Background: There are rapidly increasing numbers of immigrant workers coming for jobs in Thailand. These immigrant workers often harbor some serious communicable diseases.
Objective: To describe the prevalence of infectious diseases in these immigrant workers.
Material and Method: This is a retrospective study of immigrant workers who presented for check-ups needed for work permits at Rajavithi Hospital during 1 January 2008 to 31 December 2010. They were examined for serious infectious disease including pulmonary TB, elephantiasis, leprosy, syphilis and malaria. Their health status was analyzed.
Results: A total of 102,090 immigrant workers were examined. The majority of cases were female (58.4%) and 94.3% of the population was under the age of 40. Workers from Burma constituted the most cases, (78.9%), followed by workers from Laos (14.0%) and Cambodia (7.0%). The prevalence of infectious diseases in all workers was 1,612.3 cases per 100,000 population. Patients with pulmonary TB, elephantiasis, leprosy, syphilis and malaria were 1,112.7, 7.8, 4.9, 465.3 and 21.5 cases per 100,000 population respectively. The prevalence of TB in Burmese, Lao and Cambodian workers was 1,119.3, 885.9 and 1,493.2 cases per 100,000 population respectively. The prevalence of syphilis in Burmese, Lao and Cambodian workers was 467.8, 258.1 and 851.2 cases per 100,000 population respectively.
Conclusion: Immigrant workers with infectious diseases were 1,612.3 cases per 100,000 population. Those harboring these serious transmitted diseases may be an important factor in these diseases becoming widespread in Thailand.

Keywords: Infectious, Immigrant, Tuberculosis