Available data suggest that transmission of the poliomyelitis virus in the Region of the Americas has been interruped since 1991. Wild poliovirus type 3 was imported in 1992 from the Netherlands into a religious community in Canada which refuses immunization. There is no evidence to suggest that the virus spread outside this community.

North America (Bermuda, Canada, Greenland, St. Pierre and Miquelon, and the United States of America [with Hawaii]) extends from the Arctic to the subtropical cays of the southern USA.

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, Rocky Mountain spotted fever, tularemia, and arthropod-borne encephalitis. Recently, rodent-borne hantavirus has been identified, predominantly in the western states of the U.S.A. Lyme disease is endemic in the northeastern United States and the upper Midwest. During recent years, the incidence of certain food-borne diseases, e.g., salmonellosis, has increased in some regions. Other hazards include poisonous snakes, poison ivy, and poison oak. In the north, a serious hazard is the very low temperature in the winter.

In the USA, proof of immunization against diphtheria, measles, poliomyelitis, and rubella is now universally required for entry into school. In addition, the school entry require-ments of most states include immunization against tetanus (50 states), pertussis (44 states), and mumps (42 states).

Mainland Middle America (Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and Panama) ranges from the deserts of the north to the tropical rain forests of the southeast.

Of the arthropod-borne diseases, malaria and cutaneous and mucocutaneous leishma-niasis occur in all eight countries. Visceral leishmaniasis occurs in El Salvador, Guate-mala, Honduras and Mexico. Onchocerciasis (river blindness) is found in two small foci in the south of Mexico and four dispersed foci in Guatemala. American trypanosomiasis (Chagas' disease) has been reported to occur in localized foci in rural areas in all eight countries. Bancroftian filariasis is present in Costa Rica. Dengue fever and Venezuelan equine encephalitis may occur in all countries.

The foodborne and waterborne diseases, including amebic and bacillary dysenteries and other diarrheal diseases, and typhoid fever are very common throughout the area. All countries except Panama have reported cases of cholera in 1994. Hepatitis A occurs throughout the area. Helminthic infections are common. Paragonimiasis (oriental lung fluke) has been reported in Costa Rica, Honduras and Panama. Brucellosis occurs in the northern part of the area. Many Salmonella typhi infections from Mexico and Shigella dysenteriae type 1 infections from mainland Middle America as a whole have been caused by drug-resistant enterobacteria.

Other diseases. Rabies in animals (usually dogs and bats) is widespread throughout the area. Snakes may be a hazard in some areas.

Caribbean Middle America (Antigua and Barbuda, Aruba, Bahamas, Barbados, British Virgin Islands, Cayman Islands, Cuba, Dominica, Dominican Republic, Grenada, Guadeloupe, Haiti, Jamaica, Martinique, Montserrat, Netherlands Antilles, Puerto Rico, St. Christopher and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, Turks and Caicos Islands, and the Virgin Islands (USA)). The islands, a number of them mountainous with peaks 1000-2500 m high, have an equable tropical climate with heavy rain storms and high winds at certain times of the year.

Of the arthropod-borne diseases, malaria occurs in endemic form only in Haiti and in parts of the Dominican Republic. Diffuse cutaneous leishmaniasis was recently discov-ered in the Dominican Republic. Bancroftian filariasis occurs in Haiti and some other islands and other filariases may occasionally be found. Human fascioliasis due to Fasciola hepatica is endemic in Cuba. Outbreaks of dengue fever occur in the area, and dengue hemorrhagic fever has also occurred. Tularemia has been reported from Haiti.

Of the foodborne and waterborne diseases, bacillary and amebic dysenteries are common and hepatitis A is reported, particularly in the northern islands. No cases of cholera had been reported in the Caribbean at the time of printing. Schistosomiasis (bilharziasis) is endemic in the Dominican Republic, Guadeloupe, Martinique, Puerto Rico, and Saint Lucia, in each of which control operations are in progress, and it may also occur sporadically in other islands.

Other diseases. Other hazards may occur from spiny sea urchins and coelenterates (coral and jellyfish) and snakes. Animal rabies, particularly in the mongoose, is reported from several islands (see pp. 149).

Tropical South America (Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, and Venezuela) covers the narrow coastal strip on the Pacific Ocean, the high Andean range with numerous peaks 5000-7000 m high, and the tropical rain forests of the Amazon basin, bordered to the north and south by savanna zones and dry tropical forest or scrub.

Arthropod-borne diseases are an important cause of ill health in rural areas. Malaria (in the falciparum, malariae and vivax forms) occurs in all ten countries or areas, as do American trypanosomiasis (Chagas disease), and cutaneous and mucocutaneous leish-maniasis. There has been an increase of the latter in Brazil and Paraguay. Visceral leishmaniasis is endemic in north-east Brazil, with foci in other parts of Brazil, less frequent in Colombia and Venezuela, rare in Bolivia and Paraguay, and unknown in Peru. Endemic onchocerciasis occurs in isolated foci in rural areas in Ecuador, Venezuela, and northern Brazil. The bites of blackflies may cause unpleasant reactions. Bancroftian filariasis is endemic in parts of Brazil, Guyana and Suriname. Plague has been reported in natural foci in Bolivia, Brazil, Ecuador, and Peru. Among the arthropod-borne viral diseases, jungle yellow fever may be found in forest areas in all countries except Paraguay and areas east of the Andes; in Brazil it is confined to the northern and western states.

Epidemics of viral encephalitis and dengue fever occur in some countries of this area. Bartonellosis, or Oroya fever, a sandfly-borne disease, occurs in arid river valleys on the western slopes of the Andes up to 3,000 meters. Louse-borne typhus is often found in mountain areas of Colombia and Peru.

Foodborne and waterborne diseases are common and include amebiasis, diarrheal diseases, helminthic infections, and hepatitis A. The intestinal form of schistosomiasis (bilharziasis) is found in Brazil, Suriname, and north-central Venezuela. Paragonimiasis (oriental lung fluke) has been reported from Ecuador, Peru and Venezuela. Brucellosis is common and echinococcosis (hydatid disease) occurs, particularly in Peru. Bolivia, Brazil, Colombia, Ecuador and Peru all reported autochthonous cases of cholera in 1994.

Other diseases include rodent-borne arenavirus hemorrhagic fever in Bolivia. Hepatitis B and D (delta hepatitis) are highly endemic in the Amazon basin. Rabies has been reported from many of the countries in this area. Meningococcal meningitis occurs in epidemic outbreaks in Brazil.

Snakes and leeches may be a hazard in some areas.

Temperate South America (Argentina, Chile, Falkland Islands (Malvinas), and Uru-guay). The mainland ranges from the Mediterranean climatic area of the western coastal strip over the Andes divide on to the steppes and desert of Patagonia in the south and to the prairies of the northeast.

The arthropod-borne diseases are relatively unimportant except for the widespread occurrence of American trypanosomiasis (Chagas disease). Outbreaks of malaria occur in northwestern Argentina, and cutaneous leishmaniasis is also reported from the northeastern part of the country.

Of the foodborne and waterborne diseases, gastroenteritis (mainly salmonellosis) is relatively common in Argentina, especially in suburban areas and among children under 5 years of age. Cholera has been reported in Argentina and Chile. Typhoid fever is not very common in Argentina but hepatitis A and intestinal parasitosis are widespread, the latter especially in the coastal region. Taeniasis (tapeworm), typhoid fever, viral hepatitis, and echinococcosis (hydatid disease) are reported from the other countries.

Other diseases. Anthrax is an occupational hazard in the three mainland countries. Animal rabies is endemic in Argentina [and Chile]*. Meningococcal meningitis occurs in the form of epidemic outbreaks in Chile. Rodent-borne hemorrhagic fever is endemic in a limited zone of the pampas and in the center of the country.

* Editor's note: CDC addition.