Some types are red on the underside of the leaves. Some types are supposed to have curly(-ish) leaves. What types do you have? Are they young?

Do you have pictures?

I will post some pictures later - but I am almost positive they were not like this from the beginning. I have had them for about 6 months. They bloomed nicely at first and now they don't do bloom anymore. Two have some blooms but they are sparse and two no longer bloom at all. I looked underneath and all seemed to have developed redness on the underside of the leaf.
I read in a book about AV-s that this is called "red disease", that it is not clear what causes it (not a virus or some external pest) and that it is suspected to be due to either too little light or too little fertilizer. The former is unlikely, the latter is very likely given my husband did not feed them for 3 months or so.
They say that once it develops, the plant can become very dense at the center and the stems can become deformed(it seems to go in that direction), even though the blooms can continue to come out, sometimes more than normally expected. This latter part is not in line with what happens with mine because they no longer seem to want to bloom.
I will re-pot them and wait a couple more months and if they still don't come back, I will get rid of them, I guess.

If they werent fed for a while that would be a primary reason for lack of blooms. The leaf curling could be due to cold conditions but other factors might be involved. Need more information really, such as
What sort of light conditions are they in?
Are they still in the original mix?
How do you water?

Andrew

Here are the pictures.
Some of the leaves seem to be going soft and flappy, they curl under, and you can also see the red under the leaf. The lack of bloom is also evident.

and the other picture...

1) red backs are normal for violets that have the gene to express that trait. Plants that have red backs tend to express it more when nitrogen is high. When you feed, make sure to use a balance fertilizer OR switch to one that's slightly higher in phosphorus to encourage blooming.

2) the droopy leaves indicate a problem with the absorption of water. This can simply be that it hasn't been watered, or it could be a symptom of root-shock or root-death. Problems with the roots can be due to an infestation of beasties (such as soil mealies), or even having been over-watered. I'd lift the plant out of the pot and inspect for bugs and over-all root health. The roots should not be a woody-brown color, but rather a slightly white/translucent-brown. I would also isolate and put it in a gallon-sized ziplock bag to help increase humidity to get the leaves to stiffen up and aid in growing new roots. It also might be worth re-potting the plant in fresh soil because high nitrogen can burn the roots.

Best of luck!

OK...I re-potted and here is what I found: the roots were indeed a bit on the woody-brown side and the plant was clearly not pod-bound. The pot I had may have been too big - it was a 5" plastic pot from Wal-Mart and it was surely not 1/3 of the size of the plant.
Question is: if I do have root-rot, is it over...or could they come back? What is the difference between root rot and root death? Also, when I first saw the roots I thought they were too thin and frail, but then I re-potted a new AV and I could see that one had thin roots too - so I guess this is how AV roots look like after all. The difference was that the new AV had indeed roots that seemed more whitish and translucent and it was pot-bound.
I doctored the old ones, put them in smaller, 3 " terracota-pots (those crapy plastic pots clearly keeep the soil cloged and too damp) and I will wait to see what happens. Can I expect an actual recovery?

I've recovered a few plants from root-rot (actually too many to admit to).

The secret will be to give the violet just enough water to encourage new root growth. Just keep the soil barely moist. Any more than that and the plant will end up rotting to death. Once the leaves perk up, you can return to a more normal watering procedure.

It's typically taken about (2) months for my plants to recover.

Definitely! it is possible to get a 100% recovery. It looks like we're catching this early enough. As aegis says, the trick is keeping the soil moist, but not soggy. Do be careful with the terracotta pots as they can dry out much more quickly (which isn't a bad thing if you tend to over-water).

As for root-death vs root rot, I find root-rot requires complete doctoring and lots of cutting the crown from root-ball to get away from spreading rot. root-death isn't quite a serious (although it can still kill a plant if not addressed), and (in my opinion) easier to bounce back from. Also with root-rot I tend to notice a slight rotten/sulfury smell.

One thing I didn't do when I re-potted was to cut off part of the root ball or those longer roots that seemed brown-ish in color. I read somewhere that this needs to be done, otherwise the root-rot will continue to spread like a cancer to the plant. Given that I just re-potted a few days ago, is it OK to take the plant out again and this time doctor its roots and cut off as much as of brownish ones as I get to see in all that dirt?
Or would that be too much for the plant?
I also read that plants that have gone through root-rot, even when saved/recovered, they will take a long time to bloom again and some will never bloom again. Mine definitely look like they have no intention whatsoever to bloom any time soon. I wonder whether I should even continue to bother with them. Leaves look fine and in fact one of them seemed to have slightly hardened up the leaves that had become soft and floppy. Any input would be appreciated.

honestly I'd let the plant tell me what it wants. If the leaves have stopped being floppy and soft, I suspect it means new roots have started to grow, and it should be fine. Perhaps give it another few weeks, and should the floppy/soft leaves return, do the surgery and then house in a high-humid bag/dome. I think if you give it time, and it stays happy, you'll likely be having blooms by Christmas (if not earlier).