Role of Wildlife in Emergence of Ebola Virus in Kaigbono (Likati), Democratic Republic of the Congo, 2017.

After the 2017 Ebola virus (EBOV) outbreak in Likati, a district in northern Democratic Republic of the Congo, we sampled small mammals from the location where the primary case-patient presumably acquired the infection. None tested positive for EBOV RNA or antibodies against EBOV, highlighting the ongoing challenge in detecting animal reservoirs for EBOV.

Extensive Serological Survey of Multiple African Nonhuman Primate Species Reveals Low Prevalence of Immunoglobulin G Antibodies to 4 Ebola Virus Species.

Bats are considered a reservoir species for Ebola viruses, but nonhuman primates (NHPs) have represented a source of infection in several outbreaks in humans. Here we report serological screening of blood or fecal samples from monkeys (n = 2322) and apes (n = 2327). Thirty-six NHP species from Cameroon, Democratic Republic of the Congo, and Ivory Coast were tested with a sensitive and specific Luminex-based assay for immunoglobulin G antibodies to 4 Ebola virus species. Using the simultaneous presence of antibodies to nucleoproteins and glycoproteins to define positivity, we showed that specific Ebola virus antibodies are not widespread among NHPs. Only 1 mustached monkey (Cercopithecus cephus) from Cameroon was positive for Sudan ebolavirus. These observations support that NHPs are most likely intermediate hosts for Ebola viruses. With the increasing frequency of Ebola outbreaks, it is crucial to identify the animal reservoir and understand the ecology of Ebola viruses to inform disease control.

Survey of Ebola Viruses in Frugivorous and Insectivorous Bats in Guinea, Cameroon, and the Democratic Republic of the Congo, 2015-2017.

To clarify the role of bats in the ecology of Ebola viruses, we assessed the prevalence of Ebola virus antibodies in a large-scale sample of bats collected during 2015-2017 from countries in Africa that have had previous Ebola outbreaks (Guinea, the Democratic Republic of the Congo) or are at high risk for outbreaks (Cameroon). We analyzed 4,022 blood samples of bats from >12 frugivorous and 27 insectivorous species; 2-37 (0.05%-0.92%) bats were seropositive for Zaire and 0-30 (0%-0.75%) bats for Sudan Ebola viruses. We observed Ebola virus antibodies in 1 insectivorous bat genus and 6 frugivorous bat species. Certain bat species widespread across Africa had serologic evidence of Zaire and Sudan Ebola viruses. No viral RNA was detected in the subset of samples tested (n = 665). Ongoing surveillance of bats and other potential animal reservoirs are required to predict and prepare for future outbreaks.

Prevalence of pretreatment HIV drug resistance in Cameroon following a nationally representative WHO survey.

Background: Pretreatment HIV drug resistance (PDR) has the potential to affect treatment outcome and mortality. We present here the first nationally representative PDR study conducted in Cameroon. Methods: From February to July 2015, HIV-infected ART initiators were recruited from 24 randomly selected clinics situated in both urban and rural regions. Dried blood spot specimens were collected from study participants at these clinics and centralized in a reference laboratory in Yaoundé, Cameroon, for drug resistance testing. HIV drug resistance mutations were identified using the Stanford algorithm. Results: Overall, from the 379 participants recruited, 321 pol sequences were successfully interpreted. Two hundred and five sequences were from patients attending urban ART clinics and 116 from patients seen at rural facilities. Nine percent of sequences (29/321) were from participants reporting previous exposure to antiretrovirals. PDR prevalence among all initiators was 10.4% (95% CI 5.4%-19.1%), with 14.2% (95% CI 6.6%-27.9%) reported in urban areas and 4.3% (95% CI 1.2%-14.3%) in rural areas. Among participants with no prior exposure to antiretrovirals, PDR prevalence was 10.4% (95% CI 4.7%-21.5%) overall, with 13.5% (95% CI 5.1%-31.5%) and 5.3% (95% CI 1.4%-17.5%) reported in urban and rural areas, respectively. Conclusions: Our findings indicate that at least 10% of patients initiating ART in Cameroon carry viruses with PDR and may be at risk of premature ART failure. The high level of NNRTI-associated resistance is of particular concern and supports introduction of drugs with a higher genetic barrier to resistance.

Development of a Sensitive and Specific Serological Assay Based on Luminex Technology for Detection of Antibodies to Zaire Ebola Virus.

The recent Zaire Ebola virus (EBOV) outbreak in West Africa illustrates clearly the need for additional studies with humans and animals to elucidate the ecology of Ebola viruses (EBVs). In this study, we developed a serological assay based on the Luminex technology. Nine recombinant proteins representing different viral regions (nucleoprotein [NP], 40-kDa viral protein [VP40], and glycoprotein [GP]) from four of the five EBV lineages were used. Samples from 94 survivors of the EBOV outbreak in Guinea and negative samples from 108 patients in France were used to calculate test performance for EBOV detection and cross-reaction with other Ebola virus lineages. For EBOV antibody detection, sensitivities of 95.7%, 96.8%, and 92.5% and specificities of 94.4%, 95.4%, and 96.3% for NP, GP, and VP40, respectively, were observed. All EBOV-negative samples that presented a reaction, except for one, interacted with a single antigen, whereas almost all samples from EBOV survivors were simultaneously reactive with NP and GP (90/94) or with NP, GP, and VP40 (87/94). Considering as positive for past EBOV infection only samples that reacted with EBOV NP and GP, sensitivity was 95.7% and specificity increased to 99.1%. Comparing results with commercial EBOV NP and GP enzyme-linked immunosorbent assays (ELISAs; Alpha Diagnostic, San Antonio, TX), lower sensitivity (92.5%) and high specificity (100%) were observed with the same positivity criteria. Samples from EBOV survivors cross-reacted with GP from Sudan Ebola virus (GP-SUDV) (81.9%), GP from Bundibugyo Ebola virus (GP-BDBV) (51.1%), GP from Reston Ebola virus (GP-RESTV) (9.6%), VP40-SUDV (76.6%), and VP40-BDBV (38.3%). Overall, we developed a sensitive and specific high-throughput serological assay, and defined an algorithm, for epidemiological surveys with humans.

Assessment of gastrointestinal parasites in wild chimpanzees (Pan troglodytes troglodytes) in southeast Cameroon.

We tested 114 faecal samples from wild simian immunodeficiency virus (SIV)-positive (n = 43) and SIV-negative (n = 71) chimpanzees (Pan troglodytes troglodytes) in southeast Cameroon for the presence of gastrointestinal parasites by direct smear. We observed cysts from different protozoa (Entamoeba coli and Entamoeba histolytica / Entamoeba dispar, Endolimax nana, Iodamoeba butschlii, Chilomastix mesnili, Balantidium coli and Blastocystis cells) and trophozoites from Troglodytella abrassarti and Balantidium coli. Eggs from different helminths (strongylids, Ascaris lumbricoides, Abbreviata caucasica, Trichuris sp., Capillaria sp., Enterobius anthropopeci, Bertiella sp., Hymenolepis diminuta and an undetermined fluke) were also observed. Finally, we observed eggs that could not be properly identified and classified. We did not observe any differences between the SIV+ and SIV- samples except for the unidentified eggs. The studied chimpanzees were highly parasitised by strongylid (85.1% of prevalence), Troglodytella (43.8%) and Blastocystis (2.9%), and the frequency of the other parasites ranged from 0.9 to 8.8%. These high levels of parasite infections could represent an additional burden in a population where there is a high rate of the SIV virus in circulation.

Structural Features and Genetic Diversity in Gag Gene of Rare HIV-1 Subtypes from the Democratic Republic of Congo.

Type-1 HIV (HIV-1) group M (HIV-1M) genetic diversity is highest in the Congo Basin where the epidemic ignited a century ago. HIV-1M has diversified into multiple subtypes, sub-subtypes, and circulating and unique recombinant forms (CRFs/URFs). An unanswered question is why some rare subtypes never reached epidemic levels despite their age. Several studies identified the role of HIV-1M accessory genes nef and vpu in virus adaptation to human hosts and subsequent spread. Other reports also pointed out the pivotal role of gag in transmissibility, virulence, and replication capacity. In this study we characterized the HIV-1 gag gene of 148 samples collected in different localities of the Democratic Republic of the Congo (DRC) between 1997 and 2013. We used nested polymerase chain reaction (PCR) to amplify the whole gag gene. PCR products were sequenced either by Sanger method or by next generation sequencing on Illumina MiSeq or iSeq100 platforms. Generated sequences were used for subsequent analyses using different bioinformatic tools. Phylogenetic analysis of the generated sequences revealed a high genetic diversity with up to 22 different subtypes, sub-subtypes, CRFs. Up to 15% (22/148) URFs were identified, in addition to rare subtypes such as H, J, and K. At least two amino acid motifs present in the gag gene have been shown to modulate HIV-1 replication, budding, and fitness: the P(T/S)AP and the LYPXnL motifs. Structural analysis revealed the presence of P(T/S)AP in all the 148 sequences with the majority (136/148) bearing the PTAP. Three samples presented a duplication of this motif. The LYPXnL motif was identified in 38 of 148 sequences. There was no clear link between the frequency of these motifs and HIV-1M subtypes. In summary, we confirmed a high genetic diversity of HIV-1M in the DRC. We observed the presence of amino acid motifs important for viral replication and budding even in some rare HIV-1 subtypes. Their impact on viral fitness needs be further evaluated by in vitro studies.

Single real-time reverse transcription-PCR assay for detection and quantification of genetically diverse HIV-1, SIVcpz, and SIVgor strains.

Although antiretroviral treatment availability has improved, the virological monitoring of patients remains largely uneven across regions. In addition, viral quantification tests are suffering from human immunodeficiency virus type 1 (HIV-1) genetic diversity, fueled by the emergence of new recombinants and of lentiviruses from nonhuman primates. We developed a real-time reverse transcription-PCR (RT-PCR) assay that is relatively inexpensive and able to detect and quantify all circulating forms of HIV-1 and its simian immunodeficiency virus (SIV) precursors, SIVcpz and SIVgor. Primers and a probe were designed to detect all variants of the HIV-1/SIVcpz/SIVgor lineage. HIV-1 M plasma (n = 190; 1.68 to 7.78 log(10) copies/ml) representing eight subtypes, nine circulating recombinant forms, and 21 unique recombinant forms were tested. The mean PCR efficiency was 99%, with low coefficients of intra- and interassay variation (<5%) and a limit of quantification of <2.50 log(10) copies/ml, with a 200-µl plasma volume. On the studied range, the specificity and the analytical sensitivity were 100 and 97.4%, respectively. The viral loads were highly correlated (r = 0.95, P < 0.0001) with the reference method (generic HIV assay; Biocentric) and had no systematic difference, irrespective of genotype. Furthermore, 22 HIV-1 O plasmas were screened and were better quantified compared to the gold-standard RealTime HIV-1 assay (Abbott), including four samples that were only quantified by our assay. Finally, we could quantify SIVcpzPtt and SIVcpzPts from chimpanzee plasma (n = 5) and amplify SIVcpz and SIVgor from feces. Thus, the newly developed real-time RT-PCR assay detects and quantifies strains from the HIV-1/SIVcpz/SIVgor lineage, including a wide diversity of group M strains and HIV-1 O. It can therefore be useful in geographical areas of high HIV diversity and at risk for the emergence of new HIV variants.

Noninvasive follow-up of simian immunodeficiency virus infection in wild-living nonhabituated western lowland gorillas in Cameroon.

Simian immunodeficiency viruses infecting western lowland gorillas (SIVgor) are closely related to HIV-1 and are most likely the ancestors of HIV-1 groups O and P. At present, limited data are available on genetic diversity, transmission, viral evolution, and pathogenicity of SIVgor in its natural host. Between 2004 and 2011, 961 putative gorilla fecal samples were collected at the Campo Ma'an National Park, Cameroon. Among them, 16% cross-reacted with HIV-1 antibodies, corresponding to at least 34 infected gorillas. Combining host genotyping and field data, we identified four social groups composed of 7 to 15 individuals each, with SIV rates ranging from 13% to 29%. Eleven SIVgor-infected gorillas were sampled multiple times; two most likely seroconverted during the study period, showing that SIVgor continues to spread. Phylogenetic analysis of partial env and pol sequences revealed cocirculation of closely related and divergent strains among gorillas from the same social group, indicating SIVgor transmissions within and between groups. Parental links could be inferred for some gorillas infected with closely related strains, suggesting vertical transmission, but horizontal transmission by sexual or aggressive behavior was also suspected. Intrahost molecular evolution in one gorilla over a 5-year period showed viral adaptations characteristic of escape mutants, i.e., V1V2 loop elongation and an increased number of glycosylation sites. Here we show for the first time the feasibility of noninvasive monitoring of nonhabituated gorillas to study SIVgor infection over time at both the individual and population levels. This approach can also be applied more generally to study other pathogens in wildlife.

New STLV-3 strains and a divergent SIVmus strain identified in non-human primate bushmeat in Gabon.

BACKGROUND: Human retroviral infections such as Human Immunodeficiency Virus (HIV) or Human T-cell Lymphotropic Virus (HTLV) are the result of simian zoonotic transmissions through handling and butchering of Non-Human Primates (NHP) or by close contact with pet animals. Recent studies on retroviral infections in NHP bushmeat allowed for the identification of numerous Simian Immunodeficiency Viruses (SIV) and Simian T-cell Lymphotropic Viruses (STLV) to which humans are exposed. Nevertheless, today, data on simian retroviruses at the primate/hunter interface remain scarce. We conducted a pilot study on 63 blood and/or tissues samples derived from NHP bushmeat seized by the competent authorities in different locations across the country. RESULTS: SIV and STLV were detected by antibodies to HIV and HTLV antigens, and PCRs were performed on samples with an HIV or/and HTLV-like or indeterminate profile. Fourteen percent of the samples cross-reacted with HIV antigens and 44% with HTLV antigens. We reported STLV-1 infections in five of the seven species tested. STLV-3 infections, including a new STLV-3 subtype, STLV-1 and -3 co-infections, and triple SIV, STLV-1, STLV-3 infections were observed in red-capped mangabeys (C.torquatus). We confirmed SIV infections by PCR and sequence analyses in mandrills, red-capped mangabeys and showed that mustached monkeys in Gabon are infected with a new SIV strain basal to the SIVgsn/mus/mon lineage that did not fall into the previously described SIVmus lineages reported from the corresponding species in Cameroon. The same monkey (sub)species can thus be carrier of, at least, three distinct SIVs. Overall, the minimal prevalence observed for both STLV and SIV natural infections were 26.9% and 11.1% respectively. CONCLUSIONS: Overall, these data, obtained from a restricted sampling, highlight the need for further studies on simian retroviruses in sub-Saharan Africa to better understand their evolutionary history and to document SIV strains to which humans are exposed. We also show that within one species, a high genetic diversity may exist for SIVs and STLVs and observe a high genetic diversity in the SIVgsn/mon/mus lineage, ancestor of HIV-1/SIVcpz/SIVgor.

Human immunodeficiency viruses: SIV infection in wild gorillas.

Chimpanzees (Pan troglodytes troglodytes) from west central Africa are recognized as the reservoir of simian immunodeficiency viruses (SIVcpzPtt) that have crossed at least twice to humans: this resulted in the AIDS pandemic (from human immunodeficiency virus HIV-1 group M) in one instance and infection of just a few individuals in Cameroon (by HIV-1 group N) in another. A third HIV-1 lineage (group O) from west central Africa also falls within the SIVcpzPtt radiation, but the primate reservoir of this virus has not been identified. Here we report the discovery of HIV-1 group O-like viruses in wild gorillas.

Multiplex detection of antibodies to Chikungunya, O'nyong-nyong, Zika, Dengue, West Nile and Usutu viruses in diverse non-human primate species from Cameroon and the Democratic Republic of Congo.

BACKGROUND: Epidemic arbovirus transmission occurs among humans by mosquito bites and the sylvatic transmission cycles involving non-human primates (NHPs) still exists. However, limited data are available on the extent in NHPs infections and their role. In this study, we have developed and validated a high-throughput serological screening tool to study the circulation of multiple arboviruses that represent a significant threat to human health, in NHPs in Central Africa. METHODOLOGY/PRINCIPAL FINDINGS: Recombinant proteins NS1, envelope domain-3 (DIII) for the dengue (DENV), yellow fever (YFV), usutu (USUV), west nile (WNV) and zika (ZIKV) and envelope 2 for the chikungunya (CHIKV) and o'nyong-nyong (ONNV) were coupled to Luminex beads to detect IgG directed against these viruses. Evaluation of test performance was made using 161 human sera of known arboviral status (66 negative and 95 positive). The sensitivity and specificity of each antigen were determined by statistical methods and ROC curves (except for ONNV and USUV). All NS1 antigens (except NS1-YFV), CHIKV-E2 and WNV-DIII had sensitivities and specificities > 95%. For the other DIII antigens, the sensitivity was low, limiting the interest of their use for seroprevalence studies. Few simultaneous reactions were observed between the CHIKV+ samples and the NS1 antigens to the non-CHIKV arboviruses. On the other hand, the DENV+ samples crossed-reacted with NS1 of all the DENV serotypes (1 to 4), as well as with ZIKV, USUV and to a lesser extent with YFV. A total of 3,518 samples of 29 species of NHPs from Cameroon and the Democratic Republic of Congo (DRC) were tested against NS1 (except YFV), E2 (CHIKV/ONNV) and DIII (WNV) antigens. In monkeys (n = 2,100), the global prevalence varied between 2 and 5% for the ten antigens tested. When we stratified by monkey's biotope, the arboreal species showed the highest reactivity. In monkeys from Cameroon, the highest IgG prevalence were observed against ONNV-E2 and DENV2-NS1 with 3.95% and 3.40% respectively and in DRC, ONNV-E2 (6.63%) and WNV-NS1 (4.42%). Overall prevalence was low in apes (n = 1,418): ranging from 0% for USUV-NS1 to 2.6% for CHIKV-E2. However, a very large disparity was observed among collection site and ape species, e.g. 18% (9/40) and 8.2% (4/49) of gorillas were reactive with CHIKV-E2 or WNV-NS1, respectively in two different sites in Cameroon. CONCLUSIONS/SIGNIFICANCE: We have developed a serological assay based on Luminex technology, with high specificity and sensitivity for simultaneous detection of antibodies to 10 antigens from 6 different arboviruses. This is the first study that evaluated on a large scale the presence of antibodies to arboviruses in NHPs to evaluate their role in sylvatic cycles. The overall low prevalence (<5%) in more than 3,500 NHPs samples from Cameroon and the DRC does not allow us to affirm that NHP are reservoirs, but rather, intermediate hosts of these viruses.

Investigating the Circulation of Ebola Viruses in Bats during the Ebola Virus Disease Outbreaks in the Equateur and North Kivu Provinces of the Democratic Republic of Congo from 2018.

With 12 of the 31 outbreaks, the Democratic Republic of Congo (DRC) is highly affected by Ebolavirus disease (EVD). To better understand the role of bats in the ecology of Ebola viruses, we conducted surveys in bats during two recent EVD outbreaks and in two areas with previous outbreaks. Dried blood spots were tested for antibodies to ebolaviruses and oral and rectal swabs were screened for the presence of filovirus using a broadly reactive semi-nested RT-PCR. Between 2018 and 2020, 892 (88.6%) frugivorous and 115 (11.4%) insectivorous bats were collected. Overall, 11/925 (1.2%) to 100/925 (10.8%) bats showed antibodies to at least one Ebolavirus antigen depending on the positivity criteria. Antibodies were detected in fruit bats from the four sites and from species previously documented to harbor Ebola antibodies or RNA. We tested for the first time a large number of bats during ongoing EVD outbreaks in DRC, but no viral RNA was detected in the 676 sampled bats. Our study illustrates the difficulty to document the role of bats as a source of Ebolaviruses as they might clear quickly the virus. Given the increasing frequency of EVD outbreaks, more studies on the animal reservoir are urgently needed.

Emergence and spread of SARS-CoV-2 lineage B.1.620 with variant of concern-like mutations and deletions.

Distinct SARS-CoV-2 lineages, discovered through various genomic surveillance initiatives, have emerged during the pandemic following unprecedented reductions in worldwide human mobility. We here describe a SARS-CoV-2 lineage - designated B.1.620 - discovered in Lithuania and carrying many mutations and deletions in the spike protein shared with widespread variants of concern (VOCs), including E484K, S477N and deletions HV69Δ, Y144Δ, and LLA241/243Δ. As well as documenting the suite of mutations this lineage carries, we also describe its potential to be resistant to neutralising antibodies, accompanying travel histories for a subset of European cases, evidence of local B.1.620 transmission in Europe with a focus on Lithuania, and significance of its prevalence in Central Africa owing to recent genome sequencing efforts there. We make a case for its likely Central African origin using advanced phylogeographic inference methodologies incorporating recorded travel histories of infected travellers.

Effect of storage conditions of dried plasma and blood spots on HIV-1 RNA quantification and PCR amplification for drug resistance genotyping.

OBJECTIVES: Dried blood spots (DBS) and dried plasma spots (DPS) are easy to collect and store, and have been successfully tested as an alternative to plasma for performing virological analyses. Adequate storage conditions still need to be established and cell-associated proviral DNA in DBS can contribute to the amplified products. We evaluated these two parameters. METHODS: Residual samples from 34 HIV-1-infected patients [mean viral load (VL) = 3.93 log(10) copies/mL] were used to prepare DPS and DBS, then stored at 20 degrees C and 37 degrees C. HIV-1 nucleic acids were extracted, with or without DNase treatments, to perform HIV-1 VL quantification and nested RT-PCR to amplify the reverse transcriptase gene (798 bp). RESULTS: For DBS stored for 3 months at 20 degrees C, VL could be measured for all samples and results were comparable to plasma VL. At 37 degrees C, a slight decrease was observed after 2 and 3 months (0.16 and 0.37 log(10) copies/mL mean difference, respectively). For DPS, a significant decrease in VL (0.70 and 1.07 log(10) copies/mL after 1 and 2 months, respectively) was seen at 37 degrees C, but not at 20 degrees C. PCR amplifications from DPS were only successful for 50% of samples with an initial VL >10 000 copies/mL after 1 month at 20 degrees C. From DBS, PCR amplifications are possible until 3 months for samples with plasma VL >5000 copies/mL. VL and PCR results for DBS treated with DNase are close to results obtained for DPS. CONCLUSIONS: Virological monitoring is still feasible for DBS after 3 months of storage at 37 degrees C when VL is >5000 copies/mL, but DNA contributes largely to the final results.

Challenges of scale-up to dolutegravir-based regimens in sub-Saharan Africa.

OBJECTIVE: Evaluate the potential effectiveness of the implementation of dolutegravir (DTG)-based regimens in patients on failing current antiretroviral treatment (ART) given the high levels of nucleoside reverse transcriptase inhibitor (NRTI) resistance in Togo. DESIGN: Patients on ART attending health facilities for routine follow-up visits and for whom HIV viral load test was performed were consecutively included. METHODS: Protease, reverse transcriptase and integrase fragments were sequenced and analyzed for presence of drug resistance mutations for patients with viral load more than 1000 copies/ml. RESULTS: Among 1681 patients, 320 (19.04%) had viral load more than 1000 copies/ml and 200 were tested for drug resistance mutations. Reverse transcriptase gene was successfully sequenced for 181/200 (90.5%) patients; 140/181 (77.4%) were resistant to NRTIs and non-NRTIs, 4/181 (2.2%) to NRTIs only and 18/181 (9.9%) to non-NRTIs only. Many viral strains accumulated mutations predicting resistance to NRTIs recommended in first and second-line DTG-based ART regimens. ART switch to a DTG-based regimen after viral load testing (viral load >1000 copies/ml) or blind switch without prior viral load testing to a new DTG-based first line, estimated 31% and 47.6% of patients to be potentially on functional DTG monotherapy respectively. CONCLUSION: Overall, our results predict that, at the scale of sub-Saharan Africa a significant proportion of patients could be on functional monotherapy. To achieve the third 90 of UNAIDS objectives, implementation of DTG-based regimens should be accompanied with an accelerated scaling up of access to viral load. Studies designed to quantify the implications of use of suboptimal DTG-based regimens are also needed.

Prevalence of infection among asymptomatic and paucisymptomatic contact persons exposed to Ebola virus in Guinea: a retrospective, cross-sectional observational study.

BACKGROUND: The prevalence of Ebola virus infection among people who have been in contact with patients with Ebola virus disease remains unclear, but is essential to understand the dynamics of transmission. This study aimed to identify risk factors for seropositivity and to estimate the prevalence of Ebola virus infection in unvaccinated contact persons. METHODS: In this retrospective, cross-sectional observational study, we recruited individuals between May 12, 2016, and Sept 8, 2017, who had been in physical contact with a patient with Ebola virus disease, from four medical centres in Guinea (Conakry, Macenta, N'zérékoré, and Forécariah). Contact persons had to be 7 years or older and not diagnosed with Ebola virus disease. Participants were selected through the Postebogui survivors' cohort. We collected self-reported information on exposure and occurrence of symptoms after exposure using a questionnaire, and tested antibody response against glycoprotein, nucleoprotein, and 40-kDa viral protein of Zaire Ebola virus by taking a blood sample. The prevalence of Ebola virus infection was estimated with a latent class model. FINDINGS: 1721 contact persons were interviewed and given blood tests, 331 of whom reported a history of vaccination so were excluded, resulting in a study population of 1390. Symptoms were reported by 216 (16%) contact persons. The median age of participants was 26 years (range 7-88) and 682 (49%) were male. Seropositivity was identified in 18 (8·33%, 95% CI 5·01-12·80) of 216 paucisymptomatic contact persons and 39 (3·32%, 5·01-12·80) of 1174 (2-4) asymptomatic individuals (p=0·0021). Seropositivity increased with participation in burial rituals (adjusted odds ratio [aOR] 2·30, 95% CI 1·21-4·17; p=0·0079) and exposure to blood or vomit (aOR 2·15, 1·23-3·91; p=0·0090). Frequency of Ebola virus infection varied from 3·06% (95% CI 1·84-5·05) in asymptomatic contact persons who did not participate in burial rituals to 5·98% (2·81-8·18) in those who did, and from 7·17% (3·94-9·09) in paucisymptomatic contact persons who did not participate in burial rituals to 17·16% (12·42-22·31) among those who did. INTERPRETATION: This study provides a new assessment of the prevalence of Ebola virus infection among contact persons according to exposure, provides evidence for the occurrence of paucisymptomatic cases, and reinforces the importance of closely monitoring at-risk contact persons. FUNDING: Institut National de la Santé et de la Recherche Médicale, Reacting, the French Ebola Task Force, Institut de Recherche pour le Développement, and Montpellier University Of Excellence-University of Montpellier.

Nationwide Estimates of Viral Load Suppression and Acquired HIV Drug Resistance in Cameroon.

BACKGROUND: Population-based studies to estimate viral load (VL) suppression and rate of acquired HIV drug resistance (ADR) are essential in sub-Saharan Africa. We conducted the first nationally representative study estimating VL suppression and ADR in Cameroon. METHODS: Eligible participants were patients on antiretroviral therapy (ART) for 12 to 24 months (ART 12-24) or 48 to 60 months (ART 48-60). ART 12-24 participants were recruited from 24 randomly selected clinics in both urban and rural regions. ART 48-60 participants were recruited from 7 urban clinics. Recruitment occurred from February to August 2015. Dried blood spots (DBSs) and plasma specimens were collected and tested for HIV-1 RNA level and presence of drug resistance mutations (DRM) when VL ≥ 1000 copies/ml. RESULTS: Overall, 1064 ART 12-24 and 388 ART 48-60 participants were recruited. Viral suppression in the ART 12-24 group was 72.1% (95% CI: 66.3-77.2) overall, 75.0% (65.2-82.7) in urban sites, and 67.7% (58.3-75.8) in rural sites. In the ART 48-60 group, viral suppression was 67.7% (55.8-77.7). Overall, HIV drug resistance (HIVDR) was 17.7% (15.1-20.6) and 28.3% (17.4-42.5) in the ART 12-24 and ART 48-60 groups, respectively. However, among patients with VL ≥ 1000 copies/ml, HIVDR was identified in 63.3% (52.0-73.3) of ART 12-24 patients, and in 87.7% (67.4-96.1) of ART 48-60 patients. CONCLUSIONS: Results of this first nationwide study indicate alarming levels of virological failure and ADR in Cameroon. Better ART management is urgently needed and should focus on improving ART adherence, availability of VL monitoring, and more timely switches to second-line ART.

Serological Evidence of Ebola Virus Infection in Rural Guinea before the 2014 West African Epidemic Outbreak.

Questions remain as to whether an unnoticed Ebola outbreak occurred in Guinea before the 2014-2016 epidemic. To address this, we used a highly sensitive and specific Luminex-based assay for Ebola virus (EBOV) antibody detection to screen blood samples collected in the framework of the Demographic Health Survey performed in 2012 in Guinea. One sample (GF069) of 1,483 tested was positive at very high immunoglobulin G titer to Zaire EBOV in Guinée Forestière. Thus, at least 2 years before the 2014 EVD outbreak in Guinea, Zaire EBOV was circulating in rural areas of this country.

HIV type 1 diversity and antiretroviral drug resistance mutations in Burundi.

In 2002, an HIV surveillance study was performed among more than 5500 individuals representing the general population of urban and rural districts in Burundi. In this report, we genetically characterized a subset of the HIV-1-positive samples identified during this survey, including all the HIV-positive samples from Bujumbura, the capital city, and samples from one semiurban and one rural district. One hundred and nineteen samples were genetically characterized in the V3-V5 region of the env gene and/or in the protease and reverse transcriptase region of the pol gene. Phylogenetic analysis of 101 env/pol sequences revealed that the HIV-1 epidemic in Burundi was driven by subtype C (81.2%), followed by subtype A (7.9 %) and polC/envA recombinants (5.9%). One major mutation associated with resistance to antiretroviral drugs (ARVs) in the pol gene, as defined by the International AIDS Society Resistance Testing-USA panel, was observed in one individual, but many minor resistance-associated mutations were also present in the majority of the samples.