Tuberculosis transmission in Kenya: results of the third National Tuberculin Survey.

SETTING: Kenya, a country with a high burden of tuberculosis (TB) and human immunodeficiency virus (HIV) infection. OBJECTIVES: To assess the prevalence of TB infection, bacille Calmette-Guérin (BCG) coverage and the annual risk of tuberculosis infection (ARTI), and to compare estimates with previous findings. METHODS: A sample of primary school children aged 6-14 years from the same study districts sampled in previous surveys were tuberculin skin tested using the Mantoux method from September 2004 to July 2007. The prevalence of TB infection was estimated by the mirror method, with the mode at 17 mm. RESULTS: Of the 94 771 registered children, 76 676 (80.9%) completed the survey investigations, 12 107 (15.8%) of whom had no BCG scar. The prevalence of TB infection was estimated at 10.2%, with a corresponding ARTI of 1.1%. The ARTI obtained from the current survey is comparable to that of the 1994-1996 survey and higher than that of the 1986-1990 survey. The BCG coverage was comparable with the 1994-1996 survey and higher than in the 1986-1990 survey. CONCLUSION: TB transmission in Kenya has remained the same over the last decade, which suggests that activities undertaken by the TB control programme have been sufficient to hold TB transmission steady, but insufficient to reduce it.

Planning for PPM-DOTS implementation in urban slums in Kenya: knowledge, attitude and practices of private health care providers in Kibera slum, Nairobi.

SETTING: Kibera, the largest slum in Nairobi, Kenya. OBJECTIVE: To determine the tuberculosis (TB) knowledge, attitude and practices (KAP) of private health care providers (PHCPs) to identify their training needs and willingness to participate in a National Leprosy and Tuberculosis Control Programme (NLTP) guided TB control effort in the slum. DESIGN AND METHODOLOGY: A cross-sectional survey. The KAP of PHCPs was assessed using an interviewer administered questionnaire. RESULTS: Of 75 PHCPs interviewed, the majority (96.0%) were paramedics; 51 (77.1%) did not consider sputum smear microscopy crucial in patients presenting with prolonged cough or when a chest X-ray was suggestive of TB; of 29 (38.7%) who indicated familiarity with the drugs used in TB treatment, 20 (58.5%) would have chosen the NLTP-recommended regimens for the treatment of the various types of TB; 16 (21.3%) PHCPs indicated that they treated TB, six (37.5%) of whom were not familiar with anti-tuberculosis drug regimens. All the PHCPs referred TB suspects to the public sector for diagnosis. CONCLUSION: This study reveals a significant gap in TB knowledge among the PHCPs in Kibera slum. However, given appropriate training and supervision, there is potential for public-private mix for DOTS implementation in this setting.

Prevalence and risk factors of smoking among secondary school students in Nairobi.

OBJECTIVES: To determine the prevalence of smoking and investigate factors that may influence smoking behaviour in secondary school students in Nairobi. DESIGN: Cross-sectional survey in which a self-administered questionnaire was issued to the students. SETTING: Sampled public and private secondary schools in Nairobi. PARTICIPANTS: All the students in the selected secondary schools were included in the study. RESULTS: Five thousand, three hundred and eleven (74.1%) secondary school students were covered. There were 3658 boys and 1653 girls in the study. The mean age was 16.7 years SD +/- 1.48. The study covered 3065 (77.3%) and 2246 (70.1%) of the public and private school students respectively. A total of 1709 (32.2%) were ever-smokers. The overall rate of ever-smoking by gender among the students was 38.6% of males and 17.9% of the females. Experimentation with smoking started at five years and regular smoking at 10 years but majority of students (72.2%) started at between age 12 and 16 years. Parents' and teachers' smoking habits influenced initiation of smoking by young children while peer pressure, advertising and type of school influenced older children to smoking. About 67% of the ever-smokers stopped the habit giving various reasons. There was a strong relationship between age of smoking initiation and stoppage. Majority of the students smoked either to enhance their personalities or for stimulation. Most students smoked less than five cigarettes per day. General shops, kiosks and cigarette stalls which sell cigarettes in both packets and single sticks were the main source to students. Students smoked mostly in the evening and at night. Most student smokers were not discouraged by health warnings on the cigarette packets and awareness of the dangers of smoking. Enforceable legislation that would ban advertising and make smoking illegal was the main recommendation from the students. CONCLUSIONS: Smoking is a problem among Kenyan students. The habit starts quite early in life. Peer pressure, advertising, type of school and age influenced smoking among the students. Banning the sale of cigarettes in single sticks is recommended. Anti-smoking campaigners and specially trained school teachers should encourage attitude shaping among school children towards self confidence and adequacy.

Tuberculosis re-treatment outcomes within the public service in Nairobi, Kenya.

OBJECTIVES: This study was undertaken to describe treatment outcomes in patients started on a re-treatment drug regimen, assess the quality of follow up procedures and the adequacy of the currently advocated re-treatment drug regimen in Nairobi, Kenya. DESIGN: A retrospective study. SETTING: Mbagathi District Hospital (MDH), Nairobi, a public hospital that serves as the Tuberculosis (Tb) referral centre for Nairobi. MATERIALS AND METHODS: The Tb register at the MDH was used to identify patients who were on the re-treatment regimen for Tb. Case records for these patients were then retrieved. From these sources, information on age, sex, HIV status, previous and current tuberculosis disease and drug regimens, adherence to treatment and treatment outcomes, was obtained. Descriptive statistics was used to analyse the data. RESULTS: Of the total of 4702 patients registered at the MDH between 1996 and 1997, 593 (12.6%) were patients with either recurrent Tb, returning to treatment after default or had failed initial treatment. Of the 593 patients, case records were unavailable for 168 and 17 were children below the age of ten in whom the diagnosis of Tb was uncertain making a total of 185 patients who were excluded from the study. Of the remaining 408 patients, 77 (18.9%) were cured, 61 (15.0%) completed treatment without confirmation of cure, two (0.5%) defaulted, six (1.5%) died and 262 (64.2%) had no outcome information. There were no treatment failures. Treatment success defined as cure or treatment completion was achieved in 94.5% of the 146 patients in whom outcome data were available. HIV positive patients had a statistically significant poorer success rate (34/40, 85%) when compared with HIV negative patients (104/106, 94%), p=0.004. Mycobacterium tuberculosis culture and drug susceptibility testing, was not done. CONCLUSION: The high number of patients with no treatment outcome information at the MDH is worrying, as these patients may harbour drug resistant bacilli and reflects an inadequate follow up service for Tb re-treatment in Nairobi. However, where treatment outcomes could be assessed, the currently advocated re-treatment regimen achieved a high success rate. These observations point to an urgent need to improve Tb documentation and follow up procedures within the public service in Nairobi in order to forestall the emergence and spread of drug resistant Tb.

Tobacco consumption among primary school teachers in Nairobi.

OBJECTIVE: To determine the extent, pattern and the attendant risk factors of cigarette smoking and tobacco consumption among primary school teachers in Nairobi. DESIGN: A descriptive cross-sectional study. SETTING: The study was carried out among randomly selected Nairobi City Council primary schools in 1996. PARTICIPANTS: All the teachers in the selected primary schools were included in the study. RESULTS: Out of 910 teachers contacted, 813 responded (a response rate of 89.3%). A total of 800 teachers completed the questionnaire correctly and are the subject of the present analysis. Fifty per cent of male and three per cent of female teachers were cigarette smokers at the time of the study. The median age for starting to smoke was between 15 and 24 years. At this age, the teachers were secondary school and tertiary college students. It was observed that the age of smoking initiation seems to determine the individual's smoking status later in life. CONCLUSION: Since 57% of smokers started smoking during their secondary school days, secondary school students seem to be at a higher risk of initiating smoking. It is therefore important to target them for smoking control initiatives before they start the habit. A number of smokers were willing to quit smoking but did not know how to go about it. External assistance is therefore required for them to achieve their wish. It is also important to emphasise the need by the relevant authorities to initiate programmes for anti-smoking education in secondary schools and colleges in the country.

Tuberculosis and the HIV epidemic: increasing annual risk of tuberculous infection in Kenya, 1986-1996.

OBJECTIVES: The purpose of this study was to assess the impact of the increased incidence of tuberculosis (TB) due to HIV infection on the risk of TB infection in schoolchildren. METHODS: Tuberculin surveys were carried out in randomly selected primary schools in 12 districts in Kenya during 1986 through 1990 and 1994 through 1996. Districts were grouped according to the year in which TB notification rates started to increase. HIV prevalence in TB patients and changes in TB infection prevalence were compared between districts. RESULTS: Tuberculous infection prevalence rates increased strongly in districts where TB notification rates had increased before 1994 (odds ratio = 3.1, 95% confidence interval = 2.3, 4.1) but did not increase in districts where notification rates had increased more recently or not at all. HIV prevalence rates in TB patients were 50% in districts with an early increase in notification rates and 28% in the other study districts. CONCLUSIONS: Countries with an increasing prevalence of HIV infection will need additional resources for TB control, not only for current patients but also for the patients in additional cases arising from the increased risk of TB infection.

National tuberculin survey of Kenya, 1986-1990.

SETTING: The first tuberculin survey conducted in Kenya by the World Health Organisation in 1958-1959 found an annual risk of tuberculosis infection (ARTI) of 2.5%. OBJECTIVE: To estimate the ARTI and its trend in recent years and to compare the estimated incidence rates with the notification rates. DESIGN: A tuberculin survey was held in 12 randomly selected districts in the period 1986-1990. Tuberculin testing with 2TU PPD RT 23 + Tween 80 was performed in 40,365 primary schoolchildren aged 6-13. RESULTS: Of 14,984 non BCG-vaccinated children, 1,380 (9.2%) had indurations of > or = 10 mm. Double testing with PPD RT 23 and PPD-scrofulaceum in 980 non BCG-vaccinated children revealed a high level of infections due to mycobacteria other than tuberculosis (MOTT). Therefore, the prevalence of tuberculous infection was based on the sum of 50% of the indurations of 17 mm and all indurations of 18 mm or more multiplied by two. The prevalence of tuberculous infection in schoolchildren aged on average 8.4 years, 'weighted' for the population size according to the provisional results of the 1989 census, was calculated at 5.5%. The corresponding ARTI is 0.6%. CONCLUSION: The ARTI has declined by an average 4.6% per year. The tuberculosis problem differs from one area to the next, with the highest prevalences of infection on the coast and in Eastern Kenya, and the lowest in Western Kenya. Although the average ratio of observed and estimated incidences indicate that 70% of incident cases are notified, considerable inter-district variations are observed.

Essential drugs supply and usage as a reflection of outpatient morbidity in Kirinyaga District, Kenya.

This study was carried out in all the twenty eight Government rural health facilities (RHF's) in Kirinyaga District of Kenya. It aimed at determining whether the quantities and types of drugs supplied to the RHF's matched the morbidity patterns, and also whether the disease patterns continued to be used as a basis for requesting stocks of essential drugs. It also investigated the constraints associated with the programme with an ultimate aim of improving service delivery. The information was obtained through records review of the Bin card books, Out-patients Department (OPD) register, morbidity monthly returns, staff and patient interviews. A highly significant (p < 0.01) variation in morbidity (workload) by season of the year and between the ecological divisions of the district was observed. Significant differences were also observed between the quantities of drugs supplied and the actual monthly requirements in all the RHF's, implying that the disease patterns were not necessarily being used for requesting stocks of essential drugs. A distribution of essential drugs based on two broad ecological divisions of the district was recommended. One of the major constraints found to be associated with the Essential Drugs Programme was the delay in procurement/distribution of essential drugs to the RHF's. This was mainly due to the tendering procedures of Kit 2 by the Ministry of Health (MOH) and also occasional lack of transport at the district level.

Effect of non-tuberculous Mycobacteria infection on tuberculin results among primary school children in Kenya.

Few tuberculosis studies carried out in Kenya since 1948 have reported on the variations of the occurrence and geographical distributions of non-tuberculous Mycobacteria infection. They have however not been able to clearly relate infection outcome to the use of tuberculin tests as epidemiologic and clinical tool. The present survey, conducted by Kenya Medical Research Institute in collaboration with the International Union Against Tuberculosis and Lung Diseases between 1986 and 1990 among school children aged 6-13 years in 18 randomly selected districts, investigated the following: the prevalence of sensitivity to tuberculin PPD RT 23 and PPD scrofulaceum RS 95 sensitin; geographic distribution of the reactions from the tests and; the influence of non-tuberculous Mycobacteria on the tuberculin results. The WHO cluster sampling procedures were used to select 30 schools in each of the 18 districts. Each child was tested with an intradermal dose of 2 TU of PPD RT 23 with Tween 80 (PPD RT 23) on the right hand and 2 TU of PPD Scrofulaceum RS 95 sensitin with tween 80 (PPD RS 95) on the left hand. The results were read after 72 hours of testing. A total of 1015 BCG scar negative children was included in the survey. Of these, 981 were tested and read. Over 47% of the children did not react to both antigens while 6.1% and 22.7% reacted to human type tuberculin and environmental sensitin respectively. There was cross reaction between the two tests in 23.8% of the children from low altitude area who had more and larger reaction to the tests than the middle and higher altitude regions of the country.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-tuberculous initial drug resistance of Mycobacterium tuberculosis in Kenya: a ten-year review.

Our experience at the Respiratory Diseases Research Unit (RDRU), over the last 10 years (1981-1990) on the initial drug resistance pattern, focusing on three drugs viz: isoniazid (H), streptomycin (S) and rifampicin (R) is presented. Records on all isolates of M. tuberculosis from one specimen of every newly diagnosed patient recruited countrywide between 1981-1990 were reviewed. We analyzed records of 6,514 isolates and found that total resistance to the three drugs had increased from 8.9% to 14.4%. Resistance to H alone increased from 6.8% to 10.2% while that of S alone from 0.8% to 1.8%. Resistance to R was between 0.1% and 0.3%. Generally, the increase in the resistance trend to both H and S was statistically significant (p = < 0.05 and 0.03, respectively). Although in our analysis we did not address the possible impact of HIV infection, we hope that these findings form a basis for evaluation of this and other possible factors on the emergence of anti-TB drug resistance in future studies.

PIP: A retrospective review of medical records of 6514 Mycobacterium tuberculosis isolates of newly diagnosed patients at the Respiratory Diseases Research Unit of the Kenya Medical Research Institute between 1981 and 1990 aimed to determine the initial drug-resistance pattern for isoniazid, streptomycin, and rifampicin. Overall resistance increased from 8.9 to 14.4% (p 0.001). The increase in the resistance trend to isoniazid and to streptomycin were statistically significant (6.8-10.2; p 0.05 and 0.8-1.8; p = 0.03, respectively) as well as the trend among isolates resistant to both isoniazid and streptomycin (1.2.4; p = 0.03). The trend was more pronounced during 1987-1990 than during 1981-1986. There was no trend in the resistance to rifampicin alone (0.1-0.3%). Just 4 isolates were resistant to both isoniazid and rifampicin. Only 1 was resistant to both streptomycin and rifampicin. None were resistant to all 3 antibiotics. These first-line drugs are used widely in Kenya. These rates of initial resistance to the drugs are lower than those in other developing countries. The lower resistance rate is unlikely to continue, however, due to higher prevalence of HIV infection and the associated increase in tuberculosis incidence. These findings provide researchers a baseline with which to study M. tuberculosis drug resistance and other risk factors as drug resistance increases in Kenya.

BCG scar survey among primary school children in Kenya (1986-1990).

Bacillus Calmette Guerin (BCG) vaccination is essential in the control of tuberculosis (TB) especially in countries like Kenya where TB is still a public health problem and BCG is given to all children at birth as a matter of policy. The present survey was launched in 1986 to assess both BCG vaccination coverage and to compare its findings with the 1979/81 BCG scar survey results. Using random cluster sampling procedures, all primary school children aged 6-13 years from schools in each of 12 districts were included in the survey. A total of 46357 school children were registered. Of these, 3642 (7.9%) were excluded from the survey for a variety of reasons. Of the remaining 42715 (92.1%) children, 26781 (62.7%) had BCG scars present. Overall there was a significant upward trend of 15% in BCG vaccination coverage in the country. However, in some districts the coverage was found to have fallen quite significantly.

PIP: In 1986-1990, researchers conducted a BCG scar survey in 360 randomly selected primary schools in 12 districts in Kenya to determine BCG vaccination coverage. They used primary schools because more than 70% of all school age children were enrolled in school. They compared this survey's findings with those of the 1979-1981 BCG scar house-to-house survey. The districts included Elgeyo Marakwet, Kakamega, Kilifi, Kisii, Kitui, Siagya, Kwale, Meru, Muranga, Nakuru, Nairobi, and South Nyanza. The ages of the 42,715 healthy children ranged from 6-13 years old. 26,781 (62.7%) children had a BCG scar, indicating that the National Tuberculosis Control Program had not yet reached its target of 70% BCG vaccination coverage. Nairobi had the highest BCG coverage, while Kisii district had the lowest BCG coverage (82.73% vs. 44.01%). BCG coverage decreased as age increased (p .001). For example, 6-year-old males and females had a BCG coverage rate of 64.43% and 62.39%, respectively, while the corresponding figures for 13-year-olds were 52.93% and 49.13%. BCG vaccination coverage increased significantly between the two surveys (an increase of 15%) (60.8% vs. 62.7%; p .01). South Nyanza district experienced the greatest improvement in BCG coverage between the 2 surveys, while Kilifi district experienced the greatest decline in coverage. The greatest upward trend was observed in the Western and Rift Valley provinces, while the greatest downward trend was observed in the Coast and Eastern provinces.

A comparative study on the reliability of the fluorescence microscopy and Ziehl-Neelsen method in the diagnosis of pulmonary tuberculosis.

Pulmonary tuberculosis (PTB) is the most common presentation of tuberculosis (TB) in Kenya. For the diagnosis of PTB the sputum smear is used because it is technically simple, non-invasive and cheap. The reliability of direct smear examination for the diagnosis of TB has however frequently been questioned. To address this problem, a study comparing the reliability of fluorescence microscopy (FM) and Ziehl-Neelsen (ZN) staining method for examination of direct smear in the diagnosis of PTB was carried out at the Respiratory Disease Research Unit Laboratory, Nairobi, Kenya. A total of 1480 sputum specimens collected from patients with suspected PTB were analyzed. Two direct smears were prepared from each specimen, one stained using FM and the other using the ZN method. Culture results were used as the gold standard for assessment. Specificity was 97% and 96% for FM and ZN methods, respectively. The sensitivity of the FM method was 80% and that of the ZN method 65% (p < 0.001). Overall agreement was 86.8%. Positive smears which were missed on the ZN stained smears (15%) contained low density bacilli on both FM stained smears and on culture. The use of FM greatly improves the diagnostic value of the sputum smear especially in patients with a low density of bacilli who are likely to be missed on ZN stained smears. The method is economical in both time and expense and is recommended for laboratories handling large numbers of sputum specimens.

A study of the use of maternity and child welfare clinics in case-finding for pulmonary tuberculosis in Kenya.

This investigation is the seventh in a series of case-finding studies in Kenya. It explores the potential value of questioning mothers attending maternity and child welfare (M & CW) clinics to identify tuberculosis suspects (individuals aged 6 years or more with a cough for 1 month or more or hemoptysis) living in their households. The study was carried out in all the eight M & CW clinics in two divisions (populations 86,000 and 112,000) of two different districts. The mothers were asked to give a standard letter, which explained the possible importance of a chronic cough, to each suspect they identified and invited the suspect to attend the district hospital chest clinic. Each suspect attending the clinic was entered in a special register and two sputum specimens were collected. For those who failed to attend, the specimens were collected at a home visit. Of the total of 342 suspects living in the two study areas who were registered at the M & CW clinics during 1 year, 261 were identified by the mothers but 19 denied having received the standard letter. The remaining 81 had not been identified by mothers but had attended the M & CW clinics on their own initiative. Of the 242 suspects who received the letter, 89 (39%) attended the hospital chest clinic, 74% within a week of the letter being issued from the M & CW clinic. The main reasons given for not attending the hospital chest clinic by the remaining suspects were financial or because their cough had improved or disappeared. Sputum was collected from 238 suspects and examined bacteriologically: in six (2.5%) it was positive for tubercle bacilli on smear and culture and in a further two (0.8%) the sputum was positive on culture only. Of those attending the hospital chest clinic 2.9% were smear- and culture-positive and 4.7% were culture positive. This method of case-finding has yielded disappointing results, for only 4% of the estimated annual incidence of smear-positive cases was detected.