- Email: [email protected]
The trend of pulmonary tuberculosis in patients seen at DOTS clinics in the Federal Capital Territory, Abuja, Nigeria
Public Health (2005) 119, 405–408
The trend of pulmonary tuberculosis in patients seen at DOTS clinics in the Federal Capital Territory, Abuja, Nigeria E.B. Basseya,*, M.A. Momoha, S.O. Imadiyia, E.B. Udofiab, F.S. Miria, K.C. Anukamc, J. Epoked, M.O. Benka-Cokere, H.S.A. Aluyie a
Department of Medical Laboratory Services, Wuse General Hospital, P. O. Box 2352, Garki, Abuja, Nigeria Department of Medicine, Maitama District Hospital, Abuja, Nigeria c Department of Pharmaceutical Microbiology, University of Benin, Benin City, Nigeria d Department of Medical Microbiology and Parasitology, University of Calabar, Cross River State, Nigeria e Department of Microbiology, University of Benin, Benin City, Nigeria b
Received 9 February 2004; received in revised form 14 April 2004; accepted 13 May 2004
KEYWORDS AFB positive; Follow-up; DOTS; Tuberculosis; Diagnosis
Summary We evaluated the pattern of sputum smear positivity and assessed the effects of directly observed treatment short course (DOTS) among tuberculosis (TB) patients at the DOTS clinics in the Federal Capital Territory (FCT), Abuja. In total, 1391 patients were seen at six microscopy and treatment centres across the FCT between January and December 2003. Their sputa were screened microscopically for the presence of acid-fast bacilli (AFB) using the Ziehl-Neelsen staining technique. In total, 296 (21.3%) patients were smear positive; 201 (67.9%) were new cases and 95 (32.1%) were follow-up cases. The highest incidence of sputum smear positivity (24.8%) was found in those aged 21-30 years and the lowest incidence (6%) was found in those aged 71 years and above. No incidence of smear positivity was recorded in children aged 0-10 years. In total, 160 of the men screened were AFB positive (75% new cases, 25% follow-up cases). In comparison, 136 women were AFB positive (59.6% new cases, 40.4% follow-up cases). During the 1-year study period, two deaths were recorded. Men pose a serious threat to public health as most of the follow-up cases result in the tubercle bacilli developing resistance to available anti-TB drugs. This study demonstrated a high prevalence of infectious TB in the population screened, and therefore underlines the need for capacity building through a multisectoral approach in the fight against the disease. Cohort analysis should be the cardinal management strategy in evaluating the effectiveness of TB control through systemic follow-up and reporting of certain indicators in treatment progress and success. Q 2004 The Royal Institute of Public Health. Published by Elsevier Ltd. All rights reserved.
* Corresponding author E-mail address: [email protected] (E.B. Bassey). 0033-3506/$ - see front matter Q 2004 The Royal Institute of Public Health. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.puhe.2004.05.012
406
Introduction In 1993, the World Health Organization (WHO) declared tuberculosis (TB) to be a global emergency.1 This was the first such declaration to be made by the organization. Infectious disease remains the largest cause of illness and death in the world, and TB is responsible for the greatest number of deaths among all infectious diseases.2 It is estimated that Mycobacterium tuberculosis has infected one-third of the world’s 6 billion population and about 3 million people die of TB every year.1 The WHO has estimated that about 5000 people die of the disease and 20 000 are newly infected daily.1 In Nigeria, which ranks fourth in the world for TB incidence, over 300 000 new cases of TB and 30,000 deaths occur annually.2 As such, the National Tuberculosis and Leprosy Control Programme (NTBLCP) set up directly observed treatment short course (DOTS) and microscopy centres in the Federal Capital Territory (FCT), Abuja in 2003. These centres were established to identify, diagnose, categorize and treat all smear-positive TB patients. In Nigeria, direct microscopic examination of appropriately stained sputum specimens for tubercle bacilli is the cornerstone of TB diagnosis. The technique is simple, inexpensive, reliable and suitable in poor resource settings. Culture facilities are only available at two centres in Nigeria. This new strategy has proven to be cost effective for treatment of TB. Through a combination of technical and managerial components, DOTS makes infectious cases non-infectious, thereby breaking the cycle of transmission. DOTS also prevents the development of drug-resistant strains of TB that are often fatal and most expensive to treat.3 The aim of this study was to evaluate the trend of pulmonary TB and the effect of DOTS measures adopted by the NTBLCP in the FCT.
E.B. Bassey et al. carried out using the Ziehl–Neelsen sputum method. The sensitivity of this method varies and is dependent upon collection of good-quality sputum, smearing, staining and careful examination of smears. Bleach-treated samples lose resemblance to sputum samples and are less aesthetically offensive to laboratory scientists. The bleach sediment smear method is safer as the sputum is rendered sterile and the bleachtreated samples can be disposed of easily with other hospital waste. This can improve the yield of acid-fast bacilli (AFB). At least 300 visual fields were examined with 100! magnification using light microscopy. All TB-positive cases were promptly referred to the treatment clinics and followed-up within 2 months of intensive treatment. Two early morning sputum samples were obtained from patients who failed to respond to intensive treatment and examined for AFB.
Results Sputum samples were obtained from 1391 patients at the DOTS clinics of the NTBLCP, scattered across all the area councils in the FCT, Abuja, and examined for evidence of AFB. In total, 296 patients were AFB positive using the Ziehl–Neelsen staining method. Of these, 160 (54.1%) were male and 136 (45.9%) were female. Table 1 shows the differences in incidence between the genders. In total, 201 (67.9%) patients were new cases and 95 (32.1) were follow-up cases. Two deaths were recorded during the 1-year study (Table 2). The highest number of smear-positive patients was found in those aged 21–30 years (24.8%), and the lowest incidence was in those aged 71 years or more (10.3%). No incidence was recorded in children aged 0–10 years (Table 3). The number of smear-positive cases also varied depending on the occupation of the patients.
Methods This study was conducted in six DOTS and microcopy centres in the FCT between January and December 2003. Subjects were recruited from those attending DOTS clinics who fulfilled the inclusion criteria. Three separate freshly expectorated sputum samples (5 ml) were collected within 48 h as follows: first sample was collected in the first visit, the second sample was collected early morning, and the third spot sample when the patient brought in the early morning sample. Direct smear examination was
Table 1 Sex distribution of smear positivity among patients seen at the DOTS clinics (nZ1391). Centres
Male
Female
Positivity
Asokoro (nZ310) Gwagwalada (nZ184) Kubwa (nZ205) Kwali (nZ220) Maitama (nZ346) Nyanya (nZ126) Total: 1391
36 26 13 28 41 16
26 18 14 20 35 23
62 44 27 48 76 39
Pulmonary TB at DOTS clinics in Nigeria
407
Table 2 Percentage distribution of smear positivity among patients attending DOTS clinics.
Male Female Total
No. (%)
New cases (%)
Followup (%)
Death
160 (54.1) 136 (45.9) 296 (21.3)
120 (75.0) 81 (59.6) 201 (67.9)
40 (25.0) 55 (40.4) 95 (32.1)
2 (1.1) 0 (0) 2 (1.1)
The highest incidence was recorded in farmers (104 (35.1%)) followed by civil servants (98 (33.2%)) and traders (76 (25.6%)), while drivers had the lowest incidence (2 (0.7%)) (Table 4).
Discussion The impact of the DOTS measures on the prevalence of TB in 1391 patients seen at the DOTS clinics in the FCT was evaluated. TB is an increasing problem, especially in Africa, in terms of disease burden and resistance to conventional therapy.4 This trend may be attributed to several factors such as overcrowding, the emergence of drug resistance, rising numbers of human immunodeficiency virus (HIV)infected individuals, poverty, lack of trained personnel (especially at the primary healthcare levels), and lack of proper control and co-ordination of control programmes in Nigeria.1 Our study showed that 296 (21.3%) of the 1391 patients examined had detectable AFB in their sputa. This is in contrast with the result of a similar study that established the incidence as 16% in children, 6% in adults5 and 46% elsewhere in nigeria. This variation in AFB recovery rate may be attributed to the technique employed or the low production of AFB in sputum samples.3 The low smear positivity recorded in this study is in contrast with the findings of Selvakumar et al. (35%),6 Angeby et al. (28%),7 and Mark (26).8 This disparity in recovery rate may be due to the technique employed, quality of sputum samples produced or Table 3 Age distribution of smear positivity in patients seen at the DOTS clinics. Age (years)
No. (%)
0–10 (nZ4) 11–20 (nZ134) 21–30 (nZ451) 31–40 (nZ358) 41–50 (nZ111) 51–60 (nZ198) 61–70 (nZ77) 71C(nZ58)
0 21 112 79 24 42 12 6
(0) (15.70) (24.8) (22.1) (21.6) (21.2) (15.6) (10.3)
Table 4 Occupational distribution of smear positivity in patients seen at the DOTS clinics. Occupation
No. (%)
Farmers Traders Drivers Civil servants Food handlers Others
104 (35.1) 76 (25.6) 2 (0.7) 98 (33.2) 5 (1.7) 11 (3.6)
heavy workload in the laboratory.9 Direct smear microscopy of sputum is the only microbiological method used to confirm the diagnosis of pulmonary TB in many laboratories in Nigeria; culture of sputa and other tests are expensive and not suitable for routine processing of large samples. However, the sensitivity of smears made directly from sputum is low10 and there is a strong case for using rapid, reliable and cost-effective procedures that will improve the accuracy of the diagnosis. The use of improved staining microscopic techniques (bleach sedimentation technique) including the decontamination of the sputum with bleach (NaOCl) improves the yield of AFB, enabling a high rate of case detection and also reducing the risk of laboratory scientists acquiring the disease, since digestion of sputa with bleach kills the bacilli and removes the offensive odour of the sputa. The low smear positivity recorded in this study has significant public health implications. All the people that were underdiagnosed will remain untreated, resulting in further spread of the disease.5 In this study, adults over 71 years of age and children aged 0–10 years did not show evidence of AFB. This trend in children may be due to the massive immunization coverage (BCG) in children under 5 years of age in the last 6 years in Nigeria, the inability of children to produce good-quality sputum samples or the use of a lesssensitive technique.11 The data in this present study indicate that 136 (45.9%) females and 160 (54.1%) males were smear positive. Of these, 67.9% were new cases and 32.1% were follow-up cases. Farmers had the highest incidence (104 (31.5%)) of smear positivity, which may be an indication of their poor standard of living. Although the pattern of their houses was not sampled, it shows that people from low-resource settings are more prone to TB infections; as such, this calls for equity in the distribution of health care in Nigeria. The high incidence of new and follow-up cases recorded in the study is of concern as most of the follow-up cases were relapsed cases, indicating the possibility of non-compliance with the anti-TB drugs used in the DOTS strategy. In the recent past,
408 an increase in resistance has been reported for most of the anti-TB drugs in use. This may be attributed to several factors, including non-compliance with the five components of DOTS, i.e. government commitment to sustained TB control activities, case detection by sputum smear microscopy among symptomatic patients self-reporting to health services, standardized treatment regiment of 6–8 months for all confirmed smear-positive cases, with directly observed treatment for at least the first 2 months, a regular and uninterrupted supply of all essential anti-TB drugs, and a standard recording and reporting system that allows assessment of treatment results for each patient.8 DOTS is the most effective strategy available for controlling the pulmonary TB epidemic today. It provides good-quality diagnosis and drugs, uses the best available medications, and has a good monitoring system of the progress and cure of patients. In Nigeria, the five key components of DOTS are lacking. The NTBLCP is poorly managed. Sometimes drugs are not available at the clinics despite availability at the central store, distribution to the outpost is delayed due to lack of a vehicle, and patients on therapy are not monitored effectively. Delay in the release of counterpart funds meant for logistics by state and federal governments are critical factors that result in treatment failure leading to multidrug resistance. In conclusion, AFB microscopy as Gold Standard is inexpensive to perform, specific in high-prevalence settings, and detects the most infectious subsets of patients. These attributes place microscopy as the cornerstone in case detection. However, AFB microscopy is limited in quality and application as it requires equipment and highly trained personnel. This limits its application in field settings and ultimately impacts on TB control. This problem is made more critical by the rising incidence of low case detection in places where HIV infection is prevalent. This lack of sensitivity, along with deficiencies in case reporting, results in the identification of less than 20% of over 8 million predicted cases of TB each year.12
E.B. Bassey et al. Smear examination requires sputum collection, smearing, drying, staining and examination. Delays in reporting often occur, leading to substantial difficulties in case holding. Low case detection rate and slow reporting ultimately erode patients’s faith in the services of the laboratory. The integration of a more sensitive, rapid and patient-friendly diagnostic tool might have a significant impact on TB control by reducing diagnostic delay and period of transmission.
References 1. Raviglione MC, Dye C, Schmidt S, Kochi A. Assessment of worldwide tuberculosis control. Lancet 1997;350:624–9. 2. John C, Home N, Miller F. Clinical tuberculosis, 2nd ed. London: Macmillan; 1999. 3. Taylor JP, Bergmire SD, Suarez L. Epidemiology of drug resistant tuberculosis in Texas. Am J Epidemiol 1999;149: 359–65. 4. Eltringham IJ, Drobniewski F. Multiple-drug resistant tuberculosis; aetiology, diagnosis and outcome. Br Med Bull 1998; 54:569–78. 5. Asuquo AE, Meremiku MM, Edem C, Epoke J. Pattern of sputum smear positivity in tuberculosis patients enrolled in the tuberculosis control programmes in a Nigerian city. J Med Lab Sci 2002;11:58–62. 6. Selvakumar N, Rahman F, Garg R. Evaluation of the phenol ammonium sulphate sedimentation smear microscopy method for diagnosis of pulmonary tuberculosis. J Clin Microbiol 2002;40:3017–9. 7. Angeby KAK, Alvarado-Galvez C, Pineda-Garcial L, Hoffner SE. Improved sputum microscopy for a more sensitive diagnosis of pulmonary tuberculosis. Int J Tuberc Lung Dis 2000;4:684–7. 8. Mark DP. New diagnostic tools for tuberculosis. Int J Tuberc Lung Dis 2000;4:S182–S188. 9. Aber VR, Allen BW, Mitchson DA, Ayuma P, Edward EA, Keyes AB. Quality control in tuberculosis bacteriology: studies on isolated positive culture and the efficiency of direct smear examination. Tubercle 1980;61:23–133. 10. Irish C, Herbert J, Bennett D. Database of study of antibiotic resistant tuberculosis in the United Kingdom, 1994-1996. BMJ 1999;318:497–9. 11. Mendez AP, Raviglione MC, Laszlo A. Global surveillance for anti-tuberculosis drugs resistance 1994-1997. N Engl J Med 1998;388:164–9. 12. World Health Organization. Global Tuberculosis Control. WHO/CDS/2000.275. Geneva: WHO, 2000.
The trend of pulmonary tuberculosis in patients seen at DOTS clinics in the Federal Capital Territory, Abuja, Nigeria E.B. Basseya,*, M.A. Momoha, S.O. Imadiyia, E.B. Udofiab, F.S. Miria, K.C. Anukamc, J. Epoked, M.O. Benka-Cokere, H.S.A. Aluyie a
Department of Medical Laboratory Services, Wuse General Hospital, P. O. Box 2352, Garki, Abuja, Nigeria Department of Medicine, Maitama District Hospital, Abuja, Nigeria c Department of Pharmaceutical Microbiology, University of Benin, Benin City, Nigeria d Department of Medical Microbiology and Parasitology, University of Calabar, Cross River State, Nigeria e Department of Microbiology, University of Benin, Benin City, Nigeria b
Received 9 February 2004; received in revised form 14 April 2004; accepted 13 May 2004
KEYWORDS AFB positive; Follow-up; DOTS; Tuberculosis; Diagnosis
Summary We evaluated the pattern of sputum smear positivity and assessed the effects of directly observed treatment short course (DOTS) among tuberculosis (TB) patients at the DOTS clinics in the Federal Capital Territory (FCT), Abuja. In total, 1391 patients were seen at six microscopy and treatment centres across the FCT between January and December 2003. Their sputa were screened microscopically for the presence of acid-fast bacilli (AFB) using the Ziehl-Neelsen staining technique. In total, 296 (21.3%) patients were smear positive; 201 (67.9%) were new cases and 95 (32.1%) were follow-up cases. The highest incidence of sputum smear positivity (24.8%) was found in those aged 21-30 years and the lowest incidence (6%) was found in those aged 71 years and above. No incidence of smear positivity was recorded in children aged 0-10 years. In total, 160 of the men screened were AFB positive (75% new cases, 25% follow-up cases). In comparison, 136 women were AFB positive (59.6% new cases, 40.4% follow-up cases). During the 1-year study period, two deaths were recorded. Men pose a serious threat to public health as most of the follow-up cases result in the tubercle bacilli developing resistance to available anti-TB drugs. This study demonstrated a high prevalence of infectious TB in the population screened, and therefore underlines the need for capacity building through a multisectoral approach in the fight against the disease. Cohort analysis should be the cardinal management strategy in evaluating the effectiveness of TB control through systemic follow-up and reporting of certain indicators in treatment progress and success. Q 2004 The Royal Institute of Public Health. Published by Elsevier Ltd. All rights reserved.
* Corresponding author E-mail address: [email protected] (E.B. Bassey). 0033-3506/$ - see front matter Q 2004 The Royal Institute of Public Health. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.puhe.2004.05.012
406
Introduction In 1993, the World Health Organization (WHO) declared tuberculosis (TB) to be a global emergency.1 This was the first such declaration to be made by the organization. Infectious disease remains the largest cause of illness and death in the world, and TB is responsible for the greatest number of deaths among all infectious diseases.2 It is estimated that Mycobacterium tuberculosis has infected one-third of the world’s 6 billion population and about 3 million people die of TB every year.1 The WHO has estimated that about 5000 people die of the disease and 20 000 are newly infected daily.1 In Nigeria, which ranks fourth in the world for TB incidence, over 300 000 new cases of TB and 30,000 deaths occur annually.2 As such, the National Tuberculosis and Leprosy Control Programme (NTBLCP) set up directly observed treatment short course (DOTS) and microscopy centres in the Federal Capital Territory (FCT), Abuja in 2003. These centres were established to identify, diagnose, categorize and treat all smear-positive TB patients. In Nigeria, direct microscopic examination of appropriately stained sputum specimens for tubercle bacilli is the cornerstone of TB diagnosis. The technique is simple, inexpensive, reliable and suitable in poor resource settings. Culture facilities are only available at two centres in Nigeria. This new strategy has proven to be cost effective for treatment of TB. Through a combination of technical and managerial components, DOTS makes infectious cases non-infectious, thereby breaking the cycle of transmission. DOTS also prevents the development of drug-resistant strains of TB that are often fatal and most expensive to treat.3 The aim of this study was to evaluate the trend of pulmonary TB and the effect of DOTS measures adopted by the NTBLCP in the FCT.
E.B. Bassey et al. carried out using the Ziehl–Neelsen sputum method. The sensitivity of this method varies and is dependent upon collection of good-quality sputum, smearing, staining and careful examination of smears. Bleach-treated samples lose resemblance to sputum samples and are less aesthetically offensive to laboratory scientists. The bleach sediment smear method is safer as the sputum is rendered sterile and the bleachtreated samples can be disposed of easily with other hospital waste. This can improve the yield of acid-fast bacilli (AFB). At least 300 visual fields were examined with 100! magnification using light microscopy. All TB-positive cases were promptly referred to the treatment clinics and followed-up within 2 months of intensive treatment. Two early morning sputum samples were obtained from patients who failed to respond to intensive treatment and examined for AFB.
Results Sputum samples were obtained from 1391 patients at the DOTS clinics of the NTBLCP, scattered across all the area councils in the FCT, Abuja, and examined for evidence of AFB. In total, 296 patients were AFB positive using the Ziehl–Neelsen staining method. Of these, 160 (54.1%) were male and 136 (45.9%) were female. Table 1 shows the differences in incidence between the genders. In total, 201 (67.9%) patients were new cases and 95 (32.1) were follow-up cases. Two deaths were recorded during the 1-year study (Table 2). The highest number of smear-positive patients was found in those aged 21–30 years (24.8%), and the lowest incidence was in those aged 71 years or more (10.3%). No incidence was recorded in children aged 0–10 years (Table 3). The number of smear-positive cases also varied depending on the occupation of the patients.
Methods This study was conducted in six DOTS and microcopy centres in the FCT between January and December 2003. Subjects were recruited from those attending DOTS clinics who fulfilled the inclusion criteria. Three separate freshly expectorated sputum samples (5 ml) were collected within 48 h as follows: first sample was collected in the first visit, the second sample was collected early morning, and the third spot sample when the patient brought in the early morning sample. Direct smear examination was
Table 1 Sex distribution of smear positivity among patients seen at the DOTS clinics (nZ1391). Centres
Male
Female
Positivity
Asokoro (nZ310) Gwagwalada (nZ184) Kubwa (nZ205) Kwali (nZ220) Maitama (nZ346) Nyanya (nZ126) Total: 1391
36 26 13 28 41 16
26 18 14 20 35 23
62 44 27 48 76 39
Pulmonary TB at DOTS clinics in Nigeria
407
Table 2 Percentage distribution of smear positivity among patients attending DOTS clinics.
Male Female Total
No. (%)
New cases (%)
Followup (%)
Death
160 (54.1) 136 (45.9) 296 (21.3)
120 (75.0) 81 (59.6) 201 (67.9)
40 (25.0) 55 (40.4) 95 (32.1)
2 (1.1) 0 (0) 2 (1.1)
The highest incidence was recorded in farmers (104 (35.1%)) followed by civil servants (98 (33.2%)) and traders (76 (25.6%)), while drivers had the lowest incidence (2 (0.7%)) (Table 4).
Discussion The impact of the DOTS measures on the prevalence of TB in 1391 patients seen at the DOTS clinics in the FCT was evaluated. TB is an increasing problem, especially in Africa, in terms of disease burden and resistance to conventional therapy.4 This trend may be attributed to several factors such as overcrowding, the emergence of drug resistance, rising numbers of human immunodeficiency virus (HIV)infected individuals, poverty, lack of trained personnel (especially at the primary healthcare levels), and lack of proper control and co-ordination of control programmes in Nigeria.1 Our study showed that 296 (21.3%) of the 1391 patients examined had detectable AFB in their sputa. This is in contrast with the result of a similar study that established the incidence as 16% in children, 6% in adults5 and 46% elsewhere in nigeria. This variation in AFB recovery rate may be attributed to the technique employed or the low production of AFB in sputum samples.3 The low smear positivity recorded in this study is in contrast with the findings of Selvakumar et al. (35%),6 Angeby et al. (28%),7 and Mark (26).8 This disparity in recovery rate may be due to the technique employed, quality of sputum samples produced or Table 3 Age distribution of smear positivity in patients seen at the DOTS clinics. Age (years)
No. (%)
0–10 (nZ4) 11–20 (nZ134) 21–30 (nZ451) 31–40 (nZ358) 41–50 (nZ111) 51–60 (nZ198) 61–70 (nZ77) 71C(nZ58)
0 21 112 79 24 42 12 6
(0) (15.70) (24.8) (22.1) (21.6) (21.2) (15.6) (10.3)
Table 4 Occupational distribution of smear positivity in patients seen at the DOTS clinics. Occupation
No. (%)
Farmers Traders Drivers Civil servants Food handlers Others
104 (35.1) 76 (25.6) 2 (0.7) 98 (33.2) 5 (1.7) 11 (3.6)
heavy workload in the laboratory.9 Direct smear microscopy of sputum is the only microbiological method used to confirm the diagnosis of pulmonary TB in many laboratories in Nigeria; culture of sputa and other tests are expensive and not suitable for routine processing of large samples. However, the sensitivity of smears made directly from sputum is low10 and there is a strong case for using rapid, reliable and cost-effective procedures that will improve the accuracy of the diagnosis. The use of improved staining microscopic techniques (bleach sedimentation technique) including the decontamination of the sputum with bleach (NaOCl) improves the yield of AFB, enabling a high rate of case detection and also reducing the risk of laboratory scientists acquiring the disease, since digestion of sputa with bleach kills the bacilli and removes the offensive odour of the sputa. The low smear positivity recorded in this study has significant public health implications. All the people that were underdiagnosed will remain untreated, resulting in further spread of the disease.5 In this study, adults over 71 years of age and children aged 0–10 years did not show evidence of AFB. This trend in children may be due to the massive immunization coverage (BCG) in children under 5 years of age in the last 6 years in Nigeria, the inability of children to produce good-quality sputum samples or the use of a lesssensitive technique.11 The data in this present study indicate that 136 (45.9%) females and 160 (54.1%) males were smear positive. Of these, 67.9% were new cases and 32.1% were follow-up cases. Farmers had the highest incidence (104 (31.5%)) of smear positivity, which may be an indication of their poor standard of living. Although the pattern of their houses was not sampled, it shows that people from low-resource settings are more prone to TB infections; as such, this calls for equity in the distribution of health care in Nigeria. The high incidence of new and follow-up cases recorded in the study is of concern as most of the follow-up cases were relapsed cases, indicating the possibility of non-compliance with the anti-TB drugs used in the DOTS strategy. In the recent past,
408 an increase in resistance has been reported for most of the anti-TB drugs in use. This may be attributed to several factors, including non-compliance with the five components of DOTS, i.e. government commitment to sustained TB control activities, case detection by sputum smear microscopy among symptomatic patients self-reporting to health services, standardized treatment regiment of 6–8 months for all confirmed smear-positive cases, with directly observed treatment for at least the first 2 months, a regular and uninterrupted supply of all essential anti-TB drugs, and a standard recording and reporting system that allows assessment of treatment results for each patient.8 DOTS is the most effective strategy available for controlling the pulmonary TB epidemic today. It provides good-quality diagnosis and drugs, uses the best available medications, and has a good monitoring system of the progress and cure of patients. In Nigeria, the five key components of DOTS are lacking. The NTBLCP is poorly managed. Sometimes drugs are not available at the clinics despite availability at the central store, distribution to the outpost is delayed due to lack of a vehicle, and patients on therapy are not monitored effectively. Delay in the release of counterpart funds meant for logistics by state and federal governments are critical factors that result in treatment failure leading to multidrug resistance. In conclusion, AFB microscopy as Gold Standard is inexpensive to perform, specific in high-prevalence settings, and detects the most infectious subsets of patients. These attributes place microscopy as the cornerstone in case detection. However, AFB microscopy is limited in quality and application as it requires equipment and highly trained personnel. This limits its application in field settings and ultimately impacts on TB control. This problem is made more critical by the rising incidence of low case detection in places where HIV infection is prevalent. This lack of sensitivity, along with deficiencies in case reporting, results in the identification of less than 20% of over 8 million predicted cases of TB each year.12
E.B. Bassey et al. Smear examination requires sputum collection, smearing, drying, staining and examination. Delays in reporting often occur, leading to substantial difficulties in case holding. Low case detection rate and slow reporting ultimately erode patients’s faith in the services of the laboratory. The integration of a more sensitive, rapid and patient-friendly diagnostic tool might have a significant impact on TB control by reducing diagnostic delay and period of transmission.
References 1. Raviglione MC, Dye C, Schmidt S, Kochi A. Assessment of worldwide tuberculosis control. Lancet 1997;350:624–9. 2. John C, Home N, Miller F. Clinical tuberculosis, 2nd ed. London: Macmillan; 1999. 3. Taylor JP, Bergmire SD, Suarez L. Epidemiology of drug resistant tuberculosis in Texas. Am J Epidemiol 1999;149: 359–65. 4. Eltringham IJ, Drobniewski F. Multiple-drug resistant tuberculosis; aetiology, diagnosis and outcome. Br Med Bull 1998; 54:569–78. 5. Asuquo AE, Meremiku MM, Edem C, Epoke J. Pattern of sputum smear positivity in tuberculosis patients enrolled in the tuberculosis control programmes in a Nigerian city. J Med Lab Sci 2002;11:58–62. 6. Selvakumar N, Rahman F, Garg R. Evaluation of the phenol ammonium sulphate sedimentation smear microscopy method for diagnosis of pulmonary tuberculosis. J Clin Microbiol 2002;40:3017–9. 7. Angeby KAK, Alvarado-Galvez C, Pineda-Garcial L, Hoffner SE. Improved sputum microscopy for a more sensitive diagnosis of pulmonary tuberculosis. Int J Tuberc Lung Dis 2000;4:684–7. 8. Mark DP. New diagnostic tools for tuberculosis. Int J Tuberc Lung Dis 2000;4:S182–S188. 9. Aber VR, Allen BW, Mitchson DA, Ayuma P, Edward EA, Keyes AB. Quality control in tuberculosis bacteriology: studies on isolated positive culture and the efficiency of direct smear examination. Tubercle 1980;61:23–133. 10. Irish C, Herbert J, Bennett D. Database of study of antibiotic resistant tuberculosis in the United Kingdom, 1994-1996. BMJ 1999;318:497–9. 11. Mendez AP, Raviglione MC, Laszlo A. Global surveillance for anti-tuberculosis drugs resistance 1994-1997. N Engl J Med 1998;388:164–9. 12. World Health Organization. Global Tuberculosis Control. WHO/CDS/2000.275. Geneva: WHO, 2000.