CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Helicobacter pylori (H. Pylori) is a gram-negative microaerophilic bacterium that colonizes the gastric mucosa of more than half of the world’s population with high geographic variability. H. pylori infection is generally acquired during childhood and persists life-long in the absence of treatment with antibiotics. Most of the infected individuals remain asymptomatic for a long period. As a result, long-term colonization of H. pylori can damage the gastric mucosa causing various diseases of the upper gastrointestinal tract such as chronic gastritis, peptic ulcer, and gastric malignancies, particularly gastric cancer and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. H. pylori has been recognized as a Class I carcinogen by the International Agency for Research on Cancer and as one of the strongest known risk factors for gastric malignancies. Approximately 89% of all gastric cancers are attributed to H. pylori infection and the eradication of this infection has known to reduce gastric cancer incidence. Gastric cancer is ranked sixth in incidence ad second in mortality among all cancers worldwide based on the most recent global cancer statistics in 2018 (Ghalia et al., 2019).

1. pylori infection is acquired early in life and has been reported to play a role in the suppression of protective gastric acid barrier in children particularly in the developing countries contributing to the pathogenesis of diarrhea, malnutrition and growth failure (Weaver, 1995). The mechanism by which the organism is transmitted remains controversial. No certain environmental source has been identified (Wizla-Derambure et al. 2001) It has been proposed that humans are the only reservoir for H. pylori (McCallion et al., 1996) and that direct person-to-person transmission is the most likely mode of spread.
2. pylori infection usually has no symptoms but sometimes causes gastritis (stomach inflammation) or ulcers of the stomach or first part of the small intestine the infection is also associated with the development of certain cancers occurring in less than 20% of cases (Laird-Fick et al., 2016).

The routes of transmission of H. pylori have not been clearly identified. Houseflies have been shown to have the potential to transmit the organism mechanically implying poor sanitation is a risk factor for its spread. Transmission from person-to-person and through tubes or endoscopes have been reported. Use of water contaminated with faeces may predispose people to H. pylori infection and if the water source is a municipal water supply, this may potentiate its spread. Factors that have been associated with the acquisition of H. pylori infection include high density crowding, poor sanitary practices, family income, educational level, age, occupation, religion and poor water supply. There is great geographical variation in the prevalence of H. pylori with higher prevalence in developing than in developed countries. Knowledge of H. pylori status is very important in patient management. Diagnosis of H. pylori can be performed through invasive (rapid urease test, histology, culture, and PCR) and non-invasive methods (serological tests, stool antigen test, and urea breath test). The major disadvantage of the invasive tests is that they require endoscopic examination for obtaining the diagnostic sample and hence are difficult to use in epidemiological studies. The stool test demonstrates the presence of antigens while serology detects antibodies to H. pylori. However, serologic tests are limited by false positivity because of cross-reactions. Previous studies have confirmed the superiority of the stool antigen test over serology in terms of true outcomes and cost. There is a paucity of information on the prevalence of H. pylori and associated risk factors in Cameroon. Previous studies in Cameroon reported H. pylori prevalence of 72% (67/93) from biopsies samples with evidence of gastritis and 92.2% from gastric biopsies of patients with gastroduodenal pathologies (Agbor et al., 2018).

In 1982, two Australian researchers, Barry Marshall, a doctor of internal medicine, and Robin Warrren, a bachelor of medicine and bachelor of surgery with a pathology specialty, described the role of H. pylori infection. Leading up to the breakthrough, Dr. Warren had observed small, curved bacteria in the lower stomachs of about half of people who had stomach biopsies. He noticed signs of inflammation in the gastric mucosa (the mucus membrane of the stomach) when these unusual bacteria were present. His colleague, Dr. Marshall was interested in Warren’s research. Together they decided to conduct a study that included biopsies from 100 patients. The results of their experiment showed that a previously unknown bacterium, which was later named H. pylori, was present in nearly all patients with gastric inflammation, intestinal ulcers, and stomach ulcers. The findings led the scientists to conclude that H. pylori was a cause of these intestinal problems and the antibiotics could be an effective treatment. Warren and Marshall’s theory about H. pylori’s function wasn’t immediately accepted in the medical community. At the time, most scientists didn’t believe that bacteria could live in the human stomach. Additionally, researchers thought lifestyle factors, like diet and stress, were to blame for ulcers rather than a bacterial infection. Despite the convincing results, fellow colleagues were reluctant to recognize Warren and Marshall’s findings. The discovery that ulcers were caused by a bacterium and not lifestyle factors drastically changed how doctors approach and treat this condition. Ulcers are no longer considered a long-term debilitating problems that can’t be cured. Now a simple regimen of antibiotics and acid-reducing medicines can eliminate many cases. In a press release, the Nobel Prize Foundation concluded: “Thanks to the pioneering discovery by Marshall and Warren, peptic ulcer disease is no longer a chronic, frequently disabling condition, but a disease that can be cured by a short regimen of antibiotics and acid secretion inhibitors”. Marshall and Warren’s discovery has also prompted research into whether bacteria are possible causes for other conditions, such as Crohn disease, ulcerative colitis, rheumatoid arthritis, and atherosclerosis. At first, the bacterium was named Campylobacter pyloridis. Then it was changed to Campylobacter pylori. In 1989, the gene sequencing revealed that the bacterium didn’t belong in the Campylobacter classification, so it was renamed Helicobacter pylori. “Helico” means “spiral” or “coil” in Greek (Marshall et al., 1984).

This infection tends to be more common in developing countries than in developed countries. The prevalence rate of H. pylori infection in the United States and Canada is approximately 30%, whereas at least 70% of adults in Asia, Africa, Central America, and South America are infected with H. pylori (Howden et al., 2014).

In 2015, it was estimated that over 50% of the world’s population had H. pylori in their upper gastrointestinal tracts with this infection (or colonization) being more common in developing countries. In recent decades, however, the prevalence of H. pylori colonization of the gastrointestinal tract has declined in many countries (Bytzer et al., 2011).

1.2 Statement of the Problem

1. pylori infection remains a public health problem and a major cause of peptic ulcer and gastric, with a prevalence of about 70% in developing countries. H. pylori plays a major etiological factor in the pathogenesis of chronic gastritis, peptic ulcer disease, gastric adenocarcinoma, and mucosa associated lymphoid tissue (MALT) lymphoma. However, most of the infected subjects remain asymptomatic. The aim of this study is to determine the prevalence of H. pylori infection and the associated risk factors among patients attending Buea Regional Hospital, Buea.

1.3 Rationale of the Study

This research will help patients attending Buea Regional Hospital Southwest Region of Cameroon to know their status of H. pylori infection. This research will also enlighten the patients on how to protect themselves from gastritis. This research will also assist the patients on the associated risk factors of H. pylori infection. This research will also help the management of Buea Regional Hospital Southwest Region of Cameroon and the Ministry of Public Health, to know the prevalence and associated risk factors of H. pylori infection among patients attending Buea Regional Hospital Southwest Region of Cameroon so that to give more emphasis of H. pylori infection treatment among patients attending Buea Regional Hospital Southwest Region of Cameroon.

1.4 Research Questions

1. What is the overall prevalence of pylori among patients attending Buea Regional Hospital, Buea?
2. What is the prevalence of pylori among patients attending Buea Regional Hospital, Buea in respect to age and sex?
3. What are the associated risk factors of pylori infections?

1.5 Research Objectives

1.5.1 General Objective

The aim of this study is to determine the prevalence of H. pylori infection and to identify risk factors associated with the infection among patients attending Buea Regional Hospital, Buea Southwest Region of Cameroon.

1.5.2 Specific Objectives

1. To determine the overall prevalence of pylori among patients attending Buea Regional Hospital, Buea
2. To determine the prevalence of pylori with respect to age and sex
3. To determine the associated risk factors of pylori among patients attending Buea Regional Hospital, Buea.