HIV-1 group P infection: towards a dead-end infection?

HIV/1 group P (HIV-1/P) is the last HIV/1 group discovered and to date, comprises only two strains. To obtain new insights into this divergent group, we screened for new infections by developing specific tools, and analysed phenotypic and genotypic properties of the prototypic strain RBF168. In addition, the follow-up of the unique patient monitored so far, has raised the knowledge of the natural history of this infection and its therapeutic management. We developed an HIV-1/P specific sero-molecular strategy and screened over 29,498 specimen samples. Infectivity and evolution of the gag-30 position, considered as marker of adaptation to human, were explored by successive passages of RBF168 strain onto human PBMCs. Natural history and immuno-virological responses to combined antiretroviral therapy (cART) were analysed based on CD4 counts and plasmatic viral load evolution. No new infection was detected. Infectivity of RBF168 was found lower, relative to other main HIV groups and the conservative methionine found in the gag-30 position revealed a lack of adaptation to human. The follow-up of the patient during the five-year ART-free period, showed a relative stability of CD4 cell count with a mean of 326 mm. Initiation of cART led to rapid RNA undetectability with a significant increase of CD4, reaching 687 mm after 8 years. Our results showed that HIV-1/P strains remain extremely rare and could be less adapted and pathogenic than other HIV strains. These data lead to the hypothesis that HIV-1/P infection could evolve towards, or even already correspond to, a dead-end infection

Avant-propos

Après l’Atlas évolutif du paludisme à Madagascar, paru en 2002, la série des réalisations de l’Institut Pasteur de Madagascar (IPM) s’enrichit avec cet Atlas de la peste à Madagascar, qui paraît en coédition avec l’Institut de recherche pour le développement (IRD), l’Institut Pasteur de Paris (IP) et l’Agence universitaire de la francophonie (AUF). Cet ouvrage est le fruit du travail de plusieurs années d’un groupe multidisciplinaire de scientifiques de l’Institut Pasteur de Madagascar, du mi..

Atlas de la peste à Madagascar

La peste, un fléau du passé ? Non, une maladie d'actualité qui se réveille ici ou là comme l'attestent de récentes épidémies en Inde ou en Algérie. Après plusieurs décennies au cours desquelles la situation a été maîtrisée grâce à des efforts considérables en matière de recherche et de formation, Madagascar a en effet connu en 1991 un retour brutal de la maladie. La peste reste une menace pour d'autres pays dans le monde, et Madagascar représente actuellement un des foyers les plus actifs. Cet Atlas de la peste à Madagascar retrace l'histoire de la maladie dans ce pays et en présente, à partir d'observations originales et détaillées, un état des lieux. S'appuyant sur des données récentes issues des dernières techniques d'investigation, les auteurs mettent en avant de multiples recommandations pour la surveillance et la lutte contre cette redoutable maladie. Didactique, accompagné d'une riche iconographie, l'ouvrage est d'accès facile et s'adresse à tous ceux, personnels de santé, enseignants et étudiants, chercheurs, qui sont concernés par ce problème de santé. Maladie de la pauvreté, la peste se maintient à bas bruit dans de nombreux pays où elle peut réémerger brutalement

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

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

Detection and genetic polymorphism of human herpes virus type 8 in endemic or epidemic Kaposi's sarcoma from West and Central Africa, and South America

International audienceKaposi's-sarcoma-associated herpesvirus(KSHV)/human-herpes-virus-8(HHV-8) sequences originally detected in AIDS-associated Kaposi's sarcoma have been found in almost every KS tested, whether endemic, classic, iatrogenic or epidemic. Most of the studies on African KS involved East African patients. We report herewith the study of 17 African or Guyanan KS patients, 3 with epidemic KS (EKS) from Central African Republic, 3 from Senegal (2 EKS and 1 endemic KS), 3 EKS from Cameroon and 8 from French Guiana (3 EKS and 5 endemic KS). Serum-specific antibodies directed against latent and/or lytic HHV-8 antigens were present in 16 of them (94%), detected either by immunofluorescence assay and/or by immunoperoxidase. Polymerase chain reaction (PCR), using specific primers for HHV-8 ORF26 (233 bp) and ORF75 (601 bp), was carried out on DNA extracted from KS cutaneous biopsies, clinically uninvolved skin biopsies and peripheral-blood mononuclear cells (PBMC). HHV-8 DNA was detected in 16 out of 16 (100%) KS biopsies, regardless of their origin or clinico-pathological sub-type, in 7 out of 15 (47%) normal skin samples and 7 out of 16 (44%) PBMC. Comparative PCR, carried out in 7 patients, regularly found a much higher viral load in KS biopsies than in autologous normal skin and PBMC samples. Sequencing of fragments of the ORF26 and of the ORF75 demonstrated that the 16 HHV-8 strains were of the A, B or C sub-type. Furthermore, sequences of the entire ORF K1 of 4 strains showed that these HHV-8 strains of African origin were of the A5 or the B sub-type