Sanitation and Vector Control - Biological and Environmental Control of Disease Vectors - page 144

8

Sanitation and Vector Control

Jeroen H.J. Ensink, 1 * Flemming Konradsen 2 and Sandy Cairncross 1
1 London School of Hygiene & Tropical Medicine, London, UK;
2 University of Copenhagen, Copenhagen, Denmark

8.1 Introduction

to pathogens. Human excreta are associated
with the transmission of over 50 infectious
diseases, most of which are found in faeces, and
only few transmitted in urine (Feachem et al .,
1983). The majority of excreta-related infections
are acquired through ingestion with the
exception of schistosomiasis and hookworm,
which penetrate the skin. Diseases with a faecal
origin are responsible for high disease burden
and mortality in low income countries.
Diarrhoeal disease is associated with over 1.9
million deaths every year (Boschi-Pinto et al .,
2008), while soil-transmitted helminths, prin-
cipally Ascaris lumbricoides , Trichuris trichuria
and hookworm, infect over 1.2 billion, 800
million and 740 million people, respectively (de
Silva et al ., 2003). The absence of sanitation is
also associated with the eye disease trachoma,
which af ects 6 million people, and is the main
source of preventable blindness (Rabiu et al .,
2007).

The World Health Organization (WHO) refers to
sanitation as 'the provision of facilities and
services for the safe disposal of human urine and
faeces' (WHO, 2011). Sanitation is either
classifi ed as on-site, in which excreta is stored
and disposed of close to the household, or of -site
when it is stored and disposed of away from the
neighbourhood in which it is produced. On-site
sanitation systems include, among others, the
simple unimproved, or traditional, pit latrine,
the ventilated improved pit latrine, pour fl ush
latrines and septic tanks. The most widely used
form of of -site sanitation is water-borne
sewerage, which can either be through open
surface drains or underground conduits.
However, for many people worldwide,
sanitation is either unaf ordable or denied by
prevailing social norms, environmental con-
ditions (e.g. high groundwater table or rocky
underground), or lack of ownership of land or
household, thereby making investments in
sanitation impossible. It is estimated that 2.4
billion people lack access to basic sanitation, 1.1
billion of which regularly practise open
defecation (WHO/UNICEF, 2010). The absence
of sanitation, or poorly managed sanitary
facilities, can lead to the contamination of the
environment with human excreta and exposure

8.2 Excreta, Vectors and Disease
Transmission

The average human excretes between 20 and
750 g of stool and from 1 to 1.5 l of urine per
day depending on age, diet and climatic
conditions (Feachem et al ., 1983). When people

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