Silent dissemination of HTLV-1 in an endemic area of Argentina. Epidemiological and molecular evidence of intrafamilial transmission

Abstract

BackgroundMolecular and epidemiological studies of transmission routes and risk factors for infection by HTLV-1 are extremely important in order to implement control measures, especially because of the high prevalence of HTLV-1 in several regions of the world. San Salvador de Jujuy, Northwest Argentina, is a highly endemic area for HTLV-1 and foci of tropical spastic paraparesis/HTLV-1-associated myelopathy.ObjectiveTo gain further insight into the role of intrafamilial transmission of HTLV-1 in a highly endemic region in Argentina.MethodCross-sectional study in Northwest Argentina. Epidemiological data and blood samples were collected from 28 HTLV-1 infected subjects (index cases) and 92 close relatives/cohabitants. HTLV-1 infection was diagnosed by detection of antibodies and proviral DNA. The LTR region was sequenced and analyzed for genetic distances (VESPA software), in addition to determination and identification of polymorphisms to define HTLV-1 family signatures.ResultsFifty seven of the 120 subjects enrolled had antibodies against HTLV-1 and were typified as HTLV-1 by PCR. The prevalence rate of HTLV-1 infection in family members of infected index cases was 31.52% (29/92). The infection was significantly associated with gender, age and prolonged lactation. Identity of LTR sequences and presence of polymorphisms revealed high prevalence of mother-to-child and interspousal transmission of HTLV-1 among these families.ConclusionThere is an ongoing and silent transmission of HTLV-1 through vertical and sexual routes within family clusters in Northwest Argentina. This evidence highlights that HTLV-1 infection should be considered as a matter of public health in Argentina, in order to introduce preventive measures as prenatal screening and breastfeeding control.

Lymphotropic Viruses EBV, KSHV and HTLV in Latin America: Epidemiology and Associated Malignancies. A Literature-Based Study by the RIAL-CYTED

“…HTLV prevalence in central provinces ranged from 0% to 0.2% (0.028-0.26% HTLV-1; 0.007-0.03% HTLV-2) [281,282,284,285,[287][288][289][290][291][292][294][295][296]384]. In contrast, this incidence is increased up to 9.8% of HTLV-1 in Jujuy [280,292,385,386], and to 31.5% when Jujuy family clusters were studied [387]. Surprisingly, other Northern Argentinean cities reported low HTLV positivity, namely 0.16-0.7% in Salta that borders with Jujuy [284,292], 0.6% in Formosa [292] and 0.007% in Misiones [295].…”

The challenge of describing the epidemiology of HTLV in the Amazon region of Brazil

“…Vertical transmission is common and is probably the most important route for the maintenance of HTLV within epidemiologically closed communities, as seen with HTLV-2c among Indians communities in the Amazon area of Brazil and in urban areas [6,33,[42][43][44]. Among the Guaymi in Panama, there are relatively more infected children born from infected mothers [28,45], and among the Kubenkokre, Kayapo villagers in the Amazon region of Brazil, familial cluster studies have showed the transmission of the virus crossing one or more generations, and more than 20% of the children under 9 years of age are infected [6].…”

Family Aggregation of HTLV-1 Infection Associated with FAS -670A/G Polymorphism: A Case Report

“…Human T-lymphotropic virus 1 (HTLV-1) associated diseases were originally described as sporadic entities, but family clusters have been long reported worldwide ( Ishak et al, 1995 ; da Costa et al, 2013 ; Alvarez et al, 2016 ; Frutos et al, 2017 ). Members of the same family share transmission routes of infection, virus genotypes, host genetic background, and environmental factors that increase the risk for family aggregation of the virus infection and associated diseases.…”