Human T-Lymphotropic Viruses (1 and 2)

Chapter 269 Human T-Lymphotropic Viruses (1 and 2)





Epidemiology


HTLV-1 infects 10-20 million persons globally. It is endemic in southwestern Japan (where >10% of adults are seropositive), areas of the Caribbean including Jamaica and Trinidad (up to 6%), and in parts of sub-Saharan Africa (up to 5%). Lower seroprevalence rates are found in South America (up to 2%) and Taiwan (0.1-1%). There is microclustering with marked variability within geographic regions.


The seroprevalence of HTLV-1 and HTLV-2 in the USA in the general population is 0.01-0.03% for each virus, with higher rates with increasing age. HTLV-1 infection correlates greatest with birth in endemic areas or sexual contact with persons from endemic areas. HTLV-2 infection correlates with intravenous illicit drug use. A prevalence of approximately 18% was found in a study of illicit drug users in the USA, often with concomitant HIV infection.


HTLV-1 and HTLV-2 are transmitted as cell-associated viruses by vertical transmission from mother to child and horizontal transmission through genital secretions, contaminated blood products, and intravenous illicit drug use. Vertical HTLV-1 transmission occurs primarily via breast-feeding from infected mothers, with a 3-fold increased risk of transmission with breast-feeding for >6 mo. Intrauterine and intrapartum transmission account for <5% of vertical transmission. In Japan, approximately 20-25% of children born to infected mothers become infected, and >90% of HTLV-1-infected children have HTLV-1-infected mothers. HTLV-2 may also be transmitted via breast-feeding but has a slightly lower reported transmission rate via breast milk of approximately 14%.



Jun 18, 2016 | Posted by in PEDIATRICS | Comments Off on Human T-Lymphotropic Viruses (1 and 2)

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