I sill didn't find the specific article I was looking for (not done looking). However I found other stuff I didn't know. I wonder if the efficacy of different drugs depends more on which strain/part of the body the disease is affecting?
Nanakat was right about preventative treatment though, otherwise it's often too late if you don't go at it aggressively (several of the many articles I read said that).
The below was published by a hatchery so I didn't put 100% stock in it until I read the same thing at a govt agricultural site at:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex4616
Interesting reading also at: http://www.merckmanuals.com/vet/poultry/coccidiosis/overview_of_coccidiosis_in_poultry.html
The above link lists a bunch of the different drugs at the bottom they use for it.
http://www.millerhatcheries.com/Information/Diseases/coccidiosis.htm
The most easily recognized clinical sign of severe cecal coccidiosis is the presence of bloody droppings. Dehydration may accompany cecal coccidiosis. Coccidiosis caused by E. tenella first becomes noticeable at about three days after infection. Chickens droop, stop feeding, huddle together and by the fourth day blood begins to appear in the droppings. The greatest amount of blood appears by day five or six and by the eighth or ninth day the bird is either dead or on the way to recovery. Mortality is highest between the fourth and sixth days. Death may occur unexpectedly, owing to excessive blood loss. Birds that recover may develop a chronic illness as a result of a persistent cecal core. However, the core usually detaches itself by eight to ten days and is shed in the droppings.
E. necatrix causes a more chronic disease than E. tenella and does not produce as many oocysts. Therefore, a longer time is usually required for high levels of environmental contamination. Birds heavily infected with E. necatrix may die before any marked change is noticed in weight or before blood is found in the feces.
E. acervulina is less pathogenic than E. tenella or E. necatrix. E. acervulina is responsible for subacute or chronic intestinal coccidiosis in broilers, older birds and chickens at the point of lay. The clinical signs consist of weight loss and a watery, whitish diarrhea. At postmortem, greyish-white, pin-point foci or transversely elongated areas are visible from the outer (or serous) surface of the upper intestine. The foci consist of dense areas of oocysts and gamete (male and female sex cells) production.
E. maxima produces few marked changes in the small intestine until the fifth day after infection. After which, in severe infections, numerous small hemorrhages occur along with a marked production of thick mucus. The intestine loses tine and becomes flaccid and dilated. The inner surface is inflamed and the intestinal content consists of a pinkish mucoid secretion.
Panda 101
