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1.
Reasons for performing study: Lameness associated with lesions of the deep digital flexor tendon (DDFT) in the digit is now recognised as an important cause of lameness, but there is currently limited information about the pathological nature of the lesions. Objectives: To compare: signal intensity changes on magnetic resonance images with histopathology; and histopathological changes in the DDFT from horses with no history of foot‐related lameness (Group C) and horses with lesions of the DDFT confirmed using magnetic resonance imaging (MRI) (Group D). Methods: Transverse sections of the DDFT were harvested from 3 sites in all horses: 1) immediately proximal to the navicular bursa (E1); 2) at the level of the navicular bone (E2); and 3) close to the tendon's insertion (E3). If lesions were identified at E1 or had been identified further proximally using MRI, additional sections were obtained until, in most cases, the proximal limit of the lesion was identified. All DDFTs were graded histopathologically using predefined criteria. The MR images were reviewed to determine the location and sequences in which increased signal intensity was seen. Results: No haemorrhage or inflammatory cell infiltration was seen in any horse. At level E 1 , septal thickening, ghosting of blood vessels and blood vessel occlusion were common in Group D, but were not seen in Group C. Less commonly, there was core necrosis, only seen in Group D. At level E 2 , septal and vascular changes were most obvious in Group D. Core necrosis, dorsal splitting, crevicing and fibrillation were seen only in Group D. Septal and vascular changes were present in both Groups C and D at level E 3 , but fibrocartilaginous metaplasia, splitting, crevicing and fibrillation, or core necrosis or fibroplasia were seen only in Group D. Core lesions in Group D often extended proximal to E 1 , and ranged in length from 0.5–13 cm. Core necrosis was generally associated with increased signal intensity in fat suppressed images. Conclusions: Lesions of the DDFT in the digit appear to be primarily degenerative, and may be a sequel to vascular compromise. Increased signal intensity on fat suppressed MR images is not necessarily associated with frank fluid or evidence of inflammation, but may reflect major matrix changes in the tendon. Potential relevance: Further information about the causes of these lesions is required to develop preventative strategies.  相似文献   

2.
Magnetic resonance imaging (MRI) is a common test for dogs with suspected intradural spinal cord lesions, however studies on diagnostic performance for this test are lacking. Objectives of this multi‐institutional, retrospective, case‐control study were to estimate sensitivity and specificity of MRI for (1) distinguishing between histopathologically confirmed intradural spinal cord disease versus degenerative myelopathy in dogs, (2) categorizing intradural spinal cord diseases as neoplastic, inflammatory, or vascular; and (3) determining tumor type within the etiologic category of neoplasia. Additional aims were to (1) determine whether knowledge of clinical data affects sensitivity and specificity of MRI diagnoses; and (2) report interrater agreement for MRI classification of intradural spinal lesions. Cases were recruited from participating hospital databases over a 7‐year period. Three reviewers independently evaluated each MRI study prior to and after provision of clinical information. A total of 87 cases were sampled (17 degenerative myelopathy, 53 neoplasia, nine inflammatory, and eight vascular). Magnetic resonance imaging had excellent (>97.6%) sensitivity for diagnosis of intradural spinal cord lesions but specificity varied before and after provision of clinical data (68.6% vs. 82.4%, P = 0.023). Magnetic resonance imaging had good sensitivity (86.8%) and moderate specificity (64.7–72.5%) for diagnosing neoplasia. Sensitivity was lower for classifying inflammatory lesions but improved with provision of clinical data (48.1% vs. 81.5%, P = 0.015). Magnetic resonance imaging was insensitive for diagnosing vascular lesions (25.0%). Interrater agreement was very good for correctly diagnosing dogs with intradural lesions (? = 0.882–0.833), and good (? = 0.726–0.671) for diagnosing dogs with neoplasia.  相似文献   

3.
A dog being treated with immunosuppressive doses of prednisone and azathioprine for pancytopenia of unknown origin, developed, over a 2‐week period, multiple erythematous nodular lesions in the skin including footpads. Skin samples revealed lesions identical to those of human bacillary angiomatosis (BA). The nodules were composed of multifocal proliferations of capillaries, each lined by protuberant endothelial cells. The capillary clusters were separated by an oedematous connective tissue, lightly infiltrated with degenerate inflammatory cells, including neutrophils and macrophages. Tissue sections stained with Warthin–Starry silver stain revealed large numbers of positively stained bacilli in the stromal tissue, most heavily concentrated around the proliferating capillaries. Lesions of vascular degeneration and inflammation were evident. Bartonella vinsonii subsp. berkhoffii genotype 1 was independently amplified and sequenced from the blood and the skin tissue. The pathognomonic nature of the histological lesions, demonstration of compatible silver‐stained bacilli in the tissue, and identification of B. vinsonii subsp. berkhoffii in the blood and tissue indicates that this is most likely the aetiologic agent responsible for the lesions. Antibiotic therapy was successful in resolving the nodules. It would appear that B. vinsonii subsp berkhoffii, like Bartonella henselae and Bartonella quintana, has the rare ability to induce angioproliferative lesions, most likely in association with immunosuppression. The demonstration of lesions identical to those of human BA in this dog is further evidence that the full range of clinical manifestations of human Bartonella infection occurs also in canines.  相似文献   

4.
Background: Contrast‐enhanced ultrasonography with perflubutane microbubbles improves the diagnostic accuracy to differentiate benign and malignant focal liver lesions in dogs. Hypothesis: Perflubutane microbubbles‐enhanced ultrasonography is useful for differentiation of benign from malignant focal splenic lesions in dogs. Animals: Twenty‐nine clinical dogs with single or multiple focal splenic lesions detected by conventional ultrasonography. Methods: Prospective clinical observational study. Perflubutane microbubbles‐enhanced ultrasonography was performed in 29 dogs with focal splenic lesions. Qualitative assessment of the enhancement pattern was performed in the early vascular, late vascular, and parenchymal phases. Results: In the early vascular phase, a hypoechoic pattern was significantly associated with malignancy (P= .02) with sensitivity of 38% (95% confidence interval [CI], 25–38%) and specificity of 100% (95% CI, 84–100%). In the late vascular phase, a hypoechoic pattern was significantly associated with malignancy (P= .001) with sensitivity of 81% (95% CI, 66–90%) and specificity of 85% (95% CI, 65–95%). There was no significant difference between malignant and benign lesions during the parenchymal phase. Conclusions and Clinical Importance: Hypoechoic splenic nodules in the early and late vascular phases with perflubutane microbubbles‐enhanced ultrasonography are strongly suggestive of malignancy in dogs.  相似文献   

5.
Certain magnetic resonance (MR) enhancement patterns are often considered to be associated with a specific diagnosis but experience shows that this association is not always consistent. Therefore, it is not clear how reliably contrast enhancement patterns correlate with specific tissue changes. We investigated the detailed histomorphologic findings of intracranial lesions in relation to Gadodiamide contrast enhancement in 55 lesions from 55 patients, nine cats, and 46 dogs. Lesions were divided into areas according to their contrast enhancement; therefore 81 areas resulted from the 55 lesions which were directly compared with histopathology. In 40 of 55 lesions (73%), the histomorphologic features explained the contrast enhancement pattern. In particular, vascular proliferation and dilated vessels occurred significantly more often in areas with enhancement than in areas without enhancement (P=0.044). In 15 lesions, there was no association between MR images and histologic findings. In particular, contrast enhancement was found within necrotic areas (10 areas) and ring enhancement was seen in lesions without central necrosis (five lesions). These findings imply that necrosis cannot be differentiated reliably from viable tissue based on postcontrast images. Diffusion of contrast medium within lesions and time delays after contrast medium administration probably play important roles in the presence and patterns of contrast enhancement. Thus, histologic features of lesions cannot be predicted solely by contrast enhancement patterns.  相似文献   

6.
The protozoan parasite, Eimeria leuckarti was present in the ileal mucosa of a 7-month-old Thoroughbred filly which was destroyed with acute peritonitis resulting from perforation of the rectum. The parasite was considered to be of no clinical significance and the signs of colic noted prior to the rectal rupture were related to the vascular lesions caused by infection with Delafondia vulgaris.  相似文献   

7.
A 3‐year‐old Burmese cat was presented with a history of nonresolving crusted and papular lesions of the face and prior treatment with prednisolone. Skin biopsies revealed typical pox lesions with hyperplasia and ulceration of the epidermis and eosinophilic cytoplasmic inclusion bodies in the epidermal cells. In the upper dermis there was prominent diffuse mast cell infiltration and mild neutrophilic and eosinophilic inflammation. Rare cytoplasmic inclusion bodies were also present in swollen endothelial cells of dermal venules, which showed no other degenerative changes. Histological diagnosis was confirmed by electron microscopic evidence of pox virus particles in inclusion bodies of epidermal cells. The lesions resolved within 6 weeks with systemic antibiotic therapy and supportive care. A 2‐year‐old domestic short‐haired cat was presented with multiple disseminated papular and ulcerative pox lesions with central eschar over the entire body. Histologically, large epidermal inclusion bodies (up to 6 μm in diameter) were present. Widespread haemorrhage and vascular wall necrosis was visible in the dermis and subcutis. Some subcutaneous vessels showed neutrophilic vasculitis. In addition to diffuse dermal neutrophilic and eosinophilic inflammation, a lymphohistiocytic panniculitis was also present. The cat died as a result of massive haemorrhage and lymphedema, despite supportive care. Funding: Self‐funded.  相似文献   

8.
Pulmonary adiaspiromycosis was diagnosed in 15 of 17 common brushtail possums (Trichosurus vulpecula) examined for bovine tuberculosis. Emmonsia crescens was isolated from two of the affected animals. This is the first reported isolation of this dimorphic fungus in New Zealand. The infections varied from light to heavy with sparsely distributed, focal, 1–2 mm diameter, grey-white spherical granulomas in the lightly infected cases to innumerable foci throughout the lungs in the heavily infected cases. Histologically, the lesions were characterised by a central fungal adiaspore consistent in morphology with E. crescens located in alveolar spaces or bronchioles. These were surrounded by a cuff of granulomatous inflammation which varied in density and extent in proportion to the degree of degeneration exhibited by the organism.

The lesions in most cases of adiaspiromycosis in the possum are sufficiently distinctive to allow their differentiation from tuberculosis by gross examination, but where any doubt exists over the possibility of dual infection by Emmonsia and Mycobacterium species differentiation should be made on the basis of a histological examination of the tissue and culture for mycobacterial organisms.  相似文献   

9.
Reasons for performing study: Regional veno‐occlusive remodelling of pulmonary veins in EIPH‐affected horses, suggests that pulmonary veins may be central to pathogenesis. The current study quantified site‐specific changes in vein walls, collagen and haemosiderin accumulation, and pleural vascular profiles in the lungs of horses suffering EIPH. Hypothesis: In the caudodorsal lung regions of EIPH‐affected horses, there is veno‐occlusive remodelling with haemosiderosis, angiogenesis and fibrosis of the interstitium, interlobular septa and pleura. Methods: Morphometric methods were used to analyse the distribution and accumulation of pulmonary collagen and haemosiderin, and to count pleural vascular profiles in the lungs of 5 EIPH‐affected and 2 control horses. Results: Vein wall thickness was greatest in the dorsocaudal lung and significantly correlated with haemosiderin accumulation. Increased venous, interstitial, pleural and septal collagen; lung haemosiderin; and pleural vascular profiles occurred together and changes were most pronounced in the dorsocaudal lung. Further, haemosiderin accumulation colocalised with decreased pulmonary vein lumen size. Vein wall thickening, haemosiderin accumulation and histological score were highly correlated and these changes occurred only in the caudodorsal part of the lung. Conclusion: The colocalisation of these changes suggests that regional (caudodorsal) venous remodelling plays an important role in the pathogenesis of EIPH. Potential relevance: The results support the hypothesis that repeated bouts of venous hypertension during strenuous exercise cause regional vein wall remodelling and collagen accumulation, venous occlusion and pulmonary capillary hypertension. Subjected to these high pressures, there is capillary stress failure, bleeding, haemosiderin accumulation and, subsequently, lung fibrosis.  相似文献   

10.
The CT appearance of canine adrenal masses has been reported, but associations between imaging features and pathologic features of these lesions have not been investigated in detail. The purpose of this study was to test associations between different types of adrenal neoplasia and their CT and pathologic features. A retrospective cross‐sectional study was performed and inclusion criteria were histologic diagnosis of primary adrenal neoplasia, contrast‐enhanced CT examination of the abdomen and surgical resection of the mass or necropsy examination. For all included dogs, CT images and histopathologic specimens were reviewed independently by two veterinary radiologists and a veterinary pathologist, respectively. Seventeen dogs met inclusion criteria. Diagnoses were adenocarcinoma in nine (53%) dogs, pheochromocytoma in five (29%) dogs, and adenoma in three (18%) dogs. Pheochromocytoma was associated with CT signs of vascular invasion (likelihood ratio = 4.8, 95% CI = 1.3–18.3, P = 0.03) and macroscopic vascular invasion (likelihood ratio = 9.6, 95% CI = 1.4–65.9, P = 0.02). There was excellent agreement between signs of vascular invasion in CT images and vascular invasion at surgery or necropsy (kappa = 0.86, P = 0.001). A peripheral contrast‐enhancing rim in delayed postcontrast CT images was associated with fibrous encapsulation of the tumor (kappa = 0.53, P = 0.05), and a heterogeneous pattern of contrast distribution in delayed postcontrast CT images was associated with adrenal hemorrhage or infarction on histological examination (kappa = 0.45, P = 0.05). Findings indicated that CT enabled assessment of adrenal neoplasia features that reflected their biological behavior and pathological findings, however overlapping characteristics between tumor types limited the potential for reliably distinguishing them based on CT alone.  相似文献   

11.
A flock of New Zealand Romney lambs on a property in Hawkes Bay was examined from August 1978 to June 1979. In November, the lambs in the flock were allocated to groups as follows: 600 lambs from which groups were selected for slaughter by commercial criteria each month (selected groups); 700 lambs which were subdivided into 8 groups (random groups), one of which was sent for slaughter each month; and 25 lambs to monitor serological responses to viral infections (surveillance group). At slaughter, lesions in the anterior lobes of the lungs were classified into small, large or mottled lesions while those in the posterior regions of the diaphragmatic lobes comprised a separate group. The prevalence of the pneumonic and pleural lesions was recorded in all groups of lambs. Pneumonic lesions in lambs from the random groups were further classified after microscopic examination. The prevalence of infections with parainfluenza virus type 3, adenoviruses, Mycoplasma spp., and Pasteurella haemolytica was also recorded in the random groups. Average carcase weights of all groups of lambs were also recorded.

The prevalence of large lesions in the anterior lobes, pleural lesions and devaluation of carcases due to pleural lesions was significantly lower in the selected than in the random groups.

In the random groups, the prevalence of small lesions in the anterior lobes of the lungs was high and was not always associated with infections with the viruses, P. haemolytica or Mycoplasma spp. Microscopically, these lesions could he divided into four types as previously described. The prevalence of large lesions in the anterior lobes was low in November but increased to peak levels in February and March and then declined to intermediate levels. The prevalence of large lesions was associated with that of infections with the micro-organisms and significantly more large lesions contained P. haemolytica and Mycoplasma spp. than did small lesions or normal lungs. The prevalence of large lesions also appeared to be inversely related to the average carcase weights of the lambs. Most large lesions were similar on microscopy to those of “enzootic” or “atypical” pneumonia but were divided into four types on the basis of exudative and proliferative features. The prevalence of mottled lesions in the anterior lobes was low throughout the period of observation but peaks were observed in January and May. The peaks were associated with adenovirus infection and elevated prevalence of infection with P. haemolytica and Mycoplasma spp. Significantly more mottled lesions contained P. haemolytica than did small lesions or normal lungs. Microscopically, most mottled lesions were similar to exudative large lesions.

Lesions in the posterior diaphragmatic lobes were most numerous in November and from April to June. Their prevalence appeared to be related to anthelminthic treatment and environmental conditions. Microscopically, these lesions were typical of those following infection with Dictyocaulus filaria.  相似文献   

12.
A 5.5‐year‐old, intact male Rottweiler dog was admitted with a history of multifocal nodular tongue lesions which progressively deteriorated during the previous year. Physical examination revealed several reddish nodules with central depression on the surface of the tongue in an otherwise healthy dog. Clinicopathologic abnormalities included eosinophilia and hyperproteinemia. Lingual nodule cytopathology, histopathology, and immunohistochemistry revealed Leishmania spp. amastigotes and a severe granulomatous glossitis. The dog was also seroreactive to L infantum antigens by an indirect immunofluorescence assay. Clinical reevaluation 3 months after the institution of treatment with allopurinol and miltefosine indicated that the nodular lesions had completely regressed. In endemic areas, lingual nodular lesions may rarely be the sole clinical sign of canine leishmaniosis. Standard medical treatment may provide an excellent prognosis.  相似文献   

13.
ABSTRACT

Case history: Gradual onset of ocular opacity was observed in three gold-striped geckos (Woodworthia chrysosiretica), and five Pacific geckos (Dactylocnemis pacificus) held in two adjacent terrariums in a zoological institution located in the North Island of New Zealand. Ultraviolet light and heat had been provided for the previous 3–4 years by a fluorescent bulb, but in the last 4 weeks of winter a ceramic heat bulb had been added, situated 10?cm above the upper mesh of the cage

Clinical findings: All eight geckos presented with mostly bilateral lesions of varying severity confined to the central or upper quadrant of the spectacles. These lesions ranged from variable areas of opacity within the stroma of the spectacle to similarly distributed ulcers of the surface epithelium of both spectacles. The spectacle lesions in the Pacific geckos responded well to treatment with topical combined antimicrobial therapy, within 18–29 days. The gold-striped geckos suffered complications including dysecdysis, severe spectacle ulceration and perforation, mycotic spectaculitis, and widespread mycotic dermatitis resulting in death or leading to euthanasia.

Pathological findings: In the three gold-striped geckos, there were extensive areas of deep ulceration and replacement of the spectacle with a thick serocellular crust containing large numbers of fungal elements. The affected areas of the stroma were expanded by large deposits of proteinaceous and mucinous material, pyknotic cellular debris and moderate numbers of heterophils and macrophages as well as infiltrating fungal hyphae.

Diagnosis: Mycotic spectaculitis with ulceration and perforation, and disseminated mycotic dermatitis likely secondary to thermal burns.

Clinical relevance: This is the first report of thermal burns of the spectacle in any reptile. There was species variation in the burn severity with gold-striped geckos showing more severe lesions, possibly due to a mix of behavioural and anatomical factors. The thermal burns to the spectacles in three cases were complicated by delayed healing, perforation, dysecdysis and severe mycotic infection.  相似文献   

14.
Abstract

Tapeworms in the genus Ligula are cosmopolitan parasites whose plerocercoid stages are found worldwide in fishes of the families Cyprinidae and Catostomidae. Examination of chiselmouth Acrocheilus alutaceus, northern pikeminnow Ptychocheilus oregonensis, and bridgelip sucker Catostomus columbianus revealed the presence of Ligula in the lower Crooked River system of central Oregon. This represents the first report of Ligula intestinalis in two of these host species: chiselmouth and bridgelip sucker. Although most hosts appeared healthy, large external lesions were noted on some bridgelip suckers in close association with a Ligula plerocercoid. The largest plerocercoid recovered was 101.5 cm relaxed length and may represent the longest plerocercoid of Ligula reported from North America.  相似文献   

15.
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16.
Abstract

Avian vacuolar myelinopathy (AVM) is an often-lethal neurologic disease that affects waterbirds and their avian predators (i.e., bald eagles Haliaeetus leucocephalus) in the southern United States. Feeding trials and field surveys provided evidence that AVM is caused by a toxin-producing, undescribed cyanobacterium (UCB), which grows as an epiphyte on the leaves of submerged aquatic vegetation (SAV). Reservoirs with documented AVM epornitics support dense growth of nonnative SAV. Waterbirds ingest the toxin when feeding on aquatic plants with the epiphytic UCB, and secondary intoxication occurs when raptors consume these birds. Vegetation management has been proposed as a means to reduce waterbird exposure to the putative toxin. We fed aquatic vegetation with and without the UCB to triploid Grass Carp Ctenopharyngodon idella in laboratory and field trials. Only Grass Carp that ingested aquatic vegetation with the UCB developed lesions in the central nervous system. The lesions (viewed using light microscopy) appeared similar to those in birds diagnosed with AVM. Grass Carp that received aquatic vegetation without the UCB were unaffected. Grass Carp tissues from each treatment were fed to domestic chickens Gallus domesticus (an appropriate laboratory model for AVM) in a laboratory trial; the chickens displayed no neurologic signs, and histology revealed a lack of the diagnostic lesions in brain tissues. Results from our trials suggest that (1) triploid Grass Carp are susceptible to the AVM toxin, although no fish mortalities were documented; and (2) the toxin was not accumulated in Grass Carp tissues, and the risk to piscivorous avifauna is likely low. However, a longer exposure time and analysis of sublethal effects may be prudent to further evaluate the efficacy and risk of using triploid Grass Carp to manage aquatic vegetation in a system with frequent AVM outbreaks.

Received December 3, 2012; accepted August 2, 2013  相似文献   

17.
In 2012 when many sheep flocks in northern‐central Tasmania were experiencing a high prevalence of ovine Johne's disease, 34 wild adult fallow deer shot on or near infected properties were negative to microscopic Mptb lesions of the ileo‐caecal valve, terminal ileum and ileo‐caecal lymph nodes. This study demonstrated 95% confidence of detecting Johne's disease in this fallow deer population if ≥10% of animals were shedding Mycobacterium avium subsp. paratuberculosis in their faeces, or if ≥21% of animals were sub‐clinically infected.  相似文献   

18.
Susceptibility weighted imaging (SWI) is a high resolution, fully velocity‐compensated, three‐dimensional gradient echo (GE) MRI technique. In humans, SWI has been reported to be more sensitive than T2*‐weighted GE sequences in the identification of both intracranial hemorrhage and intra‐vascular deoxyhemoglobin. However, published clinical studies comparing SWI to T2*‐weighted GE sequences in dogs are currently lacking. The aim of this retrospective, observational study was to compare SWI and T2*‐weighted GE sequences in a group of dogs with intracranial disease. Medical records were searched for dogs that underwent a brain MRI examination that included T2*‐weighted GE and SWI sequences. The presence and appearance of non‐vascular and vascular signal voids observed on T2*‐weighted GE and SWI were compared. Thirty‐two dogs were included with the following diagnoses: presumed and confirmed intracranial neoplasia (27), cerebrovascular accidents (3), and trauma (2). Hemorrhagic lesions were significantly more conspicuous on SWI than T2*‐weighted GE sequences (P < .0001). Venous structures were well defined in all SWI sequences, and poorly defined in all dogs on T2*‐weighted GE. Susceptibility weighted imaging enabled identification of vascular abnormalities in 30 of 32 (93.8%) dogs, including: neovascularization in 19 of 32 (59.4%) dogs, displacement of perilesional veins in five of 32 (15.6%) dogs, and apparent dilation of perilesional veins in 10 of 32 (31.3%) dogs. Presence of neovascularization was significantly associated with T1‐weighted post‐contrast enhancement (P = .0184). Hemorrhagic lesions and venous structures were more conspicuous on SWI compared to T2*‐weighted GE sequences. Authors recommend adding SWI to standard brain protocols in dogs for detecting hemorrhage and identifying venous abnormalities for lesion characterization.  相似文献   

19.
AIM: To determine the prevalence of Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula) that did not have macroscopic lesions of bovine tuberculosis, and to evaluate culture of pooled tissues from multiple possums as a method for determining the M. bovis-infection status of wildlife populations in New Zealand.

METHODS: Pools of selected tissues were collected from possums from four different populations known to be infected with M. bovis. Tissue pools from individual animals, and combined pools from multiple animals, were cultured for M. bovis.

RESULTS: In the four populations investigated, the prevalence of possums with macroscopic lesions confirmed by culture to be infected with M. bovis ranged from 1 to 19 (mean 31/283; 10.9)%. The prevalence of possums with non-visible lesions that were culture positive for M. bovis in the same populations ranged from 4 to 10 (mean 24/283; 8.5)%. The mean of the log10 cfu of M. bovis of the macroscopic lesions and of the culture-positive samples that did not have visible lesions was 3.85 (SE 0.26) and 1.46 (SE 0.26) log10 cfu, respectively (p<0.01). Mycobacterium bovis was cultured from pools of 30–50 animals in the four populations studied.

CONCLUSIONS: The finding of M. bovis infection in possums with non-visible lesions identified a potential deficiency of declaring possum populations free of M. bovis on the basis of absence of macroscopic lesions. The culturing of pools of selected tissues from multiple animals without visible lesions can be used to reduce laboratory costs of possum surveys without a major reduction in the ability to detect M. bovis infection.  相似文献   

20.
Aim. To study the nature and development of experimentally induced respiratory tuberculosis in possums and compare the lesions observed with those seen in the natural disease.

Methods. Thirty-three adult possums were inoculated via the endo-bronchial route with 20–100 colony forming units of Mycobacterium bovis. The possums were killed at 1, 2, 3 and 4 weeks after inoculation and the nature and distribution of the lesions studied in detail histopatbologically. Alveolar macrophages recovered from the infected possums were also studied ultrastructurally.

Results. Macroscopic lesions were largely confined to the respiratory tract, increasing in size and number with time. Histology greatly increased the detection of the total number of lesions. The most common sites affected outside the respiratory tract were the liver and hepatic lymph nodes, but lesions were less common in peripheral lymph nodes than is observed in the natural disease. Intra-pulmonary lesions were centred on blood vessels and their associated lymphatics. Peripheral blood lymphocyte blastogenic responses to M. bovis antigens were first detected at 3 weeks after inoculation, which was 1 week after lymphocyte infiltrations were detected in the lungs, but 1 week before the majority of infections became generalised.

Conclusions. Differences in the nature of pulmonary lesions and the distribution of lesions were observed between experimentally induced and the natural disease. Rapid haematogenous and lymphatic spread occurs early in the experimentally induced disease.  相似文献   

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