Pulmonary Disease Is Associated With Human T-Cell Leukemia Virus Type 1c Infection: A Cross-sectional Survey in Remote Aboriginal Communities

Abstract

Background: The human T-cell leukemia virus type 1 (HTLV-1) subtype c is endemic to central Australia. We report the first large-scale, community-based, health survey of HTLV-1 and its disease associations in this setting.

Methods: Aboriginal community residents aged >2 years in 7 remote communities were invited to do a health survey that included a questionnaire, spirometry, and clinical examination by a physician blinded to HTLV-1 status, clinical records, and spirometry results. Blood was drawn for HTLV-1 serology and proviral load (PVL). Pulmonary disease was assessed clinically and spirometrically and, where records were available, radiologically after the clinical assessment. Associations between specific diseases and HTLV-1 status were determined using logistic regression, adjusting for available confounders.

Results: Overall, 579 residents (164 children aged 3-17 years; 415 adults) were examined (37.7% of the estimated resident population). HTLV-1 prevalences for children and adults were 6.1% and 39.3%, respectively. No associations were found between HTLV-1 and any assessed clinical condition among children. Chronic pulmonary disease and gait abnormalities were more common among adults with HTLV-1 infection. Adjusted odds ratios among participants with PVL ≥1000 per 105 peripheral blood leukocytes were 7.08 (95% confidence interval [CI], 2.67-18.74; P < .001), 9.81 (95% CI, 3.52-27.35; P < .001), and 14.4 (95% CI, 4.99-41.69; P < .001) for clinically defined chronic pulmonary disease, moderate-severe expiratory airflow limitation, and radiologically determined bronchiectasis/bronchiolitis, respectively, and 5.21 (95% CI, 1.50-18.07; P = .009) for gait abnormalities.

Conclusions: In the first study of HTLV-1 disease associations based on community recruitment and blinded assessment, HTLV-1 infection was strongly associated with pulmonary disease and gait abnormalities.

Keywords: HTLV-1; aboriginal; central Australia; gait abnormalities; pulmonary disease.