Governments of rich, "developed" countries are often interested in the health of other countries. They are especially interested in the health of neighbor countries. The reasons for this are many: if they have extra resources, they may want to share them with their neighbors; but also they may want to stop spread of diseases from their neighbor country across the border. For example, the United States is a richer country than Mexico and has little problem with measles (in children) or rabies (in mammals) in the interior, but along the border with Mexico these diseases are more common.