Experimental Mycobacterium microti Infection in Bank Voles (Myodes glareolus)

Voles are maintenance hosts of Mycobacterium microti. In line with the goal to eradicate tuberculosis (TB) in livestock, the role of this mycobacteria needs to be assessed since it might interfere with current M. bovis/M. caprae surveillance strategies. To better understand the pathogenesis of TB in voles, an experimental infection model was set up to reproduce M. microti infection in laboratory Bank voles (Myodes glareolus). Two infection routes (intragastric and intraperitoneal) and doses (105 and 106 CFU/0.1 mL) were assessed. Voles were culled at different post-infection time points. Serology, histopathology, acid-fast bacilli staining, qPCR, and mycobacterial culture from tissues were performed. In addition, qPCR from feces and oral swabs were conducted to assess bacterial shedding. The model allowed us to faithfully reproduce the disease phenotype described in free-ranging voles and characterize the pathogenesis of the infection. Most animals showed multifocal and diffuse granulomatous lesions in the liver and spleen, respectively. Less frequently, granulomas were observed in lungs, lymph nodes, muscles, and salivary gland. Mycobacterial DNA was detected in feces from a few animals but not in oral swabs. However, one contact uninfected vole seroconverted and showed incipient TB compatible lesions, suggesting horizontal transmission between voles.

Influence of Heterologous and Homologous Vaccines, and Their Components, on the Host Immune Response and Protection Against Experimental Caprine Paratuberculosis

Vaccination against paratuberculosis, a chronic disease of ruminants caused by Mycobacterium avium subsp. paratuberculosis (Map), has been considered as the most effective control method. However, protection is incomplete, and the mechanisms operating in the response of the animals to vaccination are not fully understood. Therefore, this study analyzed the immune response and the effects on protection against Map infection, elicited by paratuberculosis (Silirum®) and tuberculosis (heat-inactivated M. bovis [HIMB]) vaccines and their components in a caprine experimental model. Fifty goat kids were divided into 10 groups (n = 5) according to their vaccination (Silirum®, HIMB and nonvaccinated), immunization (inactivated bacteria or adjuvant), and/or infection. Oral challenge with Map was performed 45 days postvaccination/immunization (dpv), and animals were euthanized at 190 dpv. Peripheral immune response and proportion of lymphocyte subpopulations were assessed monthly by enzyme-linked immunosorbent assay and flow cytometry analysis, respectively. Local immune response, proportion of tissue lymphocyte subpopulations, Map detection (polymerase chain reaction), and histological examination were conducted in gut-associated lymphoid tissues. All infected groups developed paratuberculosis granulomatous lesions despite vaccination or immunization. The Silirum® and HIMB-vaccinated groups showed a considerable lesion reduction consistent with a significant peripheral cellular and humoral immune response. Besides, a lower number of granulomas were observed in groups immunized with inactivated bacteria and adjuvants in comparison to nonvaccinated and infected group. However, despite not being significant, this reduction was even higher in adjuvant immunized groups, which developed milder granulomatous lesion with no detectable peripheral immune responses associated with immunization. No changes in the peripheral and local proportion of lymphocyte subsets or local immune response were detected in relation to either vaccination/immunization or infection. Despite that paratuberculosis and tuberculosis vaccination showed a partial and cross-protection against Map infection, respectively, only histological examination could assess the progression of infection in these animals. In addition, the pattern observed in the reduction of the lesions in adjuvant immunized groups suggests the possible involvement of a nonspecific immune response that reduces the development of granulomatous lesions.

Local Assessment of the Immunohistochemical Expression of Foxp3 + Regulatory T Lymphocytes in the Different Pathological Forms Associated with Bovine Paratuberculosis

Background Mycobacterium avium subsp. paratuberculosis infected animals show a variety of granulomatous lesions: from focal forms, restricted to the gut-associated lymphoid tissue (GALT), related to latency and resistance, to diffuse lesions, with abundant (multibacillary) or scant (paucibacillary) bacteria, seen in clinical stages. Factors that determine the response to the infection and responsible for the occurrence of the different types of lesion are still not fully determined. It has been seen that regulatory T cells (Treg) play an important role in the progress of various diseases where they act on the limitation of the immunopathology associated with the immune response. In the case of paratuberculosis (PTB) the role of Treg lymphocytes in the immunity against Map is far away to be completely understood; therefore, several studies addressing this subject have appeared recently. The aim of this work was to assess, by immunohistochemical methods, the presence of Foxp3+ T lymphocytes in intestinal samples with different types of lesions seen in cows with PTB. Methods Intestinal samples of twenty cows showing the different pathological forms of PTB were evaluated: uninfected controls (n = 5), focal lesions (n = 5), diffuse paucibacillary (n = 5) and diffuse multibacillary (n = 5) forms. Foxp3+ lymphocyte distribution was assessed by differential cell count in intestinal lamina propria (LP), gut-associated lymphoid tissue (GALT) and mesenteric lymph node (MLN). Results A significant increase in the number of Foxp3+ T cells was observed in all infected animals, but this increase was only significant in cows with focal lesions and, to a lesser extent, in animals with diffuse paucibacillary forms. The former showed the highest numbers, significantly different from those found in cows with diffuse lesions, where no differences were noted between the two forms. No specific distribution pattern was observed within the granulomatous lesions in any of the groups. Conclusions The increase of Foxp3+ T cells in focal forms, that have been associated with latency or resistance to infection, suggest an anti-inflammatory action of these cells at these stages, helping to prevent exacerbation of the inflammatory response, as occurs in diffuse forms, responsible for the appearance of clinical signs.

Anisakis pegreffii Larvae in Sphyraena viridensis and Description of Granulomatous Lesions

The aim of the present study was to describe gastric granuloma caused by Anisakis pegreffii in Sphyraena viridensis caught in the central Mediterranean Sea. Sixty-eight S. viridensis specimens were collected from different fish markets on the east coast of Sicily. Coelomic organs were observed both macroscopically and with the aid of stereomicroscope. Parasite specimens and lesioned tissues were collected for identification, histological and molecular analyses. Twelve specimens (p = 17.6%) were positive for the presence of nematode larvae, morphologically identified as larvae of Anisakis sp., with values of mean abundance and mean intensity of 0.9 and 4.8, respectively. One large female specimen showed massive parasite infection associated with nodular lesions of the gastric wall. By histology, several nematode larvae encysted through the gastric wall were found. The parasite bodies were surrounded by a granulomatous reaction made up of macrophages, epithelioid cells, some lymphocytes and an external connective sheet. Molecular analysis of 18S rRNA and cox2 genes from Anisakis sp. collected larvae, identified them as A. pegreffii. The lesions here described, though macroscopically superimposable on human eosinophilic granuloma, microscopically showed significant differences in the inflammatory cells involved and in the type of immune reaction.

A Case of Langerhans Cell Histiocytosis involving the External Auditory Canal

Langerhans cell histiocytosis (LCH) is commonly characterized by abnormal function and differentiation or proliferation of monocytes. In LCH, granulomatous lesions, including langerine-positive histocytes and inflammatory infiltrates, can occur to all tissues, particularly well in the bones, skin, lungs, and pituitary gland. In case of external auditory canal LCH, conductive hearing loss may occur, and the most common symptom is otorrhea. Here we present a case that 49-year-old male with external auditory canal mass. Since no invasive findings were seen in radiologic study, endoscopic transcanal excision was performed and LCH was proven by pathologic report. We present this case of external auditory canal LCH with the review of literature.

Septal pyogenic granuloma: a continuing riddle

<p class="abstract">Pyogenic granuloma (PG) is a benign vascular lesion of the skin and mucous membranes commonly affecting the head and neck but less common in the nasal septum. Septal PG and can present with epistaxis and nasal obstruction. It is also called a lobular capillary hemangiomas (LCH) as histologically, pyogenic granuloma consists of circumscribed aggregates of capillaries arranged in lobules. Granulomatous lesions like Wegners granulomatosis, sarcoidosis and also tumours like squamous cell carcinoma, malignant melanoma can all mimic a septal PG. Surgical excision is the treatment of choice and diagnosis can be confirmed by histopathological examination. Complete resection can decrease the rates of recurrence. Here we reported a case of pyogenic granuloma of the nasal septum in a young female patient.</p>

Production of granulomas in Mycoplasma bovis infection associated with meningitis-meningoencephalitis, endocarditis, and pneumonia in cattle

Mycoplasma bovis, the most important primary pathogen in the family Mycoplasmataceae, causes pneumonia, arthritis, otitis media, and mastitis in cattle. Histopathologic pulmonary changes associated with M. bovis infection have been characterized as suppurative-to-caseonecrotic bronchopneumonia; infection in other organs has been reported in only a few studies that examined caseonecrotic endocarditis and suppurative meningitis. Granulomatous lesions associated with M. bovis infection have been reported only rarely. We studied the granulomatous inflammation associated with M. bovis infection in several organs of 21 Japanese Black cattle. M. bovis was detected by isolation and loop-mediated isothermal amplification methods; other bacteria were detected using culture on 5% blood sheep agar and a MALDI-TOF MS Biotyper. Tissues were examined by histopathology and by immunohistochemistry (IHC) using anti– M. bovis, anti-Iba1, anti-iNOS, and anti-CD204 antibodies. All 21 cases, which included 2 cases of meningitis-meningoencephalitis, 8 cases of endocarditis, and 11 cases of bronchopneumonia, had caseonecrotic granulomatous inflammation associated with M. bovis infection. The IHC for macrophages revealed a predominance of iNOS-labeled (M1) macrophages in the inner layer of the caseonecrotic granulomas associated with meningitis-meningoencephalitis, endocarditis, and bronchopneumonia in Japanese Black cattle naturally infected with M. bovis.

IMMUNOPATHOLOGICAL EFFECT OF SENSITIZED TRANSFER FACTOR ON THE ORGANS OF WHITE MICE AGAINST SALMONELLA TYPHI CHALLENGE INFECTION.

In an experimental study to evaluate the immunopathological effect of transfer factor on the reticuloendothelial organs of white mice and their protection against their challenge infection with Salmonella typhi. The results of this study were showed the followings: 1. Transfer factor recipient group: it was showed an early granulomatous lesions in the liver. Reactive hyperplasia in the T cell regions of the spleen and mediastinal lymph node. The early granulomas were persisted during 7th day and slightly regressed on 14th day postinoculation. 2. Infected group with S. typhi: It was showed a multifocal microabscesses consisted of aggregates of neutrophils in the focal area of necrosis, which was evident during 7th day and gradually transform into granulomas on 14th day postinoculation. 3. Transfer factor recipient and challenge infection group: It was showed well developed granulomatous reactions, which indicate an emergence of cellular immunity (delayed type hypersensitivity reaction). These granulomas were more evident on 7th day and slightly regressed on 14th day postinoculation; providing a transfer factor role in tissue reaction and termination of infection.

Bovine Tuberculosis in Colombia; Findings from Histopathological, Microbiological and Molecular Tests

Tuberculosis is a zoonotic infectious disease, caused by bacteria of the tuberculosis complex. Mycobacterium bovis causes tuberculosis in water buffaloes (Bubalus bubalis), and it can also infect other domestic animals, wild fauna, and humans. The diagnosis of bovine tuberculosis (bTB) through intradermal injections is challenging, and to understand the behaviour of other diagnostic tests is crucial. The aim of this research is to analyse three diagnostic tests against bTB in water buffaloes with positive test DPP. Different diagnostic tests were tested in 50 buffaloes diagnosed with bTB Cervical Comparative Test, from the Colombian lower tropic. Lesions compatible with bTB in 26 buffaloes with a positive DPP ; Four out of 2 samples of Mycobacterium bovis in DPP-positive buffaloes were isolated and confirmed positively in tissues using PCR-HRM, three buffaloes showed granulomatous lesions in histological analyses with positive microbiological isolation; 17 DPP-positive buffaloes had a positive PCR-HRM test and nine of these buffaloes showed no histological findings compatible with bTB, leading to purely molecular diagnosis. Evidence in histological, microbiological, and molecular findings in DPP is positive for the water buffaloes. None of the complementary tests showed 100% concordance with the intradermal results obtained with the Cervical Comparative Test for bTB.

An extraordinary pulmonary artery involvement in granulomatosis with polyangiitis

Granulomatosis with polyangiitis (GPA) is an autoimmune mediated systemic disease and characterized by pauci-immune vasculitis mainly of small and medium vessels with typical necrotizing granulomatous lesions in the affected tissues. A 44 year old lady who was known to have GPA presented with unusual presentation of its category with extraordinary large vessels involvement including pulmonary arteries and her condition improved with immunosuppressive therapy. We reported this case, to improve the awareness about other overlapping categories of vessels vasculitis that may involve large vessels and main pulmonary arteries and to avoid misdiagnosing these patients with category of classical large vessels vasculitis.