Just found out yesterday that I have lymphoma (cancer of the blood which is uncurable). No one knows for sure but it is possible it could be caused from a virus from HVAC service work. I work in attics sometimes that have dried rodent feces and urine in them which could cause the disease according to my doctor. I never knew this was possible, so be careful out there. Wear long sleves, long pants, gloves, dust masks, etc. Which is of course hard for me to do in Dallas Texas with its 130 degree attics. Also who knows how many awful virus' are on A/C coils? Prayers would be welcome. Thanks, Steve (48 years old, technician 31 years).