Pigoli/Sironi

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PhD Student: Claudio Pigoli

Claudio Pigoli graduated (110/110 cum laude) in Veterinary Medicine at Università degli Studi di Milano in July 2016 with a thesis concerning the development of a tissue array technique for immunohistochemical investigations of neoplastic samples. After graduation he spent a 13-months training period at the Histology Laboratory of Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna. During this period, he was involved in diagnostic histopathology, in a research project concerning new methods for the identification of microbiological, chemical and physical hazards related to the consumption of mechanically separated meats, and in the design of a research project entitled “Study and development of a histological protocol for the characterization of mycobacterial lesions in cattle and wild boar”.

 

Tutor: Prof. Giuseppe Sironi

Giuseppe Sironi completed a DVM degree at the Università degli Studi di Milano in 1984 and earned the PhD degree in Comparative Pathology of Domestic Animals in 1988. Currently he is full professor of Veterinary Pathology. Since 2011 to 2016 he was the Director of the PhD course in Animal Pathology and Veterinary Hygiene. Currently, he is the Degree Programme Director of the Veterinary Medicine Course. In the study course of Veterinary Medicine, prof. Sironi helds the courses of Veterinary Anatomic Pathology II, Pathology of wild animals, Diagnostic immunohistochemistry in Veterinary Oncology. He is author of 55 scientific papers indexed in Scopus mainly dealing with viral diseases, ultrastructural pathology and neoplastic diseases of mammals and birds.

 

Title: Mycobacteriosis in Veterinary Medicine: Morphopathology and Mycobacterial Phenotypes

Mycobacteriosis are diseases caused by bacteria of the genus Mycobacterium. They are characterized by several clinical and pathological findings, as well as significant economical and health consequences. The genus comprises both strict and opportunistic pathogens and could be divided into two groups known as M. tuberculosis complex or MTC (various species including M. tuberculosis, M. bovis and M. microti) and mycobacteria other than M. tuberculosis complex or MOTT (other species including M. avium, M. marinum and M. genavense).

In human medicine, the presence of different intralesional phenotypes of M. tuberculosis, and in particular the non-acid-fast phenotype, has had significant repercussions on diagnosis, chemotherapy, vaccine protocols and future research prospects. On the contrary, these aspects of mycobacterial infections remain unexplored in the animals.

In the veterinary field, such information will be equally influential, not only with regard to current monitoring and eradication plans, but also in the context of the impact of mycobacteria on animal health and veterinary public health. They will also be useful to understand more deeply the host-pathogen interactions in the pathogenetic dynamics, especially where more and more attention is given to spontaneous animal diseases as possible models for the study of human diseases.

Project aims

The present project will be carried out in collaboration with different Institutions and aims to study the lesions induced by the different members of the genus Mycobacterium in vertebrate animals, assessing the presence of different intralesional bacterial phenotypes and the conditions affecting their presence within the lesions.

Mycobacterial species will be identified by molecular methods while mycobacterial phenotypes and intralesional microenvironment will be studied combining immunofluorescence, fluorescence in situ hybridization and histochemical stains able to identify acid-fast bacteria.

In particular, it aims to:

  • investigate the presence of different intralesional mycobacterial phenotypes;
  • evaluate their differential distribution based on pathogen and host species;
  • investigate their presence depending on gross and microscopic features of the lesions, with particular reference to:
  • differences between lepromatous and tuberculoid forms of Paratuberculosis and cutaneous mycobacteriosis, and more generally between exudative and proliferative lesions;
  • differences between lesions produced by members of the M. tuberculosis complex group depending on the pathogenetic period of the infection, as well as the age and stage of development of the lesions themselves;
  • evaluate the presence of mycobacterial phenotypes depending on their spatial distribution within lesions (e.g. Mycobacteria in the core vs mycobacteria at the periphery of granulomatous lesions), the mycobacterial intracellular or extracellular localization and cellular phenotypes in which intracellular bacteria are contained.

 

Fig. 1 - Guinea pig, Lymph node. Numerous acid-fast bacilli inside macrophages.

M. lepraemurium infection. 1000x ZN.

 

Fig. 2 - Bovine, Lymph node. Langhans-type multinucleated giant cells.

M. bovis infection. 200x EE. Courtesy of IZSLER.