Tuberculosis control in Oman : Challenges to elimination

Abstract: Background: Tuberculosis (TB) is a global public health challenge. More than 1.7 million deaths worldwide in 2007 were attributed to TB. Directly Observed Therapy Short course (DOTS) is the globally recommended strategy for TB control. Context: The Sultanate of Oman, a middle-income country that has seen substantial economic development during the last 25 years, has made remarkable progress with regard to the control of infectious diseases including TB. In 1996, TB elimination targets for the years 2005 and 2010, were set at three and one new smear positive cases per 100,000 in the Omani national population, respectively. The 2005 target was not reached, implying the need for additional TB control efforts, including research on the various factors affecting TB incidence. Aim: The main aim of this thesis is to study TB control in Oman and to explore opportunities and challenges in relation to achieving the specified TB elimination targets in Oman. The thesis also aims to give recommendations to NTP to enhance TB control in the country. Methods: The thesis is based on four studies. In study I, the official TB notification rates for nationals and migrant workers during the period 1981 to 2005 were analyzed. Additional data on the Gross National Income per capita during the same period and estimates of the socio-economic status of 329 TB patients notified in 2004 and 2005 were also used. Study II was a cross-sectional study. Questionnaires were used to evaluate the level of suspicion and knowledge of TB among 257 private and public general practitioners in the Muscat region. In study III, 17 qualitative interviews were carried out with health care providers, to explore their perceptions and experiences of TB control in Oman. Spoligotyping of 312 isolates of Mycobacterium tuberculosis from TB patients diagnosed during 2005-2007 was carried out in study IV. Results: TB notifications declined by more than 85% from 1981 to 2005 (study I). In 2005, the highest notification rates for Omani nationals were found among persons aged 60 years and over. Approximately 95% of the 329 Omani nationals with TB diagnosed in 2004 and 2005, were living in households earning less than the gross national income per capita (Study I). Studies II and III demonstrated inadequate suspicion and knowledge of TB among general practitioners. The private health care sector providers were found to be less aware of TB than the public health care providers, and to be uninvolved in TB control (Studies II, III). Migrant workers were perceived as disadvantaged by the repatriation policy that is applied for persons diagnosed with TB (Study III). Study IV showed a predominance of strains from the Indian subcontinent. Around 50% of the migrant workers isolates were found in clusters also containing isolates from Omani patients, suggesting possible transmission between the two population groups. Conclusion: Economic development and TB control measures have probably contributed strongly to the reduced TB burden in Oman. To further improve TB control and promote TB elimination, NTP in Oman need to: i) address high-risk individuals, ii) increase awareness and knowledge of TB among frontline health care providers, iii) involve and integrate private providers within the TB control program, iv) review the repatriation policy and consider other strategies to improve TB control among migrant workers.