Does Tuberculosis Have a Seasonal Pattern among Migrant Population Entering Iran?

Document Type : Original Article


1 Mazandaran University of Medical Sciences, Sari, Iran

2 Department of Biostatistics and Epidemiology, Faculty of Health, Kerman University of Medical Sciences, Kerman, Iran

3 Neurology Research Center, Shafa Hospital, Kerman University of Medical Sciences, Kerman, Iran

4 Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran


There are few quantitative documents about the seasonal incidence of tuberculosis (TB) among immigrant populations. Concerning the significant role of recognizing seasonal changes of TB in improving the TB control program, this study determines the trend and seasonal temporal changes of TB among immigrants entering Iran.
In this longitudinal study, data from the Iranian TB register Program (from 2005 to 2011) was used. The aggregated number of monthly and seasonal TB cases was obtained by adding the daily counts. Data was analyzed by Chi-square, Independent T-test, ANOVA, and Poisson regression using Stata 11 and SPSS 20 software.
Among 74,155 registered patients with TB, 14.3% (10,587) were non-Iranian who had immigrated to Iran from 29 different countries. The highest aggregated number of seasonal and monthly incidence of TB in immigrants was observed in spring (2824, P= 0.007) and in May (1037, P< 0.001). The number of non-Iranian patients with TB increased significantly over the years (β= 0.016, P= 0.001).
This study shows that immigrants constitute a significant portion of TB patients recorded in Iran and this trend is increasing. Also, the peak incidence of this disease is the second month of the spring.


Main Subjects

  1. Moosazadeh M, Khanjani N, Bahrampoor A. Seasonality and Temporal Variations of Tuberculosis in the North of Iran. Tanaffos 2013; 12: 35–41.
  2. Ignatova A, Dubiley S, Stepanshina V, Shemyakin I. Predominance of multi-drug-resistant LAM and Beijing family strains among Mycobacterium tuberculosis isolates recovered from prison inmates in Tula Region, Russia. J Med Microbiol 2006; 55: 1413–8. doi: 10.1099/jmm.0.46575-0
  3. Hassanzadeh J, Nasehi M, Rezaianzadeh A, Tabatabaee H, Rajaeifard A, Ghaderi E. Pattern of Reported Tuberculosis Cases in Iran 2009-2010. Iran J Public Health 2013; 42: 72–8.
  4. Dye C, Watt CJ, Bleed D. Low access to a highly effective therapy: A challenge for international tuberculosis control. Bull World Health Organ 2002; 80: 437–44.
  5. Corbett EL, Bandason T, Bun Cheung YB,  Munyati S, Godfrey-Faussett P, Hayes R, et al. Epidemiology of tuberculosis in a high HIV prevalence population provided with enhanced diagnosis of symptomatic disease. PLoS Med 2007; 4: e22. doi: 10.1371/journal.pmed.0040022
  6. Moosazadeh M, Khanjani N. The Existing Problems in the Tuberculosis Control Program of Iran: A Qualitative Study. Journal of Qualitative Research in Health Sciences 2012; 1: 189–201.
  7. Nasehi M, Moosazadeh M, Amiresmaeili M, Parsaee M, Nezammahalleh A. [The Epidemiology of Factors Associated with Screening and Treatment Outcomes of Patients with Smear Positive Pulmonary Tuberculosis: A Population-Based Study]. J Mazandaran Univ Med Sci 2012; 21 : 9–18.
  8. Migliori GB, Espinal M, Danilova ID, Punga VV, Grzemska M, Raviglione MC. Frequency of recurrence among MDR-tB cases successfully treated with standardised short-course chemotherapy. Int J Tuberc Lung Dis 2002; 6: 858–64.
  9. Arshad S, Bavan L, Gajari K, Paget SNJ, Baussano I.  Active screening at entry for tuberculosis among new immigrants: a systematic review and meta-analysis. Eur Respir J 2010; 35: 1336–45. doi: 10.1183/09031936.00054709
  10. Dasgupta K, Menzies D. Cost-effectiveness of tuberculosis control strategies among immigrants and refugees. Eur Respir J 2005; 25: 1107–16. doi: 10.1183/09031936.05.00074004
  11. Cohen T, Murray M. Incident tuberculosis among recent US immigrants and exogenous reinfection. Emerg Infect Dis 2005; 11: 725. doi: 10.3201/eid1105.041107
  12. Vos AM, Meima A, Verver S, Looman CW, Bos V, Borgdorff MW, et al. High incidence of pulmonary tuberculosis persists a decade after immigration, the Netherlands. Emerg Infect Dis 2004; 10: 736–9. doi: 10.3201/eid1004.030530
  13. Lillebaek T, Andersen AB, Dirksen A, Smith E, Skovgaard LT, kok-Jensen A. Persistent high incidence of tuberculosis in immigrants in a low-incidence country. Emerg Infect Dis 2002; 8: 679. doi: 10.3201/eid0807.010482
  14. Akhtar S, Mohammad HG. Nonlinear pattern of pulmonary tuberculosis among migrants at entry in Kuwait: 1997–2006. BMC Public Health 2008; 8: 264.  doi: 10.1186/1471-2458-8-264
  15. Douglas AS, Strachan DP, Maxwell JD. Seasonality of tuberculosis: The reverse of other respiratory diseases in the UK. Thorax 1996; 51: 944–6. doi: 10.1136/thx.51.9.944
  16. Rios M, Garcia JM, Sanchez JA, Perez D. A statistical analysis of the seasonality in pulmonary tuberculosis. Eur J Epidemiol 2000; 16: 483–8.
  17. Thorpe LE, Frieden TR, Laserson KF, Wells C, Khatri GR. Seasonality of tuberculosis in India: is it real and what does it tell us? Lancet 2004; 364: 1613–4. doi: 10.1016/s0140-6736(04)17316-9
  18. Leung CC, Yew WW, Chan TYK, Tam CM, Chan CY, Chan CK, et al. Seasonal pattern of tuberculosis in Hong Kong.  Int J Epidemiol 2005; 34: 924–30.
  19. Nagayama N, Ohmori M. Seasonality in various forms of tuberculosis. Int J Tuberc Lung Dis 2006; 10: 1117–22.
  20. Luqureo FJ, Sanchez-Padilla E, Simon-Soria F, Eiros JM, Golub JE. Trend and seasonality of tuberculosis in Spain, 1996-2004. Int J Tuberc Lung Dis 2008; 12: 221–4.
  21. Schaaf HS, Nel ED, Beyers N,  Gie RP, Scott F, Donald PR. A decade of experience with Mycobacterium tuberculosis culture from children: a seasonal influence on incidence of childhood tuberculosis. Tuber Lung Dis 1996; 77: 43–6.  doi: 10.1016/s0962-8479(96)90074-x
  22. Yamamoto S, Shimizu A, KUchimura K, Ohmori MMA. Seasonal variatin in the incidence of pulmonary tuberculosis among the eldery in the Kanto area and its metrological factors. JPN J Biometeor 2003; 40: 83–92
  23. Liao CM, Hsieh NH, Huang TL, Cheng YH, Lin YJ, Chio CP, et al. Assessing trends and predictors of tuberculosis in Taiwan. BMC Public Health 2012; 12: 29. doi: 10.1186/1471-2458-12-29
  24. Fares A. Seasonality of Tuberculosis. J Glob Infect Dis 2011; 3: 46–55. doi: 10.4103/0974-777x.77296
  25. Willis MD, Winston CA, Heilig CM, Cain KP, Walter ND, Kenzie M. Seasonality of Tuberculosis in the United States, 1993-2008. Clin Infect Dis 2012; 54: 1553–60. doi: 10.1093/cid/cis235
  26. Akhtar S, Mohammad HG. Seasonality in pulmonary tuberculosis among migrant workers entering Kuwait. BMC Infect Dis 2008; 8: 3.  doi: 10.1186/1471-2334-8-3
  27. Metanat M, Sharifi-Mood B, Alavi-Naini R, Aminianfar M. [The epidemiology of tuberculosis in recent years: Reviewing the status in south-eastern Iran].  Zahedan J Res Med Sci  2012; 13: 1–7.
  28. Nasehi M, Mohammad K, Gouya MM,  Madjdzadeh SR, Zamani G, Holakoii K, et al. Health Care System Delay in Diagnosis and Treatment of Contagious Tuberculosis in I.R. IRAN – 2003. Tanaffos 2003; 2: 55–64.
  29. Taghizadeh Asl R, Mohammad K, Majdzadeh R. [Seasonality pattern of Tuberculosis in Iran]. Journal of School of Public Health 2012; 3. Available from: