[Utility of RFLP analysis for tuberculosis case management in Okinawa Prefecture].
METHODS
Routine contact actions for tuberculosis (TB) case management at Public Health Centers (PHCs) in Okinawa Prefecture, Japan.


OBJECTIVE
To examine the utility of RFLP analysis in routine contact actions for tuberculosis at PHCs and in the epidemiological surveillance of tuberculosis in Okinawa Prefecture, Japan.


METHODS
An RFLP analysis was conducted for all isolates of TB bacilli cultured from newly registered TB patients in Okinawa Prefecture between April 1996 and September 1997. When an identical band pattern was seen in isolates from two or more patients, the staff of the PHCs discussed the possible epidemiological link based on information collected from the patients by public health nurses at interviews in routine patient service.


RESULTS
The main hospitals with TB beds, which diagnose most of the TB patients in the prefecture, and the bacteriological laboratories of the PHCs, submitted TB isolates to the Research Institute of Tuberculosis, Tokyo, for analysis. The prefecture and the PHCs conducted an additional epidemiological investigation based on the analysis results. All these activities were supervised by the Tuberculosis Surveillance Committee of the Prefecture. This organization has proven to work well, so that more than 75% of bacteriologically confirmed TB patients' strains were able be analyzed during this study period. A total of 263 samples recovered from 229 TB patients were collected and analyzed. From these, seventeen clusters have been identified, varying in size from 2 to 10. Five clusters had members that appeared to be family or friends. One cluster appeared to have a common infectious source that had not clearly been detected before the RFLP analysis. However, there was also one large cluster with members that were difficult to connect to a common source of infection, suggesting the existence of an endemic strain causing isolated infections. In many cases, links suspected through the routine contact actions by public health nurses were further supported by the RFLP analysis results.


CONCLUSIONS
RFLP analysis can be a useful tool for TB control activities of the community level, such as in Okinawa Prefecture. First, it gives clues to understanding the epidemiological situation of TB infection in a population. Second, it facilitates detection common infectious sources that might otherwise remain undetected by routine contact actions. Third, it assist public health nurses' activities in routine epidemiological investigations of patients and their contacts in TB case management.
D016000:Cluster Analysis; D004812:Epidemiologic Methods; D006801:Humans; D007564:Japan / Q000453:epidemiology; D012150:Polymorphism, Restriction Fragment Length; D014376:Tuberculosis / Q000453:epidemiology* / Q000235:genetics