41.   Researchers are still unsure exactly how gum disease might cause chronic illness.

42.   River blindness is a disease caused by the parasitic worm Onchocerca volvulus, spread by the bites of tiny black flies that breed in fast-moving river water.

43.   She gave the tiger not only the customary rabies and distemper shots, but lung X-rays to determine whether the disease had caused problems in his respiratory system.

44.   She got a close-up view of the large, painful blisters the disease causes on the feet and tongues of cattle.

45.   She was immunized to prevent German measles during a future pregnancy, because the disease can cause serious birth defects.

46.   Some undetected underlying disease could have caused the uterine wall to weaken and burst.

47.   The disease can cause blurred vision, loss of balance, poor coordination, slurred speech, tremors, paralysis and blindness.

48.   The disease can cause wheat to be dwarfed or destroy its kernels in certain weather conditions.

49.   The disease causes inflammation of the lining of the brain and spinal cord.

50.   The disease causes painful, burning blisters, which victims scratch, exposing the ends of the worms.