Co-workers develop extreme low iron

Patient: Several of my co-workers and myself have been feeling extremely poor for several months now. We work with special needs children who don’t always have the best hygiene. we thought maybe we were passing a flu type bug back and forth. We have recently discovered that we all have extremely low iron. Two of the women are borderline anemic. What could be causing this? Seems a bit conquencidental

Symptoms: we are all extremely tired, have slight temperatures, some have no appetite or get nauseated.