CHAPTER ONE
INTRODUCTION
Intestinal parasites are parasites that populate the gastrointestinal tract, typically protozoa and helminthes are the two major types of intestinal parasites (D. R. Arora, and B. A. Brij, 2012). Gastrointestinal parasitic infections are endemic worldwide and have been described as constituting the greatest single worldwide cause of illness and disease (Mehraj V, Hatcher J, Beg MA .2008). These infections are associated with poor sanitary habits, lack of access to safe water and improper hygiene, thereby occurring where there is poverty (Stekee R.W.J Nutr.2003).Current estimates by World Health Organization(WHO) shows that about 3.5 billion people are infected with intestinal parasites, majority of which are children (WHO 2002). The helminthesT.trichiura, A. lumbricoides and the hookworms as well as the protozoa E. histolyticahave been observed to cause infection in 800, 1000, 900 and 48 million people respectively worldwide (WHO 2002). Gastroenteritis is a disease condition due to theinflammation of the mucousof the stomach and intestine. Many microorganisms contaminating food and watercan cause acute gastroenteritis. In most cases it runs its own course over several days. However it can be a serious condition, if the fluid loss is sever enough to cause dehydration. When food is the source of the pathogen the condition is often called food poisoning (Archeson 200)
Gastroenteritis can arise in two ways the microorganisms may actually produce a food borne infection, that is, they may first colonize the gastrointestinal tract and grow within it, then either invade host tissues or secrete exotoxins (Johnson, 1999).
Alternatively the pathogens may secrete an exotoxin that contaminates the food and is ingested by the host. This is sometimes referred to as food intoxication because the toxins ingested and the presence of the living microorganisms is not required. Because these toxins disrupt the functioning of intestinal mucosa they are called enterotoxins (Sanders and sanders 1997)
Most cases of gastroenteritis are due to viral infection about a half are caused by the rotavirus, first discovered and described at the royal children’s Hospital university of Melbourne in the early 1970 various other virus may cause the same symptoms as well as bacteria like campylobacter, protozoa and helminthes. In most cases the precise infective agent is not identified. It is only when symptoms are persisting that stools are sent for microscopy and culture in the laboratory (Nachamkin 1992).
On a global scale gastroenteritis is a massive health problem. About 5 million people die each year, mainly young children in underdeveloped countries most deaths are due to dehydration, in adequate fluid replacement and circulatory collapse. In Australia, Asia, African and South America an occasional fatality still occurs with gastroenteritis again mainly due to complication of severe dehydration. A rotavirus vaccine has been developed in Australia and may eventually have extensive worldwide application (Prescott 2005).
The main symptoms of gastroenteritis are vomiting diarrhea and cramping abdominal pain. Sometimes of fever may also be present. In more severe cases, signs of dehydration that may appear in a young child may look floppy and pale and the urine output may be reduced. These signs mean that urgent medical assessments and treatment are required.
Intestinal helminthes and protozoan infections have been recognized as significant causes ofillnesses and diseases worldwide ( Ngui R, Ishaka S, Lim YAL 2011). These are among the most common human parasiticinfections and have been associated with important morbidity and economic loss in endemicareas. Current estimates show that at least more than one quarter of the world’s populationis chronically infected with intestinal parasites and most of the infected individuals live indeveloping countries (Brooker S, Hotez PJ, Montresor A 2003). The prevalence of intestinal parasitic infections is 50% indeveloped countries, whereas it reaches up to 95%in some developing countries (E chacon-czuz 2003)
These infections are usually highly prevalent among the resource poor and socioeconomicallydeprived communities where overcrowding, poor environmental sanitation, low level ofeducation and lack of access to safe water are prevalent (Mehraj V, Hatcher J, Beg MA 2008) The infected people experience a vicious cycle of under nutrition and repeated infections leading to excess morbidity withchildren being the worst affected
For example soil transmitted helminthes (Ascarislumbricoides, Trichuristrichiuraand hookworm) have been recognized as an important public health problem and are the mostprevalent of intestinal parasitic infections among poor communities. In 2009, Hotez PJ., estimated that approximately one third of the world population is infected with at leastone species of soil transmitted helminthes, with A. lumbricoides infecting 800 million people,T. trichiura 600 million, hookworm 600 million and resulting in up to 135,000 deaths annually .With regards to intestinal protozoan infections, giardiasis caused by Giardia intestinalis, isthe most prevalent protozoa infection with estimated prevalence rates ranging from 2 to 7%in developed countries but 20 to 30% in most developing countries and affectingapproximately 200 million people worldwide (Mineno T, Avery MA 2003). Amoebiasis caused by Entamoebahistolyticais another important pathogenic protozoa affecting approximately 180 millionpeople resulting in a reported annual mortality rate of 40,000 to 110,000 (World Health Organization 2003).
Intestinal parasitic infections cause various intestinal symptoms including abdominal bloating, cramps, constipation, diarrhea, lack of appetite and vomiting. Most of these symptoms are non-specific and are similar to those of other pathogens such as viruses,bacteria and other non-infectious conditions affecting the intestinal system including irritable bowel syndrome, ulcerative colitis, pancreatitis and peptic ulcer disease (Gordon C. Cook 2009).
Intestinal parasites are common in areas with poor sanitation, dirty water, substandard crowded housing and in warm and humid environments (Micheal O Harhay, John Horton 2010). In 2008 the World Bank estimated that 1.29 billion people were living in absolute poverty, 47% of whom were in sub-Saharan Africa. These figures correlate with the high prevalence of helminthes infections in the region (Brooker S, Clement AC, Bundy DA 2006). In Kenya, depending on the city, 60-80% of Kenyan urban population lives in slums that are characterized by lack of access to water and sanitation, lack of adequate housing and poor environmental conditions which are predisposing factors for infections with intestinal parasites. For instance in Nairobi, 60% of the population lives in slums that occupy only 5% of the total land area. Kibera is a slum in Nairobi where it has been demonstrated that, poor environmental sanitation leads to water and vector borne diseases including intestinal parasites. Although entire populations in such areas are at risk,children carry the greatest burden of infection due to their behavioral and biological exposure (Bethony J, Brooker S, Albonico M 2006). For example, children tend to play in contaminated environments and are immunologically vulnerable to infections. They also are normally crowded together for large periods of time for example in schools, orphanages or slums, thereby increasing the likelihood of transmission or environmental contamination with the parasite. In agreement with this, in the year 2006 it was estimated that of the 181 million school-aged children in sub-Saharan Africa, almost half (89 million) were infected with one or more of these parasitic worms.In general and compared to the intestinal nematodes, the epidemiological data for intestinal protozoa, and nematodes excluding schistosomiasis, is limited and has not been studied systematically or included in the studies on global burden of disease accurate figures for the prevalence of these infections have been challenging to obtain, and despite their relative low frequency compared to the nematodes, they can cause significant morbidity and mortality in a large number of individuals ( Miceal O Harhay, John Horton 2010).
The public health importance of gastrointestinal parasites includes high morbidity in children and in women during their child bearing years (J. I. Mbanugo and O.C Abaziri 2002). Children are mostly infected because of their vulnerability to nutritional deficiency. Intestinal parasitic diseases remain a serious public health problem in many developing countries especially due to fecal contamination of water and food (Jimenez-Gonzalez et al., 2009; Odu et al., 2011a; Odu et al., 2013). The degree of each factor and the prevalence of Infections vary from one region to another.
1.1 AIMS AND OBJECTIVES
This study was carried out to determine the prevalence of gastrointestinal parasites among children in Okigwe, Imo State, Nigeria.
1.2 STATEMENT OF PROBLEMS
There are factors in the environment which induce poor sanitation and the filthy habits of the children ideal for transmission of gastroenteritis, therefore infection rate is expected high.
1.3 HYPOTHESIS
H0 – prevalence of gastroenteritis caused by helminthes and protozoa is common in babies.
H1 – prevalence of gastroenteritis caused by helminthes and protozoa is not common in babies