env Sequences of Simian Immunodeficiency Viruses from Chimpanzees in Cameroon Are Strongly Related to Those of Human Immunodeficiency Virus Group N from the Same Geographic Area

Abstract

Human immunodeficiency virus type 1 (HIV-1) group N from Cameroon is phylogenetically close, in env, to the simian immunodeficiency virus (SIV) cpz-gab from Gabon and SIVcpz-US of unknown geographic origin. We screened 29 wild-born Cameroonian chimpanzees and found that three (Cam3, Cam4, and Cam5) were positive for HIV-1 by Western blotting. Mitochondrial DNA sequence analysis demonstrated that Cam3 and Cam5 belonged to Pan troglodytes troglodytes and that Cam4 belonged to P. t. vellerosus. Genetic analyses of the viruses together with serological data demonstrated that at least one of the two P. t. troglodytes chimpanzees (Cam5) was infected in the wild, and revealed a horizontal transmission between Cam3 and Cam4. These data confirm that P. t. troglodytes is a natural host for HIV-1-related viruses. Furthermore, they show that SIVcpz can be transmitted in captivity, from one chimpanzee subspecies to another. All three SIVcpz-cam viruses clustered with HIV-1 N in env. The full Cam3 SIVcpz genome sequence showed a very close phylogenetic relationship with SIVcpz-US, a virus identified in a P. t. troglodytes chimpanzee captured nearly 40 years earlier. Like SIVcpz-US, SIVcpz-cam3 was closely related to HIV-1 N in env, but not in pol, supporting the hypothesis that HIV-1 N results from a recombination event. SIVcpz from chimpanzees born in the wild in Cameroon are thus strongly related in env to HIV-1 N from Cameroon, demonstrating the geographic coincidence of these human and simian viruses and providing a further strong argument in favor of the origin of HIV-1 being in chimpanzees.

A Novel γ2-Herpesvirus of the Rhadinovirus 2 Lineage in Chimpanzees

“…For all the animals from France, except one (Gorph682), only serum was available. All these great apes were seronegative for simian immunodeficiency viruses/human immunodeficiency viruses (SIV/ HIV) except two animals from Cameroon (Cam 3 and Cam 4, named in our study PanCamDja and PanCamJac, respectively) from which a SIVcpz has recently been isolated and characterized (Corbet et al 2000). Great apes from the CIRMF exhibited an HTLV Western blot seroindeterminate profile (Georges-Courbot et al 1996), but all the 35 other animals were negative for HTLV-1/STLV-1 infection.…”

“…The larger series comprises 27 wild-born animals (23 chimpanzees and 4 gorillas), originating from different parts of Cameroon, where they were originally kept as pets after their mothers had been killed by hunters. They were then gathered in a wildlife rescue center in the South West province of Cameroon, in which some of them were kept in the same enclosure, often in close contact (Corbet et al 2000). The second group (three chimpanzees and two gorillas) originated from the large animal center of the Centre International de Recherches Médi-cales, Franceville (CIRMF) in Gabon (Georges-Courbot et al 1996).…”

“…This common chimpanzee, described as a natural host of HIV-1-related viruses (Corbet et al 2000), is therefore also a natural host for distinct ␥2-herpesviruses belonging to the two Rhadinovirus genogroups, PanRHV1a and PanRHV2.…”

“…Single-round PCR amplification and sequence analysis, without interim cloning, of chimpanzee mitochondrial (mt) DNA was performed on a 498-bp segment of the mitochondrial D-loop control region (corresponding to position 15998-16497 of the human mitochondrial sequence; Anderson et al 1981) from PBMC DNA as previously described (Gao et al 1999;Corbet et al 2000). The sequences of the primers used for chimpanzee mtDNA amplification are given in Table 2.…”

Viral diseases and human evolution

“…The HIV-1 has a relatively recent zoonotic origin. It is now believed that, after being associated with chimpanzees in Western Africa (Corbet et al 2000), the HIV in half a century was able to infect millions of humans in the entire world (Zhu et al 1999, Korber et al 2000, for critical review on the pandemic see Gould 1993).…”