Giardia is a major causative agent of gastrointestinal disease in humans and causes giardiasis.The present study utilised microscopy and ELISA copro-antigen to determine the prevalence of Giardia lamblia in stool samples of children 0-5years presenting with gastroenteritis in association with body mass indices (BMI) in Kaduna Metropolis, Nigeria. Of 200 samples examined, 12 (6%) were positive for Giardialamblia using microscopy and 28 (14%) using ELISA kit. The prevalence of giardiasis was higher in males (15.89%) than females (11.83%). There was no significant difference in the level of infection in both sexes (?2=0.6811, df= 1, p= 0.4092). The highest prevalence of giardiasis was observed in 4-5 years (16.39%) while the lowest was in the 0-1 year (9.68%). There was no significant difference in the prevalence of giardiasis among the age groups (?2= 0.848, df= 4, p = 0.9319). There was no association between giardiasis and BMI (p = 0.3161). The study showed that 33% of the children were underweight, while 66% and 1% had normal weight and overweight respectively. There was a strong association between giardiasis and source of drinking water (well water), nutritional status and mother’s level of education with p-value as follows [( p=0.005: p=0.012 and p=0.0007)].The most common parasite identified in this study was Entamoeba coli (18%) followed by Giardia lamblia (14%) and the least was Strongyloides stercoralis (0.5%). There was a significant increase of infection as age increases (p=0.02797).Based on the above results, it can be concluded that the prevalence of Giardia lamblia in children 0-5 years presenting with gastroenteritis has no association with their BMI. Therefore it is important that children 0-5 years should be fed with a balanced meal. Improved personal hygiene should be encouraged and treated water should be protected from re-contamination.

CHAPTER ONE: INTRODUCTION

1.1    Background to the Study
Acute gastroenteritis presenting as infant diarrhoea remains a common illness among infants and children throughout the world. Among children in the United States, acute diarrhoea accounts for more than 1.5 million outpatients, 200,000 hospitalized inpatients and about 300 deaths per year (Zimmerman et al., 2001; CDC, 2014). It has been established that in the very poor countries of Africa, Asia and South America a child suffers up to 15 to 19 episodes of diarrhoea with 4.6 million to 6 million deaths annually (Grote et al., 2011). In Nigeria, available report indicates that more than 315,000 deaths of preschool age children occur annually as a result of infantile diarrhoea disease with 80% of the population affected (Aminu et al., 2008; Ayolabi et al., 2012).
Gastroenteritis or gastro is an illness caused by infection and/or inflammation of the digestive tract. It is characterized by nausea, vomiting, diarrhoea and/or stomach cramps. Other symptoms may include fever, headache, blood or pus in the faeces, loss of appetite, bloating, lethargy and body aches (CDC, 2014). Infectious gastroenteritis is caused by a variety of viral, bacterial and parasitic pathogens. Intestinal parasites have a worldwide distribution and have been associated with gastroenteritis in children. One of the most common intestinal protozoa parasite is Giardia lamblia (Jelinek and Neifer, 2013).
Among the intestinal flagellates, Giardia lamblia and Dientamoeba fragilis are pathogenic to man (Monali et al., 2012). The highest rates of infection are therefore encountered in developing countries (10-30% in young children). While in developed countries, infections occur mostly in persons living in closed communities, homosexual men, immigrants and of increasing importance travelers returning from highly endemic countries (Carmena et al., 2012; Jelinek and Neifer, 2013).
About 3.5 billion people are infected worldwide and about 450 million people are ill due to these infections which are mainly in children of about 2-14 years. The infections cause iron deficiency anemia, growth retardation and other physical and mental problems in children (Nyamngee et al., 2006).

Giardia is an enteric protozoan that infects a wide range of vertebrate hosts, being thecausative agent of gastrointestinal disease of humans in both developing and developed countries (Jombo et al., 2011). Giardial infection also has significant impact on livestock health, causing diarrhoea and loss of weight (Carmena et al., 2012). Global Giardia infection rates have been reported by Carmena et al. (2012) in domestic animals in Spain in the range of 3%-58% for cattle, 25% for water buffaloes, 1%-56% for sheep, 12%-36% for goats, 17%-31% for pigs and 5% for alpacas. Similarly to human giardiasis, they reported that pathogenesis of Giardia in animals is also a multifactorial process involving both parasite and host factors. The combination of these factors results in malabsorptive diarrhoea and lower weight gain (Carmena et al., 2012).
Evidence of zoonotic transmission among humans and cats living in the same community had been reported by Pereira et al. (2007). A prevalence as high as 67.5% of people under the age of 15 years infected by cross-species transmission including zoonotic transmission of G. lamblia near Kibale National Park in Western Uganda was reported by Jonhston et al. (2010). G. lamblia is not a life-threatening parasite, nevertheless, it is still considered as the most common water-borne diarrhoea-causing disease. It is important to understand the aetiology, frequency and consequences of acute diarrhoea in children (Dib et al., 2008).
Transmission is either direct, through the faecal-oral route or indirect through ingestion of contaminated water or food (Carmena et al., 2012). Giardiasis is associated with poor sanitary conditions, insufficient water treatment, daycare centers and with institutional facilities such as nursing homes (Pereira et al., 2007). Giardiasis infections can often be distinguished from viral or bacterial gastrointestinal (GI) infections by the longer duration of illness (often 7-10 days by the time of first presentation) and weight loss (Jason, 2003). Clinical manifestations are usually diarrhoea, abdominal cramps, nausea, bloating and loss of appetite. In chronic and complicated cases, cholecystitis and malabsorption may be observed (Naglaa et al., 2011). Age and body mass index were reported as risk factors associated to Giardial infection among street orphanage children in Peru by Bailey et al. (2013).
Body mass index (BMI) is a factor calculated from a child’s weight and height. It is a reliable indicator of body fitness for most children and teens and is also used as a screening method for weight categories that may lead to health problems (CDC, 2014). Growth failure is associated with increased morbidity and mortality in children and it is estimated that as many as 182 million children in developing countries are affected. Although the aetiology of growth failure is multifactorial, malnutrition and repeated infections in children have been documented as causative agents, among which G. lamblia is a hallmark cause (Amuta et al., 2009). Growth failure indicated by stunting, wasting and underweight conditions can be assessed by anthropometric indices of Height-for-Age (HAZ), Weight-for-Age (WAZ), and weight-for-height (WHZ) (Inabo et al., 2011).

1.2    Statement of Research Problem
Paediatric diarrhoea remains one of the major causes of death among infants. This is especially true in the third world countries such as Asia, Africa and Latin America, where it causes millions of death within the age group of 0 to 4 years. The main factors for high occurrence of diarrhoea in children and mortality rate are unsafe water, inadequate sanitation and/or physiological conditions such as malnutrition (Giordano et al., 2001). G. lamblia causes a worldwide health problem that requires better intervention; it was the causative agent of giardiasis, a disease which affected over 200 million people in 2002 (Lane and Lloyd, 2002). Giardiasis is the most frequently diagnosed water borne disease and the major public health concern of water utilities in the developed and developing nations (Al-Emarah and Al-Saad, 2014).
Several studies have revealed that a chronic infection of Giardia during childhood contributes to protein-energy malnutrition, vitamin A deficiency, iron deficiency anaemia, zinc deficiency and poor cognitive and educational performance in children (Seow et al., 2014). It has also been shown to have negative impact on growth and development in children and most often it occurs asymptomatic (Duran et al., 2010; Inabo et al., 2011). Ample evidence suggests that Giardia, which has been found in all classes of vertebrates also, has great potential for zoonotic transmission (Caccio et al., 2005; Carmena et al., 2012).

1.3    Justification of the Study
The World Health Organization reported that 200 million people in Asia, Africa and Latin America have symptoms of giardiasis with some 500,000 new cases a year, especially among children. The infection may produce severe acute diarrhoea in children less than five years of age with chronic infections resulting in weight loss and growth retardation (WHO, 1996). Giardiasis has been recognized in 2004 as a neglected disease by the World Health Organization (Chakaroka, 2010).Giardiasis is rarely fatal; however, deaths can be caused by extreme dehydration, mainly in infants or malnourished children (Dib et al., 2008).
Therefore, there is a need for more research on this protozoa parasite. Little is known on this parasite in children. More emphasizes are laid on bacterial and viral aetiology of diarrhoea than parasitic agents of disease in children under the age of five years old. Children under the age of five are given inadequate or no attention by most parents. Due to this reason most children tend to eat food/ drink water or have contact with companion animals like dogs, cats, pigs that are either infected or infested with parasites which has led to high prevalence of intestinal parasitosis of children in Northern Nigeria (Hamza and Biu, 2012; Muhammed et al., 2014). This research provides the current prevalence of G. lamblia and other intestinalparasites in children within the range of five years as well as the associated risk factors in Kaduna Metropolis.

1.4    Aim of the Study
The study aimed to determine the prevalence of Giardia lamblia in association with body mass indices in children under 0-5 years presenting with gastroenteritis in Kaduna Metropolis, Nigeria.

1.5    Objectives of the Study
The objectives of the study were to:

1. Detect Giardia lamblia in stool specimen of the study population using microscopy and Giardia ELISA kit.
2. Determine the Body Mass Indices of children 0-5 years presenting with gastroenteritis in relation to giardiasis.
3. Determine the risk factors associated with the cause of giardiasis.
4. Identify other possible intestinal parasites in stool samples of studied population using microscopic examination.