Centers for Disease Control

The incidence of communicable diseases is such that they are unlikely to prove a hazard for international travelers greater than that found in their own country. There are, of course, health risks, but in general, the precautions required are minimal.

Certain diseases occasionally occur, such as plague, rabies in wildlife, including bats, raccoons, foxes, and other wild animals. Coccidioidomycosis is endemic in the southwestern United States and can occur in visitors to the area. Its incidence has increased in Arizona and California in recent years. Histoplasmosis is highly endemic, especially in the Mississippi, Ohio, and St. Lawrence River valleys. Sporadic cases and large outbreaks occur.

Cases of hantavirus pulmonary syndrome have been widely distributed in North America, with the greatest concentration in the western and southwestern United States. Infections in animals were reported in agricultural regions of the United States and Canada in 2006; infection in humans is rare.

Lyme disease is endemic in northeastern, north central (upper Midwest), and Pacific coastal areas of North America. West Nile fever was first documented in the United States (New York) in 1999 and has since spread throughout continental United States and southern Canada.

Outbreaks of diarrhea caused by enterohemorrhagic Escherichia coli O157:H7 have occurred in many areas and have increased in the past decade. Campylobacter and Salmonella are the most common causes of acute bacterial diarrhea.

Isolated cases of bovine spongiform encephalopathy (BSE/mad cow disease) have been reported in Canada and the United States. For more information, see http://www.cdc.gov/ncidod/dvrd/bse/ and http://www.usda.gov.

Outbreaks and cases of pertussis have been increasing for more than a decade.