Downloaded from www.microbiologyresearch.org by IP: 54.242.247.86 On: Wed, 21 Sep 2016 13:39:41 Journal of General Virology (1996), 77, 1089 1099. Printed in Great Britain 1089 The presence of a divergent T-lymphotropic virus in a wild-caught pygmy chimpanzee (Pan paniscus) supports an African origin for the human T-lymphotropic[simian T-lymphotropic group of viruses Anne-Mieke Vandamme, 1. Hsin-Fu Liu, 1 Marianne Van Brussel, 1 Walter De Meurichy, Z Jan Desmyter 1 and Patrick Goubau 1 1 Rega Institute for Medical Research and University Hospitals, Minderbroedersstraat 10, B-3000 Leuven and 2 Royal Zoological Society of Antwerp, Koningin Astridplein 26, B-2018 Antwerpen, Belgium We isolated a divergent simian T-lymphotropic virus (STLV) (strain PP1664) from a wild-caught African bonobo (pygmy chimpanzee, Pan paniscus). Molecular and phylogenetic characterization of this virus show that it reliably separates from the two well-established primate T-lymphotropic virus types, HTLV-I/STLV-I (PTLV-I) and PTLV-II, and from a third type isolated from an African-born Papio hamadryas and designated by us as PTLV-L. Four of eight bonobos kept at the Antwerp Zoo, Belgium, showed an aberrant PTLV serology. We amplified and sequenced a 709 bp PTLV proviral tax/rex fragment from one of the reactive bonobos. It differs by about 25 % from the homologous nucleotide sequences of PTLV-I and PTLV-L and by about 17 % from PTLV-II. This is comparable to the differences among the three known types. Including the most divergent STLV-I strains sequenced to date, for example, strain PHSul sequenced here, the divergence in this region within PTLV-I is less than 11% and within PTLV-II less than 4 %. Although very divergent, this new bonobo STLV is the closest well-characterized simian relative of HTLV-II, raising the possibility of very divergent new HTLV strains. Our results show that the number of PTLV types should be considered open and that the variety of indigenous viruses in the PTLV group is greatest in Africa. Thus, as for the other primate retroviruses HIV and SIV, PTLV most probably has its origins in Africa. Introduction Human T-lymphotropic virus types I and II (HTLV-I and -II) are retroviruses associated with neurological degeneration and leukaemia in a small number of infected individuals. Since HTLV and simian T-lympho- tropic virus (STLV) cannot be separated into distinct phylogenetic lineages according to species of origin, several authors have used the term primate T-lympho- tropic viruses (PTLV) (Goubau et al., 1994; Saksena et al., 1994; Vandamme et al., 1994; Watanabe et al., 1986). The very stable genome of these viruses provides an excellent tool for investigating the origin of PTLV in * Author for correspondence. Fax +32 16 332131. e-mail vandamme@uz.kuleuven.ac.be The new sequences reported in this paper have been deposited at the EMBL database; the accession numbers are Z46344 for STLV PP 1664 and X83117-X83120 for HTLV-I ITIS, HTLV-I MOMS, HTLV-I MWMG and STLV-I PHSul respectively. general and of HTLV-I and HTLV-II in particular (Gessain et al., 1992; Komurian et al., 1991 ; Liu et al., 1994a). The discovery of divergent Asian STLV-I (Song et al., 1994; Watanabe et al., 1986) and Asian and Australian HTLV-I strains (Bastian et aL, 1992; Gessain et al., 1993) together with the presence of HTLV-II among native Amerindians (Ferrer et al., 1993; Lairmore et al., 1990; Maloney et al., 1992) support an Asian origin of PTLV. However, recent phylogenetic studies using divergent African and Asian STLV-I strains support an African origin of the African and cosmo- politan HTLV-I strains, and an Asian origin of the Melanesian and Australian HTLV-I strains, implying several separate interspecies transmissions (Koralnik et al., 1994; Saksena et al., 1994; Song et al., 1994; Vandamme et al., 1994). The available data do not allow the origin of PTLV-I to be traced to Asia or to Africa. The American origin of HTLV-II is now also being questioned, due to the discovery of HTLV-II in in- digenous African pygmy tribes (Froment et al., 1993; Goubau et al., 1992, 1993, 1996; Gessain et al., 1995) and a distinct molecular HTLV-IIb variant in Gabon 0001-3685 © 1996 SGM