National Park, South Africa. An interferon-γ response was detected against mycobacterial antigens, and lung tissue was positive for Mycobacterium bovis. This case highlights the risk that tuberculosis presents to rhinoceros in M. bovis–endemic areas.

Contact networks structured by sex underpin sex-specific epidemiology of infection

Contact networks are fundamental to the transmission of infection and host sex often affects the acquisition and progression of infection. However, the epidemiological impacts of sex-related variation in animal contact networks have rarely been investigated. We test the hypothesis that sex-biases in infection are related to variation in multilayer contact networks structured by sex in a population of European badgers Meles meles naturally infected with Mycobacterium bovis. Our key results are that male-male and between-sex networks are structured at broader spatial scales than female-female networks and that in male-male and between-sex contact networks, but not female-female networks, there is a significant relationship between infection and contacts with individuals in other groups. These sex differences in social behaviour may underpin male-biased acquisition of infection and may result in males being responsible for more between-group transmission. This highlights the importance of sex-related variation in host behaviour when managing animal diseases.

Environmental dust inhalation in the European badger (Meles meles): Systemic distribution of silica-laden macrophages, pathological changes, and association with Mycobacterium bovis infection status

Chronic inhalation of crystalline silica and silicates may lead to severe lung disease in humans, termed silicosis. The disease is an occupational health concern in miners and related professions worldwide. Silicosis is also a strong risk factor for tuberculosis in humans. Due to its subterranean lifestyle, the European badger (Meles meles) is continuously exposed to environmental dust, while this species is also susceptible to tuberculosis, caused by Mycobacterium bovis. To date, a thorough investigation of mineral dust retention and its possible implication as a risk factor for mycobacterial infection in badgers has not been performed. The aims of this retrospective histological study were (1) to describe the systemic tissue distribution of silica-laden macrophages (SLMs) in badgers; (2) to compare the amount of SLMs in tissues of badgers of differing M. bovis infection status, pulmonary SLM burden and age; and (3) to assess whether inflammation was associated with SLMs. We assessed lung, lymph nodes, liver and spleen of 60 wild-caught badgers of known M. bovis infection status for the presence of SLMs using polarizing light microscopy. SLMs were consistently present within the lungs and were widely distributed throughout the lymphatic system. No inflammatory reaction to SLMs, as occurs in human silicosis, was observed in any tissue. Distribution and amount of SLMs were similar between M. bovis positive and negative badgers, and we were not able to show an association between the amount of SLMs and M. bovis infection status. The amount of SLMs within intra- and extrathoracic lymph nodes was positively associated with the amount of pulmonary SLMs, and with age. This is the first report of substantial and systemic tissue retention of mineral dust particles in a mammalian species lacking associated chronic inflammation (i.e. silicosis). We further highlight different pathogenetic mechanisms underlying silicosis and benign SLM accumulations following siliceous dust inhalation.

Occupational exposure to human Mycobacterium bovis infection: A systematic review

BACKGROUND

Mycobacterium bovis (M. bovis) is the main causative agent of bovine zoonotic tuberculosis. The aim of this systematic review is to highlight the occupational exposure to bovine tuberculosis due to M. bovis.

METHODOLOGY/PRINCIPAL FINDINGS

A computer based literature search was carried out to identify papers published between January 2006 and March 2017. "PubMed, Cochrane Library and Science Direct" databases were searched systematically. Articles presenting the following properties were included: (i) focusing on M. bovis; (ii) concerning occupational exposure to bovine tuberculosis. A quality assessment was performed after selection of studies. Our search strategy identified a total of 3,264 papers of which 29 studies met the inclusion criteria. Of the 29 articles, 17 were cross-sectional studies (6 were of high quality and scored in the range of 6-7, 11 were of moderate quality and scored in the range 3-5), 10 were case reports, and 2 were reviews. Different occupational fields exposing to the disease were described: livestock sector, particularly in contact with dairy cattle (farmers, veterinaries and assistants, abattoir workers) and working in contact with wildlife (hunters, taxidermists).

CONCLUSIONS

A specific guideline for occupational practitioners taking care of employees exposed to bovine tuberculosis is warranted and should be tailored to level of exposure. This review was intended to be the first step of such a project. Articles were identified from various continents and countries with different socio-economic situations, broadening our understanding of the worldwide situation. Published data on occupational exposure in developed countries are scarce. We had to extrapolate findings from countries with higher prevalence of the disease.

Miliary pulmonary infection after BCG intravesical instillation: a rare, misdiagnosed and mistreated complication

Intravesical Bacillus Calmette-Guérin (BCG) immunotherapy decreases the progression risk of non-muscle-invasive bladder cancer, but potentially yields a broad spectrum of side effects. We report the case of a 73-year-old man affected by miliary pulmonary BCG infection, whose microbiological diagnosis was probably hindered by empiric fluoroquinolones, focusing on imaging and clinical work-up.

A 25-year surveillance of disseminated Bacillus Calmette-Guérin disease treatment in children in Southern Iran

Disseminated Bacillus Calmette-Guérin (BCG) disease is one of the most serious complications of BCG vaccination, mainly among immunocompromised children with high morbidity and mortality.Currently, there is no any consensus with regard to the standard regimen of antituberculosis (anti-TB) agents and duration of treatment in healthy or immunocompromised host in children. The aim of this study is to investigate the effect of various combination treatment strategies for disseminated BCG disease in children.In this cross-sectional study, the outcome of 3 different combination protocols was investigated in 59 patients.All patients were younger than 6 years old. Both possible immunocompetent and proven immunodeficient children were included in a period of 25 years (1991-2014) in a Nemazee referral teaching hospital.The minimum age was 1 month and the maximum was 60 months. The average age of patients was 8 months (8.26 ± 9.73). Out of 59 cases, 32 (54.2%) were female and 27 (45.8%) were male. Based on the primary work up, 52.5% of cases were classified as definite immunodeficient and 47.5% were classified as possible immunocompetent. Overall mortality rate was 50.8%. Mortality rate of disseminated BCG disease in immunocompetent and immunodeficient children was 28.6% and 71%, respectively. The mortality rate was not statistically different between patients treated with different treatment protocols. These results were not affected by immune status and the type of immunodeficiency.More than 2 anti-TB drugs combination will not change outcome of patient with disseminated BCG disease.

[Tuberculosis caused by Mycobacterium bovis, a re-emerging infection?]

Currently, tuberculosis (TB) is a public health problem, is present in all regions of the world and remains one of the most deadly communicable diseases, particularly associated with infection by the human immunodeficiency virus (HIV). Cases of TB Mycobacterium bovis more and more frequent, especially in vulnerable populations. TB caused by M. bovis clinical, radiological and histologically indistinguishable from tuberculosis caused by M. tuberculosis; however, there are some differences that make M. tuberculosis particular. The direct correlation between infection with M. bovis in cattle and human disease has been well documented, but the true prevalence is underestimated. Overall, the proportion of cases of human TB caused by M. bovis is low compared with M. tuberculosis, but its potential in the groups most at risk impact should not be underestimated by the impact on morbidity and mortality.

Molecular characterization of bovine tuberculosis strains in two slaughterhouses in Morocco

BACKGROUND

Bovine tuberculosis (BTB) is caused by Mycobacterium bovis, which belongs to the Mycobacterium tuberculosis complex. Mycobacterium bovis have been described to be responsible of most cases of bovine tuberculosis. Although M. tuberculosis, M. africanum and non-complex mycobacteria were isolated from cattle. In Morocco, so far, no molecular studies were conducted to characterize the strains responsible of BTB. The present study aims to characterize M. bovis in Morocco. The present study was conducted in slaughterhouses in Rabat and El Jadida. Samples were collected from 327 slaughtered animals with visible lesions suggesting BTB.

RESULTS

A total of 225 isolates yielded cultures, 95% (n = 215) of them were acid-fast (AF). Sixty eight per cent of the AF positive samples were confirmed as tuberculous mycobacteria (n = 147), 99% of these (n = 146) having RD9 and among the latter, 98% (n = 143) positive while 2% (n = 3) negative for RD4 A total of 134 samples were analyzed by spoligotyping of which 14 were in cluster and with 41 different spoligotypes, ten of them were new patterns (23%). The most prevalent spoligotypes were SB0121, SB0265, and SB0120, and were already identified in many other countries, such as Algeria, Spain, Tunisia, the United States and Argentina.

CONCLUSION

The shared borders between Algeria and Morocco, in addition to the previous importation of cattle from Europe and the US could explain the similarities found in M. bovis spoligotypes. On the other hand, the desert of Morocco could be considered as an efficient barrier preventing the introduction of BTB to Morocco from West Central and East Africa. Our findings suggest a low level endemic transmission of BTB similar to other African countries. However, more research is needed for further knowledge about the transmission patterns of BTB in Morocco.

Cost-effectiveness evaluation of bovine tuberculosis surveillance in wildlife in France (Sylvatub system) using scenario trees

Bovine tuberculosis (bTB) is a common disease in cattle and wildlife, with health, zoonotic and economic implications. Infected wild animals, and particularly reservoirs, could hinder eradication of bTB from cattle populations, which could have an important impact on international cattle trade. Therefore, surveillance of bTB in wildlife is of particular importance to better understand the epidemiological role of wild species and to adapt the control measures. In France, a bTB surveillance system for free-ranging wildlife, the Sylvatub system, has been implemented since 2011. It relies on three surveillance components (SSCs) (passive surveillance on hunted animals (EC-SSC), passive surveillance on dead or dying animals (SAGIR-SSC) and active surveillance (PSURV-SSC)). The effectiveness of the Sylvatub system was previously assessed, through the estimation of its sensitivity (i.e. the probability of detecting at least one case of bTB infection by each SSC, specie and risk-level area). However, to globally assess the performance of a surveillance system, the measure of its sensitivity is not sufficient, as other factors such as economic or socio-economic factors could influence the effectiveness. We report here an estimation of the costs of the surveillance activities of the Sylvatub system, and of the cost-effectiveness of each surveillance component, by specie and risk-level, based on scenario tree modelling with the same tree structure as used for the sensitivity evaluation. The cost-effectiveness of the Sylvatub surveillance is better in higher-risk departments, due in particular to the higher probability of detecting the infection (sensitivity). Moreover, EC-SSC, which has the highest unit cost, is more efficient than the surveillance enhanced by the SAGIR-SSC, due to its better sensitivity. The calculation of the cost-effectiveness ratio shows that PSURV-SSC remains the most cost-effective surveillance component of the Sylvatub system, despite its high cost in terms of coordination, sample collection and laboratory analysis.

Use of fecal volatile organic compound analysis to discriminate between non-vaccinated and BCG-Vaccinated cattle prior to and after Mycobacterium bovis challenge

Bovine tuberculosis is a zoonotic disease of global public health concern. Development of diagnostic tools to improve test accuracy and efficiency in domestic livestock and enable surveillance of wildlife reservoirs would improve disease management and eradication efforts. Use of volatile organic compound analysis in breath and fecal samples is being developed and optimized as a means to detect disease in humans and animals. In this study we demonstrate that VOCs present in fecal samples can be used to discriminate between non-vaccinated and BCG-vaccinated cattle prior to and after Mycobacterium bovis challenge.

Experimental Mycobacterium bovis infection in three white rhinoceroses (Ceratotherium simum): Susceptibility, clinical and anatomical pathology

Tuberculosis caused by Mycobacterium bovis is endemic in the African buffalo (Syncerus caffer) population in the Kruger National Park and other conservation areas in South Africa. The disease has been diagnosed in a total of 21 free ranging or semi-free ranging wildlife species in the country with highly variable presentations in terms of clinical signs as well as severity and distribution of tuberculous lesions. Most species are spillover or dead-end hosts without significant role in the epidemiology of the disease. White rhinoceroses (Ceratotherium simum) are translocated from the Kruger National Park in substantial numbers every year and a clear understanding of their risk to manifest overt tuberculosis disease and to serve as source of infection to other species is required. We report the findings of experimental infection of three white rhinoceroses with a moderately low dose of a virulent field isolate of Mycobacterium bovis. None of the animals developed clinical signs or disseminated disease. The susceptibility of the white rhinoceros to bovine tuberculosis was confirmed by successful experimental infection based on the ante mortem isolation of M. bovis from the respiratory tract of one rhinoceros, the presence of acid-fast organisms and necrotizing granulomatous lesions in the tracheobronchial lymph nodes and the detection of M. bovis genetic material by PCR in the lungs of two animals.

Molecular detection of M. tuberculosis and M. bovis and hematological and biochemical analyses in agricultural sprayers exposed to pesticides: A cross-sectional study in Punjab, Pakistan during 2014-2016

We determined the correlation between a pesticide exposure, physical health and susceptibility toward tuberculosis along with hematological indices and liver enzymes' alterations in sprayers exposed to pesticides. Molecular detection of Mycobacterium tuberculosis and Mycobacterium bovis was detected by targeting histone-like protein (hupB) gene. The WBC (white blood cells) and RBC (red blood cells) levels of male sprayers and non-sprayers were significantly different (P<0.05). In female spray workers, the WBC and neutrophils levels were significantly different as compared with non-sprayers. Overall, in both male and female pesticide-exposed sprayers, mean values of alanine amino transferase and aspartate amino transferase were higher as compared with unexposed workers. M. Tuberculosis were detected in 15% male sprayers and 36% female sprayers while, M. bovis was detected in 5% male sprayers and 10% female sprayers. A χ²-test indicated that there existed a significant different (P<0.05) between positive and negative M. tuberculosis and M. bovis in both male/female spray workers out of total. The susceptibility of pesticide-exposed sprayers to tuberculosis and alterations in hematology and liver enzymes is crucial for health. Toxic effects of pesticides may lead to a weak immune system and increased tuberculosis susceptibility.