The effect of TB on California communities triggered one of the state’s most effective public health responses. TB disease and death, and its economic impact, shifted from a household conversation to a serious focus among doctors and government agencies. In 1913, the state health commission launched a structured investigation of the TB problem and reported that, “constantly present in this state is [sic] between 40,000 and 50,000 tuberculous patients in active stages” . TB was the leading cause of premature death, and the average age of death from TB was 30. The Commission counted 5000 deaths each year in California and noted that each death terminated only after many months or years of suffering during which the disease could be spread to others .
The economic consequences of TB were also noticed. The Commission estimated that the cost of TB to California was over $20 million ($478.8 million in 2015 dollars) each year . Families were devastated and became homeless when the primary wage earner died or could no longer work. Many persons turned to welfare programs and the government invested in the support of Californians with TB and in the hospitals that cared for them.
Medical and public health infrastructure became stronger and concentrated on detecting TB and averting its spread. By 1920, there were well over 100 TB hospitals and sanatoria operating in California. Isolation of TB patients in sanatoria removed many contagious persons from crowded urban and congregate settings. Laws that required doctors to report TB to public health authorities and that compelled isolation helped to interrupt transmission and set the stage for local and state public health programs as well as the modern public health surveillance systems we have today. These public health programs were central in the execution of the state TB commission recommendations.
TB among cattle was also recognized as interconnected to the human TB epidemic. According to the Commission, in 1913, 15–30 % of cows were infected with tuberculosis . Consumption of raw dairy products was thought to be the source of 10–30 % of TB cases in humans . The eradication of bovine TB was initially thought an impossible feat but proved pivotal in driving down TB in humans . Eradication involved federal, state, and local governments and massive testing and culling of cows. Transmission to humans was curtailed by instituting pasteurization. While raw milk was the only milk consumed in 1900, commercially available pasteurized milk became the norm by 1936 .
The gains produced by these public health interventions were augmented by development of effective antituberculosis therapy. Especially after the middle of the 20th century when multidrug treatment became available , TB disease was driven down further and death became a fate for a minority of those with TB. Treatment shifted from inpatient to outpatient settings. Hospitals, once crowded with TB patients, became sites of care for TB patients with advanced or life-threatening illness. The TB-specific interventions coincided with other advances affecting general health and healthcare which also likely made a difference. For example, improved nutrition may have reduced progression of latent TB infection to TB disease and improved housing and working conditions may have reduced transmission. As a result, from 1913 to 1981, there was a 60 % drop in TB cases and a >90 % drop in the rate of TB in California expressed as cases per 100,000 population.
However, during the 1980s, the public health infrastructure that was built up previously in the century was neglected . Categorical funding for US TB control programs was halted beginning in 1970. The resource shift away from TB control was followed by a large increase in TB cases in the USA and California (Fig. 1). Several factors contributed to the increase, including a surge in immigration of persons with infection from high burden countries, the vulnerability of HIV-infected persons with weakened immune systems, and relaxing of public health measures and infection control. It became clear that the availability of effective antituberculosis drugs without the ongoing support of public health interventions was not enough to keep TB in check. Once again, government, doctors, and public health programs needed to work together to fight TB.
What ensued was an intensive investment in hospital infection control measures and support for patients to continue TB treatment safely after discharge from the hospital. Investments also included fiscal resources to strengthen local TB programs, expanded coverage of indigent populations with TB by the state’s Medicaid program, and use of new strategies to enable completion of treatment such as housing of homeless patients and directly observed therapy. A more robust TB surveillance system was implemented in 1993 that included reporting of drug susceptibility and TB treatment outcomes. More recently, improvements in immigrant screening have made an additional important dent in case numbers in California [8, 9].