Methods: A recent surveillance study tested 112 asymptomatic US service members previously deployed to Iraq for latent VL with interferon gamma release assays (IGRA), enzyme-linked immunosorbent assays (ELISA), rK39 immunochromatographic tests, and quantitative polymerase chain reactions (PCR). Persons with any positive result were offered a clinical consultation to assess for exposure risks, immune-suppressing conditions, and evidence of active VL, as well as to obtain baseline laboratory studies and abdominal imaging, as needed, and to provide counseling. This is a case series of the 18 subjects who underwent clinical evaluation.
Results: Among 18 latent VL subjects evaluated, 14 were IGRA+, 4 ELISA+, 0 rK39+, and 1 PCR+ (3 parasites/mL). All were male and median age was 38.5 years. Initial deployments were in 2003-08 and median total duration in Iraq was 17 months. Musculoskeletal disease was the most common comorbidity. Four subjects previously had cutaneous leishmaniasis. One subject had psoriatic arthritis and prior TNF-α inhibitor exposure, but no other substantial risks for immunosuppression were identified. There was no evidence of active VL, although 1 subject had thrombocytopenia and 2 had elevated liver enzymes. There was no abnormal imaging. No subjects were treated and those that were PCR+ and ELISA+ are being followed clinically.
Conclusion: This series highlights the first 18 US service members diagnosed with latent VL. No patients have active disease, most have an appropriate immune response (IGRA), 4 have a TH2 humoral immune response (1 of whom is immunosuppressed), and 1 has evidence of ineffective immune control with circulating parasites. We have developed an approach to the assessment and counseling of latent VL. Further studies are needed to assess the natural history and treatment of latent VL.
N. K. Copeland,
T. J. Whitman, None
N. E. Aronson, UpToDate: Chapter Author for several leishmaniasis chapters , Licensing agreement or royalty
Elsevier: Associate editor for Hunter's Tropical Medicine and Emerging Infectious Diseases , Licensing agreement or royalty