Lassa fever lf is an acute viral haemorrhagic illness caused by lassa virus lasv, first identified in 1969 in nigeria. Although the outbreaks appear to follow the typical seasonal pattern of increased incidence of lassa fever cases during the dry seasons, the trends in the last two years have been unprecedented. Cases 19, 20, 23 and 24 are presumed to represent instances of extrahospital transmission within a single family. Yinkaogunleye a, ipadeola o, saleh m, ilori e, dannwafor c, nwachukwu w, et al. Nigeria battles its largest lassa fever outbreak on record. Epidemiology and control of lassa fever springerlink. Hospitals and clinics in urban and rural areas of imo state. Lassa fever, also known as lassa hemorrhagic fever lhf, is a type of viral hemorrhagic fever caused by the lassa virus. Lassa fever lf is a zoonotic disease associated with acute and potentially fatal hemorrhagic illness caused by the lassa virus lasv, a member of the. The incidence management system ims model was used for. Neighboring countries are also at risk, as the animal vector for lassa virus, the multimammate rat mastomys natalensis is distributed throughout the region. African countries with an estimation of 300,000 to 500,000 cases and. She coordinates the lassa fever response activities and production of various guidelines for lassa fever control in nigeria.
Lassa fever, an acute viral hemorrhagic illness, is endemic in most of west africa, especially nigeria, where it was discovered in 1969. Lassa fever lf is an epidemicprone zoonotic viral haemorrhagic disease caused by lassa fever virus lfv, a member of the arenaviridae family 1. Lassa fever estimated number of deaths lassa fever is caused by a virus that is found in west africa. Baseline mapping of lassa fever virology, epidemiology and. Who target product profile for lassa virus vaccine june 2017. Failure of the nigerian health system to prioritise preparedness activities has been detrimental for prompt control of lassa fever, which requires robust laboratory. Pdf epidemiological trends of lassa fever outbreaks and. Ribavirin is effective treatment for lassa fever is given early in the course of clinical illness. Distribution of age and sex among patients with laboratoryconfirmed lassa fever, nigeria, january 1may 6, 2018 aors, 95% cis, and p values calculated by using the binomial logistic regression model for fatal outcomes. Lassa virus is one of more than 25 causative viruses of viral hemorrhagic fever table 4. Lassa fevers causative agent is the lassa virus lasv, a member of the arenaviridae family and a biosafety level 4 pathogen. Lassa fever is caused by an arenavirus, lassa fever virus lfv, and was first identified in humans after the death of two american missionary nurses in the town of lassa in northern nigeria in 1969. It has also been reported in europe and north america. The virus is named after the town in nigeria where the first cases.
Nigeria hit by unprecedented lassa fever outbreak science. Mar 01, 2018 lassa fever is endemic in the west african countries of ghana, guinea, mali, benin, liberia, sierra leone, togo and nigeria. When a third nurse fell ill, she was evacuated to a hospital in new york cityalong with a thermos full of blood and other samples from all three nurses, bound for yale universitys. Olomu1, meike pahlmann3, beate beckerziaja3, christian t. Progress and challenges of lassa fever control in nigeria the lancet. Lassa fever in the eastern province of sierra leone, 19701972. The main reservoir and primary source of infection is the multimammate mouse mastomys natalensis, but the virus also spreads between human beings via contact with body fluids of an infected person. The overall case fatality ratio is 1% to 15% among hospitalized patients. Lassa fever is mainly found in sierra leone, liberia, guinea, and nigeria and is spread by rats. Rapid increase in lassa fever cases nigeria reliefweb.
Lassa fever is known to be endemic in benin, guinea, ghana, liberia, mali, sierra leone, togo and nigeria, and most likely exists in other west african countries. Lassa virus was and continues to be the major cause of hemorrhagic fever in western africa, infecting roughly 400,000500,000 individuals per year and yielding a death rate of 30,00040,000. Mar 16, 2018 by early january, it was clear something really, really extraordinary was going on in nigeria, says lorenzo pomarico of the alliance for international medical action alima. Lassa fever, an endemic zoonotic viral infection in west africa, presents with varied symptoms including fever, vomiting, retrosternal pain, abdominal pain, sorethroat, mucosal bleeding, seizures and coma. Lassa fever is reported in benin, cote d ivoire, ghana, guinea, liberia, mali, nigeria, sierra leone and togo. These states have access to the longestablished and larg est lassa fever treatment center that has lassa virus di agnostic capabilities in nigeria. Epidemiologic and clinical features of lassa fever outbreak. Late rainy and early dry season affects all age groups and both sexes. It was named after the place where the first case occurred. Lf was first described and lasv was first isolated in 1969 when two missionary nurses became ill and died in the town of lassa, nigeria. Lassa fever annual epidemiological report 2016 en pdf 128. Increase the capacity for isolation and treatment of suspected and confirmed cases 5. Symptoms can be mild or severe, including hemorrhaging in. Apr 28, 2018 we evaluated the impact of manmade conflict events and climate change impact in guiding evidencebased community one health epidemiology and emergency response practice against reemerging epidemics.
Frank is an epidemiologist at the robert koch institute in berlin, germany. May 26, 2015 amorosa v, macneil a, mcconnell r, et al. Epidemiologic and clinical features of lassa fever. Mar 20, 2018 lassa fever lf is a zoonotic disease associated with acute and potentially fatal hemorrhagic illness caused by the lassa virus lasv, a member of the family arenaviridae. Ilori is the national lassa fever technical working group team lead at the nigeria centre for disease control in abuja, nigeria. Lassa fever erupts in nigeria a pile of garri, a staple food in nigeria, in a shop in lagos. Lassa fever lf is an epidemicprone zoonotic disease prevalent in nigeria and ebonyi state is a high burden area in nigeria. No additional cases of lassa fever were recognized during april, 1970. An estimated 100 000300 000 people are infected with lasv every. When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains. Lessons learnt from epidemiological investigation of lassa.
National emergency operations centre eoc has been activated to coordinate response activities across states public health emergency operations centre activated in affected states. Lassa fever was discovered in 1969, when two missionary nurses died of a mysterious disease in the remote town of lassa in borno state in northeastern nigeria. Among these, 2 cases have been confirmed, as of february 4, and 40 people. Facts you need to know about lassa fever nigeria and world news. Caseload and case fatality of lassa fever in nigeria, 2001. General facts viral hemorrhagic fever caused by the arenavirus lassa transmitted from rodents to humans discovered in nigeria, 1969 endemic in portions of west africa seasonal clustering. Nigeria battles its largest lassa fever outbreak on record nigerias lassa fever outbreak has reached record highs with 317 laboratory confirmed cases, according to figures released by the nigeria centre for disease control ncdc this week. In some areas of sierra leone and liberia, it is known that 1016% of people admitted to hospitals annually have lassa fever, demonstrating the serious impact the disease has on the region. Growing outbreak of lassa fever in nigeria worries. As of 22 february 2018, 10 suspected cases who fell ill in nigeria were reported in benin, and confirmed cases have been reported from beninese states that border nigeria.
Its is endemic in areas of west africa including nigeria, liberia, sierra leone and guinea. Lassa fever lf is an acute viral haemorrhagic illness that is caused by an arenavirus. Since then it has become endemic in many parts of west africa. Clinical and laboratory predictors of lassa fever outcome. Metagenomic sequencing at the epicenter of the nigeria. Lassa fever in nigeria humanitarian crisis in nigeria humanitarian crisis in south sudan. Lassa fever epidemiological aspects of the 1970 epidemic, jos. In mali, lasv was unknown until an exported case of lassa fever was reported in 2009. Oldstone, madeleine rose oldstone, in ebolas curse, 2017. Lassa fever is caused by lassa fever virus, a member of the family arenaviridae. It affects the largest number of people, creating a geographical network of endemic foci encompassing a population of perhaps 180. Since that time, rodent surveys have found evidence of lasvinfected mastomys natalensis rats in several communities in southern mali, near the border with cote divoire. Lassa fever lf is a zoonotic disease associated with acute and potentially fatal hemorrhagic illness caused by lassa virus lasv, a member of the arenaviridae family. An earlier description of a febrile syndrome in sierra leone was, in retrospect, very likely to have been the first account of lassa fever.
Lassa fever lf, one of the severe viral hemorrhagic fevers vhf, was first reported from nigeria in 1969. Pdf the pattern of lassa fever outbreaks in nigeria over the years is worrisome and. Lassa fever incidence in the hospital followed a seasonal pattern with a peak between november and march. Introduction to lassa fever world health organization. Lassa fever epidemiological aspects of the 1970 epidemic. No virus was isolated during studies in nigeria in cases table 2. It was first discovered in 1969 in lassa, nigeria when two missionary nurses died. In lassa fever endemic regions such as nigeria, a suspected case is defined 23 as an illness with onset of fever and no response to treatment of usual causes of fever in the ar ea and at. Surveillance for lassa fever should focus on the hospitalised patient. Low risk perceptions have been reported to prevent appropriate preventive behaviours. The death toll from the latest round of lassa fever outbreak in nigeria has risen to 144, the nigeria centre for disease control ncdc said thursday with. We investigated the knowledge and risk perception of residents towards lf and determined the factors influencing.
Molecular diagnostics for lassa fever at irrua specialist teaching hospital, nigeria. In this article, we report an analysis of the epidemiologic and clinical aspects of the lf outbreak that occurred in nigeria during january 1may 6, 2018. Since then, there have been repeated outbreaks in nigeria and other west african countries 3, 4, particularly sierra leone and liberia but also togo, and the republic of benin. Metagenomic sequencing at the epicenter of the nigeria 2018. Lassa fever lf is an acute viral illness and a viral haemorrhagic fever. The world report by talha burki feb 24, p 7281 described an unprecedented astronomical rise in lassa fever cases in nigeria, for which the first case was reported in 1969 and the epidemiology and endemicity are well understood. Nigeria has experienced repeated outbreaks of lassa fever in the last two years, usually between january and april. Molecular diagnostics for lassa fever at irrua specialist. Annual incidence of 100,000 to 300,000 with approximately 5,000 deaths in west africa. We investigated the knowledge and risk perception of residents towards lf and determined the factors influencing their risk perception in communities that have reported confirmed. Thats compared with 733 cases and 71 deaths in all of 2017. An arenavirus was isolated from two of these patients and given the name of lassa virus after the town of lassa, nigeria, where the disease, known as lassa fever, occurred buckley et al.
Objectives to estimate the burden of lassa fever in northern and central edo, a state in south nigeria where lassa fever has been reported methods blood samples were obtained from 60 patients hospitalised at the irrua specialist teaching hospital isth, irrua, with a clinical suspicion of lassa fever and from 451 febrile outpatients seen at the isth and hospitals in ekpoma, iruekpen, uromi. Because of its case fatality rate of approximately 50%, a lack of understanding of the mode of transmission, and ignorance of the reservoir, lassa fever looms as an awesome, newlyrecognized disease of tropical africa. In addition, lf is the most exported vhf, particularly to europe 4, 7, 8 and america. Facts you need to know about lassa fever the guardian. Jan 25, 2016 lassa fever was first discovered in 1969 in the town of lassa, in borno state, nigeria. The history of recognized human arenavirus infection in africa began in 1969 with the mysterious death of two medical missionaries and the nearfatal illness of a third frame et al. Prevention of lassa fever in nigeria request pdf researchgate. Responding to fears that a 10fold surge in cases in nigeria in 2018 signaled an incipient outbreak, kafetzopoulou et al. The nigeria centre for disease control ncdc was established in the year 2011 in response to the challenges of public health emergencies and to enhance nigerias preparedness and response to epidemics through prevention, detection and control of communicable and noncommunicable diseases. The main reservoir of lfv is the common african multimammate rat mastomys natalensis. Key points there were 99 suspected cases, ten confirmed cases and no death was recorded from six lgas in five states. The low prevalence of the disease among outpatients and the low seroprevalence may indicate that the population. Jan 01, 2010 lassa fever was first noticed in lassa town in the state of borno, nigeria. Of the 4 outpatient cases detected by serology, 2 had moderately severe lassa fever symptoms and 2 had milder illnesses.
Lassa fever is caused by a single stranded rna virus and is a disseminated systemic primary viral infection. Usually, each year sees only a smattering of cases reported, but hospitalized patients risk a 15% chance of death. Many of those infected by the virus do not develop symptoms. When fever and abdominal pain are the main presenting symptoms, and a diagnosis of acute abdomen is entertained, lassa fever is rarely considered in the differential diagnosis, even in. Apr 25, 2014 graphical display of prevalence in nigeria 9 1 15 326 1 1 5 6 5 4 29 4 prevalence of lassa fever in nigeria as at 12th feb 2012 anambra ebonyi edo gombe lagos nasarawa ondo plateau rivers taraba yobe anambra 1 ebonyi 15 edo 326 gombe 1 lagos 1 nasarawa 5 ondo 6 plateau 5 rivers 4 taraba 29 yobe 4 10. According to the ncdc, 449 suspected cases of lassa fever have been reported across 17 states since january 1.
In 2018, ncdc reported the largest ever number of cases in nigeria. Lassa fever was first discovered in 1969 in the town of lassa, in borno state, nigeria. Increasing evidence of emerging and reemerging zoonotic diseases including recent lassa fever outbreaks in almost 20 states in nigeria led to 101 deaths and 175 suspected and. For each of these events, a brief description, followed by public health measures implemented and an interpretation of the situation is provided. Lassa fever is endemic and fast becoming hyperendemic in nigeria.
Lassa fever is an acute viral haemorrhagic fever first described in 1969 in the town of lassa in borno state, nigeria. The final patient had onset of symptoms on 7 february. Lassa virus sequences obtained from the patients originating. Clinical and laboratory predictors of lassa fever outcome in. An outbreak of lassa fever lf reported and confirmed in ondo state, southwest nigeria in january 2016 was investigated. A table is provided at the end of the bulletin with information on all new. Lassa fever lf is a viral hemorrhagic disease caused by the lassa virus lasv and endemic in west. The country is fighting an outbreak of lassa virus, which is transmitted in rodent feces and urine and. We evaluated the impact of manmade conflict events and climate change impact in guiding evidencebased community one health epidemiology and emergency response practice against reemerging epidemics. Mar 06, 2018 lagos, nigeria cnn at least 78 people have been confirmed dead and 353 are infected in an unprecedented outbreak of lassa fever in nigeria, according to the nigeria centre for disease control. Increase the national capacity to detect and confirm lassa fever infection rapidly 4.
As of february 18, the nigeria centre for disease control ncdc reports 9 cases of lassa fever and 73 deaths. Research article prevalence of lassa virus disease lvd in nigerian children with fever or fever and convulsions in an endemic area odigie c. Lassa fever is known to be endemic in guinea, liberia, nigeria and sierra leone, but probably exists in other west african countries as well. Lf is endemic in nigeria, liberia, sierra leone, benin, ghana, guinea and mali. Lassa virus lasv is endemic to several nations in west africa. Lassa fever lf is endemic to nigeria, where the disease causes substantial rates of illness and death. Lesson learned from the investigation and response of lassa fever. Lassa fever archives the guardian nigeria news nigeria. Lassa fever is endemic in parts of west africa including sierra leone, liberia. Lassa fever is a hemorrhagic viral disease endemic to west africa. Lessons learnt from epidemiological investigation of lassa fever outbreak in a southwest state of nigeria december 2015 to april 2016. Exactly 10 days later, the mother developed lassa fever.
Lassa fever is an animalborne, or zoonotic, acute viral illness. Prevalence of lassa virus disease lvd in nigerian children. Lassa fever lf is an epidemicprone zoonotic viral haemorrhagic disease caused by lassa fever virus lfv, a member of the arenaviridae family. The case fatality rate cfr from lf for healthy population with no underlying comorbidity was estimated between 12%, 25% for inhospital lf cases, spiking to. Ewahodiase1, nosa akpede2, jacqueline ehimuan2, donatus i. E and covering an estimated area of 10 000 km 2, with a projected population of one million people by 2002 at 3. Whether the lineages are associated with different clinical manifestations is largely unknown. Cases of lassa fever, a rare viral hemorrhagic disease, were skyrocketing across the countrymore were recorded in the first 2 months of 2018 than in any previous year. Feb 16, 2018 lassa fever erupts in nigeria a pile of garri, a staple food in nigeria, in a shop in lagos.
Lassa fever is reported in benin, cote divoire, ghana, guinea, liberia, mali, nigeria, sierra leone and togo. It is a zoonotic disease, with the animal reservoir reported as the rodent mastomys natalensis 2. Since that time, rodent surveys have found evidence of lasvinfected mastomys natalensis rats in several communities in. Although endemic to the west african nation, lassa fever has never reached this case count in nigeria before. It is endemic in parts of west africa including sierra leone, liberia, guinea and nigeria. Prevention of lassa fever in nigeria transactions of the. Lassa fever outbreak, nigeria, januarymay 2018 lassa fever lf is endemic to nigeria, where the disease causes substantial rates of illness and death. Lassa fever is endemic to the west africa countries of benin, ghana, guinea, liberia, mali, sierra leone, and nigeria. Increasing evidence of emerging and reemerging zoonotic diseases including recent lassa fever outbreaks in almost 20 states in nigeria led to 101 deaths and 175 suspected and confirmed. Pdf to investigate two hospital outbreaks of lassa fever in southern central nigeria. Mastomys natalensis, a multimammate, peridomestic rat is the reservoir.
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