Background: In March of 2003, an outbreak of Severe Acute Respiratory Syndrome (SARS) occurred in Northern Vietnam. This outbreak began when a traveler arriving from Hong Kong sought medical care at a small hospital (Hospital A) in Hanoi, initiating a serious and substantial transmission event within the hospital, and subsequent limited spread within the community.

To evaluate the risk of transmission of SARS coronavirus outside of the health-care setting, close household and community contacts of laboratory-confirmed SARS cases were identified and followed up for clinical and laboratory evidence of SARS infection. Individual- and household-level risk factors for transmission were investigated. Nine persons with serological evidence of SARS infection were identified amongst 212 close contacts of 45 laboratory-confirmed SARS cases (secondary attack rate 4.2%, 95% CI 1.5-7). In this cohort, the average number of secondary infections caused by a single infectious case was 0.2. Two community contacts with laboratory evidence of SARS coronavirus infection had mild or sub-clinical infection, representing 3% (2/65) of Vietnamese SARS cases. There was no evidence of transmission of infection before symptom onset. Physically caring for a symptomatic laboratory-confirmed SARS case was the only independent risk factor for SARS transmission (OR 5.78, 95% CI 1.23-24.24).

Objective. Use of tuberculin skin tests (TSTs) and interferon gamma release assays (IGRAs) as part of tuberculosis (TB) screening among immigrants from high TB-burden countries has not been fully evaluated. Methods. Prevalence of Mycobacterium tuberculosis infection (MTBI) based on TST, or the QuantiFERON-TB Gold test (QFT-G), was determined among immigrant applicants in Vietnam bound for the United States (US); factors associated with test results and discordance were assessed; predictive values of TST and QFT-G for identifying chest radiographs (CXRs) consistent with TB were calculated. Results. Of 1,246 immigrant visa applicants studied, 57.9% were TST positive, 28.3% were QFT-G positive, and test agreement was 59.4%. Increasing age was associated with positive TST results, positive QFT-G results, TST-positive but QFT-G-negative discordance, and abnormal CXRs consistent with TB. Positive predictive values of TST and QFT-G for an abnormal CXR were 25.9% and 25.6%, respectively. Conclusion. The estimated prevalence of MTBI among US-bound visa applicants in Vietnam based on TST was twice that based on QFT-G, and 14 times higher than a TST-based estimate of MTBI prevalence reported for the general US population in 2000. QFT-G was not better than TST at predicting abnormal CXRs consistent with TB.

In 2002, a group of Montagnard refugees living in Cambodia was accepted for resettlement in the United States. Pre-departure malaria screening and targeted treatment was conducted to prevent morbidity, and minimize the potential for local malaria transmission post-arrival. We screened 902 of 906 refugees using rapid diagnostic tests (RDTs), microscopy, and polymerase chain reaction (PCR) analysis. Twelve (1.3%) RDT results were positive and 28 (3.1%) were indeterminate. Microscopy confirmed Plasmodium species in two of the positive RDT and one of the indeterminate results. Among a random 10% sample of negative RDT results (n = 86), none were positive by microscopy. The PCR confirmed the two microscopically (and RDT) positive specimens. The PCR result was negative for all other specimens tested. Eighteen (2.0%) refugees were treated with antimalarials. The RDTs were useful in this setting, facilitating timely, sensitive diagnosis and targeted treatment. Evaluations to determine the most appropriate interventions in other refugee settings should include cost-effectiveness analyses of alternative strategies.

Chronic helminth infections are common in refugee populations and may persist years after immigration. Asymptomatic Strongyloides stercoralis infection raises particular concern because of its potential for complications in immunosuppressed patients. We examined 172 Montagnard refugees resettled to Wake County, North Carolina from 2002 through 2003. Refugees were pretreated with albendazole for five days and screened for health conditions after arrival. Eosinophilia was present in 41 of 171 refugees at the first blood draw. Only 1 of 172 had a stool helminth (Fasciola) identified by microscopy. On repeat testing, 13 people had persistent eosinophilia. Results of serologic analysis for Strongyloides were available in 24 persons. Eosinophil counts decreased significantly after treatment with ivermectin in nine refugees (P = 0.039). Persistent eosinophilia, likely caused by Strongyloides infection, was common in this cohort of Montagnard refugees. Clinicians should understand the limitations of stool microscopy in diagnosis of strongyloidiasis, the limited effectiveness of albendazole in treating strongyloidiasis, and the importance of following-up refugees with persistent eosinophilia.