August 2011 bovine TB - How far might trace elements to improve immunity help the situation?The view of a farmer:
"The recent postings about the involvement of trace elements with TB infections may or may not have substance, but how relevent are they in the present circumstances? No animal (or person) contracts TB, whether or not clinical symptoms ensue, unless they have been in contact with the TB bacterium. The main measure of TB infection is the skin test which relies on the animal that has met the infection exhibiting some resistance to the disease. It would therefore seem logical to me that the only benefit increased resistance to TB can confer on an animal that has met the infection, is the greater certainty that it will show a reaction to the test. How does that help, or am I missing the point?
The view of a microbiologist:
"... It is worth mentioning that this interest in resistance to infection and possibility of nutrient deficiency is now becoming realised in human health too. - for example the role of Vitamin D in Multiple Sclerosis and other infections has become a hot topic. - Fashion and bandwagonning in medicine is just as bad as every other human endeavour.
The principle is not that an individual is rendered immune, but that the successful cross infection one individual to another, with an organism, is dependent on the number of organisms involved.
So if one infected individual has a good immune response, they will excrete fewer organisms and so the cycle of transmission is steadily reduced and there are fewer organisms ( for example in TB in cattle) excreted into the local environment.
In a sense this is what vaccines do too, but they may also protect the individual from clinical infection altogether. So if you have mammals (or all sorts ) that are nutritionally complete, they will have more chance of avoiding infection if the cycle of excretion and numbers of organisms available. is reduced. Conversely, animals/ humans that have discrete nutritional deficiency ( such as Vitamin D, Selenium, copper, magnesium etc ) may look OK but be failing to deal with infection as well as they could.
So we are not talking about complete protection of any one individual, but lowering the whole burden of organisms available in the environment to cause infection and onward transmission of a plague."