I cannot confirm that strongyloides eat blood but I do know they use the blood stream to move thru out the body. hence the ease that they can live in any organ, joints etc.
They are quite unique in this respect. Most parasites have a natural preference for a certain environment...not so strongyloides!
I think it takes quite a while for strongyloides to become deseminated! There natural life cycle is to enter the sole of the foot as lava. They head to the lung , and then up thru the oesophagus and down to the stomach. There they can moult once or twice and eventually become adults, and the cycle repeats. A bit like ascaris...in their presence in the lung and digestive system.
I think strongyloides spread like mad if you have a compromised immune system thru cancer or AIDs. UNLESS you have a lot of steroid/cortocosterone treatment which makes them spread like mad....