Prevalence and Associated Risk Factors of HTLV/HIV Co-Infection among People who inject Drugs (PWIDs): A Review

Abstract

Human T-cell lymphotropic viruses type 1 and 2 (HTLV1/2) and HumanImmunodeficiency Virus (HIV) co-infections show a worldwide distribution. Theprevalence varies according to geographic region, racial group and populationtype. HTLVs and HIV share similar routes of transmission and tropism forT-lymphocytes thus co-infection is common. HTLV-HIV co- infections occurfrequently among PWIDs (People Who Inject Drugs) and HIV positive patients.HTLV-1/HIV co-infection has been documented to accelerate progression toAcquired Immunodeficiency Syndrome (AIDS) while HTLV-2 has a protectiveeffect as a result of reduced HIV replication. This review primarily analyzed theglobal trends of prevalence and associated risk factors of HTLV mono-infectionand HTLV-HIV co-infection among PWIDs.Secondary objectives included an analysis on the global trends in prevalenceand risk factors of HTLV/HIV co-infections among HIV positive patients and ananalysis on HTLV subtypes present among PWIDs and HTLV-HIV co-infectedPWIDs and patients. Based on the three categories, PUBMED and Google Scholarwere systematically searched for relevant articles published between January1988 and May 2017. A total of 67 articles from different countries were reviewedand results were presented in tables. Iran reported the highest HTLV prevalenceamong PWIDs while USA and Kenya (19.3%) reported the highest prevalenceamong HTLV-HIV co-infected PWIDS and patients respectively. Introduction ofsubtypes to countries that were previously not endemic suggested transmissionsthrough immigration and travel. Based on the studies, black race and older agewere the common risk factors among HTLV-HIV co-infected PWIDs and patientsas well as HTLV infected PWIDs. High risk injection and sexual risk factorsvaried from one study to another. We recommend introduction of regular HTLVscreening alongside HIV screening in outpatient clinics that PWIDs attend so asto reduce risk of transmission and to create awareness