TABLE 4.
Collaborative Review of WGS and Epidemiologic Data for TB Cases With Plausible Sources Among Persons Who Reported Homelessness, United States, 2011–2016
| Area* | Total Cases Among Persons With Reported Homelessness and a Plausible Source† | WGS or Local Epidemiologic Data Are Consistent With Recent Transmission,‡ n (%) | WGS or Local Epidemiologic Data Not Consistent With Recent Transmission,§ n (%) | WGS or Local Epidemiologic Data Unavailable or Inconclusive,∥ n (%) |
|---|---|---|---|---|
| Atlanta, GA | 59 | 46 (78) | 0 (0) | 13 (22) |
| Chicago, IL | 16 | 7 (44) | 0 (0) | 9 (56) |
| Dallas, TX | 116 | 83 (72) | 0 (0) | 33 (28) |
| Houston, TX | 51 | 16 (31) | 2 (4) | 33 (65) |
| Los Angeles, CA | 128 | 103 (80) | 9 (7) | 16 (13) |
| Miami, FL | 17 | 4 (24) | 0 (0) | 13 (76) |
| San Diego, CA | 28 | 2 (7) | 21 (75) | 5 (18) |
| San Francisco, CA | 9 | 6 (67) | 0 (0) | 3 (33) |
| St Petersburg, FL | 5 | 5 (100) | 0 (0) | 0 (0) |
| Total | 429 | 272 (63) | 32 (7) | 125 (29) |
Area defined based on US Department of Housing and Urban Development (HUD) Continuums of Care.18 Areas included in the table have an estimated population of PEH ≥ 10,000 in 2016 and TB incidence greater than the national average of 36 cases per 100,000 PEH during 2011–2016.
Cases reviewed are the total number of TB cases among persons with reported homelessness and a recent plausible source.
Cases consistent with recent transmission are defined by having an Mycobacterium tuberculosis isolate ≤ 5 SNPs from another recent case’s isolate by wgSNP analysis, epidemiologic links documented among PEH, a genotype known to be associated with a large outbreak affecting PEH, or a diagnostic test for M. tuberculosis infection documenting recent conversion.
Cases not consistent with recent transmission are defined by having an M. tuberculosis isolate > 5 SNPs from all other recent cases’ isolates by wgSNP analysis, previously diagnosed and untreated TB infection, or strong epidemiologic evidence suggesting transmission occurred in the remote past outside the United States, or both.
Inconclusive cases are defined by having WGS and epidemiologic data unavailable, an M. tuberculosis isolate > 5 SNPs from all recent cases’ isolates but many cases/isolates missing from the wgSNP analysis, or conflicting epidemiologic information about timing of exposure or infection.
PEH indicates persons experiencing homelessness; SNPs, single nucleotide polymorphisms; TB, tuberculosis; WGS, whole-genome sequencing.