Despite a decrease in incidence of tuberculosis (TB) in Duval County, Florida, from 102 cases (11.2 per 100,000 population) in 2008 to 71 cases (8.2 per 100,000) in 2011,* analysis of Mycobacterium tuberculosis genotyping data revealed a substantial increase in the percentage of TB cases with the same genotype.† That percentage increased from 27% (10 of 37) of genotyped cases in 2008 to 51% (30 of 59) of genotyped cases in 2011 (Florida Department of Health, unpublished data, 2012). During this period, the percentage of patients with this genotype who were homeless or who abused substances also increased. Because of concern over potential ongoing TB transmission involving these hard-to-reach populations, the Duval County Health Department, Florida Department of Health, and CDC conducted an investigation during February 15–March 13, 2012. As of March 13, review of medical records and interviews with TB patients had identified 99 cases related to the cluster based on matching genotype results and epidemiologic links (48 cases), matching genotype only (22), epidemiologic links only (22), or common social risk factors for TB (e.g., homelessness, incarceration, or substance abuse within 1 year of TB diagnosis) and suspected epidemiologic links (seven). The first known case with a matching genotype occurred in 2004.
Among the 99 TB cases during 2004-2012, a total of 96 (97%) patients were U.S.-born; 78 (79%) were male; 76 (77%) were black; 78 (79%) had a history of homelessness, incarceration, or substance abuse (i.e., alcohol or illicit substances); and 43 (43%) had been homeless within 1 year of TB diagnosis. Three patients were children aged <5 years. Twenty patients had known human immunodeficiency virus infection; 13 patients, all with comorbidities, had died. Site visits and review of electronic databases that track use of Duval County homeless services and incarceration found that the TB patients had stayed in several different homeless shelters and in a local jail. In addition, social network analysis identified one particular shelter and an outpatient mental health facility that serves the homeless community as the sites of concern for TB transmission during 2010-2012.
Duval County Health Department organized the screening of approximately 2,300 persons; approximately 2,100 additional persons are considered a high priority for TB screening because of recent exposure in a congregate setting to a patient with sputum smear-positive TB.1 To control ongoing TB transmission and detect and treat additional cases of active TB disease or latent TB infection, Duval County public health workers are finding and evaluating high-priority contacts and conducting TB evaluations at sites with evidence of recent TB transmission. Long-term control measures at homeless shelters will include enhanced infection control programs involving TB education, respiratory hygiene, periodic systematic TB screening of clients and workers, and environmental controls.
Genotyping data, combined with epidemiologic investigation, enabled recognition of this cluster and subsequent understanding of chains of TB transmission. Newly available electronic data systems in Duval County that document use of homeless services, stays at homeless shelters, and incarceration at a local jail also were critical in identifying likely transmission sites. Although TB incidence continues to decline in Florida and nationwide, outbreaks still occur among homeless persons, requiring sustained and aggressive control measures.2,3 Prompt identification of TB patients through symptom screening, radiographic screening, and testing for TB infection, along with evaluation of contacts of TB patients, can be difficult in hard-to-reach populations but is crucial to achieving the national goal of TB elimination.4
Vincy Samuel, MPH, Cynthia Benjamin, Ozzie Renwick, Aaron Hilliard, PhD, Duval County Health Dept; Sherrie Arnwine, Debra Spike, Jose Zabala, MHSA, Kateesha McConnell, MPH, Max Salfinger, MD, Florida Dept of Health. Kiren Mitruka, MD, Tracie Gardner, PhD, Div of TB Elimination, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention.Emma Johns, CDC Experience Fellow. Robert Luo, MD, Madsen Beau de Rochars, MD, Raymund Dantes, MD, EIS officers, CDC. Corresponding contributor: Max Salfinger, firstname.lastname@example.org, 850-245-4350.
Robert Harmon, MD, Duval County Health Dept; Richard Hopkins, MD, Florida Dept of Health. Gail Burns-Grant, Dan Ruggiero, MPS, Jimmy Keller, DHSc, Div of TB Elimination, National Centers for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, CDC.
*Additional information available at http://www.doh.state.fl.us/disease_ctrl/tb/trends-stats/trends.html.
†Spoligotype 777776777760601, and 12-locus mycobacterial interspersed repetitive units–variable number of tandem repeats (MIRU-VNTR) pattern 224325143323.
Notes From the Field: Tuberculosis Cluster Associated With Homelessness—Duval County, Florida, 2004-2012. JAMA. 2012;308(17):1736-1737. doi:10.1001/jama.2012.10046