Executive Summary
Among all infectious diseases, tuberculosis is the leading cause of death worldwide, and Nigeria is among the states characterized by the highest burden of this infection. While tuberculosis is especially prevalent in patients with HIV and other immune system impairments, there are many other risk factors contributing to the development of the infection. They include such unhealthy behaviors as smoking and unfavorable life conditions resulting in increased exposure to Mycobacterium tuberculosis, malnutrition, and overall poor health status. Considering that the treatment of different forms of the disease is costly yet it affects poor populations most, it is pivotal to invest in its prevention through awareness-raising campaigns and promotion of screening.
Introduction
Among different infectious diseases, tuberculosis is a leading cause of mortality on the global scale and its various forms, including the drug-resistant ones, pose a significant threat to public health and security. Whereas every country in the world is affected by tuberculosis, Nigeria is among the states where the prevalence of this disease is especially high. A high rate of death due to tuberculosis has multiple economic and social implications, which make it pivotal to address this public health issue urgently and with the help of effective methods.
Considering this, the present policy brief will discuss the nature of the infection, its risk factors and the populations it affects most, the scope of infection spread in Nigeria, and the consequences of the problem in order to demonstrate why the intervention of tuberculosis on the national scale is important. The final section of the brief will outline a few evidence-based action steps that could be used to alleviate the burden of this infectious disease in the country.
Nature and Magnitude
Tuberculosis is an airborne disease caused by a pathogen known as Mycobacterium tuberculosis. The main distinguishing feature of the etiological agent of the disease is that “it can persist in the host during long-term latency without causing significant damage or transmission unless the host immunity is compromised” (Chai et al. 2). It means that even though the pathogen may be present in the host’s body for the long term, it causes actual disease and serious complications only in a relatively small number of cases (Cardona 2).
However, in an active phase of infection, M. tuberculosis affects the lungs and leads to a multitude of pulmonary symptoms. They include coughing, breathlessness, and chest pains, which may considerably range in severity and increase the risk of mortality due to respiratory problems (Fogel 527; Ravimohan et al. 1).
It is worth noting that tuberculosis can be either drug-susceptible or drug-resistant. The treatment of the former type of the infection is usually highly effective, “with 85% (66 million cases) of reported cases estimated to have been successfully treated between 1995 and 2015” (Ravimohan et al. 1). The treatment of the latter form of tuberculosis that can be non-responsive to either isoniazid or/and rifampicin, two antibiotic drugs commonly utilized in the course of pharmacological intervention for this infection, is usually more complicated, toxic, costly, and prolonged (Onyedum et al. e0180996). These characteristics of the second-line tuberculosis treatment make the prevention of the infection essential.
The scope of the public health emergency due to infection with M. tuberculosis is significant. In 2014, 1.5 million individuals died and 9.6 million persons fell ill due to this disease worldwide (Hassan et al. 1). As for Nigeria, the country is currently ranked the 4th most contributing to the global tuberculosis burden, with only India, Indonesia, and China outperforming it in this regard (Hassan et al. 1). The total number of diagnosed tuberculosis cases in Nigeria equated to 90,584 in 2015 (Hassan et al. 1).
In 2012, the prevalence rate of all forms of the infection was 323 per 100,000 of the population and the incidence rate of 338 per 100,000 (Hassan et al. 1). As the study by Onyedum et al. revealed, the prevalence of drug-resistant tuberculosis among all diagnosed patients ranges between 32% and 53% (e0180996). As reported by Adebisi et al. (2019), of multi-drug resistant 93,000 cases that took place in West Africa in 2016, 20,000 occurred in Nigeria (3).
These numbers make Nigeria the leading country in terms of all types of tuberculosis incidence in the African region. The high prevalence of drug-resistant tuberculosis can become one of the major factors that would slow down the progress in the eradication of this disease in Nigeria.
Affected Populations
Like in the case with many other disorders, tuberculosis affects different population groups unequally. According to Fogel, younger adults, especially males, healthcare workers who deal with the infection regularly, people with compromised immune systems, and those with human immunodeficiency virus (HIV) are susceptible to the disease more than others (528). According to the World Health Organization, mortality and morbidity due to tuberculosis are indeed higher in young adult men than in women: in 2017, nearly 6 million men fell ill due to the infection worldwide and 840,000 died (“Tuberculosis and Gender”).
In contrast, only 3.2 million adult women fell ill and about 500,000 died the same year (World Health Organization, “Tuberculosis and Gender”). Similarly, in Nigeria, the age groups of 25-34 and 35-44 were affected by the disease the most in 2018 (World Health Organization, Nigeria 1). Besides, 58% of new tuberculosis diagnoses that year occurred in the male population and only 34% in the female population (World Health Organization, Nigeria 1).
Noteworthily, the majority of affected healthcare practitioners frequently working with infected patients tend to be males as well. The study by Kehinde et al. revealed that among 271 employees (43.2% males and 56.8% females) of the centers specialized in the treatment of tuberculosis in Nigeria, 6 were positive for culture and all of them were men (613). Besides, approximately half of the individuals with positive acid-fast bacilli samples identified in the study (n=9) worked there for over five years (Kehinde et al. 613). It means that the duration of one’s employment in tuberculosis-related facilities seems to be a contributing factor as well since it is associated with increased exposure to M. tuberculosis pathogens.
Lastly, the high prevalence of tuberculosis in Nigeria is closely linked to the high prevalence of HIV. According to Chang et al., “tuberculosis is the leading cause of mortality among HIV-infected persons in Africa,” and the risk of having tuberculosis is about 20 times higher in patients with HIV than in non-infected individuals (1). It is observed that of 50,320 adult patients with HIV who participated in President’s Emergency Plan for AIDS Relief (PEPFAR) and the Harvard/AIDS Prevention Initiative in Nigeria (APIN) from 2005 to 2010, 11,092 (22%) were diagnosed with an active form of tuberculosis prior to the administration of antiretroviral therapy (ART) (Chang et al. 1).
Besides, 2,021 program participants were diagnosed with tuberculosis even after the initiation of ART (Chang et al. 1). These findings verify the assumption about the susceptibility of immunodeficient persons to the negative impacts of M. tuberculosis.
Risk Factors
Besides improper functions of the immune system, other risk factors that may contribute to the development of active tuberculosis are associated with poor living conditions, unhealthy lifestyles, and overall health status. For instance, along with HIV, such disorders as diabetes, silicosis, rheumatoid arthritis, and some other chronic illnesses frequently have tuberculosis as their co-morbidity (Duarte et al. 116). However, such lifestyle-related and environmental factors as malnutrition and smoking are considered to contribute to the disease progression even more than HIV and chronic disorders in some populations.
For instance, 27% of tuberculosis cases are attributed to poor nutrition in 22 countries with a high prevalence of this disease (Duarte et al. 116). At the same time, smoking may be responsible for 23% of cases of the infection in those states (Duarte et al. 116). Overall, it is valid to say that unhealthy lifestyles and poor living conditions are both closely interrelated with general social-economic factors. People living in poverty are frequently exposed to environmental hazards, lack access to healthy food options, and may tend to adopt unhealthy behaviors dominant in their communities.
The abovementioned assumption is verified by the findings of a study conducted by Iroezindu et al. in a sample of 339 HIV-positive individuals receiving ART in Nigeria (120). Iroezindu et al. revealed that the majority of HIV patients with tuberculosis belonged to a lower social class (120). Overall, besides undernutrition and propensity to engage in risky and unhealthy behaviors, a possible reason why people living in socio-economic deprivation an in overpopulated areas are at a higher risk of tuberculosis is that they tend to contact already infected individuals more often than those living in higher social classes (Duarte et al. 117).
However, non-adherence to ART, the presence of anemia, and previous history of tuberculosis were positively correlated with the development of infection in HIV-positive persons in the study by Iroezindu et al. as well (120). Thus, the health status of individuals plays a crucial role in one’s ability to withstand the onset of the disease and, in turn, can be defined by a combination of several environmental and behavioral factors.
Economic and Social Consequences
Tuberculosis and its poor management lead to an excess in various types of economic and social costs. The most obvious and direct ones are associated with the treatment of the infection, and it is valid to say that the economic burden of the disease is especially high in developing countries. For instance, in India, the leader in terms of the infection incidence, direct costs (drugs, hospital visits, hospitalization, and so forth) induced by disease care per individual equate to US $195 on average (Prasanna et al. 1).
In addition, a mean amount of indirect costs of care, including changes in income, loss of productivity, loss of savings, and so forth, equals approximately US $50.2 per person (Prasanna et al. 1). It means that regardless of whether these costs are covered by the public health insurance or are paid from patients’ pockets, the total yearly amount needed to cover tuberculosis-related healthcare expenses in high-burden states is immense.
Considering that the prevalence of the infection is particularly high in lower-income households, it is impossible to ignore the devastating economic impact of the disease on economically deprived families and individuals. For instance, among 102 Indian patients studied by Prasanna et al., about 32% experienced catastrophic costs due to tuberculosis treatment (1). At the same time, the national study with a significantly larger sample size conducted in Nigeria revealed that “at least 71% of the [tuberculosis]-affected households face catastrophic financial burdens as a result of the disease” (World Health Organization, “Nigeria Study”). Noteworthily, the impact is more severe in the case of drug-resistant tuberculosis.
While the drug-susceptible form of the infection leads to catastrophic costs in 69% of patients, multi-drug resistant infection negatively and seriously affected the economic status of 89% of diagnosed persons in the country (World Health Organization, Nigeria Study). The major reason for such a substantial adverse impact is that about 60% of all Nigerian patients with tuberculosis live below the poverty level (World Health Organization, “Nigeria Study”). This factor not only interferes with individuals’ ability to receive high-quality care but also threatens their overall long-term welfare since, due to infection-associated morbidity, they cannot engage in professional activities and earn money to sustain their existence.
Besides the risk of job loss and drop-out from schools, tuberculosis has severe negative effects on individuals’ quality of life and psychological well-being. The study by Brown et al. revealed that depression and anxiety symptoms are frequently observed in patients with tuberculosis and are particularly pronounced in those with multi-drug resistant forms of the infection (73). Combined with such potential negative and irreversible consequences of the disease as hearing loss and neuropathies, psychological consequences of tuberculosis interfere with one’s functioning, reduce their ability to perform daily activities, and may contribute to the deterioration of relationships with others (Brown et al. 73; Onazi et al. 131).
Overall, direct and indirect costs of tuberculosis are diverse and significant since the disease influences multiple spheres of patients’ lives simultaneously. At the same time, it is valid to conclude that by interfering with individuals’ capability to perform, the infection inhibits the economic development of the country since psychological and physiological morbidity leads to reduced functionality and, thus, is linked to low productivity rates and increased absenteeism.
Priority Action Steps
To eradicate tuberculosis in Nigeria, efforts must be directed at the prevention of the disease through awareness-raising activities and promotion of screening. Firstly, it is important to provide high-risk populations with greater opportunities for screening and promote this practice among them. Screening allows detecting tuberculosis in the latent stages of its development and undertaking timely measures to prevent it from transition into the active and contagious ones (Bloch). In this way, it will be possible to minimize the costs associated with the treatment of the infection.
Secondly, knowledge of risk factors contributing to the development of tuberculosis, as well as positive individual and public attitudes to this infection, are considered to be linked to engagement in protective behaviors and favorable perceptions of such preventive practices as screening (Kasa et al. 1). In contrast, the lack of knowledge and tuberculosis-related stigma characterized by perceived incurability, beliefs in myths about the etymology of the infection, and negative views on associations of tuberculosis with HIV often result in non-disclosure of the disease, non-compliance with treatment, low self-esteem, ridicule, social exclusion, and so forth (Cremers et al. e0119861).
It means that poor understanding of the origins and pathophysiology of tuberculosis and adverse attitudes to it increase individuals’ risk of infection and contribute to its spread through improper compliance with treatment or the lack of thereof. Thus, public education campaigns aimed to promote the knowledge of the disease and reduce the related stigma will assist in the prevention efforts. For better effects, it is essential to include information about such manageable exacerbating risks of tuberculosis as smoking, malnutrition, and access to health services to motivate individuals to adopt healthier behaviors.
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