Tuberculosis (TB) continues to cause illness and death in California and the California border region. During 2017-2018, the TB case rate in California was 5 per 100,000 (4,150 cases). California’s case rate has remained consistently higher than the national case rate (3 per 100,000 in 2018), and California has reported the most TB cases in the United States. The decline in TB cases has slowed in recent years. Between the peak of the epidemic in 1992 and 2000, the number of cases fell by an average of 6% each year; between 2000 and 2013, the rates declined 4% each year; between 2013 and 2017 there was only a 1% average decrease in cases each year. In fact, between 2017 and 2018, there was a 2% increase in TB cases. During 2014-2016, for which recent complete outcome data are available, 10% (625 cases) of individuals with TB in California died from TB.

CDPH is committed to preventing, controlling and eventually eliminating TB in California. Progress toward TB elimination in California is likely to be hastened by strong collaborations with national and international health partners.

California border counties are substantial contributors to the state’s TB burden, contributing 14% of the reported TB cases during 2017-2018. During this time, Imperial County reported a case rate of 25 per 100,000 (96 cases), the highest rate among all California counties. San Diego County reported a case rate of 7 per 100,000 (463 cases). Both counties reported a higher rate than that of California (Fig. 5.1).

Most individuals with TB in California during 2017-2018 were born outside the United States (82%). The most common birth country was Mexico, which accounted for 21% (871 cases) of all California TB cases. Border counties reported a higher rate of individuals with TB born in Mexico than the state average: 60% (58 cases) of all Imperial County TB cases and 28% (128 cases) of all San Diego County TB cases.

Mycobacterium bovis (M. bovis) is part of the Mycobacterium tuberculosis complex and causes TB disease in animals and humans, significantly contributing to TB morbidity in children. Transmission occurs through consumption of contaminated, unpasteurized dairy products. There were 90 cases (3% of genotyped cases) with genotyping results indicating M. bovis infection in California during 2016-2017, the most recent years for which complete data are available. During this time, approximately one-third of M. bovis cases occurred in the border region; San Diego County reported 29% of all M. bovis cases, the highest rate in California, and Imperial reported an additional two cases. Another 28% were reported in Los Angeles County. Nearly half the M. bovis cases reported consumption of raw dairy products made outside the U.S., predominantly originating in Mexico.