As King County is bringing the tuberculosis (TB) outbreak that began in 2002 among mostly homeless individuals under control, another TB outbreak has now surfaced among mostly young men of East African origin. As of July 21, the total number confirmed or suspected cases with active TB in this new outbreak is 9 individuals; contact investigations and further case finding are ongoing.

On February 24, 2004, the index case of the new outbreak, a 21 year-old Somalian male who came to United States 1998, was suspected of having TB after complaining of 2 weeks of fever and weight loss. A chest radiograph showed left hilar adenopathy, and sputum culture eventually confirmed the diagnosis of TB. On April 1, a 20 year-old male from Ethiopia (in the US since 1984) was hospitalized with symptoms of cough, fever, and weight loss over the course of several months. A chest radiograph showed bilateral cavities consistent with TB; sputum smear showed 4+ acid-fast bacilli (AFB). This patient had previously sought medical treatment in December 2003 for similar symptoms, but the diagnosis of TB was not recognized at that time. Further history and review of radiographic data eventually identified him as the likely source case who may have been infectious as early as October 2003. Between April and May, another three males of East African descent of similar ages were confirmed to have cavitary TB and AFB smears that showed 4+ AFB; all had documented normal chest radiographs within the two months prior to diagnosis. An additional two females and two males, who had social contact with the other cases, were also diagnosed with TB between April and July. All cases have been epidemiologically linked to at least one other case, the majority having had close contact with the source case. At least four of the individuals have TB strain patterns that match. Approximately 70 contacts have been identified, which does not include other contact investigations of these individuals involving jail or health care facilities.

These individuals have similar characteristics of note. All the males are in their late teens or early 20's and are of East African descent (Sudan, Ethiopia, Eritrea, or Somalia), although they have spent varying amounts of time in the US. A majority of them have had experiences dealing with, sharing, or using street drugs-most commonly crack cocaine and marijuana. Most of the men have resided for prolonged periods of time in each others' homes; some of the cases have been involved in assaults and have spent some time in jail in the past year. These individuals come from a close-knit group, and many are reluctant to share information about contacts.

In King County, the number of TB cases in the past few years has increased to all time highs in recent history, fueled, in part, by the ongoing outbreaks. In 2003, of 155 TB cases reported, three-quarters occurred in foreign-born individuals, and almost one-quarter occurred in homeless individuals. Some of the unique difficulties facing TB Control in this newest outbreak investigation include the extreme mobility of this group and their contacts, their reluctance to share information because of illegal activities, issues regarding legal residency status, presumed government intrusion, and cultural barriers to effective communication. In this light, the need for heightened awareness and case finding among health providers to this population remains crucial.

While TB should be considered in the differential diagnosis of all individuals with a prolonged cough, especially in conjunction with other constitutional symptoms, providers should be particularly aware of the possibility of TB, especially in the demographic group described above. The rapid radiographic progression from normal to cavities, as illustrated in these cases, may possibly indicate a more virulent strain of TB; symptoms of TB, despite a normal chest radiograph, should be reason enough to collect sputum for acid-fast bacilli detection and TB culture. Conversely, physicians should also consider sputum collection for an abnormal chest radiograph in this population even without any apparent symptoms. In all cases where TB is suspected, TB Control Program should be notified immediately by calling (206) 744-4579.