Email Sept 21 2009. Received fromDear Mary,
Dr Colin G Fink
Clinical Virologist & Hon. Senior Lecturer in Biological Sciences University of Warwick
Micropathology Ltd Research and Diagnosis
I read your bovinetb.blogspot reference with interest. M.Bovis is regarded as a zoonoses, of course there are well documented cases of it transferring to man. In the case of the cat diagnosed to have the disease, if the owners and immediate family remain asymptomatic, then all is well . Whether they have been exposed and have been infected with a small amount of the organisms and deal with this infection in the normal immunological way, is rather academic. Many of us meet M.Tuberculosis but remain entirely asymptomatic. The cat owners et al may be reassured. If they were to become ill and remain unwell for longer than a transient infection might be expected to last, then further investigation would be justified.
As it happens we are able, and do, diagnose Mycobacteria of all sorts- there are many different types. ( we look for the Mycobacterial DNA and then sequence it to characterise the species of Mycobacteria). But no intrusive investigation ( biopsy of lymph nodes, lung biopsies etc) to find the organism, can be medically justified in someone who is entirely well. - It would be a hazardous undertaking.