Transmission of tuberculosis among the urban homeless

JAMA. 1996 Jan;275(4):305-7.


Objective: To determine the relative frequencies of primary and reactivation tuberculosis in the urban homeless.

Design: Prospective evaluation of homeless tuberculosis patients.

Setting: Central Los Angeles, Calif.

Patients: Thirty-four homeless patients with culture-proven tuberculosis.

Interventions: IS6110-based restriction fragment length polymorphism (RFLP) analysis was performed on Mycobacterium tuberculosis isolates. If results were inconclusive, pTBN12-based RFLP analysis was performed.

Main outcome measure: Clustering of M tuberculosis isolates. A cluster consisted of two or more isolates with indistinguishable RFLP patterns.

Results: Twenty-four of 34 homeless patients had clustered isolates in six clusters.

Conclusions: The minimum percentage of cases due to primary tuberculosis in the homeless was estimated to be 53%, compared with the traditional estimate of 10% in the general population. The results suggest that primary tuberculosis caused the majority of tuberculosis cases in this population of the urban homeless in central Los Angeles.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Female
  • HIV Infections / complications
  • HIV Infections / epidemiology
  • Humans
  • Ill-Housed Persons* / statistics & numerical data
  • Los Angeles / epidemiology
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis / isolation & purification*
  • Polymorphism, Restriction Fragment Length
  • Prospective Studies
  • Recurrence
  • Tuberculosis / complications
  • Tuberculosis / diagnosis
  • Tuberculosis / epidemiology*
  • Tuberculosis / transmission
  • Urban Population / statistics & numerical data