The present case was a 5-year-old crossbred spayed female dog weighing 14 kg, born in 2013 and imported from Romania to Finland at the beginning of 2015. The first owner in Finland had several other dogs and cats. The owner changed after 6 months. The second owners had no other pets, but were frequently visited by their four children and several grandchildren. The dog was seemingly healthy until January 2018, when it first showed persistent gastrointestinal symptoms, including abdominal pain and diarrhoea, followed later also by vomiting. No respiratory symptoms were recorded. Dietary changes, and tylosin and metrodinazole treatments were tried.
Hypoalbuminaemia and hyperglobulinaemia were diagnosed and cortisone was prescribed in April. Later an abdominal ultrasound scan was performed, and masses were seen in the liver and the intestines. They both were biopsied on laparascopy in June. On histological examination, acid-fast bacilli (Ziehl-Neelsen stain) and opportunistic yeasts morphologically consistent with Histoplasma capsulatum (GSM stain) were detected, and serology for histoplasmosis was positive. Anti-yeast drug therapy was prescribed. Although the condition of the dog fluctuated over the following months, the gastrointestinal symptoms persisted and worsened, and the dog died spontaneously in October 2018, without any respiratory symptoms, and was sent to autopsy at the request of the owners.
Autopsy was performed at the Finnish Food Authority, Production and Companion Animal Pathology Section. Opportunistic yeast infection in the liver was confirmed and severe large chronic inflammatory granulomatous lesions were detected in the intestinal wall, mesenteric lymph nodes, liver and kidneys. There was one very large necrotic granuloma in the right lateral liver lobe, and a few smaller granulomas were scattered throughout the other lobes (Fig. 1). The granulomas showed a typical caseotic structure. The small intestine was acutely perforated causing septic peritonitis (Fig. 2). In addition, granulomatous interstitial pneumonia was recorded. Culture specimens were collected from the most affected sites, the liver, the mesenteric lymph nodes and the intestine, and  M. tuberculosis  was isolated on Lowenstein-Jensen, Coletsos and Coletsos Ossein (Bio-Rad) media from all collected specimens at the Finnish Food Authority, Bacteriology Section. Initial identification was done using an AccuProbe Mycobacterium tuberculosis complex kit (Gen-Probe) following the manufacturer's instructions.
Identification of  M. tuberculosis  was confirmed in the National Mycobacterial Reference Laboratory by using a Hain Lifescience Genotype MTBC kit according to the manufacturer's instructions using a SensoQuest Labcycler for PCR for the liver and intestinal isolates. Both isolates were fully susceptible by molecular testing using a Hain Genotype MTBDR PLUS kit (rifampicin, isoniazid), via a culture-based method using the Becton Dickinson MGIT system (streptomycin 1.0 microg ml-1, isoniazid 0.1 microg ml-1, rifampicin 1.0 microg ml-1, ethambutol 5.0 microg ml-1, pyrazinamide 100 microg ml-1) and by whole-genome sequencing. The sequencing pipeline included a Qiagen MagAttract HMW DNA extraction kit, Illumina Nextera XT library preparation kit, Beckman Coulter Agencourt Ampure XP magnetic bead purification, Illumina MiSeq Reagent Kit v2 on the Illumina MiSeq sequencing platform (according to the manufacturer's instructions), and PhyResSE web tool (http://www.phyresse.org/) as described elsewhere. The isolates belonged to lineage Ural (PhyResSE, SITVIT2), and their spoligotype was SIT262 by Spotyping analysis.