21.   But if the particular food that caused the infection cannot be found, it may be more difficult to prevent future outbreaks.

22.   But the clitoris also helps squeeze the urethra shut during intercourse, perhaps stopping bacteria from making their way up to the bladder and causing an infection.

23.   But one dangerous organism is resisting attempts to control it, and several others are causing more infections than in the past, the agency warned.

24.   But the virus also vanished within days of causing infection, often leaving no trace as the delicate strands of its RNA simply disintegrated in the body.

25.   But, Harrington said the bird droppings at the school that caused the infection have been cleaned up.

26.   Cigarette smoke, say researchers, can carry bacterial spores and other germs deep into the lungs, where they can germinate and cause infections.

27.   Doctors later found a malignant tumor blocking the bile duct on his liver, which caused an infection.

28.   Eating an infected banana, according to the e-mail, would cause an infection that could eat skin at a rate of two to three centimeters per hour.

29.   Even minuscule amounts of E. coli bacteria can cause infection.

30.   Enterococci, bugs that cause intestinal infections but are not as dangerous as staph, have been acquiring vancomycin resistance at an alarming rate.