Journal of Medical Virology 80:1689–1694 (2008) HIV-1 Diversity Among Inmates of Italian Prisons Benedetta Longo, 1 Stefano Novati, 2 Stefania Montieri, 1 Emanuele Pontali, 3 Fabiana Taglia, 1 Guido Leo, 4 Sergio Babudieri, 5 Giulio Starnini, 6 Roberto Monarca, 7 Barbara Suligoi, 1 Giovanni Rezza, 1 and Massimo Ciccozzi 1 * on behalf of the Italian Study Group on HIV in Prison (ISGHP) { 1 Epidemiology Unit, Department of Infectious Diseases, Istituto Superiore di Sanita`, Rome, Italy 2 Clinica Malattie Infettive, Fondazione I.R.C.C.S. San Matteo, Pavia, Italy 3 Casa Circondariale Genova-Marassi and S.C. Malattie Infettive, Ospedale Galliera, Genoa, Italy 4 Ospedale Amedeo di Savoia, Turin, Italy 5 Istituto di Malattie Infettive, Universita`di Sassari, Sassari, Italy 6 U.O. Medicina Protetta-Malattie Infettive, Ospedale Becolle, Viterbo, Italy 7 Polo Infettivologico, Centro Riferimento AIDS, ASL Viterbo, Italy In Italy, the prevalence of non-B HIV-1 subtypes ranges reportedly from 5.4% to 12.6%, yet there are no data on their circulation in prisons, where the prevalence of HIV infection is high. A retro- spective study was conducted to evaluate the circulation of non-B subtypes and to characterize their determinants in five Italian prisons. To this end an aliquot of samples of blood was taken in the period 2001–2006 from all 262 HIV-positive inmates in whom antiretroviral treatment had failed. Complete HIV-1 PR and RT regions were sequenced for all samples and subjected to phylogenetic analysis; 250 (95.4%) sequences clustered with subtype B. The non-B subtype was found in 4% of Italian prison inmates and 16.7% of non-Italian prison inmates; the overall percentage increased from 1.8% for inmates infected in 1982–1990 to 4.4% in 1991–1999 and 21.9% in 2000–2006. Factors significantly asso- ciated with non-B subtypes were an exposure to other than injecting drug use and a first positive HIV test in 2000–2006. Non-B subtypes were distributed within five monophyletic clades. In all cases but one, it was possible to correlate the history of HIV-exposure to the origin of the clade, with high bootstrap values. In conclu- sion, although the sample may not be represen- tative of the prison inmate population in Italy, the data suggest strongly that the circulation of non-B subtypes has apparently increased. Non-B subtypes were found to have been asso- ciated with heterosexual contact and time of the first HIV-positive test. Knowledge of the different subtypes circulating in prisons may be useful for tracking the epidemiology of HIV infection and for choosing antiretroviral therapy. J. Med. Virol. 80:1689 – 1694, 2008. ß 2008 Wiley-Liss, Inc. KEY WORDS: HIV subtype; phylogeny; epide- miology INTRODUCTION In Italy, as in other countries, the prevalence of HIV infection is substantially higher among prison inmates than in the general population (7.5% vs. 0.02%, respectively) [Babudieri et al., 2005; Anonymous, 2007; COA-Centro Operativo AIDS, 2007]. The high preva- lence can be explained by the high concentration of injecting drug users and persons engaging in unsafe sexual behavior [Spaulding et al., 2002]. Although most HIV-positive inmates become infected before incarcer- ation [Spaulding et al., 2002], transmission can also occur within the prisons [Testa et al., 2006], which tend to be characterized by overcrowding, promiscuity, unsafe homosexual intercourse, and a lack of hygiene. Inmates also engage in other behaviors that constitute a risk for the transmission of bloodborne viruses in general, such as tattooing and the sharing of syringes { Lorenzo Drago (Lab. Microbiologia, Dip.to Scienze Precliniche ‘‘Litavialba’’, Universita ` degli studi di Milano); Stefano Boros (Rep. Epidemiologia, Dip.to MIPI, Istituto Superiore di Sanita `, Rome); Anna Maria Ialungo (U.O. Medicina Protetta-Malattie Infettive, Ospedale Belcolle, Viterbo); Serena dell’Isola (U.O. Medicina Protetta-Malattie Infettive, Ospedale Belcolle, Viterbo); Maria Grazia Milia (Laboratorio di Biologia Molecolare, Ospedale Amedeo di Savoia, Turin); Agostina Ventura (Dip. to Scienze della Salute, Universita ` di Genoa). *Correspondence to: Massimo Ciccozzi, Epidemiology Unit, Department of Infectious Diseases, Istituto Superiore di Sanita `, Viale Regina Elena 299, 00161 Rome, Italy. E-mail: massimo.ciccozzi@iss.it Accepted 5 June 2008 DOI 10.1002/jmv.21275 Published online in Wiley InterScience (www.interscience.wiley.com) ß 2008 WILEY-LISS, INC.