Recently, I was reading, on the internet, a conversation between two racing pigeon fanciers, These two fanciers were arguing whether a specific medication might kill 99% or 100% of its targeted pathogen population. It was this conversation that caused me to write this article. My response was: Regardless of who was right concerning the kill rate of the medication in question, In most cases either result is not the desired result.
There is no way that we can maintain a 100% shield from bacterial or viral infections in our birds. It is not possible nor is it desirable. The best methodology that I know of, is to keep these pathogen populations at such low counts, that the bird's natural immune response is able to control the populations and maintain a balance within the bird.
So called evolution has created a successful symbiotic relationship between tens of thousand of bacterial and viral colonies which occupy "niches" in our biosphere (body). When this balance is upset, we get sickness. When the balance is maintained we have greater health and well being.
So, the conversation about whether a specific antibiotic kills 99% or 100% of a bacterial infections is rather moot. In a perfect world you would maintain colonies of ecoli, cocci, salmonella, etc. in manageable populations according the abilities of the bird's defense mechanisms.
For example, there are about 2500 different bacteria that live in our mouths. If you use a mouthwash, do you think you are killing 100% of the microbes in your mouth? It just does not happen, evolution has developed a balance of microbes that occupy "in symbiotic relationship" different niche environments in our bodies. If we totally eliminate one of the populations, some other bacterial or viral colony will fill the void and they may not play as nicely as the original occupant.
This was recently found out in reviewing data from a new vaccine for children under the age of two. A vaccine was developed that controlled the seven pneumococcal bacterial infections (pneumonia, meningitis and serious blood infections) which most often effect these children. The results were good and all were happy with the new vaccine and how it worked. However, it was later found that other pathogens were moving in to fill the niche that the "vaccine targeted pathogens" had originally filled, and the end result was that certain infections which historically had not been a problem were now surfacing in children under 2 years of age, and these infections were much harder to treat than the original pathogens which had been targeted by the vaccine.
Sometimes, a pathogen (our word for an "infectious agent, or more commonly germ, is a biological agent that causes disease or illness to its host") does not function as a pathogen when it's colony population is controlled but rather acts as a barrier against other more severe pathogens moving in and occupying the host. This would be an example of "competitive exclusion". They exclude other worse microbes by occupying the niche they have established in the symbiotic chain of command that functions to maintain health within the host.
As far as the vaccine goes, the new theory on this is that the company will now create a vaccine that not only targets the original seven pneumococcal bacterial infections but also an additional group that have been found to move in and occupy the niche left when the original pathogens were vaccinated against. This is the law of unintended consequences at work. We simply do not know everything that goes on "under the hood", we sometimes succeed in making one problem better only to find later that another problem has been made worse my our actions.
We are finding that in some cases, you just cannot leave a vacuum as it will be filled by something and what fills the vacuum may be worse than the original occupant. For the racing pigeon fancier who does not have the huge research facilities of major pharma companies, leave evolution alone and instead concentrate on population control of these so called "bad microbes" and not total elimination. A small colony allows the natural immune response to learn how to deal with the colony and control its population on its own. Only step in when the natural defenses are overwhelmed (high colony counts).
How one knows when to step in is the hard part. Some, utilize products called natural immunity builders in much of the same way others use medications and antibiotics on a weekly basis. For many, this is a good alternative health practice. In any case, the bottom line is that there are unintended consequences to our actions so the less we tinker with the natural processes concerning things that go on "under the hood" the better. Our goal should be to "assist" but try not to dominate the natural immune response.
In a perfect world, we would do all of our treatments of our breeders weeks before putting the birds together and not treat at all during the breeding season. In this way, the presence of small populations of these pathogens within the breeders, allows their immune response to pass "acquired immunity" to their young, both in the egg and in the pigeon milk. Treating the breeders during the breeding season only compromises this natural evolutionary process of passing immunity to the young and there may well be consequences to this over time. You can read more about this at: http://www.racingpigeonmall.com/articles/rpe-adaptive-immunity.html