The Association between Diabetes and Human T-Cell Leukaemia Virus Type-1 (HTLV-1) with Strongyloides stercoralis: Results of a Community-Based, Cross-Sectional Survey in Central Australia.

Mohammad Radwanur Talukder,Kerry Taylor,Richard Woodman,Kim Wilson,John Kaldor,Hai Pham,Lloyd Einsiedel

doi:10.3390/ijerph19042084

Abstract

In central Australia, an area that is endemic for the human T-cell leukaemia virus type-1 (HTLV-1), the prevalence of Strongyloides stercoralis and its association with other health conditions are unknown. A cross-sectional community-based survey was conducted in seven remote Aboriginal communities in central Australia, from 2014 to 2018. All residents aged ≥10 years were invited to complete a health survey and to provide blood for Strongyloides serology, HTLV-1 serology and HTLV-1 proviral load (PVL). Risk factors for Strongyloides seropositivity and associations with specific health conditions including diabetes and HTLV-1 were determined using logistic regression. Overall Strongyloides seroprevalence was 27% (156/576) (children, 22% (9/40); adults (≥15 years), 27% (147/536), varied widely between communities (5–42%) and was not associated with an increased risk of gastrointestinal, respiratory or dermatological symptoms. Increasing age, lower HTLV-1 PVL (<1000 copies per 105 peripheral blood leucocytes) compared to the HTLV-1 uninfected group and community of residence were significant risk factors for Strongyloides seropositivity in an adjusted model. A modest reduction in the odds of diabetes among Strongyloides seropositive participants was found (aOR 0.58, 95% CI 0.35, 1.00; p = 0.049); however, this was lost when body mass index was included in the adjusted model (aOR 0.48, 95% CI 0.48, 1.47; p = 0.542). Strongyloides seropositivity had no relationship with anaemia. Exploring social and environmental practices in communities with low Strongyloides seroprevalence may provide useful lessons for similar settings.

Highlights

Consistent with previous studies [35], we found no difference in BMI according to Strongyloides seropositivity and there was no association between Strongyloides infection and diabetes in the adjusted multivariate model that included BMI
Consistent with other recent studies from the far north of the NT [17,31], Strongyloides seropositivity was not associated with clinical symptoms in our cross-sectional study in this human T-cell leukaemia virus type 1 (HTLV-1) endemic area, nor was it associated with diabetes or anaemia
The single case of complicated strongyloidiasis that has been reported from this region since awareness was raised among clinicians a decade ago [5] followed iatrogenic immunosuppression without prior testing for strongyloidiasis [49]

Summary

Introduction

Infection with the soil-transmitted helminth Strongyloides stercoralis is highly prevalent in tropical and subtropical regions of the world, including Australia [1,2]. An estimated 370 million people are infected with Strongyloides stercoralis [3]. In Australia, Strongyloides is endemic across the tropical north of the country where prevalence rates range from 10 to 60% [2]. The nematode has a complicated lifecycle in which rhabditiform larvae excreted in human faeces develop into infective filariform larvae capable of entering the human host by penetrating intact skin. Larvae enter the venous blood and migrate to the small intestine by way of the lungs [4]. In contrast to other nematodes that infect

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