I was just discussing with a colleague about a new strain of virus. I wonder if medication giving rise to new tough strains of virus?

Hoping to here your thoughts.

http://www.abc.net.au/news/stories/2008/02/03/2153142.htm

Tough TB strain 'could reach Qld shores'

Posted Sun Feb 3, 2008 5:47pm AEDT

A new study says urgent intervention is needed to stop the spread of tuberculosis (TB) from Papua New Guinea into Australia.

The research, published in the Medical Journal of Australia, says strains of tuberculosis that are resistant to antibiotics are increasing in the western provinces of Papua New Guinea.

Dr Chris Coulter from Pathology Queensland says many people with the disease come to the Torres Strait Islands because a treaty allows free movement for traditional people between the islands and PNG

He says because of this, there is a risk that the disease will spread into Queensland.

"Multi-drug resistence is a major problem worldwide in the control of tuberculosis, and should spread of this organism occur in far north Queensland this would be a significant public health problem," he said.

TB was intitially brought to our shores by the Europeans:

http://www.aeras.org/tb/epidemiology/index.html

WNM

So we sending back the PNG version of the TB virus to them? a stronger one? how is that possible?

Inproper & incomplete treatment practices can enable the developement of more resistant strains of the organism, which could be the case in PNG.

WM

Curious,
"having had TB once does not confer immunity against furthur infection."

I have a natural immunity to TB. I show up positive on the skin-test, but show no signs of TB on any X-rays. In fact, I have been X-rayed for this reason so many times, I was beginning to worry I might start to glow in the dark.

Is there any clinical explanation, for the occurence of "natural immunity"?

Regards......Ralph.

Infact, many adult would be positive for the TB skin test, that is why it is not accurate for use in adults (many false positives). It is only used in children.

We, adults have a natural immunity against TB. If there was a decline in immunity (stress, malnutrition, HIV etc.) & a sudden increased exposure to TB, Only then we could see signs of clinical TB.

WNM

Thanks Anon,
I was not aware of the incidence if "false positives" in adults.

In my case, I have tested positive since I was a small boy. As I am now on the high side of fifty, I would assume that the chances of my contracting TB, are slim to nil.

Thanks......Ralph.

Once the TB skin test is positive in childhood it would be positive all throughout. Wether one becomes ill or not depends on your immunity status and the amount of TB one is exposed to at one time. Most healthy people are immune to TB and they may be positive for the TB skin test, which means they have been exposed to TB once in their life time.

WNM

Ralph,

A positive skin test shows that you have been exposed to TB germs once and that you have developed immunity against it.

It is estimated that of adults who are exposed to TB germs and develop a postive reaction on skin testing 1 in 10 (10%) will ultimately at some stage develop TB.

This proportion that will develop TB disease is high in childhood (with 50% in 1st year of life estimated to develop TB if postive skin test)and gradually drops off until a healthy adult faces a 10% chance of getting TB.

Therefore in a country where TB is common the skin test is useless as a test for TB (yet GPS in POM still use it charging up to K100 for them) and only a Chest xray will tell if you have active disease.

Why in 10 people who are equally healthy 1 develops TB disease is an interesting question. There is a tendency for some people to develop a more efficient first response to infections and this is determined by genetics; mostly those involved in what is know as the HLA system of genes. I dont think much of that is understood well.

Suffice to say that you should not allow yourself to be irradiated again only on the basis of a positive skin test only unless you actually feel unwell.

Ta