Figure 2.1. Chains of disease transmission. From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.

From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.

Figure 2.2. The triangle of human ecology. From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.

Plate 3. Household type and vulnerability. Upper left: Rural Bangladesh (2008). Houseboats where people live permanently. The river is a reservoir for cholera. Cooking is done on small stoves fueled with wood or leaves; these stoves give off a lot of smoke, which is inhaled. Upper right: Northwest Frontier Province, Pakistan, near Afghanistan border (1988). Mud and stone house where cracked walls could be habitat for sand flies that transmit visceral leishmaniasis (kalaazar). Middle left: Northeast Thailand (1968). Local (lao) houses with typical architecture—open porch/house side, on stilts (to shade animals and weaving, etc.), now with a corrugated iron roof; burning garbage pit; water jar on porch. Middle right: Southern Belize (2005). A virtually identical house to the northeast Thailand house on stilts, but almost 40 years later and halfway across the world. Lower left: Southern Belize (2005). Mayan house with thatched roof, pigs in courtyard. Lower right: Chapel Hill, North Carolina (2008). House with screens, central heating, central air conditioning. From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.

Plate 4. Resources for drinking water. Upper left: Guangxi, China (2006). Dug well with hand pump. Cement cover to protect the water. Upper right: Rural Malaysia (1974). High school lesson for making a safe well: common dipper, so individual pails don’t contaminate; protected by fence, so chickens, other animals, and small children don’t fall in. But really useless, with water table so high and contaminated water so near. Lower left: Rural Punjab, India (1984). Residential tube well in Punjab as Green Revolution prosperity transformed water safety. Lower right: Rural Bangladesh (2007). Shallow tube well painted red because of high arsenic concentrations. Arsenic occurs naturally in the shallow aquifer in much of rural Bangladesh and causes cancer when water from these wells is drunk over long periods. From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.

Plate 5. Sanitation systems. Upper left: Guagnxi, China (2006). Latrines at a school where a typhoid fever outbreak occurred. Upper right: Rural Malaysia (1974). This banana-shaded private place was designated in the national census as a latrine shared by three households. It drains right into the water! Middle left: Rural Bangladesh (2008). Latrine draining into pond that is often used for bathing or washing dishes. Middle right: Thailand (1974). Thai “squat toilet,” a common type of Asian floor toilet. It’s water-sealed, but jar must be filled with water from well to fill bowl for flushing; jar of water breeds Aedes aegypti. Lower left: Chapel Hill, North Carolina (2008). Water-sealed, water-saving toilet. Lower right: Jaipur, India (1984). Alley designated locally for defecation. From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.

Figure 2. 3. The triangle of human ecology and childhood asthma Figure 2.3. The triangle of human ecology and childhood asthma. Used by permission of Ashley Ward. From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.

Figure 2.4. The triangle of human ecology and cholera. From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.

Figure 2.5. Cholera education advertisement in Malawi. From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.

Figure 2.6. Malarial deaths in the United States, 1890. Adapted from U.S. Census Bureau (1890, map 17). From Health and Medical Geography, 4th edition, by Emch, Root, & Carrel. Copyright 2017 by The Guilford Press.