Microhemorragias cerebrales. Utilidad de las secuencias de susceptibilidad magnética (SWI) / Cerebral microbleeds. Utility of SWI sequences

Objetivo: Definir el concepto de microhemorragia cerebral y revisar las secuencias de resonancia magnética (RM) utilizadas para su valoración. Revisar cuáles son las patologías que presentan microhemorragias y que pueden beneficiarse del uso de secuencias de susceptibilidad magnética (SWI). Conclusión: Las SWI son útiles en la detección y caracterización de microhemorragias, venas y otras fuentes de susceptibilidad. La secuencia SWI mejora la sensibilidad diagnóstica con respecto a las secuencias convencionales potenciadas en T2* (eco de gradiente T2* [2D-GRE]). Las microhemorragias cerebrales pueden asociarse a diversas enfermedades, aparecer en contextos clínicos menos conocidos o servir como biomarcador tumoral en gliomas (ITTS) y como marcador de actividad inflamatoria en las placas de esclerosis múltiple (EM).(AU)

Objectives: Define the concept of cerebral microbleeds (CMB) and describe the most useful MRI sequences for detecting this finding. Review the entities that most frequently present with CMB and that may benefit from the use of susceptibility-weighted imaging (SWI) sequences. Conclusions: SWI is a useful MRI sequence for the detection and characterization of microhemorrhages, venous structures and other sources of susceptibility in imaging. SWI is particularly sensitive to local magnetic field inhomogeneities generated by certain substances and is superior to T2* GRE sequences for this assessment. CMB may be seen in different neurologic conditions, in certain infrequent clinical contexts and have a key role as a biomarker status in gliomas (ITTS) and as a marker of inflammatory activity in multiple sclerosis.(AU)

Cerebral microbleeds. Utility of SWI sequences.

OBJECTIVES: Define the concept of cerebral microbleeds (CMBs) and describe the most useful MRI sequences for detecting this finding. Review the entities that most frequently present with CMBs and that may benefit from the use of susceptibility-weighted imaging (SWI) sequences. CONCLUSIONS: SWI is a useful MRI sequence for the detection and characterization of microhemorrhages, venous structures and other sources of susceptibility in imaging. SWI is particularly sensitive to local magnetic field inhomogeneities generated by certain substances and is superior to T2* GRE sequences for this assessment. CMBs may be seen in different neurologic conditions, in certain infrequent clinical contexts and have a key role as a biomarker status in gliomas (ITTS) and as a marker of inflammatory activity in multiple sclerosis.

Analysis of deep brain stimulation of the subthalamic nucleus (STN-DBS) in patients with monogenic PRKN and LRRK2 forms of Parkinson's disease.

INTRODUCTION: Deep brain stimulation of the subthalamic nucleus (STN-DBS) is the most common surgical treatment for Parkinson's disease (PD). Patient selection and genetic background can modify the response to this treatment. The objective of this study was to compare both clinical and pharmacologic response of STN-DBS between patients with monogenic forms of PD and non-mutation carriers with idiopathic PD. METHODS: A retrospective analysis among 23 carriers of genetic mutations (8 PRKN and 15 LRRK2) and 74 patients with idiopathic PD was performed. The study included comparisons of Unified Parkinson's Disease Rating Scale (UPDRS) II and III scores, Schwab and England (S&E) scale values, Hoehn & Yahr (H&Y) stage scores, and equivalent doses of levodopa before and after the surgery (at 6 and 12 months) between both groups. RESULTS: The mean age at the time in which STN-DBS was performed was 59.5 ± 8.6. Linear mixed models showed the absence of statistically significant differences between mutation and non-mutation carriers regarding levodopa doses (p = 0.576), UPDRS II (p = 0.956) and III (p = 0.512) scores, and S&E scale scores (0.758). The only difference between the two groups was observed with respect to H&Y stage in OFF medication/ON stimulation status being lower in genetic PD at 6 months after surgery (p = 0.030). CONCLUSION: Clinical and pharmacological benefit of bilateral STN-DBS is similar in PRKN and LRRK2 mutation carriers and patients with idiopathic PD.

[Is there a relationship between white matter lesions associated with migraine and patent foramen ovale? Analysis of a series of patients with chronic migraine]. / ¿Existe relación entre las lesiones de la sustancia blanca asociadas a migraña y el foramen oval permeable? Análisis de una serie de pacientes con migraña crónica.

INTRODUCTION: White matter lesions are more prevalent in migraine patients than in the general population, especially those with a high frequency of attacks. A patent foramen ovale has been described as a possible link between migraine and white matter lesions. AIM: To determine the existence of a possible relationship between a patent foramen ovale and white matter lesions in a series of patients with chronic migraine. PATIENTS AND METHODS: Observational, single-centre, case-control study. Eighty-nine women with chronic migraine were selected. The persistence and characteristics of the patent foramen ovale were assessed by means of a transcranial Doppler study. The patent foramen ovale was classified as small, moderate or massive. Those detected at rest were considered permanent, and the others were classified as latent. The MRI protocol included T1-enhanced sagittal images, FLAIR-T2-enhanced axial images, and a proton density and T2-FSE combined sequence. The white matter lesions were classified as deep, periventricular or both. RESULTS: The prevalence of patent foramen ovale (53.6% versus 48.5%; p = 0.80) and the proportion of massive, permanent patent foramen ovale were similar among patients with and without white matter lesions. Neither was there any difference in the prevalence (55.6% versus 52.6%; p = 1.00) or the characteristics of the patent foramen ovale as a function of the distribution of white matter lesions. CONCLUSION: The results do not suggest that a patent foramen ovale intervenes in the pathophysiology of the white matter lesions observed in patients with migraine.

TITLE: ¿Existe relación entre las lesiones de la sustancia blanca asociadas a migraña y el foramen oval permeable? Análisis de una serie de pacientes con migraña crónica.Introducción. Las lesiones de la sustancia blanca son más prevalentes en los pacientes migrañosos que en la población general, especialmente en los que tienen una alta frecuencia de ataques. El foramen oval permeable se ha descrito como posible nexo de unión entre la migraña y las lesiones de la sustancia blanca. Objetivo. Determinar la existencia de una posible relación entre el foramen oval permeable y las lesiones de la sustancia blanca en una serie de pacientes con migraña crónica. Pacientes y métodos. Estudio observacional, unicéntrico, de casos y controles. Se seleccionó a 89 mujeres con migraña crónica. La persistencia y las características del foramen oval permeable se evaluaron mediante un estudio Doppler transcraneal. El foramen oval permeable se clasificó como pequeño, moderado o masivo. Se consideraron permanentes los detectados en reposo, y latentes, el resto. El protocolo de resonancia magnética incluyó imágenes sagitales potenciadas en T1, axiales potenciadas en FLAIR-T2 y secuencia combinada de densidad protónica y T2-FSE. Las lesiones de la sustancia blanca se clasificaron como profundas, periventriculares o ambas. Resultados. La prevalencia de foramen oval permeable (53,6% frente a 48,5%; p = 0,80) y la proporción de foramen oval permeable masivo y permanente fueron similares entre los pacientes con y sin lesiones de la sustancia blanca. Tampoco se encontraron diferencias en la prevalencia (55,6% frente a 52,6%; p = 1,00) o las características del foramen oval permeable en función de la distribución de las lesiones de la sustancia blanca. Conclusión. Los resultados no sugieren la intervención del foramen oval permeable en la fisiopatología de las lesiones de la sustancia blanca observadas en pacientes migrañosos.

Food-borne diseases associated with frozen berries consumption: a historical perspective, European Union, 1983 to 2013.

Epidemiological investigations of outbreaks of hepatitis A virus (HAV) and norovirus (NoV) infections in the European Union/European Economic Area (EU/EEA) in the last five years have highlighted frozen berries as a vehicle of infection. Given the increasing berry consumption in the EU over the last decades, we undertook a review of the existing evidence to assess the potential scale of threat associated with this product. We searched the literature and four restricted-access online platforms for outbreak/contamination events associated with consumption of frozen berries. We performed an evaluation of the sources to identify areas for improvement. The review revealed 32 independent events (i.e. outbreak, food contamination) in the period 1983­2013, of which 26 were reported after 2004. The identified pathogens were NoV, HAV and Shigella sonnei. NoV was the most common and implicated in 27 events with over 15,000 cases reported. A capture­recapture analysis was performed including three overlapping sources for the period 2005­2013. The study estimated that the event-ascertainment was 62%. Consumption of frozen berries is associated with increasing reports of NoV and HAV outbreaks and contamination events, particularly after 2003. A review of the risks associated with this product is required to inform future prevention strategies. Better integration of the available communication platforms and databases should be sought at EU/EEA level to improve monitoring, prevention and control of food-borne-related events.

The global threat of antimicrobial resistance: science for intervention.

In the last decade we have witnessed a dramatic increase in the proportion and absolute number of bacterial pathogens resistant to multiple antibacterial agents. Multidrug-resistant bacteria are currently considered as an emergent global disease and a major public health problem. The B-Debate meeting brought together renowned experts representing the main stakeholders (i.e. policy makers, public health authorities, regulatory agencies, pharmaceutical companies and the scientific community at large) to review the global threat of antibiotic resistance and come up with a coordinated set of strategies to fight antimicrobial resistance in a multifaceted approach. We summarize the views of the B-Debate participants regarding the current situation of antimicrobial resistance in animals and the food chain, within the community and the healthcare setting as well as the role of the environment and the development of novel diagnostic and therapeutic strategies, providing expert recommendations to tackle the global threat of antimicrobial resistance.

Defining pathogenic verocytotoxin-producing Escherichia coli (VTEC) from cases of human infection in the European Union, 2007-2010.

During 2007-2010, 13 545 confirmed human verocytotoxin (VT)-producing Escherichia coli (VTEC) infections were reported in the European Union, including 777 haemolytic uraemic syndrome (HUS) cases. Clinical manifestations were reported for 53% of cases, 64% of which presented with diarrhoea alone and 10% with HUS. Isolates from 85% of cases were not fully serotyped and could not be classified on the basis of the Karmali seropathotype concept. There is no single or combination of phenotypic or genetic marker(s) that fully define 'pathogenic' VTEC. Isolates which contain the vtx2 (verocytotoxin 2) gene in combination with the eae (intimin-encoding) gene or aaiC (secreted protein of enteroaggregative E. coli) and aggR (plasmid-encoded regulator) genes have been associated with a higher risk of more severe illness. A molecular approach targeting genes encoding VT and other virulence determinants is thus proposed to allow an assessment of the potential severity of disease that may be associated with a given VTEC isolate.

Risk ranking of pathogens in ready-to-eat unprocessed foods of non-animal origin (FoNAO) in the EU: initial evaluation using outbreak data (2007-2011).

Foods of non-animal origin (FoNAO) are consumed in a variety of forms, being a major component of almost all meals. These food types have the potential to be associated with large outbreaks as seen in 2011 associated with VTEC O104. In order to identify and rank specific food/pathogen combinations most often linked to human cases originating from FoNAO in the EU, a semi-quantitative model was developed using seven criteria: strength of associations between food and pathogen based on the foodborne outbreak data from EU Zoonoses Monitoring (2007-2011), incidence of illness, burden of disease, dose-response relationship, consumption, prevalence of contamination and pathogen growth potential during shelf life. The top ranking food/pathogen combination was Salmonella spp. and leafy greens eaten raw followed by (in equal rank) Salmonella spp. and bulb and stem vegetables, Salmonella spp. and tomatoes, Salmonella spp. and melons, and pathogenic Escherichia coli and fresh pods, legumes or grains. Despite the inherent assumptions and limitations, this risk model is considered a tool for risk managers, as it allows ranking of food/pathogen combinations most often linked to foodborne human cases originating from FoNAO in the EU. Efforts to collect additional data even in the absence of reported outbreaks as well as to enhance the quality of the EU-specific data, which was used as input for all the model criteria, will allow the improvement of the model outputs. Furthermore, it is recommended that harmonised terminology be applied to the categorisation of foods collected for different reasons, e.g. monitoring, surveillance, outbreak investigation and consumption. In addition, to assist future microbiological risk assessments, consideration should be given to the collection of additional information on how food has been processed, stored and prepared as part of the above data collection exercises.

Corrigendum to "The global threat of antimicrobial resistance: science for intervention" [New Microbes New Infect 6 (2015): 22-29].

[This corrects the article DOI: 10.1016/j.nmni.2015.02.007.].

A comparison between longitudinal shedding patterns of Salmonella Typhimurium and Salmonella Dublin on dairy farms.

Salmonella in cattle herds may behave as epidemic or endemic infections. An intensive longitudinal sampling study across all management groups and ages on six dairy farms in the UK was used to examine patterns of Salmonella shedding, following the prior identification of either Salmonella Dublin (SD) (three farms) or Salmonella Typhimurium (ST) (three farms) on the premises in the context of clinical salmonellosis. Individual faeces, pooled faeces and environmental samples (total 5711 samples), taken approximately every six weeks for 15-24 weeks, were cultured for Salmonella. SD was detected at low frequency (on any visit, 0.5-18.3 per cent of samples positive) and most consistently in calves. By contrast, ST was isolated at higher frequency (on any visit, 6.8-75 per cent of samples positive), and in higher numbers, up to 10(7) cfu/g faeces. Significantly more samples from calves were positive for ST than were positive for SD (50.6 per cent v 3.1 per cent; P < 0.001), which was also true for milking cows (46.3 per cent v 4.4 per cent; P < 0.001). The differences could help to explain the different patterns of bovine infection classically associated with these two serovars in the UK. No consistent effect upon shedding was seen among the ST-infected herds following vaccination.

Hendiduras miocárdicas: a propósito de 4 casos / Myocardial clefts: a report of four cases

Las técnicas de resonancia magnética cardiaca (RMC) actuales permiten el reconocimiento de múltiples variantes anatómicas cardiacas, como las hendiduras miocárdicas. Presentamos cuatro casos clínicos de hendiduras miocárdicas. Se trata de anomalías poco frecuentes y aparecen tanto en individuos sanos como en pacientes con diferentes afecciones cardiacas. Su etiopatogenia es desconocida, aunque se barajan varias hipótesis. Si bien la mayoría de las veces se trata de un hallazgo casual, es importante conocer su existencia porque pueden ser responsables de embolismos sistémicos (AU)

Current cardiac magnetic resonance imaging (cMRI) techniques enable many heart defects, like myocardial clefts, to be detected. We present four clinical cases of myocardial clefts. Myocardial clefts are uncommon abnormalities that are found in both healthy individuals and patients with different heart problems. The etiopathogenesis is unknown, although several hypotheses have been proposed. Although myocardial clefts are usually discovered incidentally, it is important to be aware of their existence because they can cause systemic embolisms (AU)

[Myocardial clefts: a report of four cases]. / Hendiduras miocárdicas: a propósito de 4 casos.

Current cardiac magnetic resonance imaging (cMRI) techniques enable many heart defects, like myocardial clefts, to be detected. We present four clinical cases of myocardial clefts. Myocardial clefts are uncommon abnormalities that are found in both healthy individuals and patients with different heart problems. The etiopathogenesis is unknown, although several hypotheses have been proposed. Although myocardial clefts are usually discovered incidentally, it is important to be aware of their existence because they can cause systemic embolisms.

[Review of the target for the deep brain stimulation of chronic cluster headache]. / Revision de la diana para la estimulacion cerebral profunda de la cefalea en racimos cronica.

Cluster headache is included in the group of trigeminal autonomic cephalalgias. Although the pathophysiology of cluster headache has not yet been sufficiently established, the theory of a central origin tells us that this headache is produced by hypothalamic dysfunction. More than 50 patients have been treated with deep brain stimulation of the posterior nucleus of the hypothalamus from 2001. The results show clinical improvement in more than 60% of the cases, opening a promising issue for the treatment of the cluster headache persistent after medical treatment. The surgical target that have been used until now is based on the origin of the cluster headache in the hypothalamic dysfunction. Nevertheless, It has still some open questions as the lack of proving the posterior nucleus of the hypothalamus is the real origin of the cluster headache, the lack of consensus about the anatomy of the surgical target and the variability of the structures stimulated with the surgery. The aim of this article is a review of the target used and propose another surgical target based on physiopathological concepts to explain the improvement with the deep brain stimulation in these patients.

Cavernoma intraventricular del foramen de Monro: particularidades derivadas de su localización atípica / Intraventricular cavernoma in the foramen of Monro: particularities due to its atypical location

A pesar de que los cavernomas son malformaciones vasculares relativamente frecuentes en el sistema nervioso central, su localización intraventricular, especialmente en la región del foramen de Monro, es muy poco común. Esta localización atípica les confiere una serie de rasgos diferenciales, tanto clínicos como radiológicos, que pueden dificultar en extremo su diagnóstico preoperatorio y conducir a procedimientos ineficaces, como la radioterapia o el abordaje quirúrgico neuroendoscópico, e incluso peligrosos para el paciente, como la biopsia estereotáxica.Dado lo infrecuente de la patología y con el fin de ilustrar estas dificultades diagnósticas, se presenta a continuación un caso de cavernoma intraventricular de la región del foramen de Monro (AU)

Although cavernomas are relatively common vascular malformations in the central nervous system, they are rarely located in the ventricles and are even more rarely located in the region of the foramen of Monro. This atypical location results in a series of differential clinical and radiological characteristics that can make the diagnosis of these lesions extremely difficult and lead to inefficacious procedures like radiotherapy or a neuroendoscopic surgical approach or even to procedures that endanger the patient like stereotactic biopsy.We present a case of intraventricular cavernoma in the region of the foramen of Monro with the aim of illustrating the difficulties involved in the diagnosis of this rare lesion (AU)

[Intraventricular cavernoma in the foramen of Monro: particularities due to its atypical location]. / Cavernoma intraventricular del foramen de Monro: particularidades derivadas de su localización atípica.

Although cavernomas are relatively common vascular malformations in the central nervous system, they are rarely located in the ventricles and are even more rarely located in the region of the foramen of Monro. This atypical location results in a series of differential clinical and radiological characteristics that can make the diagnosis of these lesions extremely difficult and lead to inefficacious procedures like radiotherapy or a neuroendoscopic surgical approach or even to procedures that endanger the patient like stereotactic biopsy. We present a case of intraventricular cavernoma in the region of the foramen of Monro with the aim of illustrating the difficulties involved in the diagnosis of this rare lesion.

Agenesia unilateral de la arteria carótida interna / Unilateral agenesis of internal carotid artery

Introducción. La agenesia unilateral de arteria carótida interna es una anomalía del desarrollo extremadamenterara (incidencia: 0,01%). Su diagnóstico generalmente es incidental durante la realización de una prueba radiológica.La mayoría de los casos descritos son sujetos adultos con síntomas de patología cerebrovascular. En este artículorevisamos la anatomía, el diagnóstico diferencial y las implicaciones clínicas de esta malformación, entre las que destacauna mayor prevalencia de aneurismas cerebrales. Casos clínicos. Presentamos dos casos de agenesia de arteria carótidainterna, uno en el lado derecho en una niña de 4 años, y otro en el lado izquierdo en una mujer de 58 años. Conclusiones.La tomografía computarizada de alta resolución para demostrar la ausencia de canal carotídeo en la base delcráneo y la angiorresonancia magnética son las pruebas radiológicas utilizadas para confirmar su diagnóstico. Aunquela mayoría de los casos permanecen asintomáticos, su detección es fundamental cuando se plantea una cirugía de la carótida,ya que la vascularización de ambos hemisferios cerebrales puede depender de la carótida ateromatosa que vamosa tratar(AU)

Introduction. Unilateral agenesis of the internal carotid artery is an extremely rare developmental anomaly(incidence: 0.01%). Diagnosis is often incidental in a radiological examination. Most of the cases described are in olderpatients with symptoms of cerebrovascular disorders. We review the anatomy, differential diagnosis and clinical implicationsof these malformations as the high prevalence of cerebral aneurysms. Case reports. We report the clinical and imagingfindings of two cases of agenesis of the internal carotid artery, one on the right in a 4 years old female, and another onthe left, in a 58 years old woman. Conclusions. High resolution CT to demonstrate the absence of the carotid canal atthe skull base and angio-MR are the radiological proves used to confirm the diagnosis. Although many of these casesremain asymptomatic, their recognition has important implications, specially when we are planning carotid endarterectomy,because both cerebral hemispheres may be dependent upon the atheromatous carotid(AU)

Evaluation of CHROMagar CTX, a novel medium for isolating CTX-M-ESBL-positive Enterobacteriaceae while inhibiting AmpC-producing strains.

OBJECTIVES: The aim of this study was to evaluate CHROMagar CTX (CHROMagar France), a novel agar for the selective isolation of Enterobacteriaceae expressing the bla(CTX-M) gene in the presence of enteric bacteria expressing AmpC enzymes. METHODS: A panel of 150 Gram-negative bacteria (mainly Escherichia coli, Enterobacter, Klebsiella, Pseudomonas and Salmonella) isolated from humans and animals were assembled for the purpose of evaluating CHROMagar CTX and comparing it with CHROMagar ECC with the addition of 1, 2, 4 and 8 mg/L cefotaxime or ceftazidime and with bioMérieux extended-spectrum beta-lactamase (ESBL)-Bx agar. CHROMagar CTX was also assessed for its ability to isolate bla(CTX-M) strains from farm animal faeces (n = 342). RESULTS: The panel contained CTX-M-positive (n = 70) strains (CTX-M types 1, 9, 14 and 15), ESBLs (n = 31) belonging to other families (OXA, PER, SHV, TEM, VEB), strains positive for ampC genes (n = 31), strains that overexpressed ampC (n = 6), non-ESBL/AmpC strains (n = 11) and Klebsiella oxytoca (n = 1). CHROMagar CTX was superior to other agars tested for selective isolation of Enterobacteriaceae expressing the bla(CTX-M) gene with 100% sensitivity and 64.2% specificity for CTX-M strains in the panel and 90.1% of the colonies from animal faeces plated on CHROMagar CTX were CTX-M strains. CONCLUSIONS: CHROMagar CTX is a valuable agar in situations where it is important to isolate bla(CTX-M) strains in the presence of AmpC strains. The agar may be particularly useful in veterinary studies, where AmpC-producing commensal E. coli can be encountered reasonably frequently in the enteric flora of some animal species and may also be useful, following further evaluation, for samples from humans.

Development of an oligonucleotide microarray method for Salmonella serotyping.

Adequate identification of Salmonella enterica serovars is a prerequisite for any epidemiological investigation. This is traditionally obtained via a combination of biochemical and serological typing. However, primary strain isolation and traditional serotyping is time-consuming and faster methods would be desirable. A microarray, based on two housekeeping and two virulence marker genes (atpD, gyrB, fliC and fljB), has been developed for the detection and identification of the two species of Salmonella (S. enterica and S. bongori), the five subspecies of S. enterica (II, IIIa, IIIb, IV, VI) and 43 S. enterica ssp. enterica serovars (covering the most prevalent ones in Austria and the UK). A comprehensive set of probes (n = 240), forming 119 probe units, was developed based on the corresponding sequences of 148 Salmonella strains, successfully validated with 57 Salmonella strains and subsequently evaluated with 35 blind samples including isolated serotypes and mixtures of different serotypes. Results demonstrated a strong discriminatory ability of the microarray among Salmonella serovars. Threshold for detection was 1 colony forming unit per 25 g of food sample following overnight (14 h) enrichment.

Histological observations of bovine tuberculosis in lung and lymph node tissues from British deer.

Deer are recognized as hosts of Mycobacterium bovis and assessing the role of wild cervids in perpetuating tuberculosis among cattle has motivated extensive research on several continents. In this paper, the histopathology of lymph node and lung tuberculous granulomas in M. bovis positive British deer is presented. The overall aim was to seek further insights into the potential for onward transmission from infected deer to other species, including cattle. Samples were obtained from an extensive survey of wild mammals in South-West England and from statutory tuberculosis surveillance. M. bovis culture-positive samples were characterised microscopically as to their stage of lesion advancement, number of acid-fast bacilli and granuloma encapsulation. Seventy percent of the deer developed granulomas containing far greater numbers of M. bovis bacilli than typically reported in cattle. Red and fallow deer had the largest number of poorly encapsulated granulomas often containing many hundreds of bacilli. The results are consistent with infected wild British deer being a potential source of environmental contamination and onward transmission to other species. However, further work on levels of bacillary shedding is required before this can be confirmed.

Pathology of naturally occurring bovine tuberculosis in England and Wales.

The aim of this study was to obtain a contemporary data set of pathology in tuberculin reactor and in-contact cattle in England and Wales. Four hundred animals (200 reactors and 200 in-contacts) from 242 farms located in 14 counties in Western England and Wales were examined. The mean number of lymph nodes (LNs) with tuberculosis (TB)-like lesions per TB-confirmed animal was 1.7 in reactors and 1.5 in in-contact animals. Tuberculous lesions in both reactor and in-contact animals were most commonly observed in the LNs of the thorax, followed by the head and abdomen, particularly the mediastinal, retropharyngeal and tracheobronchial LNs. Twenty-five reactors had macroscopic lesions in the palatine tonsils. Among TB-confirmed cattle, 27% of reactors and 9% of in-contact animals had gross TB-like lesions in the lungs, particularly in the caudal lobes. Gross lesions that were not TB-confirmed were parasitic granulomas (45%), bacterial or mycotic club-forming pyogranulomas (27%) and bacterial abscesses (23%). Diagnostic sensitivity was maximised when bacteriology and histopathology were used concurrently. Stage IV granulomas, alone or in combination with other stages, constituted 63% of lesions, while 16% of lesions were stage I/II granulomas. Caseous necrosis and calcification were common features of the granulomas encountered in natural Mycobacterium bovis infections, even with pathology limited to a small number of sites. Granulomas often covered large areas of histological sections and typically contained only small numbers of acid fast bacilli.