Disseminated Mycobacterium Genavense Infection in a FIV-Positive Cat

Abstract

An 8-year-old FIV-positive Australian cat was presented with coughing, periocular alopecia, pyrexia and inappetence. Skin scrapings demonstrated Demodex cati mites. Antibiotics were administered and it was treated successfully for periocular demodectic mange, but the cat continued to exhibit respiratory signs and lose weight. Further investigation revealed an ascarid infection and active chronic inflammation of undetected cause affecting the lower airways. Repetitive treatment with pyrantel failed to eradicate the ascarid infection. The cat became cachectic and developed moist ulcerative dermatitis of the neck, severe non-regenerative anaemia, leucopenia and thrombocytopenia. Necropsy and histopathology revealed mycobacteriosis affecting skin, lungs, spleen, lymph nodes, liver and kidney. Attempted culture of frozen tissues at a mycobacteria reference laboratory was unsuccessful. Paraffin-embedded, formalin-fixed tissue was retrieved and examined using PCR to amplify part of the 16S rRNA gene. A diagnosis of disseminated Mycobacterium genavense infection was made based on the presence of acid fast bacteria in many tissues and partial sequence of the 16S rRNA gene. Although M genavense has been identified previously as a cause of disseminated disease in AIDS patients, this is the first report of infection in a cat. It was suspected that the demodecosis, recurrent ascarid infections and disseminated M genavense infection resulted from an immune deficiency syndrome consequent to longstanding FIV infection.

Granulomatous Pneumonia Caused by Mycobacterium genavense in a Dwarf Rabbit (Oryctolagus cuniculus)

“…A M. genavense infection is described in the literature as a disseminated mycobacteriosis in humans and animals with granulomatous inflammation of several organs (intestine, liver, spleen, lymph nodes, bone marrow, skin, kidneys, lungs, and brain). 2,3,[7][8][9][10][11]13,14,[16][17][18] However, the lungs were the only affected organs in our case, whereas the abdominal organs and lymphatic tissues were without pathologic findings, consistent with M. genavense infection. Besides disseminated forms of nontuberculous mycobacterial infections, exclusively chronic pulmonary infections are described, commonly associated with M. kansasii or M. xenopi.…”

Impact of Genotypic Studies on Mycobacterial Taxonomy: the New Mycobacteria of the 1990s

“…genavense is the most common mycobacterial infection in birds (106), which to date are the only identified potential reservoir. Les frequent are infections in other animals, including a disseminated infection in an immunodeficient cat (67).…”

Retrospective study of feline and canine cryptococcosis in Australia from 1981 to 2001: 195 cases

“…In contrast, the present study and a number of other investigations [17,22,43] found the prevalence of these retroviral infections was comparable to reference populations of non-descript 'sick' cats. Although there are a few reports of sequential opportunistic infections in FIVpositive cats [32,46] no case Á/control studies have provided convincing evidence that any given infectious disease is seen at increase frequency in cats with chronic FIV infection. Likewise, CD4 counts in FIV-positive cats with cryptococcosis were comparable to CD4 counts in FIV-negative cats with cryptococcosis [47].…”