Mara et.al. (2010) define sanitation as safe disposal of faeces, and safe disposal here implies that people should not come in contact with the faecal matter and that people should also defecate or urinate hygienically \cite{Mara:PlosMed:2010}. Most diseases associated with poor sanitation occur in young children, less than one year old, and among poor people. Faeces contains 10^6 grams of viral load 10^4 parts of bacteria and other protozoa and each of these can affect humans adversely. Diarrhoea is a major health concern when poor sanitation facilities lead to contamination of drinking water or food with faeces. The pathway through which faeces can come in contact with food and water is referred to as F-diagram and sanitation and safe disposal are two of the best ways to stop this contact. Meta analyses indicate that proper sanitation services lead to between 30-60% reduction in diarrhoeal disease load. Other than diarrhoea, diseases such as trachoma and helminthiasis are also important. Diarrhoea leads to malnutrition in children. Trachoma can be successfully mitigated by using SAFE (Surgical intervention, Antibiotics, Face wash with water, and Environmental measures that is, sanitation); however, most measures are around antibiotics and hence wasteful of resources when it could be prevented. Helminth infections could also be mitigated with similar measures.
However, in practice most societies adopt sanitation not because of health concerns but because of social reasons, acceptance, safety, and in order to avoid inconvenience and embarrasment of going out into the field for defecation and urination. About 2.6 billion people in the world are without sanitation services and majority of them are in India. About 71% people in the villages or rural areas are without sanitation services and about 39% people who live in urban areas do not have sanitation services.
There are four reasons why despite knowing that sanitation services are essential, the progress has been slow. First, while national governments and other agencies tend to provide subsidized services to provide toilets, these benefits reach the few people who can exert influence to get these things done for them in dveloping worlds. Second, if the structures are inappropriately done, the toilets end up as firewood stacking, and cowsheds; third, some of these solutions are so expensive that people cannot afford to pay for them so they never get done; fourth, there is very little research about how to dispose effectively children's faeces and so these do not get actioned; fifth, as toilets, latrines, and faeces are "icky" subjects, these do not get the attention they deserve during times such as elections or other public engagements.
So, what can be done and what have been successful? People are moving away from governments and agencies making toilets for people to more demand driven models where communities are asking for specific toilets and are ready to assume ownership for these things. Second, using community led total sanitation systems such as ignited villages in Bangladesh have resulted in greater community ownership so that people now get together and decide they need toilets and build themselves. Third, toilet construction and maintenance and use of human waste for agriculture and use as biofuel has started being used on a commercial basis and this helps to see the disposal of faeces in different light. In contrast to rural settings, for urban spaces, safe disposal of pit emptying services have gained tractions.
The health sector is an important sector to play here. Doctors and public health specialists can either help in sanitation marketing or integrate the need for sanitation services in other services such as while bringing up immunisation services. There is a need for integrative policy setting approaches so that in urban spaces, there should be legislation about mandatory toilet construction and use of safe disposal of faeces and urine.
Summary
In summary, provision of safe water, disposal of waste through safe means and use of latrines and waste disposal, and regular washing of hands with soap and water are essential for everyone in order to prevent a range of disease conditions. Diarrhoea is the fourth most common preventable public health disease after HIV/AIDS, malaria, and tuberculosis in the world. While the burden of disease is borne mainly by people in the developing and poor countries and among the poor people in the developed countries as well, even in developed countries with adequate access to safe water, sanitation, and hygiene practices, we have seen sporadic outbreaks of gastroenteritis. In rural regions of New Zealand, often advisories for boiling your drinking water or tap water are issued particularly after heavy rainfall or other situations where the source water is contaminated. Besides diarrhoea, in the developing countries, water supply, sanitation, and hygiene practices contribute to malnutrition, lost days of work and school attendance, and loss to the workforce and economic losses, as well as enteric and parasitic diseases. On the other hand, provision of latrines and putting a stop to open defecation can lead to better health status. Under the drive of achieving millenial development goals, considerable progress has been made in terms of supplying safe water, but less success is met in sanitation measures. Rather than imposing or providing latrines, a better strategy is to create awareness and demands for sanitation and latrines in the developing countries or specific regions and also create markets and easy financing for attainment of sanitation facilities. Poor people are hit the hardest in these cases. Health professionals have a major role to play in raising awareness about hygiene practices, use of safe water and sanitation; health professionals must also press or lobby for legislations so that these practices are enforced.