Tuberculosis in a free-living brown hare (Lepus europaeus occidentalis)

A free-living brown hare (Lepus europaeus occidentalis) trapped during a survey of tuberculous possums in the Ahaura Valley, Westland, was found to have both microbiological and histopathological evidence of infection with Mycobacterium bovis. The mesenteric lymph nodes were enlarged and showed extensive caseation, tuberculous nodules were present in the liver and kidney, and there was a proliferative pleurisy. Histologically, characteristic tuberculous granulomatous foci were seen in the mesenteric lymph nodes, liver, kidney, pleura and lungs, often in association with small numbers of acid-fast organisms. This is the first report of naturally occurring tuberculosis due to M. bovis in the brown hare.     

Experimental Mycobacterium bovis infection of cattle: Effect of dose of M. bovis and pregnancy on immune responses and distribution of lesions

Groups of l8-month-old cattle were inoculated intratracheally with 5 X 10⁵ colony forming units (high dose) or 500 colony forming units (low dose) of Mycobacterium bovis to determine an appropriate dose to induce lesions similar to those seen in the natural disease. An additional group of 21–28 weeks pregnant cattle were inoculated with the high dose of M. bovis to determine if pregnancy increased the susceptibility of cattle to M. bovis infection. By 23–24 weeks after challenge, the high dose of M. bovis had induced extensive lung lesions, and tuberculous lesions were observed in the lymph nodes of the head, neck, and thoracic and abdominal cavities. In contrast, the low dose of M. bovis induced predominantly small lesions (< 1 cm diameter) which were localised to the lungs and pulmonary lymph nodes. The lesions induced by the low dose were similar to those seen in the natural disease in cattle. The majority of the high dose group cattle produced strong antibody responses to M. bovis culture filtrate, while only one low dose animal produced a detectable response. All of the M. bovis-inoculated cattle produced strong cellular immune responses to bovine PPD (skin test and interferon-γ responses). Pregnancy did not appear to affect the susceptibility to M. bovis infection, and immune responses of the cattle in this group at the end of the study were similar to those in the high dose non-pregnant group. However, from the first test after calving, the interferon-y responses of peripheral blood cultures to bovine PPD were low compared with the responses prior to calving.     

Isolation of Salmonella dublin from a sheep in New Zealand

Extract

On March 8, 1964, formalinized samples of liver, kidney and lung and fresh samples of mesenteric lymph nodes and lung from a ram hogget were submitted to the Wallaceville Animal Research Centre. The animal had died suddenly and post-mortem examination revealed intense reddening of the intestinal and abomasal mucosa and enlarged mesenteric lymph nodes, with some consolidation and pleural adhesions. Small red spots were observed on the liver surface. The possibility of salmonellosis was considered and appropriate cultures were made of the fresh material in addition to aerobic cultures on blood agar.     

Mycobacterium bovis infection in the brush-tailed possum (Trichosurus vulpecula): I. Preliminary observations on experimental infection

An Australian cattle strain of Mycobacterium bovis was injected intramuscularly into 10 brush-tailed possums (Trichosurus vulpecula) which were shown to be highly sensitive to experimental infection with this organism. The possums were killed and examined throughout the course of infection. At necropsy, gross and microscopic lesions were recorded and several tissues cultured for recovery of M. bovis. Infection spread rapidly via the lymphatic system from the injection site to the lumbar lymph nodes, then to the spleen. There was a bacteraemia after 2 week and by 6 weeks lesions were present in spleen, lymph nodes, lungs and kidneys; M. bovis proliferated rapidly and host response was minimal. Few organisms were detected in the liver where miliary lesions were found. M. bovis was excreted in large numbers in urine, faeces and discharging sinuses from subcutaneous abscesses. In two possums that died early in the infection, stress had rendered then more susceptible; infection spread more rapidly than in other possums and liver involvement was more severe. Although aerosol transmission was considered to be a possible means of spreading M. bovis, three in-contact possums did not acquire infection.     

Direct Detection of Mycobacterium bovis in Bovine Lymph Nodes by PCR

Thirty‐five lymph node samples were taken from animals with macroscopic lesions consistent with Mycobacterium bovis infection. The animals were identified by postmortem examination in an abattoir in the northwestern region of state of Paraná, Brazil. Twenty‐two of the animals had previously been found to be tuberculin skin test positive. Tissue samples were decontaminated by Petroff’s method and processed for acid‐fast bacilli staining, culture in Stonebrink and Lowenstein‐Jensen media and DNA extraction. Lymph node DNA samples were amplified by PCR in the absence and presence (inhibitor controls) of DNA extracted from M. bovis culture. Mycobacterium bovis was identified in 14 (42.4%) lymph node samples by both PCR and by culture. The frequency of PCR‐positive results (54.5%) was similar to that of culture‐positive results (51.5%, P > 0.05). The percentage of PCR‐positive lymph nodes increased from 39.4% (13/33) to 54.5% (18/33) when samples that were initially PCR‐negative were reanalysed using 2.5 μl DNA (two samples) and 1 : 2 diluted DNA (three samples). PCR sensitivity was affected by inhibitors and by the amount of DNA in the clinical samples. Our results indicate that direct detection of M. bovis in lymph nodes by PCR may be a fast and useful tool for bovine tuberculosis epidemic management in the region.     

Experimental tuberculosis in the European badger (Meles meles) after endobronchial inoculation with Mycobacterium bovis: II. Progression of infection

The aim of the study was to describe, over a period of 24 weeks, the pathological and bacteriological changes in badgers experimentally infected with Mycobacterium bovis. The badgers were infected by endobronchial instillation of 2.5 × 10⁴ colony forming units (cfu) M. bovis. After infection, the badgers were examined at 3 weekly intervals when blood and tracheal aspirates were collected. At 6, 12, 18 and 24 weeks post-infection (pi) three animals were euthanized and a detailed pathological and bacteriological examination was performed to assess the nature of the experimental disease. During the course of the study only one badger developed clinical signs of disease: a subcutaneous swelling on its head, first observed at 18 weeks pi. At post-mortem examination gross and histological lesions of tuberculosis were observed and M. bovis was recovered from all, except one badger. In the majority of badgers the endobronchial route of inoculation resulted in the establishment of infection that over 24 weeks was non-progressive with limited dissemination of infection from the thoracic cavity, mainly to the hepatic and mesenteric lymph nodes. However, in one of the badgers examined at 18 weeks pi and one at 24 weeks pi, infection was widely disseminated. The disease induced by the endobronchial inoculation displayed the characteristics of disease observed in naturally infected badgers.     

AN ABATTOIR SURVEY OF TUBERCULOSIS IN FERAL BUFFALOES

Tuberculosis lesions were found in 193 (1.7%) of 11,322 buffaloes examined during routine post-mortem inspection at 2 export abattoirs. The prevalence of tuberculosis in buffaloes supplied from 17 separate farms ranged from 0.3% to 8.22%, with the highest levels occurring on the coastal plains. Lesions were confined to one major body region in 50 of 72 randomly chosen cases of tuberculosis and to 2 or more regions in 22 cases. Thoracic lesions occurred in 65 of the 72 cases, abdominal lesions in 19, head lesions in 18 and carcase lesions in 9. In the thoracic cavity, lesions occurred most frequently in mediastinal and bronchial lymph nodes. In the head region the retropharyngeal lymph node was most frequently involved, in the abdominal cavity, the liver, and in the carcase, the deep inguinal lymph node. Tuberculosis lesions in buffaloes had a lardaceous consistency and were paler in colour and less calcified than those normally exhibited by cattle. Mycobacteria were isolated from 30 of 31 lesion samples submitted for bacteriological examination. Of the isolates, 25 were identified as Mycobacterium bovis, 3 as M. avium-intracellulare-scrofulaceum complex, one as M. fortuitum and one as M. flavescens. The M. bovis isolates from buffaloes showed minor cultural differences to those normally characteristic of bovine isolates.     

A study of cattle-to-cattle transmission of Mycobacterium bovis infection

Twenty steers, positive to the single intradermal comparative tuberculin test (SICTT), were selected fromherds with a recent history of Mycobacterium bovis infection. Ten steers, negative to SICTT, were selected from herds with no history of M. bovis infection and served as in-contact animals. The animals were divided into 10 groups, each consisting of two SICTT-positive (reactor) animals and one in-contact animal. Each group was housed in an individual loose-box for a period of 1 year. Five of the groups were fed a restricted diet for part of the experiment. All cattle were slaughtered at the end of the study period and examined at post mortem. Transmission of infection to an in-contact animal occurred in four of the 10 groups. One of the four in-contact animals, which became infected, had a retropharyngeal lymph node tubercle and M. bovis was isolated from lymph nodes without visible lesions from the other three. Two of the infected in-contact animals without visible lesions did not show any detectable cell-mediated immune response. There was no evidence that dietary, restriction had any effect on transmission of disease.     

Accidental Mycobacterium bovis infection in a veterinarian

CASE: A veterinarian developed tenosynovitis and secondary carpal tunnel syndrome following accidental inoculation of Mycobacterium bovis during the necropsy of a tuberculous possum from Westland, New Zealand.

CLINICAL RELEVANCE: M. bovis infection is a zoonotic disease, and occupational exposure to tuberculous animals places people at risk of contracting the disease.

CONCLUSIONS: Adhering to safe work practices reviewed in this article is important to minimise the risk of infection to people handling tuberculous animals.     

Evaluation of the Abbott LCx Mycobacterium Tuberculosis Assay for Direct Detection of Mycobacterium Bovis in Bovine Tissue Samples

The commercial LCx amplification assay, usually employed to detect the Myocobacterium tuberculosis complex in respiratory specimens, was evaluated by comparing the results it gave with those obtained using Löwenstein-Jensen solid medium and pathological findings on 55 lymph nodes from cattle with positive and 10 lymph nodes from cattle with negative skin tests for tuberculosis. Fifty-three cultures (51 and 2, respectively) were positive for M. bovis, while the results for the LCx assay and the histological method were positive in 48 (45, 3) and 24 (20, 4) samples, respectively. None of the samples from cattle from certified tuberculosis-free herds were positive by any of the procedures. The results obtained with the LCx assay, compared with the culture procedure, regarded as the gold standard among the diagnostic techniques, gave a specificity of 91.6% and sensitivity of 90.5%. Although the sensitivity of LCx was suboptimal, DNA of M. bovis was detected in 81.8% of the skin test-positive animals. Amplification techniques could provide a rapid and reasonably reliable tool for detecting bovine tuberculosis.     

Vaccination with Mycobacterium bovis BCG Strains Danish and Pasteur in White‐tailed Deer (Odocoileus virginianus) Experimentally Challenged with Mycobacterium bovis

Wildlife reservoirs of Mycobacterium bovis represent serious obstacles to the eradication of tuberculosis in domestic livestock and the cause for many faltering bovine tuberculosis eradication programmes. One approach in dealing with wildlife reservoirs of disease is to interrupt inter‐species and intraspecies transmission through vaccination of deer or cattle. To evaluate the efficacy of BCG vaccination in white‐tailed deer, 35 deer were assigned to one of three groups; one s.c. dose of 10⁷ CFU of M. bovis BCG Pasteur (n = 12); 1 s.c. dose of 10⁷ CFU of M. bovis BCG Danish (n = 11); or unvaccinated deer (n = 12). After vaccination, deer were inoculated intratonsilarly with virulent M. bovis. Lesion severity scores of the medial retropharyngeal lymph node, as well as all lymph nodes combined, were reduced in vaccinated deer compared to unvaccinated deer. BCG Danish vaccinated deer had no late stage granulomas characterized by coalescent caseonecrotic granulomas containing numerous acid‐fast bacilli compared to BCG Pasteur vaccinated or unvaccinated deer where such lesions were present. Both BCG strains were isolated as late as 250 days after vaccination from deer that were vaccinated but not challenged. In white‐tailed deer, BCG provides protection against challenge with virulent M. bovis. Issues related to vaccine persistence, safety and shedding remain to be further investigated.     

Experimental Infection with Mycobacterium Avium,Serotype 2, in Pigs: 3. Oral Infection with Small Doses of M. Avium*

Pigs were inoculated orally with Mycobacterium avium in doses ranging from 15.6 × 10² to 15.6 × 10⁶ viable units daily for 15 days (Table 1). The animals were necropsied 31–32 days after the last inoculation.Pigs given doses of 15.6 × 10⁶ and 15.6 × 10⁵ viable units showed delayed hypersensitivity to avian tuberculin 24 days after the last inoculation (Table 2). The pig inoculated with 15.6 × 10⁶ viable units showed macro- and/or microscopic lesions of the intestines and the liver, and of the mandibular, mesenteric and hepatic lymph nodes. Cultures showed growth of M. avium from the same tissues and from the spleen and the left tracheobronchial lymph node. The pig inoculated with 15.6 × 10⁵ viable units showed a pronounced granulomatous infiltration in the tonsils and the mesenteric lymph nodes. Growth of M. avium was obtained from the tonsils, the intestinal mucosa (Peyer patch) and the mandibular and mesenteric lymph nodes. Viable unit counts were high in the tonsils and in the mesenteric lymph nodes (Tables 3 and 4).Lower doses gave rise to a minimal tissue reaction and/or very low viable unit counts, and are not considered to be capable of producing a progressive tuberculosis.     

COMPARISON OF SONOGRAPHIC FEATURES OF BENIGN AND NEOPLASTIC DEEP LYMPH NODES IN DOGS

The differentiation of benign vs. neoplastic lymph nodes impacts patient management. Specific sonographic features are typically considered when assessing lymph nodes in dogs. However, the usefulness of these criteria in distinguishing benign vs. malignant lymph nodes remains largely unknown, especially for deep lymph nodes. Our aim was to compare sonographic features in benign and neoplastic deep lymph nodes with the hope of identifying predictive criteria. Thirty‐one deep lymph nodes (16 mesenteric, 10 medial iliac, three hepatic, one sternal, and one cranial mediastinal) in 31 dogs were examined prospectively with B‐mode and Color flow Doppler. Lymph nodes were aspirated using ultrasound‐guidance and final diagnosis were established based on cytologic and/or histopathologic interpretation. Prevalence of each sonographic feature and combinations of two features was calculated for each group and compared using a χ²‐test or Student's t‐test for unequal variances. Ten lymph nodes were benign (hyperplastic and/or inflammatory) and 21 were neoplastic. All were hypoechoic, except for one neoplastic lymph node. Maximal short‐axis diameter (P=0.0006) and long‐axis diameter (P=0.01), and SA/LA ratio (P=0.008) were increased significantly for neoplastic (2.8, 5.5 cm, and 0.50, respectively) vs. benign (1.2, 3.8 cm, and 0.34, respectively) lymph nodes. The prevalence of other features was similar between groups. Doppler evaluation was possible in 77% of lymph nodes, but there was no significant difference between groups. When any two ultrasound features were combined, the only difference between benign and neoplastic lymph nodes was for the combination of contour regularity and appearance of the perinodal fat (P=0.03).     

COMPUTED TOMOGRAPHIC CHARACTERISTICS OF PRESUMED NORMAL CANINE ABDOMINAL LYMPH NODES

Though identification of lymph nodes is essential in staging cancer patients, little has been reported about the CT features of canine abdominal lymph nodes. The purpose of this retrospective study was to describe the visibility, location, and characteristics of abdominal lymph nodes in abdominal CT studies of dogs considered unlikely to have lymphadenopathy. The relationship between the number of identified lymph nodes and intraabdominal fat ranking, body weight, and slice thickness was also investigated. A total of 19 dogs were included. At least two jejunal lymph nodes and both left and right medial iliac lymph nodes were identified in all dogs. Colic lymph nodes were not identified in any of the dogs. Visualization of all other lymph nodes varied. There were significantly more lymph nodes visible in dogs with more intraabdominal fat (P < 0.0001). No correlation between the number of identified lymph nodes and body weight (P = 0.64) or slice thickness (P = 0.76) was found. Though most of all identified lymph nodes had an elongated shape, a rounded shape was most common in splenic, pancreaticoduodenal, renal, ileocolic and caudal mesenteric lymph nodes. Most lymph nodes had a homogeneous structure before and following the intravenous administration of contrast medium. Some lymph nodes had a slightly irregular structure or were relatively more hyper attenuating in the periphery than centrally before and/or after contrast administration. Mean attenuation before contrast was 37 Hounsfield Units (HU) (range 20–52 HU), and 109 HU after contrast (range 36–223 HU). Findings indicated that the CT visibility, characteristics of different abdominal lymph nodes may be variable in dogs.     

Prevalence, biology, pathology, and public health importance of linguatulosis of camel in Iran

Linguatula serrata is a cosmopolitan zoonotic parasite with its adult form occurring in the nasal and respiratory passages of canids as the definitive hosts, while its immature stages localize in the mesenteric lymph nodes, liver, spleen, lungs, and, rarely, in other organs, such as the ocular region of herbivorous intermediate hosts. Humans can behave as both intermediate and final host and are infected by visceral and nasopharyngeal linguatulosis. Consumption of infected, improperly cooked viscera of the intermediate hosts, including sheep, goats, cattle, camels, or other herbivores containing the larval stages of this parasite is a potential source of infection of human beings with the nasopharyngeal form of linguatulosis. However, nasopharyngeal secretions or feces of carnivores containing eggs of Linguatula are the main sources for infecting human beings with the visceral form of this infection. In the present study, the prevalence of infection by nymphs of L. serrata in 101 camels in Yazd Province, central Iran, was estimated based on histopathological studies of samples from two, apparently enlarged, mesenteric lymph nodes (MLN), together with one sample from a whitish pinpoint spot on the liver and spleen of each animal. Thirteen camels (12.9%) were infected with the nymphal stage of L. serrata. Age and sex did not play a significant role in the prevalence of this parasitic infection. The number of parasites in each MLN ranged from one to six larvae. In view of the consumption of raw or undercooked liver and visceral organs of camel by humans of this region, the importance of careful inspection at slaughter needs to be emphasized.     

Disseminated Mycobacterium avium complex infection following renal transplantation in a cat

An 11-year-old cat with a history of renal transplantation and treatment with cyclosporine and prednisolone was examined because of vomiting, diarrhea, inappetence, lethargy, and weight loss. Abdominal ultrasonography revealed 2 large heteroechoic masses thought to be mesenteric lymph nodes. Ultrasound-guided biopsy was performed, and histologic examination of biopsy specimens revealed granulomatous inflammation of presumptive lymph node tissue. Examination of sections stained with acid-fast stains revealed innumerable acid-fast bacilli within histiocytes, and a presumptive diagnosis of mycobacteriosis was made. The cat's clinical condition deteriorated, and euthanasia was elected. At necropsy, granulomatous inflammation was present within the mesenteric lymph nodes, spleen, liver, small and large intestines, lungs, and bone marrow. Bacterial culture yielded Mycobacterium avium, a slow-growing, opportunistic, saprophytic mycobacterium that can cause tuberculous lesions that are clinically indistinguishable from those associated with classic tuberculosis. It is a rare cause of disseminated mycobacteriosis in human transplant recipients. To our knowledge, this is the first report of disseminated M avium complex infection in a feline transplant recipient.     

Contents of selected heavy metals in the liver, kidneys and abdominal muscle of the brown hare (Lepus europaeus Pallas, 1778) in Central Pomerania, Poland

The content of iron, zinc, copper, manganese, lead, and cadmium was determined in the kidney, liver, and abdominal muscle of the brown hare (Lepus europaeus), a species known for its bioindicative potential in environmental quality assessment. The animals assayed were divided into immature (in their first year of life; n=25) and adult (n=39). The hares were acquired in an area situated far away from major cities and direct impacts of industrial and transport pollution. The zinc content found in the assayed hare's muscles (25.9 microg/g w.w.) and that of manganese in the kidneys, liver, and muscles (2, 2.51 i 0.85 microg/g w.w., respectively) tended to be higher than those reported from the brown hare elsewhere in Europe. The content of cadmium (particularly in the kidneys) and lead proved substantial and close to those typical of the hare inhabiting industry-affected areas. Analysis of the data pooled for all the individuals showed Zn and Cd contents to increase with age in the kidneys, the liver Cd content increasing with age as well; on the other hand, the age-Cu content was negative. In addition, a number of significant correlations between the metals themselves were revealed, particularly with respect to Zn-Cd correlation in kidneys (r(s)=0.47), Fe-Cd, Zn-Cu, Mn-Zn, Mn-Cu, and Mn-Pb in the liver (r(s) of 0.42, 0.86, 0.72, 0.79, and 0.42, respectively), and Zn-Cu in the muscle (r(s)=0.56). The kidney cadmium content was higher by 81% in the adult than in the immature hare, the adult hare muscle copper content being lower by 15.5%.     

The pathogenesis of experimental endo-bronchial Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula)

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.     

Experimental tuberculosis in the European badger (Meles meles) after endobronchial inoculation with Mycobacterium bovis: II. Progression of infection

The aim of the study was to describe, over a period of 24 weeks, the pathological and bacteriological changes in badgers experimentally infected with Mycobacterium bovis. The badgers were infected by endobronchial instillation of 2.5 × 10⁴ colony forming units (cfu) M. bovis. After infection, the badgers were examined at 3 weekly intervals when blood and tracheal aspirates were collected. At 6, 12, 18 and 24 weeks post-infection (pi) three animals were euthanized and a detailed pathological and bacteriological examination was performed to assess the nature of the experimental disease. During the course of the study only one badger developed clinical signs of disease: a subcutaneous swelling on its head, first observed at 18 weeks pi. At post-mortem examination gross and histological lesions of tuberculosis were observed and M. bovis was recovered from all, except one badger. In the majority of badgers the endobronchial route of inoculation resulted in the establishment of infection that over 24 weeks was non-progressive with limited dissemination of infection from the thoracic cavity, mainly to the hepatic and mesenteric lymph nodes. However, in one of the badgers examined at 18 weeks pi and one at 24 weeks pi, infection was widely disseminated. The disease induced by the endobronchial inoculation displayed the characteristics of disease observed in naturally infected badgers.     

Mycobacterium avium abortion in a sow.

A 2-year-old sow aborted her entire near-term litter of 11. Gross and histologic examination of a fetus suggested a tuberculous infection, and a yellow-pigmented Mycobacterium avium serotype 1 was subsequently isolated from the fetal tissue. Efforts to rebreed the sow were unsuccessful. She was anergic to skin tests with purified protein derivative of M. avium on two occasions but had M. avium specific in vitro lymphocyte immunostimulation. Gross granulomatous lesions were found in the liver, kidneys, and endometrium when the sow was necropsied 5 months after the abortion. Histologic examination showed diffuse and focal non-encapsulated granulomas in lymph nodes, tonsils, kidney, liver, spleen, lung, and uterine and vaginal walls. There were a few encapsulated calcified foci in the endometrium. The centers of some granulomas in the tonsils, liver, kidneys, and some lymph nodes were caseated. The yellow-pigmented M. avium was isolated from the reproductive organs and from 11 of 12 other tissues cultured.