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Olayinka AT, Elimian K, Ipadeola O, Dan-Nwafor C, Gibson J, Ochu C, Furuse Y, Iniobong A, Akano A, Enenche L, Onoja M, Uzoho C, Ugbogulu N, Makava F, Arinze C, Namara G, Muwanguzi E, Jan K, Ukponu W, Okwor T, Anueyiagu C, Saleh M, Ahumibe A, Eneh C, Ilori E, Mba N, Ihekweazu C. Analysis of sociodemographic and clinical factors associated with Lassa fever disease and mortality in Nigeria. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000191. [PMID: 36962735 PMCID: PMC10022364 DOI: 10.1371/journal.pgph.0000191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/19/2022] [Indexed: 11/18/2022]
Abstract
Over past decades, there has been increasing geographical spread of Lassa fever (LF) cases across Nigeria and other countries in West Africa. This increase has been associated with significant morbidity and mortality despite increasing focus on the disease by both local and international scientists. Many of these studies on LF have been limited to few specialised centres in the country. This study was done to identify sociodemographic and clinical predictors of LF disease and related deaths across Nigeria. We analysed retrospective surveillance data on suspected LF cases collected during January-June 2018 and 2019. Multivariable logistic regression analyses were used to identify the factors independently associated with laboratory-confirmed LF diagnosis, and with LF-related deaths. There were confirmed 815 of 1991 suspected LF cases with complete records during this period. Of these, 724/815 confirmed cases had known clinical outcomes, of whom 100 died. LF confirmation was associated with presentation of gastrointestinal tract (aOR 3.47, 95% CI: 2.79-4.32), ear, nose and throat (aOR 2.73, 95% CI: 1.80-4.15), general systemic (aOR 2.12, 95% CI: 1.65-2.70) and chest/respiratory (aOR 1.71, 95% CI: 1.28-2.29) symptoms. Other factors were being male (aOR 1.32, 95% CI: 1.06-1.63), doing business/trading (aOR 2.16, 95% CI: 1.47-3.16) and farming (aOR 1.73, 95% CI: 1.12-2.68). Factors associated with LF mortality were a one-year increase in age (aOR 1.03, 95% CI: 1.01-1.04), bleeding (aOR 2.07, 95% CI: 1.07-4.00), and central nervous manifestations (aOR 5.02, 95% CI: 3.12-10.16). Diverse factors were associated with both LF disease and related death. A closer look at patterns of clinical variables would be helpful to support early detection and management of cases. The findings would also be useful for planning preparedness and response interventions against LF in the country and region.
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Affiliation(s)
| | - Kelly Elimian
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | | | | | - Jack Gibson
- University of Nottingham, Nottingham, United Kingdom
| | - Chinwe Ochu
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | - Yuki Furuse
- World Health Organisation, Abuja, FCT, Nigeria
| | | | - Adejoke Akano
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | - Lorna Enenche
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | - Michael Onoja
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | | | - Nkem Ugbogulu
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | - Favour Makava
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | | | | | | | - Kamji Jan
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | - Winifred Ukponu
- Georgetown University Centre for Global Health Practice and Impact, Abuja, Nigeria
| | - Tochi Okwor
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | | | - Muhammad Saleh
- Centers for Disease Prevention and Control, Abuja, Nigeria
| | | | - Chibuzo Eneh
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | - Elsie Ilori
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
| | - Nwando Mba
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria
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Abstract
Lassa fever (LF) is a lethal hemorrhagic disease primarily concentrated in the tropical savannah regions of Nigeria and the Mano River Union countries of Sierra Leone, Liberia, and Guinea. Endemic hotspots within these countries have had recurrent exposure to Lassa virus (LASV) via continual spillover from the host reservoir Mastomys natalensis. Increased trade and travel throughout the region have spread the virus to previously unexposed countries, including Ghana, Benin, Mali, and Côte d'Ivoire. In the absence of effective treatment or vaccines to LASV, preventative measures against Lassa fever rely heavily on reducing or eliminating rodent exposure, increasing the knowledge base surrounding the virus and disease in communities, and diminishing the stigmas faced by Lassa fever survivors.
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Kenmoe S, Tchatchouang S, Ebogo-Belobo JT, Ka'e AC, Mahamat G, Guiamdjo Simo RE, Bowo-Ngandji A, Demeni Emoh CP, Che E, Tchami Ngongang D, Amougou-Atsama M, Nzukui ND, Mbongue Mikangue CA, Mbaga DS, Kenfack S, Kingue Bebey SR, Amvongo Adjia N, Efietngab AN, Tazokong HR, Modiyinji AF, Kengne-Nde C, Sadeuh-Mba SA, Njouom R. Systematic review and meta-analysis of the epidemiology of Lassa virus in humans, rodents and other mammals in sub-Saharan Africa. PLoS Negl Trop Dis 2020; 14:e0008589. [PMID: 32845889 PMCID: PMC7478710 DOI: 10.1371/journal.pntd.0008589] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 09/08/2020] [Accepted: 07/13/2020] [Indexed: 12/27/2022] Open
Abstract
Accurate data on the Lassa virus (LASV) human case fatality rate (CFR) and the prevalence of LASV in humans, rodents and other mammals are needed for better planning of actions that will ultimately reduce the burden of LASV infection in sub-Saharan Africa. In this systematic review with meta-analysis, we searched PubMed, Scopus, Africa Journal Online, and African Index Medicus from 1969 to 2020 to obtain studies that reported enough data to calculate LASV infection CFR or prevalence. Study selection, data extraction, and risk of bias assessment were conducted independently. We extracted all measures of current, recent, and past infections with LASV. Prevalence and CFR estimates were pooled using a random-effect meta-analysis. Factors associated with CFR, prevalence, and sources of between-study heterogeneity were determined using subgroup and metaregression analyses. This review was registered with PROSPERO, CRD42020166465. We initially identified 1,399 records and finally retained 109 reports that contributed to 291 prevalence records from 25 countries. The overall CFR was 29.7% (22.3-37.5) in humans. Pooled prevalence of LASV infection was 8.7% (95% confidence interval: 6.8-10.8) in humans, 3.2% (1.9-4.6) in rodents, and 0.7% (0.0-2.3) in other mammals. Subgroup and metaregression analyses revealed a substantial statistical heterogeneity explained by higher prevalence in tissue organs, in case-control, in hospital outbreak, and surveys, in retrospective studies, in urban and hospital setting, in hospitalized patients, and in West African countries. This study suggests that LASV infections is an important cause of death in humans and that LASV are common in humans, rodents and other mammals in sub-Saharan Africa. These estimates highlight disparities between sub-regions, and population risk profiles. Western Africa, and specific key populations were identified as having higher LASV CFR and prevalence, hence, deserving more attention for cost-effective preventive interventions.
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Affiliation(s)
- Sebastien Kenmoe
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
| | | | - Jean Thierry Ebogo-Belobo
- Medical Research Centre, Institut of Medical Research and Medicinal Plants Studies, Yaoundé, Cameroon
| | - Aude Christelle Ka'e
- Virology Department, Chantal Biya International Reference Centre, Yaoundé, Cameroon
| | - Gadji Mahamat
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | | | - Arnol Bowo-Ngandji
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | | | - Emmanuel Che
- Vaccinology and Biobank, Chantal Biya International Reference Centre, Yaounde, Cameroon
| | - Dimitri Tchami Ngongang
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | - Marie Amougou-Atsama
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
- Medical Research Centre, Institut of Medical Research and Medicinal Plants Studies, Yaoundé, Cameroon
| | - Nathalie Diane Nzukui
- School of Health Sciences-Catholic University of Central Africa, Department of Medical Microbiology, Yaoundé, Cameroon
| | | | - Donatien Serge Mbaga
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | - Sorel Kenfack
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | | | - Nathalie Amvongo Adjia
- Medical Research Centre, Institut of Medical Research and Medicinal Plants Studies, Yaoundé, Cameroon
| | - Atembeh Noura Efietngab
- Medical Research Centre, Institut of Medical Research and Medicinal Plants Studies, Yaoundé, Cameroon
| | - Hervé Raoul Tazokong
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | - Abdou Fatawou Modiyinji
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
- Department of Animals Biology and Physiology, Faculty of Science, The University of Yaoundé I, Yaoundé, Cameroon
| | - Cyprien Kengne-Nde
- Epidemiological Surveillance, Evaluation and Research Unit, National AIDS Control Committee, Yaoundé, Cameroon
| | | | - Richard Njouom
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
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Asogun DA, Günther S, Akpede GO, Ihekweazu C, Zumla A. Lassa Fever: Epidemiology, Clinical Features, Diagnosis, Management and Prevention. Infect Dis Clin North Am 2020; 33:933-951. [PMID: 31668199 DOI: 10.1016/j.idc.2019.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Lassa fever outbreaks West Africa have caused up to 10,000 deaths annually. Primary infection occurs from contact with Lassa virus-infected rodents and exposure to their excreta, blood, or meat. Incubation takes 2 to 21 days. Symptoms are difficult to distinguish from malaria, typhoid, dengue, yellow fever, and other viral hemorrhagic fevers. Clinical manifestations range from asymptomatic, to mild, to severe fulminant disease. Ribavirin can improve outcomes. Overall mortality is between 1% and 15%. Lassa fever should be considered in the differential diagnosis with travel to West Africa. There is an urgent need for rapid field-friendly diagnostics and preventive vaccine.
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Affiliation(s)
- Danny A Asogun
- Department of Public Health, College of Medicine, Ambrose Alli University, Ekpoma, Nigeria; Department of Public Health, Institute of Lassa Fever Research and Control, Irrua Specialist Teaching Hospital, P.M.B 008, Kilometre 87, Benin City-Auchi Road, Irrua, Nigeria.
| | - Stephan Günther
- Bernhard-Nocht Institute for Tropical Medicine, Strab 74, Hamburg 20359, Germany; German Centre for Infection Research (DZIF), Partner Site Hamburg, Hamburg, Germany
| | - George O Akpede
- Department of Paediatrics, Faculty of Clinical Sciences, College of Medicine, Ambrose Alli University, Ekpoma, Nigeria
| | - Chikwe Ihekweazu
- Nigeria Centre for Disease Control, Plot 801, Ebitu Ukiwe Street, Jabi, Abuja, Nigeria
| | - Alimuddin Zumla
- Center for Clinical Microbiology, University College London, Royal Free Campus 2nd Floor, Rowland Hill Street, London NW3 2PF, United Kingdom
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Musa SS, Zhao S, Gao D, Lin Q, Chowell G, He D. Mechanistic modelling of the large-scale Lassa fever epidemics in Nigeria from 2016 to 2019. J Theor Biol 2020; 493:110209. [PMID: 32097608 DOI: 10.1016/j.jtbi.2020.110209] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/15/2020] [Accepted: 02/19/2020] [Indexed: 01/22/2023]
Abstract
Lassa fever, also known as Lassa hemorrhagic fever, is a virus that has generated recurrent outbreaks in West Africa. We use mechanistic modelling to study the Lassa fever epidemics in Nigeria from 2016-19. Our model describes the interaction between human and rodent populations with the consideration of quarantine, isolation and hospitalization processes. Our model supports the phenomenon of forward bifurcation where the stability between disease-free equilibrium and endemic equilibrium exchanges. Moreover, our model captures well the incidence curves from surveillance data. In particular, our model is able to reconstruct the periodic rodent and human forces of infection. Furthermore, we suggest that the three major epidemics from 2016-19 can be modelled by properly characterizing the rodent (or human) force of infection while the estimated human force of infection also present similar patterns across outbreaks. Our results suggest that the initial susceptibility likely increased across the three outbreaks from 2016-19. Our results highlight the similarity of the transmission dynamics driving three major Lassa fever outbreaks in the endemic areas.
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Affiliation(s)
- Salihu S Musa
- Department of Applied Mathematics, The Hong Kong Polytechnic University, Hong Kong; Department of Mathematics, Kano University of Science and Technology, Wudil, Nigeria
| | - Shi Zhao
- School of Nursing, The Hong Kong Polytechnic University, Hong Kong; JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong; Shenzhen Research Institute of Chinese University of Hong Kong, Shenzhen, China
| | - Daozhou Gao
- Mathematics and Science College, Shanghai Normal University, Shanghai, China
| | - Qianying Lin
- Department of Applied Mathematics, The Hong Kong Polytechnic University, Hong Kong; Michigan Institute for Data Science, University of Michigan, Ann Arbor, MI, USA
| | - Gerardo Chowell
- School of Public Health, Georgia State University, Atlanta, GA, USA; Fogarty International Center, National Institute of Health, Bethesda, MD, USA
| | - Daihai He
- Department of Applied Mathematics, The Hong Kong Polytechnic University, Hong Kong.
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Dan-Nwafor CC, Ipadeola O, Smout E, Ilori E, Adeyemo A, Umeokonkwo C, Nwidi D, Nwachukwu W, Ukponu W, Omabe E, Anaebonam U, Igwenyi N, Igbodo G, Eteng W, Uzoma I, Saleh M, Agboeze J, Mutbam S, de Gooyer T, Short R, Aniaku E, Onoh R, Ogah E, Nguku P, Oladejo J, Peter C, Ojo O, Ihekweazu C. A cluster of nosocomial Lassa fever cases in a tertiary health facility in Nigeria: Description and lessons learned, 2018. Int J Infect Dis 2019; 83:88-94. [PMID: 30930184 DOI: 10.1016/j.ijid.2019.03.030] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 03/22/2019] [Accepted: 03/23/2019] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Lassa fever is an acute viral haemorrhagic disease endemic in Nigeria. The 2018 Lassa fever outbreak in Nigeria was unprecedented, with 8% of all cases occurring among healthcare workers (HCWs). A disproportionately high number of these infections occurred in HCWs working in a tertiary health facility in Nigeria. This paper describes the cluster of Lassa fever infections among HCWs in a treatment centre and the lessons learnt. METHODS We analysed clinical, epidemiological and laboratory data from surveillance and laboratory records kept during the 2018 outbreak. Interviews were conducted with surviving HCWs using a questionnaire developed specifically for the investigation of Lassa fever infections in HCWs. Descriptive analysis of the data was performed in Microsoft excel. RESULTS The index case was a 15-year-old male who presented at the health facility with fever and uncontrolled nasopharyngeal bleeding, following a recent uvulectomy by a traditional healer. Overall, 16 HCWs were affected (15 confirmed and 1 probable) with five deaths (CFR-31.6%). Of the 15 confirmed cases, five (33.3%) were asymptomatic. Nine HCWs were direct contacts of the index case; the remaining six HCWs had no direct contact with the index case. HCW interviews identified a low index of suspicion for Lassa fever leading to inadequate infection prevention and control (IPC) practices as possible contributing factors to nosocomial transmission. CONCLUSION Maintaining a high index of suspicion for Lassa fever in all patients, especially in endemic areas, is essential in adhering to adequate IPC practices in health facilities in order to prevent nosocomial transmission of Lassa fever among HCWs. There is a need to continually train and sensitise HCWs on strict adherence to IPC measures while providing care, irrespective of a patient's provisional diagnosis.
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Affiliation(s)
- Chioma C Dan-Nwafor
- Nigeria Centre for Disease Control, Abuja, Nigeria; African Field Epidemiology Network, Nigeria.
| | | | | | - Elsie Ilori
- Nigeria Centre for Disease Control, Abuja, Nigeria
| | | | | | - Damian Nwidi
- Federal Teaching hospital Abakiliki Ebonyi State, Nigeria
| | - Williams Nwachukwu
- Nigeria Centre for Disease Control, Abuja, Nigeria; African Field Epidemiology Network, Nigeria
| | - Winifred Ukponu
- University of Maryland Abuja, Nigeria; Nigeria Centre for Disease Control, Abuja, Nigeria
| | - Emeka Omabe
- Federal Teaching hospital Abakiliki Ebonyi State, Nigeria
| | | | - Nneka Igwenyi
- Federal Teaching hospital Abakiliki Ebonyi State, Nigeria
| | | | - Womi Eteng
- Nigeria Centre for Disease Control, Abuja, Nigeria
| | | | | | - Joseph Agboeze
- Federal Teaching hospital Abakiliki Ebonyi State, Nigeria
| | | | | | | | | | - Robinson Onoh
- Federal Teaching hospital Abakiliki Ebonyi State, Nigeria
| | - Emeka Ogah
- Federal Teaching hospital Abakiliki Ebonyi State, Nigeria
| | | | - John Oladejo
- Nigeria Centre for Disease Control, Abuja, Nigeria
| | | | - Olubunmi Ojo
- Nigeria Centre for Disease Control, Abuja, Nigeria
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Ehlkes L, Kreuels B, Schwarz NG, May J. [Epidemiology of Ebola virus disease and of other highly contagious, life-threatening diseases with low incidence in Germany]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2016; 58:705-13. [PMID: 25997608 PMCID: PMC7080030 DOI: 10.1007/s00103-015-2165-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Das Vorkommen von Ebolafieber, der Marburgvirus-Krankheit sowie von Lassa-Fieber ist – abgesehen von vereinzelten eingeschleppten Fällen – auf den afrikanischen Kontinent beschränkt. Hämorrhagisches Krim-Kongo-Fieber kommt in Südosteuropa, jedoch bisher nicht in Deutschland vor. Weitere hämorrhagische Fiebererkrankungen sind regional auf dem südamerikanischen Kontinent verbreitet. Die Lungenpest ist die bakterielle Infektionskrankheit mit der höchsten Kontagiösität und Letalität und ist vor allem in Madagaskar und Ostafrika, aber auch in vielen anderen Ländern beheimatet, wie z. B. in Indien und in den USA. Affenpocken haben in entlegenen Regionen des Kongobeckens zu Ausbrüchen geführt, die sich in Zukunft aufgrund der nicht mehr durchgeführten Pockenimpfung häufen könnten. Das 2002/2003 neu aufgetretene Severe Acute Respiratory Syndrome (SARS) ist eine weitere Erkrankung mit hohem epidemischen Potenzial. Typisch für diese hochkontagiösen Erreger ist, dass sie meist unerkannt zwischen Reservoirtieren abseits des Menschen zirkulieren. Durch sporadischen Kontakt zwischen infizierten Tieren und dem Menschen können diese übertragen werden. Die dann folgende Mensch-zu-Mensch-Übertragung kann zu ausgedehnten Epidemien, wie dem derzeitigen Ausbruch des Ebolafiebers in Westafrika, führen.
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Affiliation(s)
- L Ehlkes
- Arbeitsgruppe Infektionsepidemiologie, Bernhard-Nocht-Institut für Tropenmedizin (BNITM), Bernhard-Nocht-Str. 74, 20359, Hamburg, Deutschland
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9
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Singh N, Levi ME. Arenavirus and West Nile virus in solid organ transplantation. Am J Transplant 2013; 13 Suppl 4:361-71. [PMID: 23465029 DOI: 10.1111/ajt.12128] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- N Singh
- Division of Nephrology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
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10
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Molecular diagnostics for lassa fever at Irrua specialist teaching hospital, Nigeria: lessons learnt from two years of laboratory operation. PLoS Negl Trop Dis 2012; 6:e1839. [PMID: 23029594 PMCID: PMC3459880 DOI: 10.1371/journal.pntd.0001839] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Accepted: 08/14/2012] [Indexed: 01/18/2023] Open
Abstract
Background Lassa fever is a viral hemorrhagic fever endemic in West Africa. However, none of the hospitals in the endemic areas of Nigeria has the capacity to perform Lassa virus diagnostics. Case identification and management solely relies on non-specific clinical criteria. The Irrua Specialist Teaching Hospital (ISTH) in the central senatorial district of Edo State struggled with this challenge for many years. Methodology/Principal Findings A laboratory for molecular diagnosis of Lassa fever, complying with basic standards of diagnostic PCR facilities, was established at ISTH in 2008. During 2009 through 2010, samples of 1,650 suspected cases were processed, of which 198 (12%) tested positive by Lassa virus RT-PCR. No remarkable demographic differences were observed between PCR-positive and negative patients. The case fatality rate for Lassa fever was 31%. Nearly two thirds of confirmed cases attended the emergency departments of ISTH. The time window for therapeutic intervention was extremely short, as 50% of the fatal cases died within 2 days of hospitalization—often before ribavirin treatment could be commenced. Fatal Lassa fever cases were older (p = 0.005), had lower body temperature (p<0.0001), and had higher creatinine (p<0.0001) and blood urea levels (p<0.0001) than survivors. Lassa fever incidence in the hospital followed a seasonal pattern with a peak between November and March. Lassa virus sequences obtained from the patients originating from Edo State formed—within lineage II—a separate clade that could be further subdivided into three clusters. Conclusions/Significance Lassa fever case management was improved at a tertiary health institution in Nigeria through establishment of a laboratory for routine diagnostics of Lassa virus. Data collected in two years of operation demonstrate that Lassa fever is a serious public health problem in Edo State and reveal new insights into the disease in hospitalized patients. In the past, diagnostic testing for Lassa fever patients in Nigeria has been performed nearly exclusively outside of the country. Patients thus were managed on-site based on clinical suspicion alone, posing risks to patients and health care workers and exhausting resources. To tackle this problem, we established a diagnostic PCR laboratory directly at a referral hospital serving a Lassa fever endemic area in Nigeria. Long-term collaboration between partners in the North and the South was crucial to implement this project. Training of laboratory staff in the partner institutions and on-site, mobilization of local human and financial resources, good management of the laboratory, a basic quality management and control system, and a stable supply chain for consumables and reagents were among the key factors for success. The laboratory reliably delivered results in a short turnaround time, despite some problems due to PCR contamination. The service has improved patient and contact management including treatment with ribavirin and led to better protection of health care workers against hospital-acquired infections. The data provide new insights into disease progression and a basis for further optimization of case management including supportive treatment.
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Ibekwe TS, Okokhere PO, Asogun D, Blackie FF, Nwegbu MM, Wahab KW, Omilabu SA, Akpede GO. Early-onset sensorineural hearing loss in Lassa fever. Eur Arch Otorhinolaryngol 2010; 268:197-201. [PMID: 20809263 DOI: 10.1007/s00405-010-1370-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2009] [Accepted: 08/19/2010] [Indexed: 11/25/2022]
Abstract
Lassa fever (LF) is a viral hemorrhagic disease which affects one-fourth to two million people annually with the fatality rate of about 10,000. It is associated with sensorineural hearing loss (SNHL) usually at the convalescent stage. Recently, cases of SNHL at the acute phase have been reported. This study was done to further investigate the incidence and features of SNHL in acute phase of LF. It is a prospective case-control study of LF patients seen with acute SNHL conducted between July 2007 and April 2009 at Irrua Specialist Teaching Hospital Nigeria. The diagnosis of acute LF was based on the clinical features and detection of IgM antibodies and/or positive Lassa virus-specific reverse transcriptase-polymerase chain reaction using primers S36+ and LVS 339 while SNHL was diagnosed clinically and confirmed with PTA and speech discrimination tests. Patients with other acute febrile illnesses were used as control. Statistical analysis was done using SPSS version 11 and Fisher's exact test while level of significance was set at p < 0.05. Out of the 37 confirmed cases of LF, 5 (13.5%) and none (0%) of the control developed early-onset SNHL (p = 0.03). Forty percent of the cases studied had negative IgM. The audiograms showed involvement at all frequency groups with pure tone average 65-85 dB and the speech discrimination 20-40%. The overall case fatality rate was 27.0%, and for early SNHL cases 60.0% (p > 0.05). The incidence of SNHL in LF infection is about 13.5% and could be a reflection of a worse disease process. There is possibility of direct viral invasion aside immunological reaction as a causative mechanism.
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Affiliation(s)
- T S Ibekwe
- Lassa Fever Research and Diagnostic Centre, Irrua Specialist Teaching Hospital, Irrua, Nigeria.
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12
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Kernéis S, Koivogui L, Magassouba N, Koulemou K, Lewis R, Aplogan A, Grais RF, Guerin PJ, Fichet-Calvet E. Prevalence and risk factors of Lassa seropositivity in inhabitants of the forest region of Guinea: a cross-sectional study. PLoS Negl Trop Dis 2009; 3:e548. [PMID: 19924222 PMCID: PMC2771900 DOI: 10.1371/journal.pntd.0000548] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 10/15/2009] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Lassa fever is a viral hemorrhagic fever endemic in West Africa. The reservoir host of the virus is a multimammate rat, Mastomys natalensis. Prevalence estimates of Lassa virus antibodies in humans vary greatly between studies, and the main modes of transmission of the virus from rodents to humans remain unclear. We aimed to (i) estimate the prevalence of Lassa virus-specific IgG antibodies (LV IgG) in the human population of a rural area of Guinea, and (ii) identify risk factors for positive LV IgG. METHODS AND FINDINGS A population-based cross-sectional study design was used. In April 2000, all individuals one year of age and older living in three prefectures located in the tropical secondary forest area of Guinea (Gueckedou, Lola and Yomou) were sampled using two-stage cluster sampling. For each individual identified by the sampling procedure and who agreed to participate, a standardized questionnaire was completed to collect data on personal exposure to potential risk factors for Lassa fever (mainly contact with rodents), and a blood sample was tested for LV IgG. A multiple logistic regression model was used to determine risk factors for positive LV IgG. A total of 1424 subjects were interviewed and 977 sera were tested. Prevalence of positive LV Ig was of 12.9% [10.8%-15.0%] and 10.0% [8.1%-11.9%] in rural and urban areas, respectively. Two risk factors of positive LV IgG were identified: to have, in the past twelve months, undergone an injection (odds ratio [OR] = 1.8 [1.1-3.1]), or lived with someone displaying a haemorrhage (OR = 1.7 [1.1-2.9]). No factors related to contacts with rats and/or mice remained statistically significant in the multivariate analysis. CONCLUSIONS Our study underlines the potential importance of person-to-person transmission of Lassa fever, via close contact in the same household or nosocomial exposure.
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Fichet-Calvet E, Rogers DJ. Risk maps of Lassa fever in West Africa. PLoS Negl Trop Dis 2009; 3:e388. [PMID: 19255625 PMCID: PMC2644764 DOI: 10.1371/journal.pntd.0000388] [Citation(s) in RCA: 199] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Accepted: 02/05/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Lassa fever is caused by a viral haemorrhagic arenavirus that affects two to three million people in West Africa, causing a mortality of between 5,000 and 10,000 each year. The natural reservoir of Lassa virus is the multi-mammate rat Mastomys natalensis, which lives in houses and surrounding fields. With the aim of gaining more information to control this disease, we here carry out a spatial analysis of Lassa fever data from human cases and infected rodent hosts covering the period 1965-2007. Information on contemporary environmental conditions (temperature, rainfall, vegetation) was derived from NASA Terra MODIS satellite sensor data and other sources and for elevation from the GTOPO30 surface for the region from Senegal to the Congo. All multi-temporal data were analysed using temporal Fourier techniques to generate images of means, amplitudes and phases which were used as the predictor variables in the models. In addition, meteorological rainfall data collected between 1951 and 1989 were used to generate a synoptic rainfall surface for the same region. METHODOLOGY/PRINCIPAL FINDINGS Three different analyses (models) are presented, one superimposing Lassa fever outbreaks on the mean rainfall surface (Model 1) and the other two using non-linear discriminant analytical techniques. Model 2 selected variables in a step-wise inclusive fashion, and Model 3 used an information-theoretic approach in which many different random combinations of 10 variables were fitted to the Lassa fever data. Three combinations of absenceratiopresence clusters were used in each of Models 2 and 3, the 2 absenceratio1 presence cluster combination giving what appeared to be the best result. Model 1 showed that the recorded outbreaks of Lassa fever in human populations occurred in zones receiving between 1,500 and 3,000 mm rainfall annually. Rainfall, and to a much lesser extent temperature variables, were most strongly selected in both Models 2 and 3, and neither vegetation nor altitude seemed particularly important. Both Models 2 and 3 produced mean kappa values in excess of 0.91 (Model 2) or 0.86 (Model 3), making them 'Excellent'. CONCLUSION/SIGNIFICANCE The Lassa fever areas predicted by the models cover approximately 80% of each of Sierra Leone and Liberia, 50% of Guinea, 40% of Nigeria, 30% of each of Côte d'Ivoire, Togo and Benin, and 10% of Ghana.
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Affiliation(s)
- Michele T Jay
- California Department of Health Services, Division of Communicable Disease Control, 1616 Capitol Ave, Sacramento, CA 95899-7413, USA
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Abstract
Lassa virus is a RNA virus belonging to the family of Arenaviridae. It was discovered as the causative agent of a hemorrhagic fever--Lassa fever--about 30 years ago. Lassa fever is endemic in West Africa and is estimated to affect some 100,000 people annually. Great progress in the understanding of the life cycle of arenaviruses, including Lassa virus, has been made in recent years. New insights have been gained in the pathogenesis and molecular epidemiology of Lassa fever, and state-of the-art technologies for diagnosing this life-threatening disease have been developed. The intention of this review is to summarize in particular the recent literature on Lassa virus and Lassa fever. Several aspects ranging from basic research up to clinical practice and laboratory diagnosis are discussed and linked together.
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Affiliation(s)
- Stephan Günther
- Department of Virology, Bernhard-Nocht-Institute of Tropical Medicine, Hamburg, Germany.
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Affiliation(s)
- J B McCormick
- University of Texas, School of Public Health, Brownsville, TX, USA
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Coker AO, Isokpehi RD, Thomas BN, Fagbenro-Beyioku AF, Omilabu SA. Zoonotic infections in Nigeria: overview from a medical perspective. Acta Trop 2000; 76:59-63. [PMID: 10913768 DOI: 10.1016/s0001-706x(00)00091-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Infections of domestic and wild animals that are transmitted directly or by an arthropod vector to humans are a major cause of morbidity and mortality worldwide and particularly in Nigeria. With a population of over 100 million and the need for improved health care delivery, Nigerians are at considerable risk considering the seriousness of these infections. Zoonotic infections that are endemic in Nigeria include tuberculosis, trypanosomiasis, toxoplasmosis, taeniasis, rabies, lassa fever and yellow fever. Zoonotic food-borne infections (caused by Campylobacter, Salmonella and Escherichia coli O157:H7) and cryptosporidiosis are emerging. Sporadic cases such as strongyloidiasis, ascariasis, leptospirosis, scabies, pentastomiasis and African histoplasmosis have been reported. There is a need to determine the prevalence of tick-borne zoonoses. Prevention and control of zoonoses in humans is by vaccination, treatment and health education. As a first measure to improve control, the link between veterinary and medical officers, which is presently very weak, needs to be strengthened. Furthermore, regional multidisciplinary approaches to the control of zoonotic infections should be adopted in West Africa, which take into consideration the huge inter-border traffic.
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Affiliation(s)
- A O Coker
- Campylobacter Research Laboratory, Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Idiaraba, Nigeria.
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