Mycobacterium tuberculosis disease in Somali immigrants in Minnesota

To characterize pulmonary and extrapulmonary Mycobacterium tuberculosis cases in the Somali community in Minnesota.

Retrospective chart review of active tuberculosis cases in Somalis reported to the Minnesota Department of Health between January 1993 and June 1998.

Ethnic Somalis in the state of Minnesota with M tuberculosis diagnosed by positive culture or radiographic findings consistent with tuberculosis and clinical improvement when treated with antituberculous drugs.

Eighty-two Somali patients were diagnosed with tuberculosis during the study period. Extrapulmonary disease (typically lymphadenopathy) was present in 46% (n = 38). The 1997 incidence of tuberculosis in Minnesota's Somali population was estimated at 170 cases per 100,000 population compared with a national incidence of 20.5 per 100,000 among African Americans and 2.5 per 100,000 among whites. Ninety percent of Somali patients were < 40 years of age; 63% were diagnosed within 1 year of immigration, and > 90% had positive results with the purified protein derivative skin test. M tuberculosis was confirmed in 24 of 25 isolates from extrapulmonary cases. Multidrug resistance was present in 3.4%, and only two patients had AIDS.

Somalis have a high incidence of active disease, with frequent extrapulmonary involvement in the absence of AIDS, clinical presentation shortly after immigration, and infrequent infection with resistant organisms. Health-care providers should maintain an increased awareness for tuberculosis when evaluating Somali immigrants.