Clinical associations of Human T-Lymphotropic Virus type 1 infection in an indigenous Australian population.
BACKGROUND
In resource-poor areas, infectious diseases may be important causes of morbidity among individuals infected with the Human T-Lymphotropic Virus type 1 (HTLV-1). We report the clinical associations of HTLV-1 infection among socially disadvantaged Indigenous adults in central Australia.


RESULTS
HTLV-1 serological results for Indigenous adults admitted 1(st) January 2000 to 31(st) December 2010 were obtained from the Alice Springs Hospital pathology database. Infections, comorbid conditions and HTLV-1 related diseases were identified using ICD-10 AM discharge morbidity codes. Relevant pathology and imaging results were reviewed. Disease associations, admission rates and risk factors for death were compared according to HTLV-1 serostatus. HTLV-1 western blots were positive for 531 (33.3%) of 1595 Indigenous adults tested. Clinical associations of HTLV-1 infection included bronchiectasis (adjusted Risk Ratio, 1.35; 95% CI, 1.14-1.60), blood stream infections (BSI) with enteric organisms (aRR, 1.36; 95% CI, 1.05-1.77) and admission with strongyloidiasis (aRR 1.38; 95% CI, 1.16-1.64). After adjusting for covariates, HTLV-1 infection remained associated with increased numbers of BSI episodes (adjusted negative binomial regression, coefficient, 0.21; 95% CI, 0.02-0.41) and increased admission numbers with strongyloidiasis (coefficient, 0.563; 95% CI, 0.17-0.95) and respiratory conditions including asthma (coefficient, 0.99; 95% CI, 0.27-1.7), lower respiratory tract infections (coefficient, 0.19; 95% CI, 0.04-0.34) and bronchiectasis (coefficient, 0.60; 95% CI, 0.02-1.18). Two patients were admitted with adult T-cell Leukemia/Lymphoma, four with probable HTLV-1 associated myelopathy and another with infective dermatitis. Independent predictors of mortality included BSI with enteric organisms (aRR 1.78; 95% CI, 1.15-2.74) and bronchiectasis (aRR 2.07; 95% CI, 1.45-2.98).


CONCLUSIONS
HTLV-1 infection contributes to morbidity among socially disadvantaged Indigenous adults in central Australia. This is largely due to an increased risk of other infections and respiratory disease. The spectrum of HTLV-1 related diseases may vary according to the social circumstances of the affected population.
Flinders University/Northern Territory Rural Clinical School, Alice Springs Hospital, Alice Springs, Northern Territory, Australia ; SAPathology, Flinders Medical Centre, Bedford Park, Adelaide, South Australia, Australia.
Lloyd
L
Einsiedel
Flinders University/Northern Territory Rural Clinical School, Alice Springs Hospital, Alice Springs, Northern Territory, Australia.
Tim
T
Spelman
Remote Health, Alice Springs, Northern Territory, Australia.
Emma
E
Goeman
Institut Pasteur, Unité d'Epidémiologie et Physiopathologie des Virus Oncogènes, Département de Virologie, Paris, France ; CNRS, UMR 3569, Paris, France.
Olivier
O
Cassar
Clinical Information Analyst, Central Australian Health Network, Alice Springs Hospital, Alice Springs, Northern Territory, Australia.
Mick
M
Arundell
Institut Pasteur, Unité d'Epidémiologie et Physiopathologie des Virus Oncogènes, Département de Virologie, Paris, France ; CNRS, UMR 3569, Paris, France.
Antoine
A
Gessain
D000328:Adult; D001315:Australia / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D015490:HTLV-I Infections / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology; D006760:Hospitalization / Q000706:statistics & numerical data; D015368:Human T-lymphotropic virus 1 / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D044382:Population Groups; D016036:Seroepidemiologic Studies; D016019:Survival Analysis