Here are the symptoms of Giardia: I found an article on this sickness. I hope it helps.
Day 1 ~ slight cut back on amount of food eaten and slightly back on water consumption ( about 25% each) ~ mild diarrhea, with the feces being rounder, softer, more moist than normal and covered with a rather shiny mucous. This is a situation sometimes seen with chinchillas, without alarm to us because the mucous disappears quickly.
Day 2 ~ eats only about 1/2 of it's food and 1/2 to 2/3 normal amount of water ~ mild diarrhea, again the same as before. We may think he/she is only being picky and will do better tomorrow. If 2 or more chins are housed together it is hard to know which one is not eating or drinking.
Day 3 ~ will only eat oats or soft food, no regular hard pellets and 1/2 normal amount of water or less ~ mild diarrhea as before, but less of it. You may think it is getting better and not to worry because the diarrhea is almost gone and surely he/she will perk up tomorrow.
Day 4 ~ Chins will not eat food, not even treats and is down to 1/4 normal amount of water consumption. The chins seem to be more irritable than normal. The diarrhea is replaced by feces that appear to have some partially undigested food in them, is firmer, little moisture and less than the normal amount in number. Eyes not wide open as they usually are and are dull in appearance. By now it is obvious that she is not feeling well. She appears listless, quiet, showing signs of dehydration and loss of weight, withdrawn to a corner or a hut and not come to the front of the cage to meet you as they normally would. Finally you realize there is really something wrong, but it is almost to late now or it may already be to late.
Day 5 ~Chin will not eat or drink ~ no feces seen ~ completely listless ~ very weak can not, or barely can, stand on it's own ~ as it progresses ~ loss of control of head ~ chin found laying at the front of the cage underneath water bottle, as if to draw your attention to it ~ slight twitching or tremors can be seen ~ almost completely dehydrated ~ labored breathing ~ gulping for air, followed by death within minutes, but sometimes up to several hours.