A review of the recent advances on Lassa fever with special reference to molecular epidemiology and progress in vaccine development

Lassa fever, a viral hemorrhagic fever caused by the Lassa virus (LASV), is endemic in West Africa and is associated with high morbidity and mortality. At least three of the four proposed seven lineages of LASV are found in Nigeria, where the multimammate rat, Mastomys natalensis, serves as the primary reservoir. Endemic countries report approximately 200,000 infections and 5,000 deaths annually, with Nigeria experiencing thousands of infections and hundreds of deaths including healthcare workers. The aim of this review is to provide scientific information for better understanding of the evolutionary biology, molecular epidemiology, pathogenesis, diagnosis, and prevention of Lassa fever in Nigeria and other endemic regions worldwide, which can lead to improved control efforts and reduce morbidity and mortality from recurrent epidemics. To achieve this aim, observational studies such as case series, cross-sectional and cohort studies published between December 2017 and September 2022 were searched for on various online databases including Google Scholar, Africa Journals Online (AJOL), Research Gates, PubMed, PMIC, NCDC, and WHO websites. Although the origin and evolutionary history, and the transmission dynamics of Lassa virus have been revealed through recent. molecular epidemiological studies, the factors that drive the evolution of the virus remain unclear. Genetic changes in the viral genome may have enabled the virus to adapt to humans. Diagnosis of Lassa fever has also advanced from basic serological tests to more sophisticated methods such as quantitative real time polymerase chain reaction (qRT-PCR) and sequencing, which are particularly useful for identifying outbreak strains. Several vaccines, including recombinant vesicular stomatitis virus (rVSV), virus-like particle (VLP), and DNA-based vaccines, have shown promise in animal models and some have progressed to phase 2 clinical trials. Preventing and controlling Lassa fever is critical to safeguard the health and well-being of affected communities. Effective measures such as rodent control, improved sanitation, and early detection and isolation of infected individuals are essential for reducing transmission. Ongoing research into the genetic and ecological factors that drive the evolution of Lassa virus is necessary to reduce the impacts of Lassa fever.

A review of the recent advances on Lassa fever with special reference to molecular epidemiology and progress in vaccine development

Lassa fever, a viral hemorrhagic fever caused by the Lassa virus (LASV), is endemic in West Africa and is associated with high morbidity and mortality. At least three of the four proposed seven lineages of LASV are found in Nigeria, where the multimammate rat, Mastomys natalensis, serves as the primary reservoir. Endemic countries report approximately 200,000 infections and 5,000 deaths annually, with Nigeria experiencing thousands of infections and hundreds of deaths including healthcare workers. The aim of this review is to provide scientific information for better understanding of the evolutionary biology, molecular epidemiology, pathogenesis, diagnosis, and prevention of Lassa fever in Nigeria and other endemic regions worldwide, which can lead to improved control efforts and reduce morbidity and mortality from recurrent epidemics. To achieve this aim, observational studies such as case series, cross-sectional and cohort studies published between December 2017 and September 2022 were searched for on various online databases including Google Scholar, Africa Journals Online (AJOL), Research Gates, PubMed, PMIC, NCDC, and WHO websites. Although the origin and evolutionary history, and the transmission dynamics of Lassa virus have been revealed through recent molecular epidemiological studies, the factors that drive the evolution of the virus remain unclear. Genetic changes in the viral genome may have enabled the virus to adapt to humans. Diagnosis of Lassa fever has also advanced from basic serological tests to more sophisticated methods such as quantitative real time polymerase chain reaction (qRT-PCR) and sequencing, which are particularly useful for identifying outbreak strains. Several vaccines, including recombinant vesicular stomatitis virus (rVSV), virus-like particle (VLP), and DNA-based vaccines, have shown promise in animal models and some have progressed to phase 2 clinical trials. Preventing and controlling Lassa fever is critical to safeguard the health and well-being of affected communities. Effective measures such as rodent control, improved sanitation, and early detection and isolation of infected individuals are essential for reducing transmission. Ongoing research into the genetic and ecological factors that drive the evolution of Lassa virus is necessary to reduce the impacts of Lassa fever

La fièvre de Lassa, une fièvre hémorragique virale causée par le virus de Lassa (LASV), est endémique en Afrique de l'Ouest et est associée à une morbidité et une mortalité élevées. Au moins trois des quatre lignées proposées de LASV se trouvent au Nigeria, où le rat multimammaire, Mastomys natalensis, sert de réservoir principal. Les pays endémiques signalent environ 200,000 infections et 5,000 décès par an, le Nigéria connaissant des milliers d'infections et des centaines de décès, y compris des travailleurs de la santé. L'objectif de cette revue est de fournir des informations scientifiques pour une meilleure compréhension de la biologie évolutive, de l'épidémiologie moléculaire, de la pathogenèse, du diagnostic et de la prévention de la fièvre de Lassa au Nigeria et dans d'autres régions endémiques du monde, ce qui peut conduire à des efforts de contrôle améliorés et réduire la morbidité et la mortalité des épidémies récurrentes. Pour atteindre cet objectif, des études observationnelles telles que des séries de cas, des études transversales et de cohorte publiées entre décembre 2017 et septembre 2022 ont été recherchées sur diverses bases de données en ligne, notamment Google Scholar, Africa Journals Online (AJOL), Research Gate, PubMed, PMIC, Sites Web du NCDC et de l'OMS. Bien que l'origine et l'histoire évolutive, ainsi que la dynamique de transmission du virus de Lassa aient été révélées par des études épidémiologiques moléculaires récentes, les facteurs qui déterminent l'évolution du virus restent flous. Des modifications génétiques du génome viral pourraient avoir permis au virus de s'adapter à l'homme. Le diagnostic de la fièvre de Lassa est également passé des tests sérologiques de base à des méthodes plus sophistiquées telles que la réaction quantitative en chaîne par polymérase en temps réel (qRTPCR) et le séquençage, qui sont particulièrement utiles pour identifier les souches épidémiques. Plusieurs vaccins, y compris le virus recombinant de la stomatite vésiculeuse (rVSV), les particules pseudo-virales (VLP) et les vaccins à base d'ADN, se sont révélés prometteurs dans des modèles animaux et certains ont progressé vers des essais cliniques de phase 2. La prévention et le contrôle de la fièvre de Lassa sont essentiels pour préserver la santé et le bien-être des communautés touchées. Des mesures efficaces telles que le contrôle des rongeurs, l'amélioration de l'assainissement et la détection et l'isolement précoces des personnes infectées sont essentielles pour réduire la transmission. Des recherches continues sur les facteurs génétiques et écologiques qui déterminent l'évolution du virus de Lassa sont nécessaires pour réduire les impacts de la fièvre de Lassa.

Profil Épidémiologique et Mycologique de l'Otomycose à l'Hôpital Général de Référence de Niamey (Niger) / Epidemiological and my cologica l profile of otomycosisat the Genera l Reference Hospital o f Niamey (Niger

But. Décrire les caractéristiques épidémiologiques et mycologiques de l'otomycose à Niamey. Méthodologie.Il s'est agi d'une étude rétrospective menée sur 3ans au service d'ORL et CCF de l'Hôpital Général de Référence, portant sur les patients chez qui le diagnostic d'otomycose a été posé. Les paramètres étudiés étaient épidémiologiques et mycologiques. Résultats. En 3 ans, nous avons enregistré 447 consultations pour otites dont 56 avaient une otomycose, soit une fréquence de 12,53% de l'ensemble des otites et 58,92% des otites externes. L'âgemoyen était de 35,75 ans (extrêmes de 2 et 70 ans). La tranche d'âge de 31 à 60 ans représentait 58,93% des patients. Nous avons retrouvéune prédominance féminine (67,85%), (p=0,0752). Les principaux facteurs favorisant l'otomycose étaient le nettoyage de l'oreille au coton tige ou à la plume de volaille : (53,57%),le port du turban ou de couvre-chef, (46,42%), la baignade (16.07%), l'étroitesse du conduit auditif externe (8,92%) et le port de prothèse auditive externe intra-conduit (5,35%,). Sur le plan mycologique, le Candida albicanset l'Aspergilus nigeront représenté respectivement 19,44% et 33,33% des espèces fongiques isolées en culture. Conclusion. L'otomycose est une infection fréquente en Orl à Niamey. Le nettoyage de l'oreille au coton tige ou à la plume de volaille venait au premier rang des facteurs favorisant l'otite fongique. L'Aspergilus nigeret le Candida albicansétaient les germes les plus fréquemment isolés.

Profil épidémiologique des urgences chirurgicales viscérales pédiatriques au Centre Hospitalier Universitaire de Libreville / Epidemiological profile of pediatric visceral surgical emergencies at the Libreville University Hospital Center

Objectif : Etudier les urgences chirurgicales viscérales pédiatriques au Centre Hospitalier Universitaire de Libreville (CHUL).Patients et méthodes : Il s'agissait d'une étude prospective transversale monocentrique descriptive réalisée au CHUL du 1er janvier 2018 au 30 juin 2019. Les patients âgés de 0 à 15 ans ayant présenté une urgence chirurgicale viscérale dans les services des urgences, chirurgie viscérale et thoracique et de réanimation néonatale et néonatalogie ont été inclus.Résultats : Cette étude portait sur 156 patients. L'âge moyen était de 6,67 ans avec une prédominance du sexe masculin (107/49). Quarante-deux patients étaient référés d'autres structures sanitaires. La symptomatologie évoluait depuis plus de 3 jours chez 42,3% patients. Des explorations à visée diagnostique étaient réalisées dans 145 cas, dont 90 échographies, 51 radiographies de l'abdomen sans préparation et 4 TDM. Le délai de prise en charge était de plus de 6 heures dans 82,1% cas. La pathologie la plus rencontrée était l'appendicite aigue (53 cas). Nous avions répertorié 9 décès dont 7 en post-opératoire. La durée moyenne d'hospitalisation était de 7 jours avec des extrêmes de 3 et 54 jours.Conclusion : Les urgences chirurgicales viscérales occupent une place de choix dans la pathologie chirurgicale en général et chez l'enfant en particulier. La mortalité concerne majoritairement les nouveau-nés porteurs de malformations congénitales.

Objective: To study pediatric visceral surgical emergencies at the Center Hospitalier Universitaire de Libreville (CHUL).Patients and methods: This was a descriptive single-center cross-sectional prospective study carried out at the CHUL from January 1, 2018 to June 30, 2019. Patients aged 0 to 15 years having presented a visceral surgical emergency in the emergency departments, surgery visceral and thoracic and neonatal resuscitation and neonatology were included. Results: This study involved 156 patients. The average age is 6.67 years with a predominance of the male sex (107/49).Forty-two patients were referred from other health facilities. Symptoms have evolved for more than 3 days in 42.3% of patients. Diagnostic scans were performed in 145 cases, including 90 ultrasounds and 51 unprepared abdominal xrays and 4 CT scans. The time to treatment was more than 6 hours in 82.1% of cases. The most common pathology was acute appendicitis (53 cases). We have identified 9 deaths, including 7 postoperative. The average length of hospital stay was 7 days with extremes of 3 and 54 days. Conclusion: Visceral surgical emergencies occupy a prominent place in surgical pathology in general and in children in particular. Mortality mainly concerns newborns with congenital malformations.

Molecular epidemiology of hepatitis C virus (HCV) in Kadun State

Objective: To determine the distribution of hepatitis C virus (HCV) genotypes and subtypes among blood donors and outpatients attendees positive for antibody to HCV (anti-HCV). Justification: Hepatitis C virus (HCV) continues to be a major disease burden on the world and Man is the only known natural host of Hepatitis C virus (Chivaliez and Pawlotsky; 2007). There is no published data on the prevalence of the genotypes and subtypes of HCV in Kaduna State. Setting: Three hospitals one in each of the 3 senatorial zones in Kaduna State. Patients: Blood donors who reported for blood donation and outpatient department attendees. Method: Antibody detection by a third generation HCV ELISA (Biotech Laboratories; UK); HCV RNA and genotyping by Reverse Transcriptase polymerase chain reaction with genotype-specific primers. (Sacace Biotechnologies; UK). Results: of the 259 plasma specimens screened for Hepatitis C virus in this study; 20(7.7) were positive for anti-HCV antibodies by ELISA and 16(6.2) of the antibodies positive specimen were positive for HCV RNA. Of the 139 blood donors tested; 8 (5.8) were HCV RNA positive. Similarly; 120 were tested from the outpatient Department attendees and 8 (6.7) were HCV RNA positive. Hepatitis C virus genotype 1b was found in the entire HCV RNA positive sample. Conclusions: The findings of 6.2prevalence of HCV infection based on HCV RNA test confirmed that there is Hepatitis C virus in Kaduna State with genotype 1b as the predominant genotype found in all the three senatorial zones

Molecular Epidemiology of Malaria in Cameroon XXIX. Characterization of DHFR and Drug Resistance Markers and Efficacy of Sulfadoxine-Pyrimethamine Monotherapy in Children in Niete(HEVECAM)

In most African countries ; sulfadoxine-pyrimethamine ( Sp) had been the second-line drug to treat chloraquine in resistant Plasmodium falciparum infections in the 1990s and early 2000s . Although its use a monotherapy has been restricted in recent years ; SP has become important for intermittent preventive treatement (IPT) in pregnant women in Africa ; and some countries have been resorting to the combination artesunate -SP for the treatement of uncomplicated malaria .Therefore ; the evaluation of its efficacy remains relevant.In this study ; 58 symptomatic children were treated with SP according to the standard World Health Organization protocol and followed for 14 days .The sequences of P.Falciparum dihydrofolate reductase (dhfr)and dihydropteroate synthase (dhps) genes were determined to correlate these genetic markers and clinical outcome .In addition; blood samples form patients who did not satisfy the inclusion criteria were analysed for the presence of the key dhfr mutation .Results do not suggest any correlation between the observed mutations and SP treatement failure but show a high prevalence of mutations associated with resistance to antifolate drugs and sulfa drugs .However ; it will be important to pursue clinical studie on SP efficacy and epidemiological surveys using these molecular markers ; in particular because in Cameroon the major markers proposed to be highly associated with SP failure elsewhere in the world ; i.e.dhfr mutant codon Glu-540; have not yet been repoted

Methicillin Resistance in Staphylococcus aureus: a Review of the Molecular Epidemiology; Clinical Significance and Laboratory Detection Methods

BACKGROUND: Despite the volume of knowledge; enhanced surveillance and infection control measures adopted by health care institutions to address the endemicity and frequent disease outbreaks by methicillin-resistant Staphylococcus aureus (MRSA) in hospitals and health care facilities worldwide; infections due to this organism are still responsible for about 50of hospital acquired S. aureus infections; with increasing morbidity and mortality. OBJECTIVE: To provide regional clinicians with current information on the molecular epidemiology; laboratory detection and clinical aspects of MRSA. METHODS: A review of published literatures on MRSA in Medical Libraries and bibliographic citations on PubMed; Medline and Africa Index Medicus on molecular epidemiology and clinical diseases caused by MRSA and the assessment of the recent laboratory diagnostic approaches. RESULTS: This review showed that there has been intercontinental spread of some highly pathogenic clones of MRSA threatening to create public health hazard of unprecedented proportion; with the greatest challenge to mankind; being the development of resistance to multiple antibiotics; which in recent times had included resistance to vancomycin and other glycopeptides; the only antibiotic group effective against it. Added to this burden is the emergence of more virulent strains of community-associated MRSA (CAMRSA) which at the turn of the century; has been increasingly reported to cause infections and outbreaks in populations without predisposing risk factors; with attendant high morbidity and mortality. CONCLUSION: There is need for active MRSA surveillance by healthcare institutions in Africa to identify potential outbreaks; and vigilance in the enforcement of infection control measures such as rational prescription of antibiotics; handwashing; disinfection and sterilization that can limit the emergence and spread of more resistant clones of MRSA