Dear Editor,Lassa virus(LASV)is the causative agent of the acute viral hemorrhagic Lassa fever(LF),which is classified into Mammarenavirus within the Arenaviridae family,with a single-stranded,negative-sense,bisegment...Dear Editor,Lassa virus(LASV)is the causative agent of the acute viral hemorrhagic Lassa fever(LF),which is classified into Mammarenavirus within the Arenaviridae family,with a single-stranded,negative-sense,bisegmented RNA genome.Due to its high pathogenicity and lethality,LASV is considered as a priority threat to public health,with an estimated cases of 300,000 infections and 5000 deaths annually.LASV was first isolated and described as a clinical entity in 1969 in Lassa,Nigeria(Garry,2023).LASV isolates of different geographic and host origins are highly diverse in genomic sequences and phylogenetically classified into up to seven lineages,with each lineage predominately localized in specific countries.Although the research on LF has been carried out for decades since the pathogen first characterized,there is no approved antiviral drugs or vaccines for clinical use against LASV to date(Grant et al.,2023).One possible reason that hindered the development of countermeasures is that the preclinical studies on authentic LASV are restricted in high bio-containment biosafety level 4(BSL-4)facilities.In this letter,we describe isolation,and characterization of the LASV from the clinical samples.And we applied a coadministration assay of antiviral drugs for LASV by using a clinically isolated Mammarenavirus lassaense strain in the BSL-4 facility,aiming to investigate new therapeutic strategies for LASV infection.展开更多
Objective This study reports the first imported case of Lassa fever(LF)in China.Laboratory detection and molecular epidemiological analysis of the Lassa virus(LASV)from this case offer valuable insights for the preven...Objective This study reports the first imported case of Lassa fever(LF)in China.Laboratory detection and molecular epidemiological analysis of the Lassa virus(LASV)from this case offer valuable insights for the prevention and control of LF.Methods Samples of cerebrospinal fluid(CSF),blood,urine,saliva,and environmental materials were collected from the patient and their close contacts for LASV nucleotide detection.Whole-genome sequencing was performed on positive samples to analyze the genetic characteristics of the virus.Results LASV was detected in the patient’s CSF,blood,and urine,while all samples from close contacts and the environment tested negative.The virus belongs to the lineage IV strain and shares the highest homology with strains from Sierra Leone.The variability in the glycoprotein complex(GPC)among different strains ranged from 3.9%to 15.1%,higher than previously reported for the seven known lineages.Amino acid mutation analysis revealed multiple mutations within the GPC immunogenic epitopes,increasing strain diversity and potentially impacting immune response.Conclusion The case was confirmed through nucleotide detection,with no evidence of secondary transmission or viral spread.The LASV strain identified belongs to lineage IV,with broader GPC variability than previously reported.Mutations in the immune-related sites of GPC may affect immune responses,necessitating heightened vigilance regarding the virus.展开更多
Objective:Studies on the occupational health risks and experiences of healthcare waste handlers since the decline in coronavirus disease 2019(COVID-19)incidence are scarce in Nigeria.The current study aimed to examine...Objective:Studies on the occupational health risks and experiences of healthcare waste handlers since the decline in coronavirus disease 2019(COVID-19)incidence are scarce in Nigeria.The current study aimed to examine what seemed as the"hidden"and rarely researched area of practice from the standpoint of different stakeholders in a Nigerian Lassa fever treatment hospital.The primary objective was to understand the nature of waste handlers'practices and experiences and identify areas for improvement centred on supporting the development of best practices,in accordance with the World Health Organisation(WHO)guidelines.Methods:This study employed a qualitative case study design,gathering data from healthcare waste handlers(n=34)through four focus groups.Additionally,four in-depth interviews were conducted with ward managers and the infection control team to gain insight into the organisational framing of waste handling practice,the perceived challenges faced by waste handlers from their perspectives,and the provision of training and support.The qualitative data were audio-recorded and transcribed verbatim through manual processes and subjected to a reflexive thematic analysis conducted manually.Results:The findings revealed that waste handlers were subjected to various occupational health risks,including back pain,needlestick injuries,psychological distress,fatigue,anxiety,and prolonged exposure to sunlight.Concerns were raised regarding the inadequate supply of personal protective equipment and other essential tools,which suggests a need for organisational commitment to ensure the continual availability of these resources to protect the health and safety of these employees.A critical issue identified was the lack of comprehensive training for waste handlers,highlighting a form of organisational negligence.The consensual views expressed by the waste handlers indicated a sense of dissatisfaction with their working environment,largely attributable to organisational and societal stigmatisation.Furthermore,the study underscored that the hospital management faced significant financial constraints and advocated for increased funding to effectively implement best practice standards.Conclusion:To effectively manage healthcare waste and reduce hazards to waste handlers,the organisational leadership should prioritise training and support.This initiative will not only benefit the waste handlers but also the patients,other healthcare workers,and the general public.Although the findings focus on the case context of a Nigerian Lassa fever treatment hospital,the wider implications of this study are linked to the role of institutional support for waste handling practice.Moreover,it extends to the potential positions of institutions as displaying a form of"benign anomie"in not ensuring the wellbeing of waste handlers through sufficient regulation and governance focused on prioritisation,processes,and procedures.The study highlights the relevance of embedding WHO guidelines in other similar contexts as part of implementation across institutions involved with waste handling.展开更多
Background: In recent times, there has been an increase in the number of Lassa fever cases resulting from the several episodes of Lassa fever epidemics ravaging Nigeria and other West African countries. The presence o...Background: In recent times, there has been an increase in the number of Lassa fever cases resulting from the several episodes of Lassa fever epidemics ravaging Nigeria and other West African countries. The presence of Lassa virus in rodents other than the major reservoir (Mastomys natalensis) has been a public health concern as to the actual burden of the disease. It is therefore of a public health necessity to explore the LASV RNA habouring potential of several species of rodents in endemic as well as non-endemic areas for proper prevention of emergence of outbreaks in non-endemic areas. Objectives: The aim of this study was to detect the presence of LASV RNA in different species of rodents in Ikorodu, Lagos state and Abeokuta, Ogun state. Methods: A total of ninety one (91) rodents were captured from Ikorodu, Lagos State (61 rodents) and Abeokuta, Ogun State (30 rodents), euthanized, bled, and plasma obtained for the detection of LASV RNA by Reverse Transcriptase Polymerase Chain Reaction. Results: A total of 91 rodents consisting of 77 Rattus rattus and 14 Crocidura spp. The S segment of LASV RNA was not in any of the 91 rodents’ plasma samples. Conclusion: The rodents captured within the rural communities of Ikorodu, Lagos State and Abeokuta, Ogun State were found not to habour the LASV RNA. This study is limited by the relatively small sample size. Similar studies should be encouraged both in endemic and non-endemic areas in order to understand the actual burden of Lassa fever as well as put into check future epidemics.展开更多
Lassa virus(LASV)is an enveloped,negative-sense RNA virus that causes Lassa hemorrhagic fever.Successful entry of LASV requires the viral glycoprotein 1(GP1)to undergo a receptor switch from its primary receptor alpha...Lassa virus(LASV)is an enveloped,negative-sense RNA virus that causes Lassa hemorrhagic fever.Successful entry of LASV requires the viral glycoprotein 1(GP1)to undergo a receptor switch from its primary receptor alpha-dystroglycan(α-DG)to its endosomal receptor lysosome-associated membrane protein 1(LAMP1).A conserved histidine triad in LASV GP1 has been reported to be responsible for receptor switch.To test the hypothesis that other non-conserved residues also contribute to receptor switch,we constructed a series of mutant LASV GP1 proteins and tested them for binding to LAMP1.Four residues,L84,K88,L107,and H170,were identified as critical for receptor switch.Substituting any of the four residues with the corresponding lymphocytic choriomeningitis virus(LCMV)residue(L84 N,K88E,L10F,and H170S)reduced the binding affinity of LASV GP1 for LAMP1.Moreover,all mutations caused decreases in glycoprotein precursor(GPC)-mediated membrane fusion at both pH 4.5 and 5.2.The infectivity of pseudotyped viruses bearing either GPCL84N or GPCK88E decreased sharply in multiple cell types,while L107F and H170S had only mild effects on infectivity.Using biolayer light interferometry assay,we found that all four mutants had decreased binding affinity to LAMP1,in the order of binding affinity being L84 N>L107F>K88E>H170S.The four amino acid loci identified for the first time in this study have important reference significance for the in-depth investigation of the mechanism of receptor switching and immune escape of LASV occurrence and the development of reserve anti-LASV infection drugs.展开更多
<strong>Introduction: </strong>Lassa fever is a disease of public health importance because of the associated morbidity and high case fatality rate among hospitalized patients. Even after recovery, there m...<strong>Introduction: </strong>Lassa fever is a disease of public health importance because of the associated morbidity and high case fatality rate among hospitalized patients. Even after recovery, there may be residual problems such as sensorineural hearing loss. The initial presentation of Lassa fever may be with non-specific symptoms similar to what is seen in the more common febrile illnesses such as malaria or typhoid fever. In such a setting therefore, timely diagnosis of Lassa fever may be difficult. <strong>Case Report: </strong>We report a case of Lassa fever that presented to our institution. She was a middle aged woman who had non-specific symptoms of febrile illness and who died in less than 48 hours of admission. She had a subtle bleeding on the lip just before death which was what raised the suspicion for Lassa fever. Laboratory confirmation of Lassa fever was made retrospectively.<strong> Conclusion: </strong>When the presenting symptoms are non-specific, a high index of suspicion is required for timely recognition of Lassa fever. Early diagnosis is important for prompt therapeutic intervention as well as for limiting the spread of the disease. This is the second case of Lassa fever presenting to our hospital, but the first published case of Lassa fever from our hospital.展开更多
Background: Lassa fever cases outside Africa are seen as imported cases of Lassa fever. Timely diagnosis of imported Lassa fever is important for timely intervention necessary to reduce the morbidity and mortality ass...Background: Lassa fever cases outside Africa are seen as imported cases of Lassa fever. Timely diagnosis of imported Lassa fever is important for timely intervention necessary to reduce the morbidity and mortality associated with Lassa fever, and this requires the knowledge of the clinical manifestations of Lassa fever. Purpose: This review was done to see how clinical diagnosis of imported Lassa fever can be facilitated based on the clinical presentations of imported cases of Lassa fever in Lassa fever non-endemic region. Methods: The relevant articles for the review were obtained from the databases of PubMed and Google Scholar. Results: The clinical presentations of the imported Lassa fever cases consisted of multisystem involvement and were similar to those of Lassa fever patients who were treated in the Lassa fever endemic region. Conclusions: History of recent travel to, or residence in, Lassa fever endemic region is an important clue for clinical diagnosis of Lassa fever. The 2011 CDC surveillance case definition and the modified Khan case definition for Lassa fever may aid clinical diagnosis of Lassa fever. Any clinically suspected case of Lassa fever should have a laboratory confirmation.展开更多
The membrane-proximal external region(MPER)of Lassa virus(LASV)glycoprotein complex(GPC)is critical in modulating its functionality.Till now,the high-resolution structure of the intact GPC,including MPER is not availa...The membrane-proximal external region(MPER)of Lassa virus(LASV)glycoprotein complex(GPC)is critical in modulating its functionality.Till now,the high-resolution structure of the intact GPC,including MPER is not available.In this study,we used alanine substitution to scan all 16 residues located in LASV MPER.Western blotting and quantification fusion assay showed that the residues located at the C terminus of the HR2(M414 and L415)and N terminus of the MPER(K417 and Y419)are critical for GPC-mediated membrane fusion function.Furthermore,cell surface biotinylation experiments revealed that M414 A,K417 A and Y419 A expressed similar levels as WT,whereas L415 A mutant led to a reduction of mature GPC on the cell surface.Moreover,substitution of these residues with the similar residue such as M414 L,L415 I,K417 R and Y419 F would partly compensate the loss of the fusion activity caused by the alanine mutant in these sites.Results from this study showed that several key residues in the MPER region are indispensable to promote the conformational changes that drive fusion events and shed light on the structure analysis of LASV GPC and anti-LASV therapeutics.展开更多
Lassa virus(LASV)belongs to the Mammarenavirus genus(family Arenaviridae)and causes severe hemorrhagic fever in humans.The glycoprotein complex(GPC)contains eleven N-linked glycans that play essential roles in GPC fun...Lassa virus(LASV)belongs to the Mammarenavirus genus(family Arenaviridae)and causes severe hemorrhagic fever in humans.The glycoprotein complex(GPC)contains eleven N-linked glycans that play essential roles in GPC functionalities such as cleavage,transport,receptor recognition,epitope shielding,and immune response.We used three mutagenesis strategies(asparagine to glutamine,asparagine to alanine,and serine/tyrosine to alanine mutants)to abolish individual glycan chain on GPC and found that all the three strategies led to cleavage inefficiency on the 2nd(N89),5th(N119),or 8th(N365)glycosylation motif.To evaluate N to Q mutagenesis for further research,it was found that deletion of the 2nd(N89Q)or 8th(N365Q)glycan completely inhibited the transduction efficiency of pseudotyped particles.We further investigated the role of individual glycan on GPC-mediated immune response by DNA immunization of mice.Deletion of the individual 1st(N79Q),3rd(N99Q),5th(N119Q),or 6th(N167Q)glycan significantly enhanced the proportion of effector CD4+cells,whereas deletion of the 1st(N79Q),2nd(N89Q),3rd(N99Q),4th(N109Q),5th(N119Q),6th(N167Q),or 9th(N373Q)glycan enhanced the proportion of CD8+effector T cells.Deletion of specific glycan improves the Th1-type immune response,and abolishment of glycan on GPC generally increases the antibody titer to the glycan-deficient GPC.However,the antibodies from either the mutant or WT GPC-immunized mice show little neutralization effect on wild-type LASV.The glycan residues on GPC provide an immune shield for the virus,and thus represent a target for the design and development of a vaccine.展开更多
The Lassa virus(LASV)is endemic in West Africa and causes severe hemorrhagic Lassa fever in humans.The glycoprotein complex(GPC)of LASV is highly glycosylation-modified,with 11 N-glycosylation sites.All 11 N-linked gl...The Lassa virus(LASV)is endemic in West Africa and causes severe hemorrhagic Lassa fever in humans.The glycoprotein complex(GPC)of LASV is highly glycosylation-modified,with 11 N-glycosylation sites.All 11 N-linked glycan chains play critical roles in GPC cleavage,folding,receptor binding,membrane fusion,and immune evasion.In this study,we focused on the first glycosylation site because its deletion mutant(N79Q)results in an unexpected enhanced membrane fusion,whereas it exerts little effect on GPC expression,cleavage,and receptor binding.Meanwhile,the pseudotype virus bearing GPC_(N79Q)was more sensitive to the neutralizing antibody 37.7H and was attenuated in virulence.Exploring the biological functions of the key glycosylation site on LASV GPC will help elucidate the mechanism of LASV infection and provide strategies for the development of attenuated vaccines against LASV infection.展开更多
Background: Lassa Hemorrhagic Fever (LHF) is endemo-epidemic in West Africa with seasonal outbreaks raising a major public health issue. Nigeria borders Benin by the Tchaourou Commune. Since 2016, Tchaourou commune ha...Background: Lassa Hemorrhagic Fever (LHF) is endemo-epidemic in West Africa with seasonal outbreaks raising a major public health issue. Nigeria borders Benin by the Tchaourou Commune. Since 2016, Tchaourou commune has been affected every year by this epidemic. Objective: To study how an action on the health social determinants can contribute to ending this epidemic in Tchaourou commune, Benin. Methods: This cross-sectional study was conducted in Tchaourou commune. All of the cases of LHF occurring in 2016-2018 were retrospectively tracked throughout the commune. The health workers and 172 participants of the general population of villages of the cases were enrolled. We used absolute frequency to describe the LHF cases because of their small number. The descriptive analyses were performed using EPI-INFO 7.1.14. Results: Overall, 27 cases of LHF occurred in Tchaourou. In these 27 cases, 12 were Laboratory-Confirmed. All 4 probable cases died while 42% and 18% died in the confirmed and suspected cases, respectively. Most (75%) of the cases were female. By direct observations, the commune had a weak health-promoting environment for fighting against LHF outbreak. According to the health care staff in the commune, the interventions were for controlling the outbreak and not the promoting interventions to preventing further outbreaks. Conclusion: To fight effectively against the Lassa fever, it is necessary to act on different social determinants of health with community participation, empowerment and health control. The fight against Lassa fever remains a major challenge facing developing countries like Benin.展开更多
Introduction: Lassa viral hemorrhagic fever is common in West Africa. Almost 300,000 persons are affected each year with 5000 deaths. The mice of the genus mastomys is the wild tank. Objective: The aim of our study is...Introduction: Lassa viral hemorrhagic fever is common in West Africa. Almost 300,000 persons are affected each year with 5000 deaths. The mice of the genus mastomys is the wild tank. Objective: The aim of our study is to describe clinic, therapeutic and evolution of the affected patients during February-March 2017 epidemic that occurred in the north of Togo. Methodology: Our study is a record review study from patients’ record, who were hospitalized from February, 1st to March, 31st 2017 at Mango hospital. Lassa diagnosis was performed by PCR. They patients have received Ribavirin and blood transfusion when necessary. Results: We have reported 5 clinical observations of Lassa viral hemorrhagic fever. Patients came from Benin (03 cases), from Burkina-Faso (1 case), from Togo (1 case) and were 25, 34, 60, 52 years old and a premature baby of 13 days. External hemorrhage and abdominal pains were the main symptoms. Fever was observed for all the cases. Complications were marked by hemorrhages and shocks. Only 3 patients had benefitted of Antiviral therapy with Ribavirin. The other 2 patients did not benefit from the treatment because the diagnosis of Lassa fever was done the day they dead before the treatment started. Lethality was 80% (4 cases) with a highly secured burial. Effective management of contacts was done. Conclusion: Diagnostic and therapeutic delays of patients are responsible of the bad prognosis of the disease.展开更多
Introduction: Lassa viral hemorrhagic fever is caused by the Lassa virus. The aim of our study is to describe the therapeutic itinerary of the 4 cases of Lassa virus hemorrhagic of February-March 2017 epidemic that oc...Introduction: Lassa viral hemorrhagic fever is caused by the Lassa virus. The aim of our study is to describe the therapeutic itinerary of the 4 cases of Lassa virus hemorrhagic of February-March 2017 epidemic that occurred in Mango. Methodology: Our study is a transverse retro-prospective and descriptive study from February, 1st to March, 31st 2017 that dealt with 4 confirmed Lassa fever cases declared positive on the PCR basis;hospitalized or deceased at the hospital “Esperance” of Mango;support center of Lassa viral hemorrhagic fever. Results: we reported 4 clinical observations of Lassa viral hemorrhagic fever diagnosed on the PCR basis during the Lassa fever epidemic. Patients came from Benin (2 cases) or from Burkina-Faso (1 case) and were 25, 60, 52 years old and a premature baby of 13 days. The reasons for admission were external hemorrhage, a pultated tonsillitis and abdominal pains. Fever was observed for all the cases. Complications were marked by hemorrhages and shocks. Only two patients benefitted from Antiviral therapy with Ribavirin and were declared healed. The other two patients did not benefit from the treatment due to diagnostic and therapeutic delays. Lethality was 75% (3 cases) with a highly secured burial. Effective management of contacts was established. Conclusion: Diagnostic and therapeutic delays of patients are responsible of the Dark Prognosis of Lassa fever during the epidemic.展开更多
Background: Lassa fever is a viral haemorrhagic fever associated with several complications which include hearing loss. Hearing loss in Lassa fever may become residual with its negative impact on the quality of life. ...Background: Lassa fever is a viral haemorrhagic fever associated with several complications which include hearing loss. Hearing loss in Lassa fever may become residual with its negative impact on the quality of life. Purpose: This paper is a review of various studies on Lassa fever related hearing loss. Methods: Systematic literature review was done on articles on Lassa fever patients and Lassa fever survivors. Relevant articles published in English between 1969 and 2021 were searched for using Google Scholar and PubMed databases. Eight studies which met the inclusion criteria were finally selected and included in the review. The variables of interest were extracted from the full-text articles. Results: Lassa fever related hearing loss occurs in both sexes and in all age groups. The incidence of self-reported hearing loss ranged from 12.5% to 30% with a mean of 17.6%. The incidence of audiometrically determined sensorineural hearing loss ranged from 13.5% to 29% with a mean of 22.1%. Hearing loss persisted in 64% of those that were followed up. Cases of hearing loss varied in severity, ranging from mild to profound. No successful specific treatment for Lassa fever related hearing loss was reported apart from hearing rehabilitation. Conclusion: Hearing loss among Lassa fever patients remains a major challenge. Lack of effective treatment for Lassa fever related hearing loss is a serious gap in the management of Lassa fever patients which should be addressed in future research.展开更多
Introduction: Annual outbreak of Lassa Fever (LF) has been reported in Ondo State over the years. We analyzed LF surveillance data from January 2014 to December 2019 to describe the epidemiological pattern of the outb...Introduction: Annual outbreak of Lassa Fever (LF) has been reported in Ondo State over the years. We analyzed LF surveillance data from January 2014 to December 2019 to describe the epidemiological pattern of the outbreak. Method: Lassa fever dataset from January 2014 to December 2019 was obtained from the State Ministry of Health. Variables analyzed include date of onset of symptom, age, gender, place (Local Government Area, LGA) and outcome of laboratory test. Data were summarized using frequencies, proportions, chart and maps. Results: From January 2014 and December 2019, 2141 suspected LF cases were reported. Of these, 551 cases were laboratory confirmed with 134 deaths recorded. The LF cases (suspected vs. confirmed) reported increased in 2016 (73 vs. 19), 2017 (207 vs. 76), 2018 (452 vs. 159) and 2019 (856 vs. 285) respectively. Most of the confirmed cases (89.5%) were ≥15 years while more than half (53.7%) were males. Prior to 2016, only two LGAs (Owo and Ose) recorded continued transmission of the disease. However, between 2016 and 2019, the disease had spread to 8 neighboring LGAs (P < 0.001) with the CFR declining from 67% in 2015 to 20% in 2019. Conclusion: We found an unusual increase in the suspected LF cases reported between January 2016 and December 2019 with a corresponding increase in the confirmed cases and high annual case fatality rates. Hence, we recommend intensified surveillance activities to enhance timely reporting of cases and laboratory confirmation to ensure early commencement of treatment to reduce the case fatality rate.展开更多
Lassa Fever is endemic to the eastern region of Sierra Leone. It is a haemorrhagic disease that is often transmitted from rats to humans and then human to humans. Ecological disturbances such as changes in land use in...Lassa Fever is endemic to the eastern region of Sierra Leone. It is a haemorrhagic disease that is often transmitted from rats to humans and then human to humans. Ecological disturbances such as changes in land use involving conversion of natural ecosystems to agriculture, mining or for urban expansion are reported to bring humans into close contact with animals such as the Mastomys rat that carries the Lassa Fever virus thereby posing health problems.The nature and extent of such ecological disturbances or land use changes within areas known to be endemic to Lassa Fever are not clearly understood from a research context in Sierra Leone. This study was therefore undertaken to identify the pattern of changes in land use and cropping practices and their potential to bring humans into close interactions with the Mastomys rat that is the host for the Lassa Fever virus. Four communities were chosen for the study, two rural (Lalehun and Majihun) and two urban (Lambayama section in Kenema City and Largo Square section in Segbwema Town). Different vegetation and land use/cropping practices were identified and observations were made on the pattern of changes at different times in the cropping year. There were four common vegetation and cropping practices found in all communities: upland rice intercropping, old fallow, young fallow, and swamp rice cultivation. The study revealed the variations in land use patterns and cropping practices between urban and rural settlements. Agro-forestry practices such as perennial cash crops cacao and rubber plantations were more common in rural communities. The study also revealed that while fallow vegetation persisted in rural areas there had been expansion of settlements into old fallow vegetation indicating a greater threat to the persistence of natural ecosystem in urban than in rural settlements. These disturbances resulted in habitat fragmentation and increased the likelihood of contact between humans and animal species (e.g. Mastomys rat) associated with various habitats.展开更多
Lassa fever is a viral haemorrhagic fever found mostly in West Africa where it is endemic but generates periodic outbreaks in the dry seasons. The virus is spread by the rat species named mastomys natalensis. While th...Lassa fever is a viral haemorrhagic fever found mostly in West Africa where it is endemic but generates periodic outbreaks in the dry seasons. The virus is spread by the rat species named mastomys natalensis. While the illness is minor in most cases, the mortality is significant in hospitalized patients. Few completely equipped treatment centers existed in Nigeria previous to current increase in frequency requiring demand for new treatment centers without the full complement of essential capabilities. Aim: To analyze the profile and treatment outcome in patients hospitalized in one of such new resource-constrained centers at the Benue State University Teaching Hospital Makurdi, Nigeria. Methodology: This was a retrospective, descriptive hospital-based research encompassing January 2020 to March 2023. Medical records of those admitted to the isolation center were reviewed. The relevant data was coded and analyzed using IBM SPSS version 23. Results: One hundred and ten (110) individuals were hospitalized for probable or suspected Lassa fever throughout the research period. A total of 35 confirmed patients satisfied the inclusion criteria and were included as the study subjects. There were 23 (65.7%) men and 12 (34.3%) females. Their mean age was 35.36 ± 12.21 years (range 15-61 years). The treatment outcome showed that 24 (75%) survived and were discharged, 5 (15.6%) were referred out of the facility for dialysis and 3 died, providing a mortality of 8.6%. The causes of mortality in study patients were acute kidney injury and encephalopathy. Conclusion: Lassa fever is endemic in Benue state with all types of individuals afflicted. The outcome of treatment was good despite resource difficulties. Lassa fever can be successfully managed even in resource-challenged situations typically encountered in developing countries.展开更多
Introduction:On August 3,2024,a suspected case of Lassa fever was identified in Sichuan Province,likely imported from an endemic region.Local CDCs promptly initiated investigation and implemented preventive measures u...Introduction:On August 3,2024,a suspected case of Lassa fever was identified in Sichuan Province,likely imported from an endemic region.Local CDCs promptly initiated investigation and implemented preventive measures upon receiving this report.Methods:The response included epidemiological investigations,contact tracing and management,hospital infection control measures,environmental disinfection,laboratory testing,biological sample management,and risk communication strategies.Results:The patient was confirmed as China’s first imported case of Lassa fever on August 6.The investigation identified 12 close contacts and 71 general contacts.By August 24,all contacts had completed medical observation without developing any symptoms consistent with Lassa fever.The patient recovered with residual hearing loss and was discharged on September 24 following expert verification.Conclusions:The increasing frequency of international travel and ongoing globalization have elevated the risk of novel infectious disease importation,including Lassa fever.Simultaneously,the widespread adoption of metagenomic sequencing for diagnosing unexplained illnesses in healthcare settings has enhanced pathogen detection sensitivity,enabling more precise identification of emerging infectious agents.展开更多
Lassa fever(LF)is a serious acute viral hemorrhagic illness that is endemic to West Africa where it affects an estimated two million people and results in up to 10000 deaths each year.The disease is caused by the Lass...Lassa fever(LF)is a serious acute viral hemorrhagic illness that is endemic to West Africa where it affects an estimated two million people and results in up to 10000 deaths each year.The disease is caused by the Lassa virus(LASV),part of the Arenaviridae family,and is primarily transmitted through contact with urine or feces of infected Mastomys natalensis rodents.Human-to-human transmission,particularly in healthcare and community settings,further amplifies the risk of spread.Since its discovery in 1969,LF continues to be a neglected tropical disease with significant health impacts,especially in vulnerable populations such as pregnant females and those with weakened immune systems.The clinical spectrum of LF varies from mild,flu-like symptoms to severe complications including bleeding,brain inflammation,and multiple organ dysfunction with neonates and pregnant female showing the highest fatality rates.Accurate diagnosis is hindered by symptom overlap with common regional illnesses such as malaria and typhoid,underlining the urgent need for strengthened diagnostic infrastructure and rapid testing methods.While ribavirin remains the main antiviral treatment,its effectiveness depends heavily on early administration.Currently,no approved vaccine exists;however,promising candidates like vesicular stomatitis virus(VSV)ΔG-LASVGPC,INO-4500,and measles virusbased(MV)-LASV are undergoing preclinical and early-phase clinical evaluation,exhibiting encouraging immune responses in animal and human studies.A comprehensive strategy combining public health education,rodent control measures,robust infection prevention in clinical settings,and international cooperation in vaccine and drug research is essential to curb the impact of LF.展开更多
基金supported by the National Key Research and Development Program of China(2022YFC2303300,2023YFC2605504)the National Natural Science Foundation of China(82172273 and 31670165)the Open Research Fund Program of the State Key Laboratory of Virology of China(2023JZZD-01).
文摘Dear Editor,Lassa virus(LASV)is the causative agent of the acute viral hemorrhagic Lassa fever(LF),which is classified into Mammarenavirus within the Arenaviridae family,with a single-stranded,negative-sense,bisegmented RNA genome.Due to its high pathogenicity and lethality,LASV is considered as a priority threat to public health,with an estimated cases of 300,000 infections and 5000 deaths annually.LASV was first isolated and described as a clinical entity in 1969 in Lassa,Nigeria(Garry,2023).LASV isolates of different geographic and host origins are highly diverse in genomic sequences and phylogenetically classified into up to seven lineages,with each lineage predominately localized in specific countries.Although the research on LF has been carried out for decades since the pathogen first characterized,there is no approved antiviral drugs or vaccines for clinical use against LASV to date(Grant et al.,2023).One possible reason that hindered the development of countermeasures is that the preclinical studies on authentic LASV are restricted in high bio-containment biosafety level 4(BSL-4)facilities.In this letter,we describe isolation,and characterization of the LASV from the clinical samples.And we applied a coadministration assay of antiviral drugs for LASV by using a clinically isolated Mammarenavirus lassaense strain in the BSL-4 facility,aiming to investigate new therapeutic strategies for LASV infection.
基金supported by Public Health Talent Training and Surport Plan(National Administration of Disease Prevention and Control)Research and application of new technology for rapid monitoring and tracing of emergent infectious diseases among entry-exit population(2024YFFK0056)Monitoring,Early warning and Response of Major Infectious Diseases(2022ZDZX0017).
文摘Objective This study reports the first imported case of Lassa fever(LF)in China.Laboratory detection and molecular epidemiological analysis of the Lassa virus(LASV)from this case offer valuable insights for the prevention and control of LF.Methods Samples of cerebrospinal fluid(CSF),blood,urine,saliva,and environmental materials were collected from the patient and their close contacts for LASV nucleotide detection.Whole-genome sequencing was performed on positive samples to analyze the genetic characteristics of the virus.Results LASV was detected in the patient’s CSF,blood,and urine,while all samples from close contacts and the environment tested negative.The virus belongs to the lineage IV strain and shares the highest homology with strains from Sierra Leone.The variability in the glycoprotein complex(GPC)among different strains ranged from 3.9%to 15.1%,higher than previously reported for the seven known lineages.Amino acid mutation analysis revealed multiple mutations within the GPC immunogenic epitopes,increasing strain diversity and potentially impacting immune response.Conclusion The case was confirmed through nucleotide detection,with no evidence of secondary transmission or viral spread.The LASV strain identified belongs to lineage IV,with broader GPC variability than previously reported.Mutations in the immune-related sites of GPC may affect immune responses,necessitating heightened vigilance regarding the virus.
基金Bangor University,UK supported this study through the International Science Partnerships Fund(ISPF)。
文摘Objective:Studies on the occupational health risks and experiences of healthcare waste handlers since the decline in coronavirus disease 2019(COVID-19)incidence are scarce in Nigeria.The current study aimed to examine what seemed as the"hidden"and rarely researched area of practice from the standpoint of different stakeholders in a Nigerian Lassa fever treatment hospital.The primary objective was to understand the nature of waste handlers'practices and experiences and identify areas for improvement centred on supporting the development of best practices,in accordance with the World Health Organisation(WHO)guidelines.Methods:This study employed a qualitative case study design,gathering data from healthcare waste handlers(n=34)through four focus groups.Additionally,four in-depth interviews were conducted with ward managers and the infection control team to gain insight into the organisational framing of waste handling practice,the perceived challenges faced by waste handlers from their perspectives,and the provision of training and support.The qualitative data were audio-recorded and transcribed verbatim through manual processes and subjected to a reflexive thematic analysis conducted manually.Results:The findings revealed that waste handlers were subjected to various occupational health risks,including back pain,needlestick injuries,psychological distress,fatigue,anxiety,and prolonged exposure to sunlight.Concerns were raised regarding the inadequate supply of personal protective equipment and other essential tools,which suggests a need for organisational commitment to ensure the continual availability of these resources to protect the health and safety of these employees.A critical issue identified was the lack of comprehensive training for waste handlers,highlighting a form of organisational negligence.The consensual views expressed by the waste handlers indicated a sense of dissatisfaction with their working environment,largely attributable to organisational and societal stigmatisation.Furthermore,the study underscored that the hospital management faced significant financial constraints and advocated for increased funding to effectively implement best practice standards.Conclusion:To effectively manage healthcare waste and reduce hazards to waste handlers,the organisational leadership should prioritise training and support.This initiative will not only benefit the waste handlers but also the patients,other healthcare workers,and the general public.Although the findings focus on the case context of a Nigerian Lassa fever treatment hospital,the wider implications of this study are linked to the role of institutional support for waste handling practice.Moreover,it extends to the potential positions of institutions as displaying a form of"benign anomie"in not ensuring the wellbeing of waste handlers through sufficient regulation and governance focused on prioritisation,processes,and procedures.The study highlights the relevance of embedding WHO guidelines in other similar contexts as part of implementation across institutions involved with waste handling.
文摘Background: In recent times, there has been an increase in the number of Lassa fever cases resulting from the several episodes of Lassa fever epidemics ravaging Nigeria and other West African countries. The presence of Lassa virus in rodents other than the major reservoir (Mastomys natalensis) has been a public health concern as to the actual burden of the disease. It is therefore of a public health necessity to explore the LASV RNA habouring potential of several species of rodents in endemic as well as non-endemic areas for proper prevention of emergence of outbreaks in non-endemic areas. Objectives: The aim of this study was to detect the presence of LASV RNA in different species of rodents in Ikorodu, Lagos state and Abeokuta, Ogun state. Methods: A total of ninety one (91) rodents were captured from Ikorodu, Lagos State (61 rodents) and Abeokuta, Ogun State (30 rodents), euthanized, bled, and plasma obtained for the detection of LASV RNA by Reverse Transcriptase Polymerase Chain Reaction. Results: A total of 91 rodents consisting of 77 Rattus rattus and 14 Crocidura spp. The S segment of LASV RNA was not in any of the 91 rodents’ plasma samples. Conclusion: The rodents captured within the rural communities of Ikorodu, Lagos State and Abeokuta, Ogun State were found not to habour the LASV RNA. This study is limited by the relatively small sample size. Similar studies should be encouraged both in endemic and non-endemic areas in order to understand the actual burden of Lassa fever as well as put into check future epidemics.
基金supported by the National Key Research and Development Program of China(2023YFC2605504,2022YFC2303300)the National Natural Sciences Foundation of China(82172273 and 31670165)+3 种基金the Open Research Fund Program of the State Key Laboratory of Virology of China(2023JZZD-01)the Health research project of Shaanxi Province(2022D040)the Science and Technology Planning Project of Shaanxi Provincial Education Department(22JK0545)the Natural Science Basic Research Program of Shaanxi(2024JC-YBQN-0922).
文摘Lassa virus(LASV)is an enveloped,negative-sense RNA virus that causes Lassa hemorrhagic fever.Successful entry of LASV requires the viral glycoprotein 1(GP1)to undergo a receptor switch from its primary receptor alpha-dystroglycan(α-DG)to its endosomal receptor lysosome-associated membrane protein 1(LAMP1).A conserved histidine triad in LASV GP1 has been reported to be responsible for receptor switch.To test the hypothesis that other non-conserved residues also contribute to receptor switch,we constructed a series of mutant LASV GP1 proteins and tested them for binding to LAMP1.Four residues,L84,K88,L107,and H170,were identified as critical for receptor switch.Substituting any of the four residues with the corresponding lymphocytic choriomeningitis virus(LCMV)residue(L84 N,K88E,L10F,and H170S)reduced the binding affinity of LASV GP1 for LAMP1.Moreover,all mutations caused decreases in glycoprotein precursor(GPC)-mediated membrane fusion at both pH 4.5 and 5.2.The infectivity of pseudotyped viruses bearing either GPCL84N or GPCK88E decreased sharply in multiple cell types,while L107F and H170S had only mild effects on infectivity.Using biolayer light interferometry assay,we found that all four mutants had decreased binding affinity to LAMP1,in the order of binding affinity being L84 N>L107F>K88E>H170S.The four amino acid loci identified for the first time in this study have important reference significance for the in-depth investigation of the mechanism of receptor switching and immune escape of LASV occurrence and the development of reserve anti-LASV infection drugs.
文摘<strong>Introduction: </strong>Lassa fever is a disease of public health importance because of the associated morbidity and high case fatality rate among hospitalized patients. Even after recovery, there may be residual problems such as sensorineural hearing loss. The initial presentation of Lassa fever may be with non-specific symptoms similar to what is seen in the more common febrile illnesses such as malaria or typhoid fever. In such a setting therefore, timely diagnosis of Lassa fever may be difficult. <strong>Case Report: </strong>We report a case of Lassa fever that presented to our institution. She was a middle aged woman who had non-specific symptoms of febrile illness and who died in less than 48 hours of admission. She had a subtle bleeding on the lip just before death which was what raised the suspicion for Lassa fever. Laboratory confirmation of Lassa fever was made retrospectively.<strong> Conclusion: </strong>When the presenting symptoms are non-specific, a high index of suspicion is required for timely recognition of Lassa fever. Early diagnosis is important for prompt therapeutic intervention as well as for limiting the spread of the disease. This is the second case of Lassa fever presenting to our hospital, but the first published case of Lassa fever from our hospital.
文摘Background: Lassa fever cases outside Africa are seen as imported cases of Lassa fever. Timely diagnosis of imported Lassa fever is important for timely intervention necessary to reduce the morbidity and mortality associated with Lassa fever, and this requires the knowledge of the clinical manifestations of Lassa fever. Purpose: This review was done to see how clinical diagnosis of imported Lassa fever can be facilitated based on the clinical presentations of imported cases of Lassa fever in Lassa fever non-endemic region. Methods: The relevant articles for the review were obtained from the databases of PubMed and Google Scholar. Results: The clinical presentations of the imported Lassa fever cases consisted of multisystem involvement and were similar to those of Lassa fever patients who were treated in the Lassa fever endemic region. Conclusions: History of recent travel to, or residence in, Lassa fever endemic region is an important clue for clinical diagnosis of Lassa fever. The 2011 CDC surveillance case definition and the modified Khan case definition for Lassa fever may aid clinical diagnosis of Lassa fever. Any clinically suspected case of Lassa fever should have a laboratory confirmation.
基金the National Key Research and Development Program of China (2018YFA0507204)the National Natural Sciences Foundation of China (31670165)+1 种基金Wuhan National Biosafety Laboratory,Chinese Academy of Sciences Advanced Customer Cultivation Project (2019ACCP-MS03)the Open Research Fund Program of the State Key Laboratory of Virology of China (2018IOV001)。
文摘The membrane-proximal external region(MPER)of Lassa virus(LASV)glycoprotein complex(GPC)is critical in modulating its functionality.Till now,the high-resolution structure of the intact GPC,including MPER is not available.In this study,we used alanine substitution to scan all 16 residues located in LASV MPER.Western blotting and quantification fusion assay showed that the residues located at the C terminus of the HR2(M414 and L415)and N terminus of the MPER(K417 and Y419)are critical for GPC-mediated membrane fusion function.Furthermore,cell surface biotinylation experiments revealed that M414 A,K417 A and Y419 A expressed similar levels as WT,whereas L415 A mutant led to a reduction of mature GPC on the cell surface.Moreover,substitution of these residues with the similar residue such as M414 L,L415 I,K417 R and Y419 F would partly compensate the loss of the fusion activity caused by the alanine mutant in these sites.Results from this study showed that several key residues in the MPER region are indispensable to promote the conformational changes that drive fusion events and shed light on the structure analysis of LASV GPC and anti-LASV therapeutics.
基金This work was supported by the National Key Research and Development Program of China(2018YFA0507204)the National Natural Sciences Foundation of China(31670165)+1 种基金Wuhan National Biosafety Laboratory,Chinese Academy of Sciences Advanced Customer Cultivation Project(2019ACCP-MS03)the Open Research Fund Program of the State Key Laboratory of Virology of China(2018IOV001).Author Contributions。
文摘Lassa virus(LASV)belongs to the Mammarenavirus genus(family Arenaviridae)and causes severe hemorrhagic fever in humans.The glycoprotein complex(GPC)contains eleven N-linked glycans that play essential roles in GPC functionalities such as cleavage,transport,receptor recognition,epitope shielding,and immune response.We used three mutagenesis strategies(asparagine to glutamine,asparagine to alanine,and serine/tyrosine to alanine mutants)to abolish individual glycan chain on GPC and found that all the three strategies led to cleavage inefficiency on the 2nd(N89),5th(N119),or 8th(N365)glycosylation motif.To evaluate N to Q mutagenesis for further research,it was found that deletion of the 2nd(N89Q)or 8th(N365Q)glycan completely inhibited the transduction efficiency of pseudotyped particles.We further investigated the role of individual glycan on GPC-mediated immune response by DNA immunization of mice.Deletion of the individual 1st(N79Q),3rd(N99Q),5th(N119Q),or 6th(N167Q)glycan significantly enhanced the proportion of effector CD4+cells,whereas deletion of the 1st(N79Q),2nd(N89Q),3rd(N99Q),4th(N109Q),5th(N119Q),6th(N167Q),or 9th(N373Q)glycan enhanced the proportion of CD8+effector T cells.Deletion of specific glycan improves the Th1-type immune response,and abolishment of glycan on GPC generally increases the antibody titer to the glycan-deficient GPC.However,the antibodies from either the mutant or WT GPC-immunized mice show little neutralization effect on wild-type LASV.The glycan residues on GPC provide an immune shield for the virus,and thus represent a target for the design and development of a vaccine.
基金the National Key Research and Development Program(2022YFC2303300,2018YFA0507204)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0490000)the Na-tional Natural Science Foundation of China(82172273,31670165).
文摘The Lassa virus(LASV)is endemic in West Africa and causes severe hemorrhagic Lassa fever in humans.The glycoprotein complex(GPC)of LASV is highly glycosylation-modified,with 11 N-glycosylation sites.All 11 N-linked glycan chains play critical roles in GPC cleavage,folding,receptor binding,membrane fusion,and immune evasion.In this study,we focused on the first glycosylation site because its deletion mutant(N79Q)results in an unexpected enhanced membrane fusion,whereas it exerts little effect on GPC expression,cleavage,and receptor binding.Meanwhile,the pseudotype virus bearing GPC_(N79Q)was more sensitive to the neutralizing antibody 37.7H and was attenuated in virulence.Exploring the biological functions of the key glycosylation site on LASV GPC will help elucidate the mechanism of LASV infection and provide strategies for the development of attenuated vaccines against LASV infection.
文摘Background: Lassa Hemorrhagic Fever (LHF) is endemo-epidemic in West Africa with seasonal outbreaks raising a major public health issue. Nigeria borders Benin by the Tchaourou Commune. Since 2016, Tchaourou commune has been affected every year by this epidemic. Objective: To study how an action on the health social determinants can contribute to ending this epidemic in Tchaourou commune, Benin. Methods: This cross-sectional study was conducted in Tchaourou commune. All of the cases of LHF occurring in 2016-2018 were retrospectively tracked throughout the commune. The health workers and 172 participants of the general population of villages of the cases were enrolled. We used absolute frequency to describe the LHF cases because of their small number. The descriptive analyses were performed using EPI-INFO 7.1.14. Results: Overall, 27 cases of LHF occurred in Tchaourou. In these 27 cases, 12 were Laboratory-Confirmed. All 4 probable cases died while 42% and 18% died in the confirmed and suspected cases, respectively. Most (75%) of the cases were female. By direct observations, the commune had a weak health-promoting environment for fighting against LHF outbreak. According to the health care staff in the commune, the interventions were for controlling the outbreak and not the promoting interventions to preventing further outbreaks. Conclusion: To fight effectively against the Lassa fever, it is necessary to act on different social determinants of health with community participation, empowerment and health control. The fight against Lassa fever remains a major challenge facing developing countries like Benin.
文摘Introduction: Lassa viral hemorrhagic fever is common in West Africa. Almost 300,000 persons are affected each year with 5000 deaths. The mice of the genus mastomys is the wild tank. Objective: The aim of our study is to describe clinic, therapeutic and evolution of the affected patients during February-March 2017 epidemic that occurred in the north of Togo. Methodology: Our study is a record review study from patients’ record, who were hospitalized from February, 1st to March, 31st 2017 at Mango hospital. Lassa diagnosis was performed by PCR. They patients have received Ribavirin and blood transfusion when necessary. Results: We have reported 5 clinical observations of Lassa viral hemorrhagic fever. Patients came from Benin (03 cases), from Burkina-Faso (1 case), from Togo (1 case) and were 25, 34, 60, 52 years old and a premature baby of 13 days. External hemorrhage and abdominal pains were the main symptoms. Fever was observed for all the cases. Complications were marked by hemorrhages and shocks. Only 3 patients had benefitted of Antiviral therapy with Ribavirin. The other 2 patients did not benefit from the treatment because the diagnosis of Lassa fever was done the day they dead before the treatment started. Lethality was 80% (4 cases) with a highly secured burial. Effective management of contacts was done. Conclusion: Diagnostic and therapeutic delays of patients are responsible of the bad prognosis of the disease.
文摘Introduction: Lassa viral hemorrhagic fever is caused by the Lassa virus. The aim of our study is to describe the therapeutic itinerary of the 4 cases of Lassa virus hemorrhagic of February-March 2017 epidemic that occurred in Mango. Methodology: Our study is a transverse retro-prospective and descriptive study from February, 1st to March, 31st 2017 that dealt with 4 confirmed Lassa fever cases declared positive on the PCR basis;hospitalized or deceased at the hospital “Esperance” of Mango;support center of Lassa viral hemorrhagic fever. Results: we reported 4 clinical observations of Lassa viral hemorrhagic fever diagnosed on the PCR basis during the Lassa fever epidemic. Patients came from Benin (2 cases) or from Burkina-Faso (1 case) and were 25, 60, 52 years old and a premature baby of 13 days. The reasons for admission were external hemorrhage, a pultated tonsillitis and abdominal pains. Fever was observed for all the cases. Complications were marked by hemorrhages and shocks. Only two patients benefitted from Antiviral therapy with Ribavirin and were declared healed. The other two patients did not benefit from the treatment due to diagnostic and therapeutic delays. Lethality was 75% (3 cases) with a highly secured burial. Effective management of contacts was established. Conclusion: Diagnostic and therapeutic delays of patients are responsible of the Dark Prognosis of Lassa fever during the epidemic.
文摘Background: Lassa fever is a viral haemorrhagic fever associated with several complications which include hearing loss. Hearing loss in Lassa fever may become residual with its negative impact on the quality of life. Purpose: This paper is a review of various studies on Lassa fever related hearing loss. Methods: Systematic literature review was done on articles on Lassa fever patients and Lassa fever survivors. Relevant articles published in English between 1969 and 2021 were searched for using Google Scholar and PubMed databases. Eight studies which met the inclusion criteria were finally selected and included in the review. The variables of interest were extracted from the full-text articles. Results: Lassa fever related hearing loss occurs in both sexes and in all age groups. The incidence of self-reported hearing loss ranged from 12.5% to 30% with a mean of 17.6%. The incidence of audiometrically determined sensorineural hearing loss ranged from 13.5% to 29% with a mean of 22.1%. Hearing loss persisted in 64% of those that were followed up. Cases of hearing loss varied in severity, ranging from mild to profound. No successful specific treatment for Lassa fever related hearing loss was reported apart from hearing rehabilitation. Conclusion: Hearing loss among Lassa fever patients remains a major challenge. Lack of effective treatment for Lassa fever related hearing loss is a serious gap in the management of Lassa fever patients which should be addressed in future research.
文摘Introduction: Annual outbreak of Lassa Fever (LF) has been reported in Ondo State over the years. We analyzed LF surveillance data from January 2014 to December 2019 to describe the epidemiological pattern of the outbreak. Method: Lassa fever dataset from January 2014 to December 2019 was obtained from the State Ministry of Health. Variables analyzed include date of onset of symptom, age, gender, place (Local Government Area, LGA) and outcome of laboratory test. Data were summarized using frequencies, proportions, chart and maps. Results: From January 2014 and December 2019, 2141 suspected LF cases were reported. Of these, 551 cases were laboratory confirmed with 134 deaths recorded. The LF cases (suspected vs. confirmed) reported increased in 2016 (73 vs. 19), 2017 (207 vs. 76), 2018 (452 vs. 159) and 2019 (856 vs. 285) respectively. Most of the confirmed cases (89.5%) were ≥15 years while more than half (53.7%) were males. Prior to 2016, only two LGAs (Owo and Ose) recorded continued transmission of the disease. However, between 2016 and 2019, the disease had spread to 8 neighboring LGAs (P < 0.001) with the CFR declining from 67% in 2015 to 20% in 2019. Conclusion: We found an unusual increase in the suspected LF cases reported between January 2016 and December 2019 with a corresponding increase in the confirmed cases and high annual case fatality rates. Hence, we recommend intensified surveillance activities to enhance timely reporting of cases and laboratory confirmation to ensure early commencement of treatment to reduce the case fatality rate.
文摘Lassa Fever is endemic to the eastern region of Sierra Leone. It is a haemorrhagic disease that is often transmitted from rats to humans and then human to humans. Ecological disturbances such as changes in land use involving conversion of natural ecosystems to agriculture, mining or for urban expansion are reported to bring humans into close contact with animals such as the Mastomys rat that carries the Lassa Fever virus thereby posing health problems.The nature and extent of such ecological disturbances or land use changes within areas known to be endemic to Lassa Fever are not clearly understood from a research context in Sierra Leone. This study was therefore undertaken to identify the pattern of changes in land use and cropping practices and their potential to bring humans into close interactions with the Mastomys rat that is the host for the Lassa Fever virus. Four communities were chosen for the study, two rural (Lalehun and Majihun) and two urban (Lambayama section in Kenema City and Largo Square section in Segbwema Town). Different vegetation and land use/cropping practices were identified and observations were made on the pattern of changes at different times in the cropping year. There were four common vegetation and cropping practices found in all communities: upland rice intercropping, old fallow, young fallow, and swamp rice cultivation. The study revealed the variations in land use patterns and cropping practices between urban and rural settlements. Agro-forestry practices such as perennial cash crops cacao and rubber plantations were more common in rural communities. The study also revealed that while fallow vegetation persisted in rural areas there had been expansion of settlements into old fallow vegetation indicating a greater threat to the persistence of natural ecosystem in urban than in rural settlements. These disturbances resulted in habitat fragmentation and increased the likelihood of contact between humans and animal species (e.g. Mastomys rat) associated with various habitats.
文摘Lassa fever is a viral haemorrhagic fever found mostly in West Africa where it is endemic but generates periodic outbreaks in the dry seasons. The virus is spread by the rat species named mastomys natalensis. While the illness is minor in most cases, the mortality is significant in hospitalized patients. Few completely equipped treatment centers existed in Nigeria previous to current increase in frequency requiring demand for new treatment centers without the full complement of essential capabilities. Aim: To analyze the profile and treatment outcome in patients hospitalized in one of such new resource-constrained centers at the Benue State University Teaching Hospital Makurdi, Nigeria. Methodology: This was a retrospective, descriptive hospital-based research encompassing January 2020 to March 2023. Medical records of those admitted to the isolation center were reviewed. The relevant data was coded and analyzed using IBM SPSS version 23. Results: One hundred and ten (110) individuals were hospitalized for probable or suspected Lassa fever throughout the research period. A total of 35 confirmed patients satisfied the inclusion criteria and were included as the study subjects. There were 23 (65.7%) men and 12 (34.3%) females. Their mean age was 35.36 ± 12.21 years (range 15-61 years). The treatment outcome showed that 24 (75%) survived and were discharged, 5 (15.6%) were referred out of the facility for dialysis and 3 died, providing a mortality of 8.6%. The causes of mortality in study patients were acute kidney injury and encephalopathy. Conclusion: Lassa fever is endemic in Benue state with all types of individuals afflicted. The outcome of treatment was good despite resource difficulties. Lassa fever can be successfully managed even in resource-challenged situations typically encountered in developing countries.
基金Supported by Beijing Natural Science Foundation(L222027)Major and Application Projects of Chengdu Science and Technology Key R&D Support Plan(2021-YF09-00061-SN).
文摘Introduction:On August 3,2024,a suspected case of Lassa fever was identified in Sichuan Province,likely imported from an endemic region.Local CDCs promptly initiated investigation and implemented preventive measures upon receiving this report.Methods:The response included epidemiological investigations,contact tracing and management,hospital infection control measures,environmental disinfection,laboratory testing,biological sample management,and risk communication strategies.Results:The patient was confirmed as China’s first imported case of Lassa fever on August 6.The investigation identified 12 close contacts and 71 general contacts.By August 24,all contacts had completed medical observation without developing any symptoms consistent with Lassa fever.The patient recovered with residual hearing loss and was discharged on September 24 following expert verification.Conclusions:The increasing frequency of international travel and ongoing globalization have elevated the risk of novel infectious disease importation,including Lassa fever.Simultaneously,the widespread adoption of metagenomic sequencing for diagnosing unexplained illnesses in healthcare settings has enhanced pathogen detection sensitivity,enabling more precise identification of emerging infectious agents.
文摘Lassa fever(LF)is a serious acute viral hemorrhagic illness that is endemic to West Africa where it affects an estimated two million people and results in up to 10000 deaths each year.The disease is caused by the Lassa virus(LASV),part of the Arenaviridae family,and is primarily transmitted through contact with urine or feces of infected Mastomys natalensis rodents.Human-to-human transmission,particularly in healthcare and community settings,further amplifies the risk of spread.Since its discovery in 1969,LF continues to be a neglected tropical disease with significant health impacts,especially in vulnerable populations such as pregnant females and those with weakened immune systems.The clinical spectrum of LF varies from mild,flu-like symptoms to severe complications including bleeding,brain inflammation,and multiple organ dysfunction with neonates and pregnant female showing the highest fatality rates.Accurate diagnosis is hindered by symptom overlap with common regional illnesses such as malaria and typhoid,underlining the urgent need for strengthened diagnostic infrastructure and rapid testing methods.While ribavirin remains the main antiviral treatment,its effectiveness depends heavily on early administration.Currently,no approved vaccine exists;however,promising candidates like vesicular stomatitis virus(VSV)ΔG-LASVGPC,INO-4500,and measles virusbased(MV)-LASV are undergoing preclinical and early-phase clinical evaluation,exhibiting encouraging immune responses in animal and human studies.A comprehensive strategy combining public health education,rodent control measures,robust infection prevention in clinical settings,and international cooperation in vaccine and drug research is essential to curb the impact of LF.
