CHAPTER ONE: INTRODUCTION

1.1 Background

Gastrointestinal parasites are micro-organisms that live in the intestine, some cause problems while others can live for long periods in the bowel without causing any symptoms or require treatment [1]. Parasitic infections remain a critical public health concern worldwide, disproportionately affecting vulnerable populations, particularly children in low and middle-income countries [2]. These infections, caused by protozoa and helminths, lead to significant morbidity and mortality, contributing to malnutrition, anemia, stunted growth, impaired cognitive development, and reduced school performance among children [2]. Parasitic infections have worldwide distribution, but are mostly prevalent and endemic in tropical and subtropical countries, particularly in rural communities with poor sanitation [3].  The World Health Organization (WHO) recommends treating all school children at regular intervals with deworming drugs in areas where helminth infection is common [4]. Intestinal parasitic infections are among the most neglected tropical diseases, causing over 3.5 billion infections and significant morbidity in about 450 million people [5]. They can be largely categorized into two groups, protozoans (e.g. Entamoeba histolytical, Giardia duodenalis, Trichomonas horminis, Balatidium coli etc) and helminthes (e.g. Ascaris lumobricoides, Trichuris trichiura, Nesator americanus etc). These gastrointestinal parasites (GIPs) flourish in settings characterized by warm temperature, humidity, poor sanitation, dirty water and crowded housing [1].

Globally, parasitic infections are widespread, with over 1.5 billion people affected by soil-transmitted helminths (STHs) such as Ascaris lumbricoides, Trichuris trichiura, and hookworms, as of 2020 [6]. The WHO estimates that more than 267 million preschool-aged children and over 568 million school-aged children require preventive chemotherapy for parasitic infections annually [6]. More than 50% of the population has Intestinal parasitic infections (IPIs) in some of the regions of Sub-Saharan Africa (SSA) [7]. Giardia lamblia, E. histolytica, and cryptosporidium are the most common intestinal protozoal infections in developing countries. In developed countries, IPIs are more common than intestinal helminthic infections (IHIs) [7]. In the United States, Giardia lamblia, Cryptosporidium parvum, Blastocystis spp., Cyclospora cayetanensis, Cystoisospora belli, and Entamoeba histolytica are the common intestinal protozoal infections, and Enterobius vermicularis is the most prevalent helminthic infection [7].

 Protozoal parasites, especially cryptosporidiosis and giardiasis, cause diarrhoea and contribute to impaired growth, neurocognitive development and mortality. Entamoeba histolytica causes dysentery and may have subtler effects on child growth [8]. Helminth infections, including hookworm (Necator americanus, Ancylostoma duedenale), roundworm (Ascaris lumbricoides), and whipworm (Trichuris trichiura), collectively known as intestinal (or soil) transmitted helminths, as well as schistosomiasis, are among the most common infections found in children worldwide, infecting almost 2 billion people [9]. Schistosomiasis, a neglected tropical disease (NTD) of poverty ranks second among the most widespread parasitic disease in various nations in sub-Saharan Africa [10]. These diseases are causes of about 534,000 deaths annually in sub-Saharan Africa [10]. Similarly, over 400 million individuals in Africa are infected with soil-transmitted helminths (STHs), with school-aged children being the most vulnerable [11].

Cameroon, like many sub-Saharan African countries, is endemic to a variety of parasitic infections, including, STHs, schistosomiasis, and lymphatic filariasis [12]. STHs also pose a major challenge, with studies showing infection rates ranging from 25% to 75% among school-aged children, depending on the region [12]. The burden of parasitic infections is worsened in rural areas where resources are limited [13]. A study conducted in the Northwest Region in 2018 by Sama et al. found that IPIs were prevalent among school-aged children, with an overall prevalence of 35.6%, and higher rates in rural schools compared to urban ones [13]. Ascaris lumbricoides, Trichuris trichiura, and hookworms were the most commonly identified helminths, while Giardia lamblia was a leading protozoan parasite [14]. The majority of these infections occur in vulnerable groups in association with limited healthcare, poor nutrition, and poverty, a low level of community and personal hygiene, and limited access to safe water or sanitary facilities [15-18].

An intestinal protozoan is transmitted by the fecal-oral route (soiled hands, ingestion of food or water contaminated with feces) and exhibits a life cycle consisting of a cyst stage and a trophozoite stage [19,20]. This study aims at determining the prevalence and risk factors associated with gastrointestinal protozoans amongst school aged children living in some rural and urban districts of Bamenda, in order to contribute to existing data on the epidemiology of protozoans in Cameroon, and make recommendations for further regional and nationwide control programs.

1.2 Statement of the problem

Parasitic infections are a major health issue in Cameroon, especially among school-aged children. In 2017 [8], a nationwide study revealed that soil-transmitted helminths (STHs) are widespread, with rural areas being heavily affected. The Northwest Region, including Bamenda, has high prevalence rates of 25% to 75% for intestinal parasites [13, 14]. Studies found that helminths like Ascaris lumbricoides, Trichuris trichiura, and hookworms are common among school-aged children, particularly in rural areas where behaviors like walking barefoot and poor hygiene increase risk [12]. However, there is limited data comparing the burden of infections in Bamenda’s urban and rural health districts. This study aims to address this gap by determining the prevalence, common types, and risk factors of gastrointestinal parasitic infections in school-aged children in four schools in both urban and rural districts of Bamenda.

1.3 Research questions

1.3.1 Main research question

What is the prevalence and risk factors associated with gastrointestinal parasitic infections among school-aged children in four selected schools across both urban and rural health districts of Bamenda?

1.3.2 Specific research questions

1. What is the prevalence of parasitic infections among school-aged children in four selected schools across both urban and rural health districts of Bamenda
2. What are the most common types of parasitic infections affecting school-aged children in four selected schools across both urban and rural health districts of Bamenda?
3. What are the risk factors associated with parasitic infections among school-aged children in four selected schools across both urban and rural health districts of Bamenda?

1.4   Hypothesis

 1.4.1 Null hypothesis

There is a low prevalence and few risk factors associated with gastrointestinal parasitic infections among school-aged children in four selected schools across both urban and rural health districts of Bamenda.

 1.4.2 Alternative hypothesis

There is a high prevalence and high-risk factors associated with gastrointestinal parasitic infections among school-aged children in four selected schools across both urban and rural health districts of Bamenda.

1.5 Objective of the study

1.5.1 Main objective

To determine the prevalence and assess associated risk factors of gastrointestinal parasitic infections among school-aged children in four selected schools across both urban and rural health districts of Bamenda.

1.5.2 Specific objectives

1. To determine the prevalence of gastrointestinal parasitic infections among school-aged children in four selected schools across both urban and rural health districts of Bamenda.
2. To identify the most common types of gastrointestinal parasitic infections among school-aged children in four selected schools across both urban and rural health districts of Bamenda.
3. To identify the risk factors associated with gastrointestinal parasitic infections among school-aged children in four selected schools across both urban and rural health districts of Bamenda.