Infection by Mycobacterium bovis in a dog from Brazil

Abstract

Tuberculosis (TB) is a chronic disease caused by bacteria belonging to the Mycobacterium tuberculosis complex (MtbC). This disease rarely affects dogs. Canine infections are usually caused by M. tuberculosis. Mycobacterium bovis infections are rare in dogs and associated with consumption of raw milk or contaminated products. Here, we report a Boxer dog who had a M. bovis infection and was admitted to a Brazilian veterinary hospital with a presumptive diagnosis of chronic ehrlichiosis. Despite receiving treatment for chronic ehrlichiosis, it progressed to death. TB was diagnosed during post-mortem examinations using histopathological analysis. Ziehl-Neelsen staining revealed acid-fast bacilli in the kidneys, liver, mesentery, and a mass adhered to the liver. Further, PCR-restriction analysis was performed to identify mycobacteria in the samples. A restriction profile compatible with MtbC was found in the lungs. In addition, PCR-based MtbC typing deletions at different loci of chromosome 9 enabled the identification of M. bovis in the lungs. Therefore, it is very essential to perform differential diagnosis of TB in dogs with non-specific clinical signs and who do not respond to treatment, particularly those who had been in contact with TB-infected cattle or owners. Further, we highlight the use of molecular methods for the identification of bacilli, improving the diagnosis and aiding epidemiological studies.

ACVIM consensus statement on the diagnosis and treatment of chronic hepatitis in dogs

“…Leishmaniasis is associated with CH, usually causing granulomatous inflammation . Multiple other systemic diseases can have hepatic involvement with the potential to cause CH ( Neospora , toxoplasmosis, Sarcocystis , histoplasmosis, Mycobacterium , shistosomiasis, visceral larva migrans), but lesions typically are acute and necrotizing and part of a multisystemic disorder …”

“…52,53 Multiple other systemic diseases can have hepatic involvement with the potential to cause CH (Neospora, toxoplasmosis, Sarcocystis, histoplasmosis, Mycobacterium, shistosomiasis, visceral larva migrans), but lesions typically are acute and necrotizing and part of a multisystemic disorder. [61][62][63][64][65][66][67][68][69][70][71][72][73][85][86][87][88]…”

Mycobacterium avium: an Emerging Pathogen for Dog Breeds with Hereditary Immunodeficiencies

“…Furthermore, the number of M. bovis, and to a lesser extent by the closely related M. caprae, infections in humans might well be underestimated because of a lack of diagnostic surveillance programs [26]. Nevertheless, M. bovis infections are rare in dogs and, as in humans, mostly associated with consumption of raw milk or contaminated byproducts from affected ruminants [27][28][29]. Clinical findings of infected dogs vary from respiratory signs and cutaneous lesions to gastrointestinal signs accompanied by fever, inappetence, and weight loss.…”

Mycobacterium tuberculosis SIT42 Infection in an Abused Dog in Southern Italy

“…Around 10 million new human cases are diagnosed every year, and it is classified as 1 of the top 10 causes of death worldwide (1). A few studies have reported TB incidence in dogs, and most cases have identified M. tuberculosis as the prevalent species (2,3), although cases of M. bovis, M. avium, M. pinnipedi, M. africanum, and M. microti infections have been occasionally described (4)(5)(6)(7)(8)(9)(10).…”