Endemicity and genetic diversity of Hepatitis delta virus among Pygmies in Cameroon, Central Africa.

OBJECTIVE: A single study conducted about three decades ago on hepatitis D virus (HDV) infection among Baka pygmies in Cameroon reported a very high anti-HDV antibodies prevalence of 46%, but HDV genetic diversity has not been studied in this population. The genetic diversity of strains from endemic ancient populations may help to understand the origin and evolutionary history of viruses. This study aimed to investigate the HDV seroprevalence and the genetic diversity in three remote Cameroonian Pygmies with chronic HBV infection. RESULTS: An unusually high 69% (36/52) level of HDV infection was found among HBsAg-positive pygmies in Cameroon. HDV RNA was detected and sequenced in 38.8% (14/36). The phylogenetic analysis revealed that 9/14 strains (64.3%) were identified and classified as genotype 1 (HDV-1) and 5/14 (35.6%) as genotype 7 (HDV-7), respectively with a bootstrap value of 100%. The further analysis showed the co-circulation of highly diverse HDV genotypes HDV-1 and HDV-7 in this population. These results highlight the endemicity of HDV infection in Central Africa. The highly diverse HDV-1 and HDV-7 in pygmies suggest an African origin of HDV. However, further studies are needed with larger sample size.

Highly Pathogenic Avian Influenza A(H5N8) Virus, Cameroon, 2017.

Highly pathogenic avian influenza A(H5N8) viruses of clade 2.3.4.4 spread into West Africa in late 2016 during the autumn bird migration. Genetic characterization of the complete genome of these viruses detected in wild and domestic birds in Cameroon in January 2017 demonstrated the occurrence of multiple virus introductions.

Characterization of Hepatitis C Virus Recombination in Cameroon by Use of Nonspecific Next-Generation Sequencing.

The importance of recombination in the evolution and genetic diversity of the hepatitis C virus (HCV) is currently uncertain. Only a small number of intergenotypic recombinants have been identified so far, and each has core and envelope genes classified as belonging to genotype 2. Here, we investigated two putative genotype 4/1 recombinants from southern Cameroon using a number of approaches, including standard Sanger sequencing, genotype-specific PCR amplification, and non-HCV-specific Illumina RNA sequencing (RNA-seq). Recombination between genotypes 1 and 4 was confirmed in both samples, and the parental lineages of each recombinant belong to HCV subtypes that are cocirculating at a high prevalence in Cameroon. Using the RNA-seq approach, we obtained a complete genome for one sample, which contained a recombination breakpoint at the E2/P7 gene junction. We developed and applied a new method, called Deep SimPlot, which can be used to visualize and identify viral recombination directly from the short sequence reads created by next-generation sequencing in conjunction with a consensus sequence.

Human parvovirus 4 infection, Cameroon.

In a post hoc analysis of samples collected in 2009, we determined seroprevalence of parvovirus 4 (PARV4) among elderly Cameroonians. PARV4 seropositivity was associated with receipt of intravenous antimalarial drugs, intramuscular streptomycin, or an intramuscular contraceptive, but not hepatitis C virus seropositivity. Findings suggest parenteral acquisition of some PARV4 infections.

Transmission of hepatitis C virus among spouses in Cameroon and the Central African Republic.

Heterosexual transmission of hepatitis C virus (HCV) is uncommon, with few studies undertaken in Central Africa. To determine the frequency of inter-spouse HCV transmission, cross-sectional studies of elderly individuals in Ebolowa, Cameroon and Nola, Central African Republic, in which, respectively, 24 and 83 long-term couples had been identified, were examined further. Blood samples were tested for antibody to HCV. Anti-HCV positive samples were genotyped by phylogenetic analysis of a fragment of the NS5B gene. In Nola, 4 out of 9 (44.4%) wives of anti-HCV positive husbands and 1 out of 74 (1.4%) wives of anti-HCV negative husbands were anti-HCV positive (P < 0.001); in Ebolowa, the corresponding proportions were 10 out of 15 (66.7%) and 3 out of 9 (33.3%) (P = 0.21). After adjustment for age and site-specific risk factors of HCV infection, HCV seropositivity of the wives remained associated with their husbands' HCV serostatus, significantly so in Nola (P = 0.003) and marginally in Ebolowa (P = 0.06). In 7 out of 14 concordant seropositive couples, the genotype could be determined in both spouses. Four couples were infected with different genotypes, while three were infected with the same genotype. Thus, serological concordance between the spouses was related to a combination of infections acquired independently and inter-spouse transmission. It could not be determined whether inter-spouse transmission occurred sexually, through blood-blood contact, or otherwise. Inter-spouse transmission may have contributed to the high prevalence among elderly populations of Central Africa since some patients infected during healthcare subsequently transmitted the virus to their spouse.

High prevalence and predominance of hepatitis delta virus genotype 1 infection in Cameroon.

Antibodies to the hepatitis delta virus (HDV) were found in 17.6% of 233 hepatitis B virus surface antigen-positive subjects in Cameroon. Phylogenetic analyses showed the presence of HDV-1, HDV-5, HDV-6, and HDV-7 genotypes. These results enrich the limited data on HDV prevalence and molecular diversity in Cameroon.

Characterization of a new simian immunodeficiency virus strain in a naturally infected Pan troglodytes troglodytes chimpanzee with AIDS related symptoms.

BACKGROUND: Data on the evolution of natural SIV infection in chimpanzees (SIVcpz) and on the impact of SIV on local ape populations are only available for Eastern African chimpanzee subspecies (Pan troglodytes schweinfurthii), and no data exist for Central chimpanzees (Pan troglodytes troglodytes), the natural reservoir of the ancestors of HIV-1 in humans. Here, we report a case of naturally-acquired SIVcpz infection in a P.t.troglodytes chimpanzee with clinical and biological data and analysis of viral evolution over the course of infection. RESULTS: A male chimpanzee (Cam155), 1.5 years, was seized in southern Cameroon in November 2003 and screened SIV positive during quarantine. Clinical follow-up and biological analyses have been performed for 7 years and showed a significant decline of CD4 counts (1,380 cells/mm³ in 2004 vs 287 in 2009), a severe thrombocytopenia (130,000 cells/mm³ in 2004 vs 5,000 cells/mm³ in 2009), a weight loss of 21.8% from August 2009 to January 2010 (16 to 12.5 kg) and frequent periods of infections with diverse pathogens.DNA from PBMC, leftover from clinical follow-up samples collected in 2004 and 2009, was used to amplify overlapping fragments and sequence two full-length SIVcpzPtt-Cam155 genomes. SIVcpzPtt-Cam155 was phylogenetically related to other SIVcpzPtt from Cameroon (SIVcpzPtt-Cam13) and Gabon (SIVcpzPtt-Gab1). Ten molecular clones 5 years apart, spanning the V1V4 gp120 env region (1,100 bp), were obtained. Analyses of the env region showed positive selection (dN-dS >0), intra-host length variation and extensive amino acid diversity between clones, greater in 2009. Over 5 years, N-glycosylation site frequency significantly increased (p < 0.0001). CONCLUSIONS: Here, we describe for the first time the clinical history and viral evolution of a naturally SIV infected P.t.troglodytes chimpanzee. The findings show an increasing viral diversity over time and suggest clinical progression to an AIDS-like disease, showing that SIVcpz can be pathogenic in its host, as previously described in P.t.schweinfurthii. Although studying the impact of SIV infection in wild apes is difficult, efforts should be made to better characterize the pathogenicity of the ancestors of HIV-1 in their natural host and to find out whether SIV infection also plays a role in ape population decline.

Hepatitis B and C virus infections in the three Pygmy groups in Cameroon.

A high (11.8%) level of hepatitis B virus (HBV) infection was found among 524 Pygmies in Cameroon, whereas the extent of hepatitis C virus (HCV) infection in the same population was low (0.6%). Phylogenetic analyses showed cocirculation of two HBV genotypes, HBV-A3 and -E. Taken together, our results suggest different epidemiological scenarios concerning HBV and HCV infections in this population.

Risk factors for hepatitis C virus transmission in colonial Cameroon.

BACKGROUND: In southern Cameroon, where SIV(cpz), the source of human immunodeficiency virus 1 (HIV-1) group M, is prevalent among wild chimpanzees, approximately 50% of some human birth cohorts have been infected with hepatitis C virus (HCV) through unclear mechanisms. METHODS: To evaluate indirectly the hypothesis that medical interventions contributed to the early emergence of HIV-1, we conducted a cross-sectional study of 451 inhabitants of Ebolowa in southern Cameroon aged 60 years, using HCV as a marker of parenteral transmission of blood-borne viruses. We administered a questionnaire and tested serum for antibodies against HCV. Viral gene sequences were obtained from HCV-positive sera. Molecular clock analyses provided an independent source of information on epidemic history. RESULTS: A total of 252 participants (56%) were HCV seropositive. HCV sequences were amplified and genotyped from 171 individuals. Independent risk factors for HCV seropositivity were older age, having received intravenous treatment against malaria, and having attended an ethnic school (women only), whereas having been circumcised by a traditional practitioner (men only) tended to be associated with HCV. In addition, transfusions were associated with HCV genotype 1 transmission. Molecular clock analyses of HCV genotypes 1, 2, and 4 revealed that each independently underwent exponential growth during the first half of the 20th century. CONCLUSIONS: Medical interventions (intravenous antimalarial drugs, transfusions) and to a lesser extent traditional practices (circumcision) were associated with the massive transmission of HCV among this population decades ago. This finding supports the hypothesis that medical interventions contributed to the transmission of blood-borne viruses, perhaps including SIV(cpz) and HIV-1, in the same region during the early 20th century.

Detection and characterization of hepatitis B virus strains from wild-caught gorillas and chimpanzees in Cameroon, Central Africa.

Previous epidemiological studies have reported a high prevalence of hepatitis B virus (HBV) infection in chimpanzees in Gabon and Congo, Central Africa. There is no data for this species from Cameroon. To date few cases of active HBV infection have been documented in gorillas and only one complete HBV sequence has been described from a wild-caught gorilla originating from Cameroon and housed in Germany. Since gorillas are apes found in Cameroon, we thus investigated the prevalence and genetic relationships of HBV infecting apes in this area. We subjected 185 wild-caught apes' plasmas, including 159 from chimpanzees and 26 from gorillas to ELISA screening for HBV surface antigen (HBsAg). Subsequently, we detected HBV DNA, sequenced the whole HBV genome and performed phylogenetic analysis. Eleven (6.9%) chimpanzees and 3 (11.6%) gorillas plasma were found HBsAg positive, of which 8 and 3 were positive for HBV DNA, respectively. Phylogenetic analyses revealed that the 3 new gorilla HBV sequences grouped together with the single available HBV sequence from gorilla. Evidence of recombination between HBV Pan troglodytes troglodytes and Pan troglodytes vellerosus was observed in two of the Cameroonian strains. Findings from our study show that HBV infection is endemic in wild-born gorillas and chimpanzees in Cameroon, and that there is evidence of recombination between HBV strains circulating in chimpanzees. We demonstrated the existence of gorillas' specific HBV strains distinct but related to those found in chimpanzees living in the same habitat in Cameroon, providing substantial evidence of species association of HBV in NHPs.

Highly pathogenic avian influenza virus subtype H5N1 in ducks in the Northern part of Cameroon.

Highly pathogenic avian influenza (HPAI) virus was first detected in Cameroon in February 2006. Analysis of NA sequences of the virus demonstrated that it is closely related to the H5N1 isolates from Northern Nigeria, Sudan and Ivory Coast, suggesting a common virus ancestor.

Simian immunodeficiency virus infection in wild-caught chimpanzees from cameroon.

Simian immunodeficiency viruses (SIVcpz) infecting chimpanzees (Pan troglodytes) in west central Africa are the closest relatives to all major variants of human immunodeficiency virus type 1 ([HIV-1]; groups M, N and O), and have thus been implicated as the source of the human infections; however, information concerning the prevalence, geographic distribution, and subspecies association of SIVcpz still remains limited. In this study, we tested 71 wild-caught chimpanzees from Cameroon for evidence of SIVcpz infection. Thirty-nine of these were of the central subspecies (Pan troglodytes troglodytes), and 32 were of the Nigerian subspecies (Pan troglodytes vellerosus), as determined by mitochondrial DNA analysis. Serological analysis determined that one P. t. troglodytes ape (CAM13) harbored serum antibodies that cross-reacted strongly with HIV-1 antigens; all other apes were seronegative. To characterize the newly identified virus, 14 partially overlapping viral fragments were amplified from fecal virion RNA and concatenated to yield a complete SIVcpz genome (9,284 bp). Phylogenetic analyses revealed that SIVcpzCAM13 fell well within the radiation of the SIVcpzPtt group of viruses, as part of a clade including all other SIVcpzPtt strains as well as HIV-1 groups M and N. However, SIVcpzCAM13 clustered most closely with SIVcpzGAB1 from Gabon rather than with SIVcpzCAM3 and SIVcpzCAM5 from Cameroon, indicating the existence of divergent SIVcpzPtt lineages within the same geographic region. These data, together with evidence of recombination among ancestral SIVcpzPtt lineages, indicate long-standing endemic infection of central chimpanzees and reaffirm a west central African origin of HIV-1. Whether P. t. vellerosus apes are naturally infected with SIVcpz requires further study.

Simian T cell leukaemia virus type I subtype B in a wild-caught gorilla (Gorilla gorilla gorilla) and chimpanzee (Pan troglodytes vellerosus) from Cameroon.

A serological survey for human T cell leukaemia virus (HTLV)/simian T cell leukaemia virus (STLV) antibodies was performed in 61 wild-caught African apes, including five gorillas and 56 chimpanzees originating from south Cameroon. Two young animals, a gorilla (Gorilla gorilla gorilla) and a chimpanzee (Pan troglodytes vellerosus), exhibited a pattern of complete HTLV-I seroreactivity. Sequence comparison and phylogenetic analyses using the complete LTR (750 bp) and a 522 bp fragment of the env gene indicated the existence of two novel STLV-I strains, both of which belonged to HTLV-I/STLV-I molecular clade subtype B, specific to central Africa. These first STLV-I strains to be characterized in gorilla and chimpanzee were closely related to each other as well as to several HTLV-I strains originating from inhabitants of south Cameroon, including pygmies. Such findings reinforce the hypothesis of interspecies transmission of STLV-I to humans, leading to the present day distribution of HTLV-I in central African inhabitants.

Low rate of mother-to-child transmission of HIV-1 after nevirapine intervention in a pilot public health program in Yaoundé, Cameroon.

OBJECTIVE: To determine the percentage of infected children for whom nevirapine (NVP) was used to prevent peripartum mother-to-child transmission (MTCT) of HIV in Yaoundé, Cameroon. DESIGN: The study was a prospective Public Health Pilot Program covering a 3-year period (January 2000-December 2002). METHODS: Counseled and consenting HIV-1-positive pregnant women were given a single dose of NVP at the onset of labor. Babies were given 2 mg/kg NVP syrup within the first 72 hours of life. NVP-treated children were regularly followed up and examined for HIV-1 infection at 6-8 weeks and 5-6 months through plasma viral load (VL) quantification with the bDNA system. RESULTS: One hundred twenty-three children were diagnosed with perinatal HIV-1 infection at 6-8 weeks and 5-6 months. Thirteen children (10.6% [13/123]; 95% confidence interval, 5.1-16) were infected and presented with high VLs, in general >500,000 copies/mL. Two children had intermediate VLs (between 50 and 3500 copies/mL) at both time points. One hundred seven children (87%) were considered not infected at 6-8 weeks of age. CONCLUSIONS: Our results indicate that the HIV-1 MTCT rate 6-8 weeks after NVP administration was not >13% (16/123), thus demonstrating the effectiveness of NVP for lowering the risk of HIV-1 MTCT in real-life settings.

Molecular epidemiology of simian T-lymphotropic virus (STLV) in wild-caught monkeys and apes from Cameroon: a new STLV-1, related to human T-lymphotropic virus subtype F, in a Cercocebus agilis.

A serological survey for human T-lymphotropic virus (HTLV)/simian T-lymphotropic virus (STLV) antibodies was performed in 102 wild-caught monkeys and apes from 15 (sub)species originating from Cameroon. Two animals (a Mandrillus sphinx and a Cercocebus agilis) exhibited a complete HTLV-1 seroreactivity pattern while two others lacked either the p24 (a Mandrillus sphinx) or the MTA-1/gp46 bands (a Pan troglodytes). Sequence comparison and phylogenetic analyses, using a 522 bp env gene fragment and the complete LTR, indicated that the two mandrill STLV strains belonged to the HTLV/STLV subtype D clade while the chimpanzee strain clustered in the HTLV/STLV subtype B clade. The Cercocebus agilis STLV strain, the first one found in this species, was closely related to the two HTLV/STLV subtype F strains. Such data indicate that the African biodiversity of STLV-1 in the wild is far from being known and reinforces the hypothesis of interspecies transmission of STLV-1 from monkeys and apes to humans leading to the present day distribution of HTLV-1 in African inhabitants.