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close this book Water purification, distribution and sewage disposal for Peace Corps volunteers
close this folder Section 7: Scope of disposal system projects in host communities
View the document Overview:
View the document Public health importance of excreta disposal
View the document How disease is carried from excreta
View the document The characteristics of an adequate system
View the document Possible sanitary measures in rural areas
View the document Soil and ground-water pollution
View the document Location of latrines and other excreta disposal facilities
View the document Sludge accumulation and the life of a pit privy
View the document Community participation
View the document Family participation
View the document Role of health department and other agencies
View the document Public versus private latrines
View the document Human factors
View the document Lesson plans

How disease is carried from excreta

Man is the reservoir of most of the diseases that destroy or incapacitate him. The faecal-borne infectious and infestations already mentioned are the cause of tremendous losses in death and debility. It is interesting to note that all these diseases are controllable through good sanitation, especially through sanitary excrete disposal.

In the transmission of these diseases from the sick, or from carriers of disease, to the healthy, the chain of events, as shown in Fig. 59 , is similar to that for many communicable diseases. In order to transmit disease, the following factors are necessary:

1. causative agent;

2. reservoir or source of infection of the causative agent;

3. mode of escape from the reservoir;

4. mode of transmission from the reservoir to the potential new host;

5. mode of entry into the new host;

6. susceptible host.

Fig. 59A Transmission of Disease from Excreta

Channels of Transmission of Disease from Excreta

Fig. 59B Stopping the Transmission of Faecal-borne Diseases by Means of Sanitation

The absence of a single one of these six conditions makes the spread of disease impossible. As may be seen from the diagram in Fig. 59, there are many ways in which the causative agent of enteric disease reaches a new host. In different parts of the world, different modes of transmission may assume various degrees of importance: in some areas, water, food, and milk may be most important; in others, lies and other insects; and in still others, direct contact may assume a major role. What is most probable is a combination of all, and the sanitary worker must assume that this is the case and guard against all modes of transmission.