CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND OF THE STUDY

Tuberculosis (TB) is a contagious, infectious disease, due to Mycobacterium tuberculosis (MT), which usually lasts throughout the life course and determines the formation of tubercles in different parts of the body [1]. MT has very ancient origins: it has survived over 70,000 years and it currently infects nearly 2 billion people worldwide [2]; with around 10.4 million new cases of TB each year, almost one third of the world’s population are carriers of the TB bacillus and are at risk for developing active disease [3]. TB has always been associated with a high mortality rate over the centuries, and also nowadays, it is estimated to be responsible for 1.4 million TB deaths, among infectious diseases after human immunodeficiency virus (HIV) [3]. Due to its infectious nature, complex immunological response, chronic progression and the need for long-term treatment, TB has always been a major health burden; in more recent years, the appearance of multi-drug resistant forms and the current TB-HIV epidemic, associated with its severe social implications, treating and preventing TB have represented a permanent challenge over the course of human history [4, 5].

        The ability of Mycobacterium tuberculosis (MTB) to acquire mutations that result in resistance to antituberculosis drugs was described when the very first clinical trial with streptomycin was conducted 70 years ago [1]. Unfortunately, we have allowed the bacillus to mutate to a practically untreatable form through the selective pressure of inadequate treatment regimens administered by national tuberculosis (TB) programs that are poorly structured and implemented [2]. Worldwide resistance to antituberculosis drugs is preventing the control and eventual eradication of TB, which is still a leading cause of death globally (3). The World Health Organization (WHO) estimated that globally in 2015 there were 580 000 new cases of multidrug-resistant TB (MDR-TB, that is, with simultaneous resistance to at least rifampin and isoniazid) or rifampin-resistant TB (RR-TB), but only 125 000 of them (20%) were diagnosed and reported. It is also estimated that 250 000 patients died from MDR-TB/RR-TB in 2015. According to the WHO 2016 Global Tuberculosis Report (4), in 2015, 3.9% of new TB cases and 21% of previously treated cases had MDR-TB/RR-TB; approximately 9.5% of those had extensively drug-resistant TB (XDR-TB, that is, with resistance to at least rifampin, isoniazid, any fluoroquinolone, and any second-line injectables). Even more serious, XDR-TB strains have now mutated to what has been called totally drug-resistant TB (TDR-TB), which represents the most extreme form of drug resistance. Patients with TDR-TB harbor strains that are resistant to all the drugs for which we have the ability to test in a mycobacterial laboratory. The WHO has recommended avoiding the use of the TDR-TB term since these patients still might have one or two “usable drugs” available for treatment. The term recommended by the WHO for these patients is resistance beyond extensively drug-resistant tuberculosis [2]. Highly resistant MTB strains (MDR, XDR, and beyond XDR) will be transmitted in the community, leading to treatment failure when these new cases are treated empirically with a combined regimen of the first-line drugs (5). MDR-TB and XDR-TB require treatment with drugs that are generally less effective, more toxic, and considerably more expensive than first-line drugs; in addition, treatment must be prolonged for 18 to 24 months. This reduced efficacy and increased costs of drug regimens make the treatment of MDR-TB/XDR-TB virtually unaffordable to TB programs in countries with limited resources, which, almost without exception, have the highest rates of drug-resistant TB [6].

1.2 STATEMENT OF THE PROBLEM

According to the WHO 2016 report [4], globally, only 57% of the pulmonary cases reported to WHO were bacteriologically confirmed. The undiagnosed cases, including ones caused by drug-resistant strains, will go untreated and will transmit the disease in the community mainly because on non-adherence to first line tuberculosis treatment. An urgent priority is to diagnose all cases as early as possible, including those that are drug resistant, and treat them until they are cured. Therefore, an imperative in everyday practice is to diagnose tuberculosis and rule out drug resistance as quickly and as accurately as possible. This will require an increase in laboratory capacity in every country in order to allow the detection of drug resistance to first- and second-line drugs in every case of TB. In fact, one of the core components of the WHO post-2015 End TB Strategy is universal drug susceptibility testing (DST). It is to this regard that the study is based on drug adherence to first line tuberculosis treatment.

1.3 AIM AND OBJECTIVES OF THE STUDY

The study seeks to examine drug adherence to first line tuberculosis treatment. The objectives of the study are:

1. To determine the causes and mode of transmission of tuberculosis
2. To ascertrain the level of tuberculosis burdern in Nigeria
3. To determine the need for drug adherence to first line tuberculosis treatment
4. To recommend preventive measure for the spread of tuberculosis in Nigeria

1.4 RESEARCH QUESTIONS

The following research questions guide the objectives of the study:

1. What are the causes and mode of transmission of tuberculosis?
2. What is the level of tuberculosis burdern in Nigeria?
3. Is there need for drug adherence to first line tuberculosis treatment?
4. What are preventive measure for the spread of tuberculosis in Nigeria?

1.5 STATEMENT OF THE HYPOTHESIS

H0: drug adherence to first line tuberculosis treatment is not satisfactory

H1: drug adherence to first line tuberculosis treatment is satisfactory

1.6 SIGNIFICANCE OF THE STUDY

The study on drug adherence to first line tuberculosis treatment will be of immense help to the entire health sector in Nigeria towards the preventive measure for the control of tuberculosis. The study findings of the study will highlight the causes and mode of transmission of tuberculosis. The study will also serve as a source of information to higher institutions and other researchers and contribute to the body of the existing literature on drug adherence to first line tuberculosis treatment.

1.7 SCOPE OF THE STUDY

The study covers on drug adherence to first line tuberculosis treatment

1.8 LIMITATION OF THE STUDY

TIME CONSTRAINTS: One the challenges experienced by the researcher is the issue of time; the research will simultaneously engage in departmental activities like seminars and attendance to lectures. But the researcher was able to meet up with the deadline for the submission of the project.

FINANCIAL CONSTRAINTS: Every research work needs funding; however lack of adequate funds might affect the speed of the researcher in getting materials for completion of the project

1.9 DEFINITION OF TERMS

TUBERCULOSIS: Tuberculosis (TB) is a potentially serious infectious disease that mainly affects the lungs. The bacteria that cause tuberculosis are spread from person to person through tiny droplets released into the air via coughs and sneezes

DRUG ADHERENCE: Medication adherence is typically defined as a ratio of the number of drug doses taken to the number of doses prescribed over a given time period, eg, as the medication possession ratio (MPR)