Injury. Booklice feed on molds and will overrun cereals and similar materials that support mold growth. Their presence, therefore, is a nuisance and can render some foods unfit. The starchy paste of wallpaper and books also can support mold growth or may be attacked directly by booklice.
Hip dysplasia is caused by a subluxation in the hip joint. This creates abnormal wear and erosion of the joint and as a result arthritis and pain develop. The disease process is fairly straightforward; the controversy starts when we try to determine what predisposes animals to contracting the disease.
In a dog with normal hips, all of these factors work together to cause the joint to function smoothly and with stability. Hip dysplasia is associated with abnormal joint structure and a laxity of the muscles, connective tissue, and ligaments that would normally support the joint.