Pathology 1

Research title:

Pathology of mycobacterial diseases in domestic animals

Tutor: Mario Caniatti


Contact details

Università degli Studi di Milano

Dipartimento di Medicina Veterinaria (DiMeVet)

Via G. Celoria, 10

20133 Milano


Phone +39 02 503 18114

Fax +39 02 503 18106

E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.


State of the art

Molecular techniques, such as restriction fragment length polymorphism (RFLP) or variable number tandem repeat (VNTR) provide definitive information useful in conducting epidemiologic investigations (Park Y et al., 2000). Animals are also used as models of mycobacterial infection (Orme IM and Ordway DJ, 2016). Mycobacterial infections of animals are re-emerging diseases of primary importance for both economic and public health reasons. The genus Mycobacterium contains a number of strict and opportunistic pathogens that afflict humans and animals alike. Mycobacteria are differentiated into two groups known as the “M. tuberculosis complex” (M. tuberculosis, M. bovis, M. microti, M. africanum,  M. pinnipedii, M. caprae, and M. canetti)and mycobacteria other than the “M. tuberculosis complex” (MOTT). For diagnostic purposes, when numerous mycobacteria are present in the sample, they are detected in routine stained cytology samples using a Romanowsky-type stain.  On the other hand, in histology they cannot be detected using routine stains such as H&E. Hence, cytochemistry (Ziehl-Neelsen stain), immunochemistry or molecular biology techniques are essential to the diagnosis. For a rapid diagnosis of mycobacteriosis, the slow growth of some  (e.g M. tuberculosis, M. bovis…) used to be a limiting factor. In recent years, rapid assays based on molecular biology were developed and have been applied. Nucleic acid amplification techniques such as the PCR are very useful in the rapid diagnosis of infections by Mycobacterium spp (Tevere VJ et al., 1996; Drosten C et al., 2003).




Aims of the project

The present project encompasses a multi-disciplinary approach to study mycobacterial diseases in domestic and non-domestic animals. Domestic animals share our environment and can be a source of human infection and, in turn, can be infected. Moreover, both in animals and humans, prolonged therapy together with a severe limit of drug choice, has resulted in the emergence of strains that are increasingly resistant to the few available antibiotics. The proposed project aims at characterizing mycobacteria and related lesions from several animal species under a pathological, microbiological and molecular point of views. The study focuses mainly in cases of mycobacteriosis of dogs, cats, cattle and possibly on other domestic and non-domestic species. In this project M. tuberculosis, M. bovis, Mycobacterium avium subspecies paratuberculosis (MAP), and M. lepraemurium would be the main mycobacteria studied. Cytology and histology would be used for diagnostic and morphologic studies. Host response would be studied on histology evaluating cytokines by immunochemistry (e.g. TNF-alfa) and subsets of inflammatory cell types (e.g. lymphocytes). Immunohistochemical localization of tubercle bacilli or their components that persist in the granulomas having lost the property of staining with acid-fast stain would be studied to assess the advantage of immunostaining over conventional Ziehl-Neelsen staining and further to study IHC staining pattern. The identification of mycobacterium species in cases of mycobacteriosis in small animals would be investigated evaluating the efficacy of polymerase chain reaction (PCR) and sequencing of a rRNA hypervariable region. A prospective study including cytopathology, histology and microbiology mainly in companion animals mycobacteriosis would start.


Recent publications of the tutor in the field

1. Cell tube block: a new technique to produce cell blocks from fluid cytology samples.

Marcos R, Santos M, Marrinhas C, Caniatti M.

Vet Clin Pathol. 2017 Feb 13. doi: 10.1111/vcp.12446. [Epub ahead of print]

2. Cytocentrifuge preparation in veterinary cytology: a quick, simple, and affordable manual method to concentrate low cellularity fluids.

Marcos R, Santos M, Marrinhas C, Correia-Gomes C, Caniatti M.

Vet Clin Pathol. 2016 Dec;45(4):725-731.

3. Cutaneous Lymphoma at Injection Sites: Pathological, Immunophenotypical, and Molecular Characterization in 17 Cats.

Roccabianca P, Avallone G, Rodriguez A, Crippa L, Lepri E, Giudice C, Caniatti M, Moore PF, Affolter VK.

Vet Pathol. 2016 Jul;53(4):823-32

4. Intra-abdominal fluid aspirate from a dog.

Crippa V, Ghisleni G, Avallone G, Caniatti M.

Diagn Cytopathol. 2016 Feb;44(2):119-20.

5. Feline upper respiratory tract lymphoma: site, cyto-histology, phenotype, FeLV expression, and prognosis.

Santagostino SF, Mortellaro CM, Boracchi P, Avallone G, Caniatti M, Forlani A, Roccabianca P.

Vet Pathol. 2015 Mar;52(2):250-259