Global & Disaster Medicine

Archive for the ‘Lassa Fever’ Category

WHO: Lassa Fever Infographic

Nigeria: 15 newly recorded Lassa Fever cases raise the outbreak total to 510 cases.

Nigeria Center for Infection Control

The Lassa fever outbreak in Nigeria grew by 23 cases in the past week


 In the reporting Week 11 (11th – 17th March, 2019) 23 new confirmedi cases were reported from nine states – Edo(8), Ondo(4), Ebonyi(3), Bauchi(3), Taraba(1), Imo(1), Enugu(1), Benue(1) and Kebbi(1) with four new deaths in Edo (2), Benue(1) and Bauchi(1) States  From 1st January to 17th March, 2019, a total of 1801 suspectedi cases have been reported from states. Of these, 495 were confirmed positive, 15 probable and 1277 negative (not a case)-Table 1  Since the onset of the 2019 outbreak, there have been 114* deaths in confirmed cases. Case fatality ratio in confirmed cases is 23.0%

Weekly summary of major outbreaks in Africa


Plague: Uganda
2 Cases
1 Death:  50% CFR

Ebola virus disease: Democratic Republic of the Congo
921 Cases
582 Deaths:  63% CFR

Hepatitis E: Namibia
4 669 Cases
41 Deaths: 0.9% CFR

Lassa fever: Nigeria
420 Cases
93  Deaths: CFR 22.1%




From 1 January through 10 February 2019, 327 cases of Lassa fever (324 confirmed cases and three probable cases) with 72 deaths (case fatality ratio = 22%) have been reported in Nigeria


Lassa Fever – Nigeria

Disease outbreak news
14 February 2019

From 1 January through 10 February 2019, 327 cases of Lassa fever (324 confirmed cases and three probable cases) with 72 deaths (case fatality ratio = 22%) have been reported across 20 states and the Federal Capital Territory, with the majority of cases being reported from Edo (108) and Ondo (103) states. Twelve cases have been reported among healthcare workers in seven states – Edo (4), Ondo (3), Ebonyi (1), Enugu (1), Rivers (1), Bauchi (1) and Benue (1) including one death in Enugu.

The number of confirmed cases reported across Nigeria remains high. In week 6, 2019 (week ending 10 February 2019), 37 new confirmed cases including 10 deaths (case fatality ratio = 27%) were reported from nine states across Nigeria. The majority of cases were reported from Ondo (12) and Edo (10) states. The number of confirmed cases reported in week 6, 2019 represents a slight decrease compared to week 5 when 68 confirmed cases were reported (Figure 1).

Of the 3746 contacts identified since January 2019, 2658 are still under follow-up while 1045 have completed 21 days of follow-up. Sixty contacts became symptomatic, of which 39 tested positive.

Ninety-one case-patients are currently in admission at treatment centers across the country. The case-patients are being treated with standard supportive care.

Figure 1: Number of confirmed and probable Lassa fever cases in Nigeria reported by the week of illness onset from 1 January through 10 February 2019

Source: Nigeria Centre for Disease Control (NCDC)

Public health response

  • On 22 January 2019, the Nigeria Center for Disease Control (NCDC) declared the outbreak an emergency.
  • Multi-sectoral One Health national rapid response teams have been deployed to Ondo, Edo, Ebonyi, Plateau, and Bauchi to support field investigation and response activities.
  • Enhanced surveillance is ongoing in all states following alert communication and a press release from NCDC.
  • Treatment of Lassa fever cases is also ongoing at designated treatment centres across the country.
  • Risk communication and community engagement activities continue in the states. National awareness was improved through the recently concluded international Lassa fever conference which took place from 16 through 17 January 2019.

WHO risk assessment

Lassa fever is a viral haemorrhagic fever that is transmitted to humans via contact with food or household items contaminated with rodent urine or faeces. Person-to-person infections and laboratory transmission can also occur. The overall case fatality rate is 1%; it is 15% among patients hospitalized with severe illness. There is currently no approved vaccine. Early supportive care with rehydration and symptomatic treatment improves survival.

Although Lassa fever is known to be endemic in Nigeria with the peak season anticipated from December through June, the current increase in new confirmed cases and deaths should be monitored closely and addressed appropriately. Cases in neigbouring Benin and Togo potentially originating from Nigeria have been reported in previous years and therefore neighbouring countries should be monitored accordingly.

With twelve confirmed cases so far among healthcare workers, there is evidence of nosocomial transmission of the disease amidst reports of inadequate infection prevention and control (IPC) supplied in some health facilities and complacency on the part of health workers towards maintaining IPC measures.

WHO advice

Prevention of Lassa fever relies on community engagement and promoting hygienic conditions to discourage rodents from entering homes. In healthcare settings, staff should consistently implement standard infection prevention and control measures when caring for patients to prevent nosocomial infections. WHO continues to advice all countries in the Lassa fever belt on the need to enhance early detection and treatment of cases to reduce the case fatality rate as well as strengthen cross-border collaboration.

WHO does not recommend any travel or trade restriction to Nigeria based on the currently available information.

For more information on Lassa fever, please see the link below:

Nigeria: A Lassa fever outbreak affecting people in 16 states has grown to 213 confirmed cases, including 41 deaths.


Lassa fever sensitization campaign in a school in Taraba state, Northeast Nigeria.

Lassa Fever Outbreak in Benin


EVENT DESCRIPTION On 7 December 2018, the Ministry of Health in Benin notified WHO of an outbreak of Lassa fever in Borgou Department, located in the north-east, at the border with Nigeria. The event was initially reported by the departmental health authority on 6 December 2018, following detection of a suspected Lassa fever case in the Departmental University Hospital Centre (CHUD) of Borgou-Alibori in Parakou city.

The case-patient, a 22-year old Beninese housewife who live in Taberou village, Kwara State, Nigeria, reportedly developed a febrile illness on 23 November 2018 while in Nigeria, from where she initially sought medical treatment. However due to lack of improvement, the family brought her back home to Benin on 29 November 2018 and she was admitted to the teaching hospital (the same day), presenting with fever, haematemesis (vomiting blood), and melaena (blood in her stools). The disease eventually progressed in the subsequent days, with conjunctival hyperaemia, severe weakness and dysphagia, among other symptoms. Blood and urine specimens were obtained and shipped to the viral haemorrhagic fever national laboratory in Cotonou, arriving on 6 December 2018. Test results released on 7 December 2018 were positive for Lassa fever by reverse transcription polymerase chain reaction (RT-PCR).

On 6 December 2018, the spouse of the confirmed index case was found to have symptoms and a blood specimen was obtained, and the test result also turned out positive for Lassa fever. On 9 December 2018, one of the two children of the confirmed cases (a couple) developed high fever and a blood specimen was obtained and the initial test result was negative. However, a repeat sample tested positive for Lassa fever.

As of 16 December 2018, three confirmed cases have been reported, with no deaths. The three patients are admitted in the CHUD and all are reported to be in good clinical condition. A total of 33 contacts, including 24 health professionals, four carers and four patients, have been identified and are being monitored. Further epidemiological investigations are ongoing.

PUBLIC HEALTH ACTIONS On 7 December 2018, the Minister of Health held a press conference to declare the Lassa fever outbreak and provide information on preventive measures to the public. The Ministry of Health convened an emergency meeting of the Crisis Management Committee (CMC) on 7 December 2018 to plan and institute response measures to the outbreak. Structures of the CMC have been activated, including the sub-committees and coordination meetings have been scheduled at the national and sub-national levels. The national rapid response team have been deployed to the affected area to conduct detailed epidemiological investigations and support local response efforts. Isolation and treatment rooms have been prepared to manage the suspected and confirmed cases. Medical commodities, including personal protective equipment, medicines, and medical consumables previously positioned are being used, while additional supplies are being mobilized. Surveillance has been enhanced, including active case search, identification and follow-up of contacts. Public health education and sensitization of the population is ongoing, in particular native healers, opinion, religious and traditional leaders. Dissemination of public awareness messages on prevention measures through local radios and other communication channels is taking place. Aware raising activities have been conducted, targeting taxi and motorcycle-taxi drivers, community relays, religious leaders, teachers and traditional healers, aimed to improve case detection and prevention of Lassa fever infections.

SITUATION INTERPRETATION An outbreak of Lassa fever has been confirmed in Benin, with an epidemiological link to Kwara State in Nigeria. The national authorities have moved quickly in the bid to contain this outbreak, to prevent further spread and establishment of local transmission. Several measures have been instituted, including contact identification and follow-up, aimed to promptly detect, isolate and investigate suspected cases for speedy laboratory confirmation. Further investigations are also ongoing to better understand the outbreak.
However, this event should be a wakeup call to the national authorities to step up preparedness measures for Lassa fever across the country, especially along the borders with Nigeria. Functional port health services and cross border surveillance is paramount, in light of the fact that the index case in this event crossed the border with symptoms. Improving routine universal precautions in healthcare settings is also critical, since about 70% of contacts during this event are health professionals.

Weekly Epidemiological Report from the Nigeria CDC

Nigeria CDC

In the reporting week ending on September 30, 2018:

o There were 173 new cases of Acute Flaccid Paralysis (AFP) reported. None was confirmed as polio. The last reported case of polio in Nigeria was in August 2016. Active case search for AFP is being intensified with the goal to eliminate polio in Nigeria.

o There were 2052 suspected cases of Cholera reported from 42 LGAs in seven States (Adamawa – 107, Borno – 702, Gombe – 90, Kaduna – 2, Katsina – 585, Yobe – 162 and Zamfara – 404). Of these, 26 were laboratory confirmed and 18 deaths were recorded.

o Nine suspected cases of Lassa fever were reported from seven LGAs in five States (Bauchi – 1, Edo – 5, FCT – 1, Nasarawa – 1 & Rivers – 1). Four were laboratory confirmed and no death was recorded.

o There were eight suspected cases of Cerebrospinal Meningitis (CSM) reported from five LGAs in five States (Ebonyi – 1, Edo – 2, Ondo – 2, Taraba – 1 & Yobe – 2). Of these, none was laboratory confirmed and no death was recorded.

o There were 124 suspected cases of measles reported from 30 States. None was laboratory confirmed and one death was recorded.


Lassa Fever: 9 new confirmed cases were reported from three different states in Nigeria


In the reporting Week 31 (July 30-August 5, 2018) nine new confirmedi cases were reported from Edo(7), Ondo(1) and Enugu(1) with two new deaths from Edo(1) and Enugu (1) 

Enugu state recorded the first confirmed case in the state since the beginning of the outbreak with death in the confirmed case  From 1st January to 5th August 2018, a total of 2334 suspected cases have been reported from 22 states. Of these, 481 were confirmed positive, 10 are probable, 1844 negative (not a case) 

Since the onset of the 2018 outbreak, there have been 123 deaths in confirmed cases and 10 in probable cases.

Case Fatality Rate in confirmed cases is 25.6%  

In the reporting week 31, no new healthcare worker was infected. Thirty-nine health care workers have been affected since the onset of the outbreak in seven states

A total of 6383 contacts have been identified from 22 states. Of these 439(6.9%) are currently being followed up, 5846 (91.6%) have completed 21 days follow up while 10(0.2%) were lost to follow up. 88 (1.4%) symptomatic contacts have been identified, of which 30 (34%) have tested positive from five states

Lassa fever national multi-partner, multi-agency Technical Working Group(TWG) continues to coordinate response activities at all levels

WHO: List of Blueprint priority diseases (i.e. diseases and pathogens to prioritize for research and development in public health emergency contexts)


2018 annual review of the Blueprint list of priority diseases

For the purposes of the R&D Blueprint, WHO has developed a special tool for determining which diseases and pathogens to prioritize for research and development in public health emergency contexts. This tool seeks to identify those diseases that pose a public health risk because of their epidemic potential and for which there are no, or insufficient, countermeasures. The diseases identified through this process are the focus of the work of R& D Blueprint. This is not an exhaustive list, nor does it indicate the most likely causes of the next epidemic.

The first list of prioritized diseases was released in December 2015.

Using a published prioritization methodology, the list was first reviewed in January 2017.

February 2018 – Second annual review

The second annual review occurred 6-7 February, 2018. Experts consider that given their potential to cause a public health emergency and the absence of efficacious drugs and/or vaccines, there is an urgent need for accelerated research and development for*:

  • Crimean-Congo haemorrhagic fever (CCHF)
  • Ebola virus disease and Marburg virus disease
  • Lassa fever
  • Middle East respiratory syndrome coronavirus (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS)
  • Nipah and henipaviral diseases
  • Rift Valley fever (RVF)
  • Zika
  • Disease X

Disease X represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease, and so the R&D Blueprint explicitly seeks to enable cross-cutting R&D preparedness that is also relevant for an unknown “Disease X” as far as possible.

A number of additional diseases were discussed and considered for inclusion in the priority list, including: Arenaviral hemorrhagic fevers other than Lassa Fever; Chikungunya; highly pathogenic coronaviral diseases other than MERS and SARS; emergent non-polio enteroviruses (including EV71, D68); and Severe Fever with Thrombocytopenia Syndrome (SFTS).

These diseases pose major public health risks and further research and development is needed, including surveillance and diagnostics. They should be watched carefully and considered again at the next annual review. Efforts in the interim to understand and mitigate them are encouraged.

Although not included on the list of diseases to be considered at the meeting, monkeypox and leptospirosis were discussed and experts stressed the risks they pose to public health. There was agreement on the need for: rapid evaluation of available potential countermeasures; the establishment of more comprehensive surveillance and diagnostics; and accelerated research and development and public health action.

Several diseases were determined to be outside of the current scope of the Blueprint: dengue, yellow fever, HIV/AIDs, tuberculosis, malaria, influenza causing severe human disease, smallpox, cholera, leishmaniasis, West Nile Virus and plague. These diseases continue to pose major public health problems and further research and development is needed through existing major disease control initiatives, extensive R&D pipelines, existing funding streams, or established regulatory pathways for improved interventions. In particular, experts recognized the need for improved diagnostics and vaccines for pneumonic plague and additional support for more effective therapeutics against leishmaniasis.

The experts also noted that:

  • For many of the diseases discussed, as well as many other diseases with the potential to cause a public health emergency, there is a need for better diagnostics.
  • Existing drugs and vaccines need further improvement for several of the diseases considered but not included in the priority list.
  • Any type of pathogen could be prioritised under the Blueprint, not only viruses.
  • Necessary research includes basic/fundamental and characterization research as well as epidemiological, entomological or multidisciplinary studies, or further elucidation of transmission routes, as well as social science research.
  • There is a need to assess the value, where possible, of developing countermeasures for multiple diseases or for families of pathogens.

The impact of environmental issues on diseases with the potential to cause public health emergencies was discussed. This may need to be considered as part of future reviews.

The importance of the diseases discussed was considered for special populations, such as refugees, internally displaced populations, and victims of disasters.

The value of a One Health approach was stressed, including a parallel prioritization processes for animal health. Such an effort would support research and development to prevent and control animal diseases minimising spill-over and enhancing food security. The possible utility of animal vaccines for preventing public health emergencies was also noted.

Also there are concerted efforts to address anti-microbial resistance through specific international initiatives. The possibility was not excluded that, in the future, a resistant pathogen might emerge and appropriately be prioritized.


*The order of diseases on this list does not denote any ranking of priority.



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