Paratuberculosis is a chronic granulomatous enteritis caused by Mycobacterium avium subsp. Paratuberculosis that affects a wide variety of domestic and wild animals. It is considered one of the diseases with the highest economic impact on the ruminant industry. Despite many efforts and intensive research, paratuberculosis control still remains controversial, and the existing diagnostic and immunoprophylactic tools have great limitations. Thus, models play a crucial role in understanding the pathogenesis of infection and disease, and in testing novel vaccine candidates. Ruminant animal models can be restricted by several reasons, related to space requirements, the cost of the animals, and the maintenance of the facilities. Therefore, we review the potential and limitations of the different experimental approaches currently used in paratuberculosis research, focusing on laboratory animals and cell-based models. The aim of this review is to offer a vision of the models that have been used, and what has been achieved or discovered with each one, so that the reader can choose the best model to answer their scientific questions and prove their hypotheses. Also, we bring forward new approaches that we consider worth exploring in the near future.

Paratuberculosis (PTB) is a chronic granulomatous enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP) that affects a wide variety of domestic and wild animals. It is considered as one of the diseases with the highest economic impact in the ruminant industry. Despite many efforts and intensive research, PTB control is still controversially discussed and diagnostic and immunoprophylactic tools lack great limitations. Thus, models play a crucial role in understanding the pathogenesis of infection and disease, and in testing novel vaccine candidates. Here, we review the potential and limitations of different experimental approaches currently used in PTB research, focusing on laboratory animals and cell based models. The aim of this review is to offer a vision of the models that have been used and what has been achieved or discovered with each one so that the reader can choose the best model to answer their scientific questions and prove their hypotheses. Also, we bring forward new approaches that we consider worth exploring in the near future.

This article explores SARS-CoV-2 infection in dogs that have had close contact with humans diagnosed with COVID in Argentina. Affirmative molecular identification of the virus was achieved through RT-PCR analysis of oropharyngeal and rectal swabs from the dog as well as a nasal swab from the guardian. Positive results for the dog were confirmed through a LAMP/CRISPR assay and real time PCR. SARS-CoV-2 genomic RNA was successfully obtained from these samples, and the analysis of a partial sequence of the spike gene (ranging from amino acid 428 to 750) allowed us to classify both genomic sequences as Gamma variants, with a single amino acid variation in position 726. We evaluated the specific humoral immune response of the dog by an indirect ELISA using the Argentinian kit COVID AR IgG ELISA test adapted for domestic dogs, and pseudo-neutralization conducted with SARS-CoV-2 pseudotyped particles. We also evaluated the specific cellular immune response of the dog through a lymphoproliferation assay, using purified spike protein as specific stimulus. This work provides evidence of the human-to-dog transmission of SARS-CoV-2 in Argentina, underscoring the One Health concept and reinforcing surveillance methods in pets.