I found out recently that i am allergic to dust and dust mites. i now have a lung infection. could the two be related? i bought allergy pillow cases for the dust mites. what else can i do to prevent getting sick due to dust?

Barriers/filters: Dust mites live off the dead skin you shed. Pillow & mattress covers can reduce your exposure, but you must also launder sheets regularly. Several vendors have particle filters that can reduce dust/mite load & HVAC systems can use allergy grade filters. Any & all lung contamination from dust/allergy/smoke/etc. increase frequency of lung infections. Just look at what happens to smokers.

Avoidance of dust: The two conditions may or may not be related. Avoid dust by cleaning your home well, mattress and pillow covers and using a HEPA filter unit. A flu vaccine is recommended unless otherwise contraindicated and avoid smoke.