Posted on 05TH SEP 2017
tagged Lassa Fever, West Africa; Nigeria

A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases

Date: Fri 25 Aug 2017
Source: Nigeria Centre for Disease Control, Weekly Epidemiological Report 7(32) [edited]

2016/2017 Lassa fever outbreak after action review meeting, 21-22 Aug 2017
Lassa fever experts from all over Nigeria and beyond gathered in the Federal Capital Territory (FCT), Abuja for 2 days to review the 2016/2017 Lassa fever outbreak and propose preparedness plans for subsequent outbreaks. The Nigeria Centre for Disease Control (NCDC) together with the World Health Organisation and supporting partners, hosted the Lassa fever outbreak after action review meeting on the 21 and 22 Aug 2017. Participants were drawn from the states affected by the outbreak this year [2017], Lassa fever treatment facilities, diagnostic laboratories, NCDC surveillance, laboratory, and health emergency response teams, Federal Ministry of Agriculture and Rural Development, Federal Ministry of Environment, and other key stakeholders. Technical support was provided by WHO Africa Regional Office (AFRO) and the National Lassa fever Steering Committee.

The event was declared open on the 1st day by the Honourable Minister of State for Heath, Dr Osagie Enahire, who applauded the NCDC for its efforts towards stemming the tides of Lassa fever in Nigeria and charged all present to find a lasting solution to the menace of the disease in the country. The chairperson of the National Steering Committee, Prof Oyewale Tomori gave an overview of Lassa fever outbreak since the virus was discovered in 1969 with a critical review of control efforts taken in the past which have not yielded needed results. He decried the unsustainable efforts that have plagued the surveillance system in Nigeria and called on every stakeholder to realign their activities to achieve a common goal of a strengthened surveillance system, which can be used as a strong tool in the fight against Lassa fever. He urged participants present to focus on finding practical solutions towards elimination of the disease.

A national report of the 2016/2017 Lassa fever outbreak was presented. As at epi-week 33 (14-20 Aug 2017), a total of 764 suspected cases have been reported across 19 states (Ogun, Taraba, Rivers, Nasarawa, Edo, Ondo, Bauchi, Ebonyi, Plateau, Kaduna, Gombe, Cross-River, Borno, Kano, Kogi, Enugu, Anambra, Lagos, and Kwara). 247 of these cases were confirmed and 14 classified as probable cases. A total of 83 deaths have been recorded, with 69 of them in confirmed cases. Case fatality rate is 33.6 percent in confirmed and probable cases and 15.1 percent in all cases (confirmed, probable, and suspected). The response activities carried out by the NCDC, including the development of Viral Haemorrhagic Fever [VHF] guidelines, deployment of rapid response teams, provision of ribavirin and other medical supplies to states and several others, were also discussed.

Robust discussions were held by the participants following various presentations made, which all focused on preparedness and response to Lassa fever outbreak. The 2-day meeting provided an opportunity to reflect on the events which led to the 2016/2017 Lassa fever outbreak in each state and also to conduct out a detailed review of the response activities carried out by the affected States and the NCDC. In addition, gaps in preparedness, response and surveillance activities were highlighted and pragmatic steps to be taken to bridge these gaps were proposed.

Working groups were created in line with the 6 thematic areas under the incident management system (IMS) for Lassa fever -- coordination/case management/infection prevention and control, laboratory, logistics, surveillance/data management and risk communication. Focus group discussions were held within these working groups during which best practises and challenges in the 2016/2017 Lassa fever outbreak were highlighted. Practical recommendations were made by every group in their individual thematic areas and in cross-cutting areas. Each state was enjoined to follow up with these recommendations, as it applies to their particular needs and circumstances and to also incorporate them in their state-specific Lassa fever preparedness work plan.

The NCDC affirmed its resolve to continue to ensure that the disease burden caused by Lassa fever, and indeed all epidemic-prone diseases in Nigeria is reduced. The steps taken at this meeting will serve as added incentives towards establishing a finish line for the scourge of Lassa fever. All stakeholders and the general public are called upon to work with the governments in the various States towards a collaborative plan for the control and elimination of Lassa fever.

1. Lassa fever
Please note that the data reflect the routine reports, that is, all suspected cases including the laboratory positive and negative cases
1.1. 19 suspected cases of Lassa fever with 4 laboratory confirmed and 2 deaths (CFR, 10.53 percent) were reported from 7 LGAs [local government areas] (9 states; Edo - 8, Kwara - 5, Ogun - 1, Ondo - 1, Oyo - 1, Plateau - 1, and Yobe - 2) in week 32 [week ending 13 Aug 2017], 2017 compared with 5 suspected cases and 2 deaths (CFR, 40 percent) reported from 5 LGAs (4 states) at the same period in 2016.
1.2. Laboratory results of the 19 suspected cases were 4 positives for Lassa fever (Edo - 2, Ogun - 1, and Ondo - 1) while 9 were negative for Lassa fever and other VHFs (Edo - 6, Oyo - 1, Plateau - 1, and Yobe -2) while 5 pending (Kwara - 5).
1.3. Between weeks 1 and 32 ([1 Jan-13 Aug 2017], 393 suspected Lassa fever cases with 97 laboratory confirmed cases and 58 deaths (CFR, 14.80 percent) from 74 LGAs (25 states) were reported compared with 787 suspected cases with 75 laboratory confirmed cases and 90 deaths (CFR, 11.44 percent) from 128 LGAs (27 states) during the same period in 2016 (Figure 1 --[available at the source URL above]).
1.4. Between weeks 1 and 52 2016, 921 suspected Lassa fever cases with 109 laboratory confirmed cases and 119 deaths (CFR, 12.92 percent) from 144 LGAs (28 states and FCT) were reported compared with 430 suspected cases with 25 laboratory confirmed cases and 40 deaths (CFR, 9.30 percent) from 37 LGAs (14 states and FCT) during the same period in 2015 (Figure 2).
1.5. Investigation and active case search ongoing in affected states with coordination of response activities by the NCDC with support from partners.
1.5.1. National Lassa Fever Working Group meeting and weekly National Surveillance and Outbreak Response meeting on-going at NCDC to keep abreast of the current Lassa fever situation in the country.
1.5.2. Response materials for VHFs prepositioned across the country by NCDC at the beginning of the dry season.
1.5.3. New VHF guidelines have been developed by the NCDC (National Viral Haemorrhagic Fevers Preparedness guidelines, Infection Prevention and Control of VHF and Standard Operating Procedures for Lassa fever management) and are available on the NCDC website.
1.5.4. Ongoing reclassification of reported Lassa fever cases
1.5.5. Ongoing review of the variables for case-based surveillance for VHF
1.5.6. VHF case-based forms completed by affected States are being entered into the new VHF management system. This system allows for the creation of a VHF database for the country.
1.5.7. NCDC team sent to Edo state to support Lassa fever data harmonization & updating of VHF case-based management database
1.5.8. Confirmed cases are being treated at identified treatment/isolation centres across the States with Ribavirin and necessary supportive management also instituted.
1.5.9. Onsite support was earlier provided to Ogun, Nasarawa, Taraba, Ondo, and Borno states by the NCDC and partners.
1.5.10. Offsite support provided by NCDC/partners in all affected states
1.5.11. NCDC and partners are providing onsite support in Ondo and Plateau states.
1.5.12. States are enjoined to intensify surveillance and promote Infection, Prevention and Control (IPC) measures in health facilities.

Figure 1: Map of Nigeria showing areas affected by Lassa fever, week 1- 32, 2016 and 2017
Figure 2: Map of Nigeria showing areas affected by Lassa fever, week 1-53, 2015 and week 1-52, 2016

Table of cases by state, cumulative data weeks 1-32 [1 Jan-13 Aug 2017] as of 18 Aug 2017:
State: Cases / Laboratory confirmed / Deaths
Adamawa: 6 / 0 / 2
Akwa Ibom 1 / 1 / 0
Bauchi: 11 / 4 / 4
Benue: 1 / 0 / 0
Cross River: 7 / 0 / 1
Ebonyi: 4 / 1 / 1
Edo: 151 / 33 / 9
Enugu: 1 / 1 / 1
FCT: 2 / 0 / 0
Gombe: 17 / 0 / 1
Jigawa: 1 / 0 / 0
Kadun: 1 / 0 / 0
Kano: 23 / 2 / 10
Katsina: 4 / 0 / 0
Kebbi: 1 / 0 / 1
Kogi: 3 / 1 / 1
Kwara: 5 / 0 / 0
Lagos: 1 / 1 / 0
Nasarawa: 29 / 6 / 2
Ogun: 14 / 2 / 0
Ondo: 29 / 20 / 7
Oyo: 1 / 0 / 0
Plateau: 30 / 9 / 7
Rivers: 6 / 1 / 0
Taraba: 38 / 12 / 9
Yobe: 6 / 3 / 2
Total: 393 / 97 / 58

Communicated by:
Olutayo Olajide Babalobi
Lecturer and Consultant Epizootiologist
(One Health, Participatory Epizootiology and Veterinary ICT Research Group)
Department of Veterinary Public Health and Preventive Medicine
Faculty of Veterinary Medicine
University of Ibadan
Ibadan, Nigeria

[Overall, case numbers have increased by 27 confirmed, 9 laboratory confirmed, and 3 deaths since Fri 4 Aug 2017.

Once again, ProMED-mail thanks Dr Olutayo Olajide Babalobi for sending in the epidemiological report above.

As noted in earlier comments, Lassa fever remains a problem in Nigeria because the virus is endemic there. Virus transmission to humans occurs when people are in contact with the reservoir rodent host, the multimammate mouse (in the genus _Mastomys_) or their excreta. Transmission also occurs in health facilities when personal protective equipment is not employed and barrier-nursing practices are not adequate to protect staff from blood and secretions of infected patients.

Images of mastomys mice, the rodent reservoir of Lass fever virus, can be seen at

Maps of Nigeria can be accessed at and - Mod.TY]

See Also
Lassa fever - West Africa (32): Nigeria 20170819.5262007
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Lassa fever - West Africa (25): Nigeria 20170629.5140763
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Lassa fever - West Africa (23): Nigeria (ON) 20170622.5124247
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Lassa fever - West Africa (16): Nigeria (BA) 20170412.4967018
Lassa fever - West Africa (15): Nigeria (KO) 20170404.4947996
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Lassa fever - West Africa (13): update 20170328.4931422
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Lassa fever - West Africa (09): Nigeria (BO) 20170302.4875164
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Lassa fever - West Africa (03): Nigeria (RI) 20170122.4782917
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Lassa fever - West Africa (01): Nigeria (OG) 20170101.4735363