Human T-lymphotropic virus type 1 infection and disease in Spain

Abstract

: Human T-lymphotropic virus type 1 (HTLV-1) infection is a neglected disease despite roughly 15 million people are chronically infected worldwide. Lifelong less than 10% of carriers develop life-threatening diseases, mostly a subacute myelopathy known as tropical spastic paraparesis (TSP) and a lymphoproliferative disorder named adult T-cell leukemia (ATL). HTLV-1 is efficiently transmitted perinatally (breastfeeding), sexually (more from men to women) and parenterally (transfusions, injection drug user (IDU), and transplants). To date there is neither prophylactic vaccine nor effective antiviral therapy. A total of 327 cases of HTLV-1 infection had been reported at the HTLV-1 Spanish registry until December 2016, of whom 34 had been diagnosed with TSP and 25 with ATL. Overall 62% were Latin American immigrants and 13% were persons of African origin. The incidence of HTLV-1 in Spain has remained stable for nearly a decade with 20-25 new cases yearly. Of the 21 newly diagnosed HTLV-1 cases during year 2016, one was a native Spaniard pregnant woman, and four presented with symptomatic disease, including three with ATL and one with TSP. Underdiagnosis of HTLV-1 in Spain must be high (iceberg model), which may account for the disproportionate high rate of symptomatic cases (almost 20%) and the late recognition of preventable HTLV-1 transmissions in special populations, such as newborns and transplant recipients. Our current estimate is of 10 000 persons living with HTLV-1 infection in Spain. Given the large flux of immigrants and visitors from HTLV-1 endemic regions to Spain, the expansion of HTLV-1 screening policies is warranted. At this time, it seems worth recommending HTLV testing to all donor/recipient organ transplants and pregnant women regardless place of birth. Although current leukoreduction procedures largely prevent HTLV-1 transmission by blood transfusions, HTLV testing of all first-time donors should be cost-effective contributing to unveil asymptomatic unaware HTLV-1 carriers.

Clinical Presentation of Individuals With Human T-Cell Leukemia Virus Type-1 Infection in Spain

“…More than 45 centers are members of the Spanish HTLV Network, distributed across the whole national geography. Participating centers and major epidemiological findings have already been described elsewhere [12]. Uniform case report forms collecting demographics, epidemiological features, clinical signs, and manifestations are filled out for each new diagnosis by the respective doctor in charge.…”

Multiple recombinant events in human T-cell Leukemia virus Type 1: complete sequences of recombinant African strains

“…Samples collected in Spain belong to the repository of specimens from the Spanish HTLV Network, which is held at the Puerta de Hierro Research Institute in Madrid. Further data from this biological collection have been reported elsewhere [16]. All individuals have given their informed consent.…”

HTLV testing of solid organ transplant donors

“…On the other hand, roughly 4.5 out of the 47 million people currently living in Spain are foreigners, more than half coming from HTLV‐1 highly endemic regions, mostly Latin America, due to strong cultural and ancestry links. Furthermore, the country is a frequent destination for tourists with 75 million annual visitors …”

“…This is the case for Latin Americans coming to Spain. Since year 1988, there is a national register of HTLV‐1 cases in Spain . A total of 369 cases had been reported until December 2018.…”

“…A total of 369 cases had been reported until December 2018. Although most cases are foreigners, 15% of cases are native Spaniards that often acknowledge sexual contacts with individuals coming from HTLV‐1 highly endemic regions …”