An outbreak of influenza A in a nursing home.

An outbreak of influenza A occurred in an elderly population in a Maryland nursing home between December 8, 1980 and January 13, 1981 and involved 76 of the 170 residents. Throat swabs from two of 10 acutely ill residents yielded influenza A virus similar to the A/Taiwan/1/79 strain. Fourfold or greater increases in the titer of complement-fixing (CF) or hemagglutination-inhibiting (HI) antibodies were detected in paired sera from four of five ill residents and from none of four well residents.

An outbreak of hepatitis B in a dental practice.

In September 1978, cases of hepatitis B in two patients treated by the same dentist led to investigation of a dental practice in Baltimore, Maryland. The dentist had had acute hepatitis B in June 1978 and had remained positive for hepatitis B surface antigen and hepatitis B e antigen over the ensuing 6 months. He had continued to work while infected, wearing surgical gloves to minimize the risk of transmitting infection.

Bat-associated histoplasmosis in Maryland bridge workers.

An epidemic of acute prolonged febrile respiratory disease affecting nine of 19 workers on a Maryland State bridge maintenance crew was diagnosed as histoplasmosis by serologic testing in all and by isolation of the organism in one. In our investigation, it was revealed that work on a particular bridge was associated with disease. Culture of bat guano from the site two months later revealed H.