Abiotic medium: untreated water, transmission of diseases (Mexico)
Basic measures of daily hygiene (such as washing your hands or chlorinating water at the place of consumption) are part of lifestyles which characterise cultural environment. Taking such steps can reduce cases of diarrhoea by half, and together with vaccinations, are the main measures for preventing morbidity and mortality from infections.
Gastro-intestinal infections are mainly transmitted via untreated water. Rotavirus is the main infecting agent for diarrhoea, but the cost of a vaccine is unaffordable for poorer countries. Infant diarrhoea is still the second cause of death for under 5s in Africa and Asia.
Male water bearers, like the Mexican in the picture, usually carry water differently from women. In this case the jars or chochocoles hang on straps which are attached to his head.
Photo: Joaquín Otero Ubeda