51.   The high rate at which Williams appears to have spread the virus has provoked a mixture of alarm and fascination among public health officials.

52.   The possibility that Louganis would spread the virus during the Olympics was negligible.

53.   The scientists speculate that the virus is spread by nasal secretions or saliva.

54.   The rumor was that a site spread viruses along with the electronic cards it delivered.

55.   The virus cannot be spread through casual contact.

56.   The virus is spread through bodily fluids and secretions, though not through casual contact.

57.   The virus is spread through saliva and feces.

58.   The virus is primarily spread by fecal contamination of food and water or through person-to-person contact.

59.   The virus is spread by household or sexual contact with an infected person or by eating contaminated food or by drinking contaminated water.

60.   The virus is spread mainly by contaminated needles and other exposure to infected blood.