Naked Science Forum

Life Sciences => Cells, Microbes & Viruses => Topic started by: eardowel on 14/12/2010 10:30:03

Title: Could I be resistant to TB?
Post by: eardowel on 14/12/2010 10:30:03

John Yockachonis asked the Naked Scientists:
   
I am wondering if I am resistant to TB, or to what degree I am.

My mum got an inoculation of some type at about 17-18 years of age. She says it was called BCG. She says she was told then that her first born would have the most resistance, and subsequent children would have less and less. I'm the youngest of four. (She's 72 now)
 
Also, my dad had TB at about age 17, and said he spent a year in bed, and took two years to feel up to snuff again. He lost the use of over 1/2 a lung in the illness. He contracted it at school from a lunch lady, as did over twenty other kids. Many died. (He's 78 now)
 
Now, I've learned of epigenetics. I'm curious if I have immunity or resistance to TB due to his illness possibly effecting his genes after his illness, and maybe more due to my mum's inoculation. 
 
Also, if epigenics plays a role, my mum had scarlet fever as a young girl. Would I have resistance to it as well?

What do you think?

Title: Could I be resistant to TB?
Post by: CliffordK on 14/12/2010 14:45:47

A mother can transfer some antibodies to an infant.  However, they disappear very rapidly.  If you had your mothers antibodies, and were infected with TB shortly thereafter, you could have developed an immunity.

The BCG vaccine is apparently a live vaccine, but I believe it generates a vigorous immune response and is killed.  Thus, the vaccine bacteria is unlikely to be passed to children.

Anyway, the test for TB is a relatively simple skin test.  Your physician could administer it in a couple of minutes, send you home, and you could return a couple of days later to get it read.

One of the reasons that BCG is not commonly used in the USA is that it can confound the TB skin test, so a positive skin test in a patient that has had the BCG vaccine is inconclusive.  If you had TB exposure 50 years ago, a positive skin test might indicate immunity as that would be a long time for a sub-clinical infection.

If, however, the skin test is negative, then you would not have TB Immunity.

Scarlet Fever is caused by Strep Throat.

Title: Could I be resistant to TB?
Post by: eardowel on 18/12/2010 12:00:15

Thanks. Reading your response reminded me that she was told never to take the TB skin test after receiving her inoculation. She was the dietary director at our local hospital, and I worked there as an aide while I was in high school. Everyone was required to have the skin test yearly, but mum had to explain each year, for the first few, why she could not take it.
I've had many TB skin tests, and none produced even a mild irritation.