Development of a Surveillance Definition for United States-Mexico Binational Cases of Tuberculosis

OBJECTIVES

Consistently collected binational surveillance data are important in advocating for resources to manage and treat binational cases of tuberculosis (TB). The objective of this study was to develop a surveillance definition for binational (United States-Mexico) cases of TB to assess the burden on US TB program resources.

METHODS

We collaborated with state and local TB program staff members in the United States to identify characteristics associated with binational cases of TB. We collected data on all cases of TB from 9 pilot sites in 5 states (Arizona, California, Colorado, New Mexico, and Texas) during January 1-June 30, 2014, that had at least 1 binational characteristic (eg, "crossed border while on TB treatment" and "received treatment in another country, coordinated by an established, US-funded, binational TB program"). A workgroup of US state, local, and federal partners reviewed results and used them to develop a practical surveillance definition.

RESULTS

The pilot sites reported 87 cases of TB with at least 1 binational characteristic during the project period. The workgroup drafted a proposed surveillance definition to include 2 binational characteristics: "crossed border while on TB treatment" (34 of 87 cases, 39%) and "received treatment in another country, coordinated by an established, US-funded, binational TB program" (26 of 87 cases, 30%). Applying the new proposed definition, 39 of 87 pilot cases of TB (45%) met the definition of binational.

CONCLUSION

Input from partners who were responsible for the care and treatment of patients who cross the United States-Mexico border was crucial in defining a binational case of TB.

Unexpected decline in tuberculosis cases coincident with economic recession - United States, 2009

BACKGROUND

Since 1953, through the cooperation of state and local health departments, the U.S. Centers for Disease Control and Prevention (CDC) has collected information on incident cases of tuberculosis (TB) disease in the United States. In 2009, TB case rates declined -11.4%, compared to an average annual -3.8% decline since 2000. The unexpectedly large decline raised concerns that TB cases may have gone unreported. To address the unexpected decline, we examined trends from multiple sources on TB treatment initiation, medication sales, and laboratory and genotyping data on culture-positive TB.

METHODS

We analyzed 142,174 incident TB cases reported to the U. S. National Tuberculosis Surveillance System (NTSS) during January 1, 2000-December 31, 2009; TB control program data from 59 public health reporting areas; self-reported data from 50 CDC-funded public health laboratories; monthly electronic prescription claims for new TB therapy prescriptions; and complete genotyping results available for NTSS cases. Accounting for prior trends using regression and time-series analyses, we calculated the deviation between observed and expected TB cases in 2009 according to patient and clinical characteristics, and assessed at what point in time the deviation occurred.

RESULTS

The overall deviation in TB cases in 2009 was -7.9%, with -994 fewer cases reported than expected (P < .001). We ruled out evidence of surveillance underreporting since declines were seen in states that used new software for case reporting in 2009 as well as states that did not, and we found no cases unreported to CDC in our examination of over 5400 individual line-listed reports in 11 areas. TB cases decreased substantially among both foreign-born and U.S.-born persons. The unexpected decline began in late 2008 or early 2009, and may have begun to reverse in late 2009. The decline was greater in terms of case counts among foreign-born than U.S.-born persons; among the foreign-born, the declines were greatest in terms of percentage deviation from expected among persons who had been in the United States less than 2 years. Among U.S.-born persons, the declines in percentage deviation from expected were greatest among homeless persons and substance users. Independent information systems (NTSS, TB prescription claims, and public health laboratories) reported similar patterns of declines. Genotyping data did not suggest sudden decreases in recent transmission.

CONCLUSIONS

Our assessments show that the decline in reported TB was not an artifact of changes in surveillance methods; rather, similar declines were found through multiple data sources. While the steady decline of TB cases before 2009 suggests ongoing improvement in TB control, we were not able to identify any substantial change in TB control activities or TB transmission that would account for the abrupt decline in 2009. It is possible that other multiple causes coincident with economic recession in the United States, including decreased immigration and delayed access to medical care, could be related to TB declines. Our findings underscore important needs in addressing health disparities as we move towards TB elimination in the United States.

Limited utility of name-based tuberculosis contact investigations among persons using illicit drugs: results of an outbreak investigation

Persons named by a patient with tuberculosis (TB) are the focus of traditional TB contact investigations. However, patients who use illicit drugs are often reluctant to name contacts. Between January 2004 and May 2005, 18 isoniazid-resistant TB cases with matching Mycobacterium tuberculosis genotypes (spoligotypes) were reported in Miami; most patients frequented crack houses and did not name potentially infected contacts. We reviewed medical records and re-interviewed patients about contacts and locations frequented to describe transmission patterns and make recommendations to control TB in this population. Observed contacts were not named but were encountered at the same crack houses as the patients. Contacts were evaluated for latent TB infection with a tuberculosis skin test (TST). All 18 patients had pulmonary TB. Twelve (67%) reported crack use and 14 (78%) any illicit drug use. Of the 187 contacts evaluated, 91 (49%) were named, 16 (8%) attended a church reported by a patient, 61 (33%) used a dialysis center reported by a patient, and 19 (10%) were observed contacts at local crack houses. Compared to named contacts, observed contacts were eight times as likely to have positive TST results (relative risk = 7.8; 95% confidence interval = 3.8-16.1). Dialysis center and church contacts had no elevated risk of a positive TST result. Testing observed contacts may provide a higher yield than traditional name-based contact investigations for tuberculosis patients who use illicit drugs or frequent venues characterized by illicit drug use.