Well, in a very surprising turn of events, we found out this week that Dotter has latent tuberculosis! You probably didn't think people GOT tuberculosis in Australia, did you (I know I didn't!) - but Australia has ~5 cases per 100,000 people - a very low rate, but definitely there. There's a good information sheet available here.
There was a student with active TB at Dotter's school, in one of her computing classes, coughing, untreated, and very infectious (they've now been treated, of course, and are hopefully much better!).
The ACT Health Department / Canberra Hospital screened around 170 students and staff who were in contact with this person, and Dotter (along with others) has had a positive test result. Her chest x-ray was clear, so she doesn't have active TB, and isn't infectious (so none of her family or friends needs to be tested).
When exposed to TB, the body basically 'encapsulates' the bacteria, and it stays in the system. In about 10% of cases, the TB later becomes active, and that's when the person gets very sick (coughing, fevers etc leading to death if untreated) and is infectious.
Because of her autoimmune problems (the type 1 diabetes, and what is starting to looking more like lupus, unfortunately), she is at very high risk of the latent TB becoming active within the next few years - it's almost a certainty. The TB Nurse said in her 9 years of working in this area Dotter was the most at risk person she'd ever come across (!), and the doctor was similarly emphatic about her being treated.
She'll be on a special TB-specific antibiotic (provided free by the Hospital) for 6 months, and needs to have regular blood tests to check that her liver is coping with the drug OK, and will also be on a Vitamin B6 supplement. Side effects can include things like pins and needles in her hands and feet, and increased fatigue (!!). She'll be closely monitored over the time.
Bugger bugger bugger.