Rabies on Mexico's northern border, 1969-1980.

The United States-Mexico Border is 3,183 km long, running overland for 1,117 km and along rivers for 2,066 km (see Figure 1). Geographically, the border area is a desert plain broken by a mountainous zone in the region of the two Californias. The border’s highest altitude is 1,200 meters above sea level, which is reached where the border passes by Dtiuglas, Arizona (U.S.A.) and Agua Prieta, Sonora (Mexico). The climate of this region is arid or semiarid, the annual rainfall being less than 5.1 cm. What rain there is normally falls between June and October-except on the Pacific Coast, where it rains in the winter months (I), The typically desert fauna includes a wide variety of mammals, most notably coyotes, foxes, skunks, and a number of bat species (2-3). In 1961 Mexico’s Secretariat of Public Health and Social Welfare (SSA) launched a border rabies control program (PRF) as part of its national rabies control program. The aim of both these programs is to reduce canine rabies in urban areas. The border program covers 12 border cities, which were incorporated into it by stages. In 1966 the program was extended to five cities-these being Ensenada, Tijuana, and Mexicali in Baja California and San Luis Rio