Faecal-oral paradigm: part 2

As shown in part one of the blog, the discovery of the fecal oral paradigm in urban areas is not new thanks to the fundamental contributions of John Sunderland, John Snow and others in the 19th century, linking cholera and many other diarrhoeal diseases to the consumption of faecal matter.  Despite this issues of poor urban sanitation and faecal-oral transmission remain prevalent in urban areas within Africa and in many other parts of the world. This blog outlines the current situation with regards the faecal-oral paradigm.

Despite significant attempts  to improve urban water and sanitation facilities, ill health remains of significant concern in many developing countries and has been found to be the primary cause of numerous childhood illnesses in African countries including Kenya, Uganda and Tanzania (Tumwine et al., 2002). Diarrhea and the faecal-oral paradigm remains one of the most prominent health problems. At the end of the International Drinking Water Supply ad Sanitation Decade in 2000, there were four billion cases of diarrhea a year and 2.2 million deaths, the majority of which were children under the age of five (JMP, 2000). Furthermore, Tumwine et al., (2002) revisited the original Drawers of Water study, surveying 1015 households in 33 sites across Uganda, Tanzania. They found that since the original study in 1967, diarrhea in the week before the survey increased from 6 to 18% and 16 to 21% in Kenya and Uganda. Tanzania was the only country out of the three to reduce the prevalence of diarrhea modestly from 11 to 8%.

These figures are now 13 years old and since then the Millennium Development Goals have challenged the global community to improve access to freshwater and improved sanitation. However, the recent UNICEF/WHO JMP report seem to point to a similar state of affairs. The MDG sanitation target has been missed by a significant margin. The 2000 JMP reported that '2.4 billion people have no access to any form of improved sanitation services' (JMP, 2000). The 2015 report (JMP) reads '2.4 billion [are left] without access to improved sanitation facilities'. Most live in three regions including Sub-Saharan Africa were 700 million are without improved sanitation which equates to less than 20% of its population have access to improved facilities . (figure 1). Within Nigeria for instance, the percentage of the population with access to improved sanitation has fallen from 38% (1990) to 33% (2015). Levels of open defecation have increased from 7% to 15% (JMP,2015).

Population in 2015 without improved sanitation, Source: JMP (2015)

 Overall, nothing has changed despite 2.1 billion people gaining access to improved sanitation since 1990 (JMP,2015). One of the main reasons for this is that within many parts of the world urban sanitation improvements are not keeping up with population growth.  Population growth presents a In particular challenge for urban areas within Africa (and globally). Within Sub-Saharan Africa for instance, where urban population has increased by 169% since 1990, there has been a decline in water or sanitation coverage in urban areas in 14 out of 46 countries (JMP, 2015). Figure 2 highlights how gains in access to improved sanitation are struggling to outpace population growth, particularly in urban areas. In Sub-Saharan Africa, growth in improved sanitation coverage is just 0.4 times population growth.

Population growth is outpacing improvements in sanitation, especially in urban areas, Source: JMP (2015)

Furthermore, in addition to the potential for illness and death, evidence from a study which undertook analysis from nine cohort studies in five developing countries indicated that high exposure to diarrhea prior to 24 months of age was associated with a greater frequency of stunting past 24 months of age and this was constant across the range of studies (Checkley et al. 2008). The chance of stunting at 2 years increased multiplicatively with each exposure to and day of diarrhea prior to 24 months.

In part 3 of this blog I discuss the range of arguments as to the most effective methods to restrict faecal-oral transmission and thus which approaches  should be pursued to prevent disease incidence.