Can we ‘WaSH’ infectious diseases out of slums?

Abstract

The world is becoming increasingly urban and most of this growth is taking place in urban slums of the developing world. The current (2019) global population stands at 7.7 billion, with approximately one billion (13%) living in urban slums. By 2030 the world's population is projected to grow to 8.5 billion, with an estimated two billion (24%) living in slums. Slums are typically overcrowded, with most residents sharing a single room with four to five family members. There is usually no formal sewage or waste disposal system. Open sewage, with antimicrobial-resistant organisms, typically flows just outside the door, which during the rainy season often enters the home and contaminates the household drinking source. Hygiene is difficult if not impossible to maintain, hence the significant burden of infectious diseases, especially those with a faecal-oral mode of transmission. Transmission is year-round and the leading enteric pathogens are rotavirus, Cryptosporidium, Shigella, Campylobacter, Salmonella typhi, and Vibrio cholera. Water, sanitation, and hygiene (WaSH) will be crucial components of a future integrated control strategy for infectious diseases in slums. Cheap WaSH interventions have been trialled, but their impact has been modest and short-lived. More expensive WaSH alternatives that will provide lasting change now need to be explored. Can we 'WaSH' infectious diseases out of slums?

Slums, Space, and State of Health—A Link between Settlement Morphology and Health Data

“…The living conditions of these people are characterized by, for example, overcrowding, insecure tenure, and/or poor access to infrastructure, such as sanitary facilities. The latter has a considerable impact on the health of the inhabitants [2][3][4]. For this reason, several of the United Nations Sustainable Development Goals mention the inhabitants of slums and the necessary improvement of their living conditions both explicitly (Goal 11-sustainable cities and communities) and implicitly (Goal 3-good health and well being; Goal 6-clean water and sanitation; Goal 9-industry, innovation, and infrastructure).…”

The role of chemical exposures in reducing the effectiveness of water–sanitation–hygiene interventions in Bangladesh, Kenya, and Zimbabwe

“…None of these technologies are considered effective against chemical toxicants in drinking water. However, it is now well understood that exposure to chemicals, in particular during developmental windows of increased vulnerability, can dysregulate immune function in ways that lead to greater susceptibility to pathogens and reduced effectiveness of vaccinations against infectious diseases (Erickson, 2019;Granum et al, 2013;Remais, Zeng, Li, Tian, & Engelgau, 2013;Ross, Rahman, Alam, Zaman, & Qadri, 2020;Winans, Humble, & Lawrence, 2011). Accordingly, one possible explanation for why traditional WASH interventions have failed to produce health benefits is that they are designed to control microbial pathogens but are not capable of removing chemical toxicants (Box 1).…”

The Impact of Household Waste on Slum Neighborhoods

“…Every household produces waste, which, if not handled properly, will harm environmental conditions. Besides being dangerous to the environment, it also disturbs human health because in the waste content some germs and bacteria cause various diseases [3]. Household waste, both in the form of liquid and solid, can pollute the soil, damage the water ecosystem, affect the community's drinking water sources, source disease seeds, and cause unpleasant odors [4].…”

“…Organic waste is classified as waste with characteristics that it is easier to decompose and decompose by microorganisms. Besides, there is also inorganic waste, which has no carbon element, such as plastics, rubber, batteries, and cans [3], [6]. Inorganic waste requires time and a long process to decompose, such as waste from used cans containing rusty sediments that can damage soil structure and pollute water.…”