Bad Apple and TB Prevention

Tuberculosis (TB) is a chronic infectious disease of Public Health importance caused by bacteria known as Mycobacterium tuberculosis and affects people in most countries of the world. Almost every organ of the body can be affected but Pulmonary Tuberculosis (PTB) accounts for more than 80% involvement. The commonest symptom of PTB is persistent cough lasting two weeks or more, usually accompanied with one or more of weight loss, malaise, drenching night sweat, loss of appetite, low grade fever, chest pain, dyspnea or hemoptysis.

TB is highly preventable and curable. However, patients are placed on medication for as long as 6-8 months (depending on the drug regimen) and poor compliance results in multiple (MDR) or extreme drug resistance (XDR) TB both of which have very poor prognosis.

Global Situation of Tuberculosis

In 2010, there were 8.8 million incident cases of TB, equivalent to 128 cases per 100 000 population and 1.45 million TB-related deaths globally. About 13% of cases occur among people living with HIV (PLHIV) while 290 000 cases of MDR-TB are estimated to exist.  Most of the estimated number of cases in 2010 occurred in Asia (59%) and Africa (26%); smaller proportions of cases occurred in the Eastern Mediterranean Region (7%), the European Region (5%) and the Region of the Americas (3%). India and China accounted for 40% of the world’s notified cases. 92% of the global TB cases are found in 97 countries most of which are developing countries. 22 countries with 80% of global TB cases were classified as high-TB burden countries (HBC) and have been given priority attention since 2000. In 2009, there were an estimated 9.7 million children who were orphans as a result of parental deaths caused by TB. The disease is also more common among men than women, and affects mostly adults in the economically productive age groups; around two-thirds of cases are estimated to occur among people aged 15–59 years. Treatment success rate among new cases of smear positive pulmonary TB was 87% in 2009.²  

In Nigeria, TB, Malaria and HIV/AIDS are major causes of mortality across all age groups. TB interests me because it’s not just a global disease of public health importance but my country, Nigeria ranks 5^th among the high-TB burden disease countries.²The prevalence of TB is estimated at 199 cases per 100 000, far above the global prevalence.² A Study by GI Pennap et al demonstrated statistically significant relationship between low socioeconomic status and high TB burden in Nasarawa State, Northern Nigeria.³ Lower literacy, higher unemployment, higher poverty index are associated with higher TB incidence. The Fulani (tribe) nomads and communities also drink unpasteurized milk from their cattle accounting for relative high cases of abdominal TB (extra-pulmonary TB).³   The distribution of TB follows similar pattern as HIV/AIDS. In 2006, 30 in every 100 persons living with HIV/AIDS had TB. 4

This poses a monumental task in achieving the Millennium Development Goals (MDGs) of halting and then reversing new TB infections by 2015 relative to 1990 levels.

Etiology of Tuberculosis

Mycobacerium tuberculosis is transmitted from a person with TB disease to another person through inhalation of droplets when such person coughs spits or sneezes. In general, a relatively small proportion of people infected with Mycobacterium tuberculosis will go on to develop TB disease. The risk of exposure depends on presence of a person with untreated PTB or poor ventilation or overcrowded areas; risk of developing TB is much higher among immune-deficient individuals such as People Living with HIV/IDS, systemic illness like diabetes mellitus, patients on cancer chemotherapy, prolonged use of steroids, chronic alcoholism and malnutrition.

As an endemic population, many Nigerians have dormant TB infection which could easily be reactivated. Unhealthy behaviors linked to the high TB burden in Nigeria include but not limited to failure or refusal to immunize children, consumption of unpasteurized milk, indiscriminate abuse of cheap local but unrefined alcoholic drinks, declining of HIV screening by high risk groups, harmful cultural practices like female genital cutting and building of homes without adequate ventilation. The strong presence of some religious faith which campaigns against use of contraceptive devices including condoms and relative weak health system are also contributory.⁵

TB Prevention: 'Bad Apple' vs 'Curve Shifters'

Huge financial resources are being committed annually by TB endemic countries and the global community in diagnosis and treatment of TB disease. Ironically, most of the highly endemic countries are among the world’s poorest countries. Among 97 countries for which trends can be assessed since 2006, funding is expected to reach US$ 4.4 billion in 2012, an increase from  US$3.5 billion in 2006.² All these money are being spent on diagnosis and treatment of cases which is the main focus of the World Health Organization (WHO) Stop TB Strategy. This is a ‘Bad Apple’ approach as such huge amount of money is being utilized to control TB among a population at the tail of the Geoffrey Rose Curve. 

The Rose Curve is a graphical representation of a group or population distribution of a health behavior of interest. It is a quadratic curve with the level of health-related behavior on the horizontal axis and the percentage population with that behavior on the vertical axis. It depicts that a small percentage of the population are at both extremes of a health-related behavior while most people are near the average point. This curve can be plotted for various health-related behaviors such as salt consumption, drinking habit, sexual behavior, exercising, personal hygiene, smoking habit, vaccination against infectious diseases, etc. According to Tom Farley & Deborah Cohen - two public health experts, disease control strategies using diagnosis and treatment have over the years proven not very effective as they target the small high risk population while more deaths are recorded among the majority apparently not-at-risk population. Individual health-related behaviors may fall on any side of the curve while that of the group is represented by the entire curve.¹ The “curve shifters” refer to four key features that affect the environment and influence the daily behavior and norms of a population and can be used to achieve a healthy behavioral change in a whole population. 

WHO admitted in her 2011 report that MDG target for TB cannot be attained in 2015 especially in the African Region. Rather than spending so much on a less successful curative approach, I strongly feel a better result would be achieved should Nigeria and other countries with similar health system create a better environment and promote healthy behavioral pattern using the Farley & Cohen "curve shifters" as described below;  

Accessibility: The Nigerian government has a policy of free vaccination of all children less than 5 years against preventable endemic diseases including TB.  However, the vaccines are only free in government-owned health facilities. The rural population most of who live below one dollar per day cannot afford to pay for vaccination. Accessibility to BCG vaccine can be increased if the government builds more health centers and/or partner(s) with the private local health centers closer to underserved population to provide free vaccination services. Malnutrition is one of the commonest causes of Under-5 mortality in Nigeria and a significant portion die from TB infection. Many rural dwellers are subsistence farmers but their farm produce perish due to lack of proper preservation. Food can be made more available and accessible if modern preservation methods are provided. Pasteurized milk should be subsidized and accessibility increased by states of the Fulani tribes.   Free condoms should be made more accessible by installing Condom dispensers in clinics, tertiary institutions and public places like hotels, supermarkets and motor parks. This would reduce risk directly of HIV and opportunistic TB infection indirectly.

On the other hand, accessibility to alcohol and tobacco use should be restricted.

Physical Structures: A Study to determine the factors responsible for the high incidence of TB among children who received BCG vaccination in Okposi, South East Nigeria, found that the vaccines lost potency because the cold chain was not maintained by the local health facility.⁶ As a country with irregular supply of electricity, solar powered refrigerators should be provided to all health facilities while government intensifies efforts to stabilize power supply by building more power stations. Some people complain they don’t enjoy sex with the use of condoms. Making condoms thinner and more sensitive can increase its utilization.  Building of physical infrastructure like good roads, potable water supply and electricity in most communities would accelerate development, promote economic activities and reduce unemployment and poverty. More housing should be provided to prevent overcrowding in highly populated cities.

Social Structure: With increased accessibility to BCG vaccine, a law or policy that would make refusal or failure to vaccinate children a punishable offense and can be helpful. Promotion of community participation in health promotion by strengthening the link between the local community associations to the public health institutions through relevant policies can improve compliance with existing policies that promote healthy behavioral change.

Imposition of heavy tax on the cheap local alcoholic spirits which are mostly abused will reduce its consumption. Indoor, outdoor or workplace smoking bans can be implemented by states and local health authorities. Policies that provide minimum acceptable house standard allowing proper ventilation in buildings should be enacted and enforced especially in the rural areas.

Media: A major challenge in acceptance of immunization was a misinformation that led to the rejection of vaccines by some families. Community and religious leaders and their followers can be more educated through a combination of direct engagement and use of local ‘town-criers’, print and electronic media to promote vaccination and other healthy behaviors in the community. Pornography in prints and electronic media should be reduced to the barest minimum to check indiscriminate sex and HIV transmission. 

In conclusion, the WHO Stop TB Strategy would record more success if Nigeria and other high-TB countries if more money is voted into providing physical and social environments that would improve the socio-economic status and consequently promote healthy behavior of the people using the "curve shifters" as discussed above. Efforts on treatment of diagnosed cases and prevention of HIV  and other chronic diseases should be sustained as they are not mutually exclusive. 

References

11. Tom Farley and Deborah A. Cohen, Prescription for a Healthy Nation. Beacon Press, Boston, MA. ©2005

22. World Health Organization; WHO Report 2011, Global Tuberculosis Control

33. G. I. Pennap, S. Makpa & S. Ogbu – Prevalence of HIV/AIDS among Tuberculosis Patients in a rural community in Northern Nigeria. Trakia Journal of Sciences, Vol. 9, No2, pp 40-44, 2011, Copyright © 2011 Trakia University

44. Nigerian Federal Ministry of Health, National TB & Leprosy Control Program; 2006 National TB Sentinel Survey

55. Family Health International; Community TB Care in Nigeria: a project review, ©2009 fhi

66. Ndukwe, S.O, et al; Factors responsible for the Incidence of TB among Children who received BCG Vaccination in Okposi, South East Nigeria; National Postgraduate Medical Journal (Public Health Edition) 2004