The imprint of the Slave Trade in an African American population: mitochondrial DNA, Y chromosome and HTLV-1 analysis in the Noir Marron of French Guiana

<p>Abstract</p> <p>Background</p> <p>Retracing the genetic histories of the descendant populations of the Slave Trade (16^th-19^thcenturies) is particularly challenging due to the diversity of African ethnic groups involved and the different hybridisation processes with Europeans and Amerindians, which have blurred their original genetic inheritances. The Noir Marron in French Guiana are the direct descendants of maroons who escaped from Dutch plantations in the current day Surinam. They represent an original ethnic group with a highly blended culture. Uniparental markers (mtDNA and NRY) coupled with HTLV-1 sequences (<it>env </it>and LTR) were studied to establish the genetic relationships linking them to African American and African populations.</p> <p>Results</p> <p>All genetic systems presented a high conservation of the African gene pool (African ancestry: mtDNA = 99.3%; NRY = 97.6%; HTLV-1 e<it>nv </it>= 20/23; HTLV-1 LTR = 6/8). Neither founder effect nor genetic drift was detected and the genetic diversity is within a range commonly observed in Africa. Higher genetic similarities were observed with the populations inhabiting the Bight of Benin (from Ivory Coast to Benin). Other ancestries were identified but they presented an interesting sex-bias. Whilst male origins spread throughout the north of the bight (from Benin to Senegal), female origins were spread throughout the south (from the Ivory Coast to Angola).</p> <p>Conclusions</p> <p>The Noir Marron are unique in having conserved their African genetic ancestry, despite major cultural exchanges with Amerindians and Europeans through inhabiting the same region for four centuries. Their maroon identity and the important number of slaves deported in this region have maintained the original African diversity. All these characteristics permit to identify a major origin located in the former region of the Gold Coast and the Bight of Benin; regions highly impacted by slavery, from which goes a sex-biased longitudinal gradient of ancestry.</p

Simian Foamy Virus Transmission from Apes to Humans, Rural Cameroon

Bites from apes efficiently transmit the foamy virus to humans in natural settings in central Africa

Frequent and Recent Human Acquisition of Simian Foamy Viruses Through Apes' Bites in Central Africa

Human infection by simian foamy viruses (SFV) can be acquired by persons occupationally exposed to non-human primates (NHP) or in natural settings. This study aimed at getting better knowledge on SFV transmission dynamics, risk factors for such a zoonotic infection and, searching for intra-familial dissemination and the level of peripheral blood (pro)viral loads in infected individuals. We studied 1,321 people from the general adult population (mean age 49 yrs, 640 women and 681 men) and 198 individuals, mostly men, all of whom had encountered a NHP with a resulting bite or scratch. All of these, either Pygmies (436) or Bantus (1085) live in villages in South Cameroon. A specific SFV Western blot was used and two nested PCRs (polymerase, and LTR) were done on all the positive/borderline samples by serology. In the general population, 2/1,321 (0.2%) persons were found to be infected. In the second group, 37/198 (18.6%) persons were SFV positive. They were mostly infected by apes (37/39) FV (mainly gorilla). Infection by monkey FV was less frequent (2/39). The viral origin of the amplified sequences matched with the history reported by the hunters, most of which (83%) are aged 20 to 40 years and acquired the infection during the last twenty years. The (pro)viral load in 33 individuals infected by a gorilla FV was quite low (<1 to 145 copies per 105 cells) in the peripheral blood leucocytes. Of the 30 wives and 12 children from families of FV infected persons, only one woman was seropositive in WB without subsequent viral DNA amplification. We demonstrate a high level of recent transmission of SFVs to humans in natural settings specifically following severe gorilla bites during hunting activities. The virus was found to persist over several years, with low SFV loads in infected persons. Secondary transmission remains an open question

Genetic Determination and Linkage Mapping of Plasmodium falciparum Malaria Related Traits in Senegal

Plasmodium falciparum malaria episodes may vary considerably in their severity and clinical manifestations. There is good evidence that host genetic factors contribute to this variability. To date, most genetic studies aiming at the identification of these genes have used a case/control study design for severe malaria, exploring specific candidate genes. Here, we performed a family-based genetic study of falciparum malaria related phenotypes in two independent longitudinal survey cohorts, as a first step towards the identification of genes and mechanisms involved in the outcome of infection. We studied two Senegalese villages, Dielmo and Ndiop that differ in ethnicity, malaria transmission and endemicity. We performed genome-scan linkage analysis of several malaria-related phenotypes both during clinical attacks and asymptomatic infection. We show evidence for a strong genetic contribution to both the number of clinical falciparum malaria attacks and the asymptomatic parasite density. The asymptomatic parasite density showed linkage to chromosome 5q31 (LOD = 2.26, empirical p = 0.0014, Dielmo), confirming previous findings in other studies. Suggestive linkage values were also obtained at three additional chromosome regions: the number of clinical malaria attacks on chromosome 5p15 (LOD = 2.57, empirical p = 0.001, Dielmo) and 13q13 (LOD = 2.37, empirical p = 0.0014 Dielmo), and the maximum parasite density during asymptomatic infection on chromosome 12q21 (LOD = 3.1, empirical p<10−4, Ndiop). While regions of linkage show little overlap with genes known to be involved in severe malaria, the four regions appear to overlap with regions linked to asthma or atopy related traits, suggesting that common immune related pathways may be involved

High frequency of HTLV-1 infection in Bantus and Pygmies from rural Cameroon bitten by non-human primates during hunting: High frequency of HTLV-1 infection in Bantus and Pygmies from rural Cameroon bitten by non-human primates during hunting

International audienceHTLV-1 infection is endemic in Central Africa, as well as the closely related STLV-1 found in several non-human primates (NHPs). Like other retroviruses, acquisition through interspecies transmission is strongly suggested but needs to be investigated. We analyzed 269 selected individuals (254 men, 15 women, average age 43.5 years) for whom a direct contact (mainly a severe bite) with a NHP occurred. This happened mostly during hunting activities and involved bleeding and body fluids exchange with at least saliva/blood contact. The same number of persons who live in the same villages/settlements but did not report any bite by NHPs was matched according to sex, age and ethnicity. Both groups include either Pygmies or Bantus living in the rain forest of South Cameroon. Plasma were tested for HTLV serology by WB, and proviral DNA was searched in buffy-coat DNA by 3 HTLV generic and one HTLV-1 specific PCR. HTLV-1 prevalence was of 8.5% (23/269) among bitten individuals versus 1.5% (4/269) observed in the controls (p<0.001). The 23 HTLV-1+ bitten individuals reported a gorilla (17), chimpanzee (3) or monkey (3) bite. Interestingly, 13/23 were coinfected by a simian foamyvirus, for which cross-species transmission from NHP to humans through bites is demonstrated. Moreover, familial studies excluded the other established routes of virus acquisition among some positive bitten individuals. Lastly, a phylogenetic analysis showed a HTLV-1 subtype F in a bitten subject closely related to the STLV-1 strain from a Cercocebus agilis with whom he was in contact, thus strengthening these new findings

Analyse des enjeux éthiques soulevés au cours d’un programme de recherche épidémiologique de dix années en Guyane française : limites de l’encadrement actuel et solutions adoptées

International audienceBACKGROUND: This paper discusses the ethical aspects of a large research program in virology, conducted since 1994 and which has evolved in parallel with the elaboration of bioethics laws in France. This research, which involved the collection of a considerable amount of epidemiological data in the field, focused on epidemiological determinants (mother to child transmission, genetic susceptibility/resistance) of the human oncogenic retrovirus human T cell lymphotropic virus type 1 (HTLV-1). Data were collected from a specific population (Noirs Marrons) living in remote areas in French Guiana (South America). This ethnic group of African descent is highly endemic for HTLV-1 and associated adult T cell leukemia/lymphoma. The population has lived for two centuries on either side of the Maroni river, which constitutes the frontier between French Guiana and Surinam. The low socioeconomic and education levels of a large part of this population are mainly explained by a recent housing/residence fixation on the French side of the Maroni river. It is also linked to significant immigration from Surinam due to the civil war, which lasted for five years in the late 1990s, in this country. Conducting epidemiological surveys in this peculiar context illustrates the limitations of the available current legal framework in France for such studies. Indeed, several important ethical issues arose concerning not only individual and population benefits, but also specificities of the given information and of the informed consent. Another question concerns individual information feed-back in such a context of persistent viral infection, with a very low disease incidence, in a population with a relatively low education level. The goal of this work was mainly to report several of the ethical issues encountered and to discuss possible ways of achieving better information deliver and consent procedures in such a context. Indeed, these procedures should include new ideas and regulations promoting a real partnership, in order to conduct long-term epidemiological studies in populations with a low education level

Species distribution of encountered NHP for the 198 individuals in the «contact group».

<p>Description of the NHP species was done by the concerned individuals themselves and a record was made on the written questionnaire. Visuals were showed to help them precisely identify the animal. Others = <i>C. neglectus, Papio, Colobus, cercocebus, Mandrills.</i></p

Serological and molecular results patterns for SFV detection.

<p>A) Western blot results using purified classical chimpanzee antigen sero-positive samples (lanes 3, 4, 6, 10, 12). Sero-indeterminate (lanes 2, 7, 8, 14). Sero-negative samples (lanes 5, 9, 11, 13). Positive SFV control serum from a gorilla-infected human (lane 15), and a macaque (lane PC). B) Nested PCR detection of 465 bp Integrase sequences of SFV M = molecular weight marker. CN = Negative Control. HFV = Human foamy virus, positive control, H2O = Water.</p