Tuberculosis due toMycobacterium bovisin pet cats associated with feeding a commercial raw food diet

Abstract

Objectives Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex, can infect cats and has proven zoonotic risks for owners. Infected cats typically present with a history of outdoor lifestyle and hunting behaviour, and cutaneous granulomas are most commonly observed. The aim of this study is to describe an outbreak of tuberculous disease commencing with six young cats, living exclusively indoors in five different households across England, being presented to separate veterinarians across the UK with a variety of clinical signs. Methods Investigations into the pyogranulomatous lesions, lymphadenopathy and/or pulmonary disease of these cases consistently identified infection with M bovis. Infection was confirmed by PCR, where possible, or was indicated with a positive interferon-gamma release assay (IGRA), where material for PCR was unavailable. Incontact, cohabiting cats were screened by IGRA and follow-up testing was undertaken/advised where results were positive. A lifestyle investigation was undertaken to identify the source of infection. Results Six clinically sick cats and seven in-contact cats were identified with evidence of M bovis infection. Five clinical cases were either too sick to treat or deteriorated despite therapy, giving a mortality rate of 83%. Lifestyle investigations revealed the common factors between clusters to be that affected cats had mycobacterial infections speciated to M bovis, were exclusively indoor cats and were fed a commercially available raw food product produced by a single manufacturer. The Food Standards Agency, Animal & Plant Health Agency, Public Health England and the food manufacturer concerned have been notified/informed. Other possible sources of exposure for these cats to M bovis were explored and were excluded, including wildlife contact, access to raw milk, the presence of rodent populations inside the buildings in which the cats lived and exposure to known infectious humans. Conclusions and relevance Upon investigations, our results provide compelling, if circumstantial, evidence of an association between the commercial raw diet of these cats and their M bovis infections.

Current Standards and Practices Within the Therapy Dog Industry: Results of a Representative Survey of United States Therapy Dog Organizations

“…The feeding of raw meat diets to dogs is controversial for a number reasons, one of which is the potential transmission of infectious pathogens to humans (18)(19)(20)(21). All of the facility guidelines specify that animals being fed raw meat diets and treats should be excluded from participating in AAIs, but only 13% of the Group 2 organizations surveyed reported this as a restriction-somewhat fewer than the 19% reported previously by Linder et al (11)-and only one of the Group 1 organizations did so.…”

Animal tuberculosis: impact of disease heterogeneity in transmission, diagnosis, and control

“…Cases of cat‐to‐human transmission are supposed to represent a limited risk, but were reported by the British Government in 2014 (British Government, 2014). More recently, in 2019, a study by O’ Halloran and co‐workers discussed the impacts of cat‐to‐human transmission due to a case of consumption of commercial raw food by pet cats (O’Halloran et al, 2019).…”

How to…

“…Commercial raw diets appear to contain animal products from a wide variety of species (Mehlenbacher et al 2012;van Bree et al 2018;Weese et al 2005), and may include components imported from outside the EU, that are subject to classification and labelling under non-EU regulatory regimes. Furthermore, there may be lapses in compliance with inspection regimes, such as was recently reported for venison in raw cat food (O'Halloran et al 2019).…”

“…UK under unusual circumstances (young, indoor cats fed a particular venison-containing raw diet) and with an unusual visceral disease pattern, such that the body of circumstantial evidence compellingly points to a dietary source (O'Halloran et al 2019). There is also evidence of secondarily-infected human owners in the same outbreak.…”