TABLE 2.

Classification of place and time period of transmission of TB cases in the Rotterdam region, 1995 to 2006

CriterionaPlace of infectionTime of infection for patients infected in The Netherlandse
Infected in a foreign countryIndeterminatebInfected in The Netherlands≤2 yrs>2 yrsUnknown
ConfirmedProbablyProbablyConfirmed
Cases with a unique fingerprint (n = 919)
    Cases in immigrants (n = 700)
        Arrived in The Netherlands after 1/1/1993376
        In residence before 1/1/1993 and had documented contact with PTB case in The Netherlands1811c18
        In residence before 1/1/1993 and had documented history of frequent travel to countries where TB is endemic79
        In residence before 1/1/1993 and lived more yrs in foreign country than in The Netherlands in the pregenotyping period170
        In residence before 1/1/1993 without identified risks56
    Cases in nonimmigrants (n = 219)
        Documented contact with PTB case in The Netherlands391c38
        Documented history of frequent travel to countries where TB is endemic32
        No documented risks148148
Cases with a clustering fingerprint (n = 1,108)
    No preceding PTB in the clusterd (n = 62)2921 12 2 c 10
    Diagnosis within 3 mo of arrival32
    Not in residence in The Netherlands with a clustered TB case32
    Cases with a confirmed epidemiological link 258 195 63
    Cases with a possible epidemiological link 190 185 5
    Cases without an established epidemiological link 534 401 133
Cases without a DNA fingerprint (n = 609)
    Documented contact with PTB case in The Netherlands19215438
    Documented contact with PTB case in a foreign country13
    Chest X-ray abnormalities or positive TST at entrance screening43
    Cases in immigrants who lived more yrs in a foreign country than in The Netherlands151
    Cases in immigrants without other documented risks70
    Cases in nonimmigrants with documented history of frequent travel to countries where TB is endemic14
    Cases of recurrent TB in nonimmigrants1313
    Cases in nonimmigrants without documented risks113113
Total (n = 2,636)525467126838680939466113
%19.917.74.831.825.835.617.74.3
  • a Dates are given as month/day/year. PTB, pulmonary tuberculosis; TST, tuberculin skin test.

  • b Twenty-two of 56 and 21 of 70 cases had unknown dates of arrival in The Netherlands.

  • c Patients were infected by a visiting person later diagnosed with infectious TB shortly after leaving The Netherlands.

  • d These clustered cases without a preceding PTB were classified according to the trees for unique fingerprints.

  • e The classification of time of infection for 994 clustered cases infected in The Netherlands, presented in boldface in this table, is explained in Fig. 1.