National Tuberculosis Genotyping and Surveillance Network: Design and Methods

The National Tuberculosis Genotyping and Surveillance Network was established in 1996 to perform a 5-year, prospective study of the usefulness of genotyping Mycobacterium tuberculosis isolates to tuberculosis control programs. Seven sentinel sites identified all new cases of tuberculosis, collected information on patients and contacts, and obtained patient isolates. Seven genotyping laboratories performed DNA fingerprinting analysis by the international standard IS6110 method. BioImage Whole Band Analyzer software was used to analyze patterns, and distinct patterns were assigned unique designations. Isolates with six or fewer bands on IS6110 patterns were also spoligotyped. Patient data and genotyping designations were entered in a relational database and merged with selected variables from the national surveillance database. In two related databases, we compiled the results of routine contact investigations and the results of investigations of the relationships of patients who had isolates with matching genotypes. We describe the methods used in the study

Acute Hemorrhagic Conjunctivitis: Investigation of a Large-scale Community Outbreak in Dade County, Florida

An outbreak of acute hemorrhagic conjunctivitis (AHC) due to enterovirus type 70 occurred in Dade County, Florida, from September to December 1981. Younger age groups, members of larger households, and the poor were at significantly greater risk of acquiring AHC than others in the community. Schoolchildren were most likely to introduce AHC into the household. After exclusion of all affected children from school, there was a dramatic reduction in reported cases, with attack rates declining more rapidly for school-aged children than for other age groups. Although AHC spread readily among family members, a retrospective study of 124 affected households showed an association between lower attack rates and simple hygienic measures. Should outbreaks of AHC recur, measures to reduce transmission should include exclusion of affected schoolchildren and educating the public about hygienic precautions.(JAMA 1983;249:1283-1289

DNA Fingerprinting of Mycobacterium tuberculosis Isolates from Epidemiologically Linked Case Pairs

DNA fingerprinting was used to evaluate epidemiologically linked case pairs found during routine tuberculosis (TB) contact investigations in seven sentinel sites from 1996 to 2000. Transmission was confirmed when the DNA fingerprints of source and secondary cases matched. Of 538 case pairs identified, 156 (29%) did not have matching fingerprints. Case pairs from the same household were no more likely to have confirmed transmission than those linked elsewhere. Case pairs with unconfirmed transmission were more likely to include a smear-negative source case (odds ratio [OR] 2.0) or a foreign-born secondary case (OR 3.4) and less likely to include a secondary case <15 years old (OR 0.3). Our study suggests that contact investigations should focus not only on the household but also on all settings frequented by an index case. Foreign-born persons with TB may have been infected previously in high-prevalence countries; screening and preventive measures recommended by the Institute of Medicine could prevent TB reactivation in these cases