CHAPTER ONE
INTRODUCTION
1.1    BACKGROUND TO THE STUDY
Cholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae 01 and 0139( Riyan 2004 & WHO 2010). The main symptoms are profuse watery diarrhea and vomiting. Transmission is primarily through consuming contaminated drinking water or food. The severity of the diarrhea and vomiting can lead to rapid dehydration and electrolyte imbalance. Every year there is an estimated 3-5 million cholera cases and 100,000-120,000 deaths due cholera. The short incubation period of two to five days, enhance the potentially explosive pattern of out breaks (Faruque 2008 and WHO 2010). Cholera transmission is closely linked to inadequate environmental management. Typical at-risk areas include peri-urban slums, where basic infrastructure is not available, as well as camps for internally displaced people or refugees, where minimum requirements of clean water and sanitation are not met.  The consequences of a disaster – such as disruption of water and sanitation systems, or the displacement of populations to inadequate and overcrowded camps – can increase the risk of cholera transmission should the bacteria be present or introduced.
Epidemics have never arisen from dead bodies. Cholera remains a global threat to public health and a key indicator of lack of social development. Recently, the reemergence of cholera has been noted in parallel with the ever-increasing size of vulnerable populations living in unsanitary conditions (Emch 2008 and WHO, 2010).
Two serogroups of v. cholera – 01 and 0139 – causes out breaks (Alexander 2008).  v. cholera 01 causes the majority of outbreak, while 0139  -first indentified in Bangladash in 1992 –is confined to South-East Asia. Non-01 and non-0139 v. cholera can cause mild diarrhea but dot not generate epidemics. The bacteria are transmitted via contaminated drinking water or food.  Pathogenic v. cholera can survive refrigeration and freezing in food supplies. (Reildl et al 2002) The dosage of bacteria required to cause an infection in healthily volunteers via oral administration of living vibrios is greater than  1000 organisms (Hartely 2006 ).  After consuming an antacid, however, cholera development in most volunteers after consumption of only  100 cholera  vibrios experiments also show that  vibrios consumed with food are more likely to cause infection than those from water alone (Finkelstein 1996). Cases tend to be clustered by location as well as season, with most infections occurring in children ages 1-5 years (WHO 2010).
Cholera is severe water-born infectious disease caused by the bacterium  vibrio cholerae.   In 2005, 131,943 cases including 2,272 deaths have notified from 52 countries. The year was marked by a particular significant series of outbreaks in West Africa, which affected 14 countries and accounted for 58% of all cholera cases world-wide (WHO 2006). In the same year Nigeria had 4,477 cases and 174 deaths. There was reported case of cholera in 2008 in Nigeria in which 429 death out of 6,330 cases. More so, 2,304 cases in Niger State in which 114 were reported death in 2008 (NBS 2009). Recent years have seen a strong trend of cholera outbreak in developing countries, including among others, those in India (2007), Iraq (2008), Congo (2008), Zimbabwe (2008-2009), Haiti (2010), Kenya (2010). Koko in Edo State (1989). In Nigeria, according to UN figure, 1,555 people have died since January and 38,173 cases have been reported. The figure is more than four times the death toll the government reported in August (Guardian. 2010)