INFECTIOUS DISEASES Seroprevalence of HTLV-I and HTLV-II infection among immigrants in northern Italy F. Ansaldi 1 , M. Comar 1 , P. D’Agaro 1 , S. Grainfenberghi 3 , L. Caimi 2 , F. Gargiulo 2 , B. Bruzzone 4 , R. Gasparini 4 , G. Icardi 4 , F. Perandin 2 , C. Campello 1 & N. Manca 2 1 Department of Public Medical Sciences, University of Trieste and IRCCS ‘Burlo Garofolo’; 2 Department of Laboratory Diagnostics, Institute of Microbiology, University of Brescia; 3 Department of Dermatology, Spedali Civili, Brescia; 4 Department of Health Sciences, University of Genoa, Italy Accepted in revised form 24 January 2003 Abstract. To assess the prevalence of human T cell leukemia virus type 1 (HTLV-I) and 2 (HTLV-II) infection and the associated risk factors among im- migrants living in Northern Italy, we surveyed 3017 open-population subjects from three geographical areas and 371 prisoners. In the open population, the overall prevalence was 0.3% for HTLV-I and 0.1% for HTLV-II, while among prisoners, HTLV-I and HTLV-II infection were detected in 1.4 and 0.8% of subjects, respectively. HTLV-I prevalence was higher in subjects with multiple sexual partners or sexually transmitted diseases. This association was significant in the open-population group and close to significance in prisoners. Multivariate analysis showed that human immunodeficiency virus (HIV) seropositivity remained significantly associated with HTLV-I infection in both targeted populations (OR: 11.2 in the open population; OR: 9.9 among pris- oners), whereas sexual exposure was associated with HTLV-I seropositivity only for prisoners (OR: 14.3). No independent variable was related to HTLV-II infection. Key words: Human T cell leukemia virus type 1 and type 2, Immigrants, Prevalence, Risk factors Introduction The ways of transmission of human T cell leukemia virus type 1 (HTLV-I) and 2 (HTLV-II) are generally similar to those of human immunodeficiency virus (HIV). These include mainly transfusion of cellular blood products, sharing of injecting equipment con- taminated with infected blood, sexual contact and mother-to-child transmission by breastfeeding [1, 2]. HTLV-I is endemic in Southern Japan, markedly in Kyushu and in the Okinawa Islands, the Caribbean islands and South America, sub-Saharian Africa and Melanesia [3, 4]. HTLV-II is frequently found among native populations of America and among African pygmy tribes in Zaire and Cameroon [5, 6]. In Europe HTLV-I/II infection seems to be very rare, basing on seroprevalence rates among blood donors [7, 8]. Nevertheless, cases of ATL (i.e. adult T cell leukemia/ lymphoma) and HTLV-I associated myelopathy have been reported in European-born patients, thus sug- gesting the existence of small foci areas [9, 10]. The same epidemiological pattern is found in Italy, where sporadic cases or small family clusterings have been reported in low-risk population [11, 12]. Moreover, the epidemiological reservoir of these two retroviruses is restricted to injecting drug users (IDUs), while the proportion of infected subjects in centres for sexually transmitted diseases (STD) is less than 1% [13, 14]. Over the last few decades, demographic changes related to migration have hit Italy and the epidemi- ological profile is likely to have been affected. Two main factors should be considered: on the one hand, the large number of subjects entering Italy from HTLV-I and HTLV-II endemic areas as the Carib- bean, parts of Africa and South America; on the other hand, the influence of personal behaviour and social conditions among the immigrant population. In Italy, information on seroprevalence and risk factors for HTLV-I/II infection is very poor. The aim of this study is to evaluate the prevalence of HTLV-I/ II infected immigrants from the open population and among inmates in three cities of Northern Italy where immigration has been recently substantial. Materials and methods Population From February 1996 to April 2000, 3388 immigrants were enrolled. Three-thousand and seventeen subjects were from the open-population of three northern Italian cities: Genoa, Brescia and Trieste. They are medium-sized towns (the first has around 700,000 inhabitants; and others 250,000 each) with large im- migrant communities. In Brescia and Trieste the European Journal of Epidemiology 18: 583–588, 2003. Ó 2003 Kluwer Academic Publishers. Printed in the Netherlands.