Prevalence of human T-lymphotropic virus type 1 and 2 infection in Sweden.
BACKGROUND
Prevalence data on human T-lymphotropic virus types 1 and 2 (HTLV-1/2) in Sweden have not been updated since 1995. The seroprevalence among blood donors at that time was 0.2/10,000. A few years earlier, a high prevalence of HTLV-2 was found in intravenous drug users (IDUs) in Stockholm (3.4%). The objective of this study was to update information on the seroprevalence of HTLV in several study groups.


METHODS
Serum samples from pregnant women, hepatitis C virus (HCV)-positive individuals, and IDUs in Stockholm were investigated for HTLV-1/2 antibodies. Data from the mandatory HTLV-1/2 screening (2003-2006) of in vitro fertilization (IVF) clients were compiled, as well as data from new blood donors.


RESULTS
Eight out of 35,000 IVF patients were positive for anti-HTLV-1/2 (seroprevalence 2.3 per 10,000). Of the anti-HCV-positive individuals (n = 355), 1 sample was HTLV-1-positive (28.2 per 10,000). From 1995 to 2007, 18 HTLV-positive new blood donors were identified out of approximately 550,000 individuals tested (0.3 per 10,000). Thirty-five of 1079 tested IDUs were screening reactive.


CONCLUSIONS
Since the start of screening in 1994, there has been no increased seroprevalence of HTLV-1/2 among blood donors in Sweden. Seroprevalence among Swedish IVF patients is 10 times higher than among blood donors. This finding is comparable to a 2003 European seroprevalence study of pregnant women in 7 countries. However, the possibility that the IVF group includes individuals with a higher risk of acquiring sexually transmitted infections, including HTLV, than the general population cannot be ruled out.
Department of Laboratory Medicine, Örebro University Hospital, Örebro, Sweden. kerstin.malm@orebroll.se
Kerstin
K
Malm
Bengt
B
Ekermo
Kristina
K
Hillgren
Sven
S
Britton
Hans
H
Fredlund
Sören
S
Andersson
D000328:Adult; D001782:Blood Donors / Q000706:statistics & numerical data; D016009:Chi-Square Distribution; D055030:Drug Users / Q000706:statistics & numerical data; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data; D015490:HTLV-I Infections / Q000453:epidemiology* / Q000821:virology; D015491:HTLV-II Infections / Q000453:epidemiology* / Q000821:virology; D006526:Hepatitis C / Q000453:epidemiology / Q000821:virology; D006801:Humans; D008297:Male; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology / Q000821:virology; D016036:Seroepidemiologic Studies; D015819:Substance Abuse, Intravenous / Q000453:epidemiology / Q000821:virology; D013548:Sweden / Q000453:epidemiology