Baobab Index

Lipoprotein(a) [Lp(a)] is a low-density lipoprotein-like particle covalently bound to apolipoprotein(a) and encoded by the LPA gene. Elevated plasma levels of Lp(a) are a well-established, independent, and causal risk factor for cardiovascular disease. While the epidemiology of Lp(a) has been extensively mapped in non- African populations, the burden and distribution of Lp(a) in African populations remain under-characterized despite its unique genetic, phenotypic, ethnolinguistic and ancestral diversity. The primary objective was to synthesize existing literature to determine the prevalence and distribution of elevated Lp(a) levels in apparently healthy African individuals residing on the African continent. This systematic review included observational studies (cross-sectional, cohort, and case-control) involving apparently healthy adults (≥18 years) in Africa. The review systematically searched PubMed/MEDLINE, Embase, Scopus, African Journals Online, and Google Scholar without language or date restrictions to capture the full breadth of historical and contemporary data. Data were extracted using a standardized form capturing study characteristics, population demographics, assay methods and quantitative outcomes. Methodological quality was assessed using the Newcastle-Ottawa Scale. A total of 17 studies met the inclusion criteria, representing populations from West Africa (Nigeria, Ghana) Central Africa (Cameroon), Southern Africa (South Africa, Zimbabwe), and North Africa (Morocco, Tunisia). Studies in Ghana reported prevalence rates of elevated Lp(a) (>30 mg/dL) between 30-61%. Lp(a) mean levels ranged from 12.7 mg/dL to 54.5 mg/dL depending on the cohort and assay used. Females exhibited higher Lp(a) levels than males across most African cohorts. Clinically, elevated Lp(a) was associated with hypertension, type 2 diabetes mellitus, ischemic stroke, myocardial infarction and anti-retroviral drug use. Elevated Lp(a) is a common, genetically determined trait in Africa rather than a rare dyslipidemia. Far from being a benign variant, it acts as a significant amplifier of cardiovascular risk, particularly in the presence of rising incident rates of hypertension and diabetes. Addressing this burden requires the adoption of standardized, isoform-independent assays and the development of population-specific risk thresholds to guide targeted preventive cardiovascular care.

Dengue virus is endemic globally, throughout tropical and sub-tropical regions. While the number of epidemics due to the four DENV serotypes is pronounced in East Africa, the total number of cases reported in Africa (16 million infections) remained at low levels compared to Asia (70 million infections). The French Armed forces Health Service provides epidemiological surveillance support in the Republic of Djibouti through the Bouffard Military hospital. Between 2011 and 2014, clinical and biological data of suspected dengue syndromes were collected at the Bouffard Military hospital and analyzed to improve Dengue clinical diagnosis and evaluate its circulation in East Africa. Examining samples from patients that presented one or more Dengue-like symptoms the study evidenced 128 Dengue cases among 354 suspected cases (36.2% of the non-malarial Dengue-like syndromes). It also demonstrated the circulation of serotypes 1 and 2 and reports the first epidemic of serotype 3 infections in Djibouti which was found in all of the hospitalized patients in this study. Based on these results we have determined that screening for Malaria and the presence of the arthralgia, gastro-intestinal symptoms and lymphopenia < 1,000cell/ mm3 allows for negative predictive value and specificity of diagnosis in isolated areas superior to 80% up to day 6. This study also provides evidence for an epidemic of Dengue virus serotype 3 previously not detected in Djibouti.

Millimeter Waves (MMW) will be used in the next-generation of high-speed wireless technologies, especially in future Ultra-Broadband small cells in 5G cellular networks. Therefore, their biocompatibilities must be evaluated prior to their massive deployment. Using a microarray-based approach, we analyzed modifications to the whole genome of a human keratinocyte model that was exposed at 60.4 GHz-MMW at an incident power density (IPD) of 20 mW/cm2 for 3 hours in athermic conditions. No keratinocyte transcriptome modifications were observed. We tested the effects of MMWs on cell metabolism by co-treating MMW-exposed cells with a glycolysis inhibitor, 2-deoxyglucose (2dG, 20 mM for 3 hours), and whole genome expression was evaluated along with the ATP content. We found that the 2dG treatment decreased the cellular ATP content and induced a high modification in the transcriptome (632 coding genes). The affected genes were associated with transcriptional repression, cellular communication and endoplasmic reticulum homeostasis. The MMW/2dG co-treatment did not alter the keratinocyte ATP content, but it did slightly alter the transcriptome, which reflected the capacity of MMW to interfere with the bioenergetic stress response. The RT-PCR-based validation confirmed 6 MMW-sensitive genes (SOCS3, SPRY2, TRIB1, FAM46A, CSRNP1 and PPP1R15A) during the 2dG treatment. These 6 genes encoded transcription factors or inhibitors of cytokine pathways, which raised questions regarding the potential impact of long-term or chronic MMW exposure on metabolically stressed cells.

In French Polynesia, respiratory tract clinical isolate M26, displayed unusual phenotype and contradictory phylogenetic affiliations, suggesting a hitherto unidentified rapidly-growing Mycobacterium species. The phenotype of strain M26 was further characterized and its genome sequenced. Strain M26 genome consists in a 5,732,017-bp circular chromosome with a G + C% of 67.54%, comprising 5,500 protein-coding genes and 52 RNA genes (including two copies of the 16 S rRNA gene). One region coding for a putative prophage was also predicted. An intriguing characteristic of strain M26's genome is the large number of genes encoding polyketide synthases and nonribosomal peptide synthases. Phylogenomic analysis showed that strain M26's genome is closest to the Mycobacterium phlei genome with a 76.6% average nucleotide identity. Comparative genomics of 33 Mycobacterium genomes yielded 361 genes unique to M26 strain which functional annotation revealed 84.21% of unknown function and 3.88% encoding lipid transport and metabolism; while 48.87% of genes absent in M26 strain have unknown function, 9.5% are implicated in transcription and 19% are implicated in transport and metabolism. Strain M26's unique phenotypic and genomic characteristics indicate it is representative of a new species named "Mycobacterium massilipolynesiensis". Looking for mycobacteria in remote areas allows for the discovery of new Mycobacterium species.

The seventh cholera pandemic has heavily affected Africa, although the origin and continental spread of the disease remain undefined. We used genomic data from 1070

Djibouti is a small country in the Horn of Africa with a high TB incidence (378/100,000 in 2015). Multidrug-resistant TB (MDR-TB) and resistance to second-line agents have been previously identified in the country but the extent of the problem has yet to be quantified. A national survey was conducted to estimate the proportion of MDR-TB among a representative sample of TB patients. Sputum was tested using XpertMTB/RIF and samples positive for MTB and resistant to rifampicin underwent first line phenotypic susceptibility testing. The TB supranational reference laboratory in Milan, Italy, undertook external quality assurance, genotypic testing based on whole genome and targeted-deep sequencing and phylogenetic studies. 301 new and 66 previously treated TB cases were enrolled. MDR-TB was detected in 34 patients: 4.7% of new and 31% of previously treated cases. Resistance to pyrazinamide, aminoglycosides and capreomycin was detected in 68%, 18% and 29% of MDR-TB strains respectively, while resistance to fluoroquinolones was not detected. Cluster analysis identified transmission of MDR-TB as a critical factor fostering drug resistance in the country. Levels of MDR-TB in Djibouti are among the highest on the African continent. High prevalence of resistance to pyrazinamide and second-line injectable agents have important implications for treatment regimens.

In low-income countries of the Horn of Africa, pulmonary infections are usually considered as tuberculosis, which diagnosis relies on clinical data and positive microscopic observation. This strategy allows non-tuberculous mycobacteria to escape detection, facilitating their emergence in populations. A non-tuberculous mycobacterium strain FB-527 was unexpectedly cultured from the sputum of a Djiboutian patient otherwise diagnosed with multi-drug resistant (MDR) tuberculosis. The sequencing of the rpoB and 16S rRNA genes showed that the isolate was identical to strain FI-09026 previously named "Mycobacterium simulans" and reported only once from a Somali patient. Strain FB-527 mimicked Mycobacterium tuberculosis colonies and enzymatic profile using API ZYM strip and was in vitro resistant to rifampicin and isoniazid. Isolation of two MDR mycobacteria complicated the diagnosis and therapeutic management of the patient. We here report on the complete description of strain FB-527 and strain FI-09026 including genome sequencing, finalizing the description of the proposed new species "Mycobacterium simulans".

Non-human primates (NHPs) are known hosts for adenoviruses (AdVs), so there is the possibility of the zoonotic or cross-species transmission of AdVs. As with humans, AdV infections in animals can cause diseases that range from asymptomatic to fatal. The aim of this study was to investigate the occurrence and diversity of AdVs in: (i) fecal samples of apes and monkeys from different African countries (Republic of Congo, Senegal, Djibouti and Algeria), (ii) stool of humans living near gorillas in the Republic of Congo, in order to explore the potential zoonotic risks. Samples were screened by real-time and standard PCRs, followed by the sequencing of the partial DNA polymerase gene in order to identify the AdV species. The prevalence was 3.3 folds higher in NHPs than in humans. More than 1/3 (35.8%) of the NHPs and 1/10 (10.5%) of the humans excreted AdVs in their feces. The positive rate was high in great apes (46%), with a maximum of 54.2% in chimpanzees (

The medical authority in China, especially in Wuhan city, reported on December 2019 a large number of highly fatal, rapidly spreading viral pneumonia caused by an unknown coronavirus. The common history of all the patients was their visiting a Wuhan's whole food store, where live animals and seafood are sold. Irrespective of the efforts of the Chinese authorities, the virus spread rapidly all over the world by travelers, provoking widespread attention by the media and panic. Many previous coronavirus epidemics had been recorded, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), and the recently newly discovered epidemic is named coronavirus disease of 2019 (COVID-19). This disease is caused by SARS Coronavirus-2 (SARS-CoV-2), and this virus is antigenically related to the SARS virus (SARS-CoV), which had been detected in 2002, depending on clinical, serological, and molecular findings. There is rapid competition among the researchers to discover the source of the virus, understand the mechanism of the disease development, establish treatment strategies, and determine the factors affecting the incidence of infection and severity of the disease, and focus on the production of a vaccine. Coronaviruses are a group of single-stranded, positive-sense RNA genome viruses; its genome length varies from 26 to 32 kb. Coronavirus causes mild to severe respiratory disorders. In December 2019, several cases of pneumonia of unknown causes were found in Wuhan city, which is located in the Hubei province in China. Chinese health authorities investigated the problem and found that a new virus caused such infection and, using next-generation sequencing, found the 2019 novel coronavirus (2019-nCoV). It has been transferred from humans to humans and animals to humans (zoonotic). Coronaviruses cause multiple respiratory problems, varying from common cold to severe infections such as SARS. General symptoms of infection include fatigue, cough, and breathing problems such as shortness of breath, as described by World Health Organization. Serious cases may result in pneumonia, renal failure, and even death. We address current information about the new SARS Coronavirus-2 as well as the COVID-19 disease caused by it in this review.

Since the start of COVID-19 pandemic the Republic of Djibouti, in the horn of Africa, has experienced two epidemic waves of the virus between April and August 2020 and between February and May 2021. By May 2021, COVID-19 had affected 1.18% of the Djiboutian population and caused 152 deaths. Djibouti hosts several foreign military bases which makes it a potential hot-spot for the introduction of different SARS-CoV-2 strains. We genotyped fifty three viruses that have spread during the two epidemic waves. Next, using spike sequencing of twenty-eight strains and whole genome sequencing of thirteen strains, we found that Nexstrain clades 20A and 20B with a typically European D614G substitution in the spike and a frequent P2633L substitution in nsp16 were the dominant viruses during the first epidemic wave, while the clade 20H South African variants spread during the second wave characterized by an increase in the number of severe forms of COVID-19.