Posted on 30TH JUN 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 23 Jun 2017
Source: Nigeria Centre for Disease Control [NCDC] Weekly Epidemiological Report 7(23) [edited]

1. Lassa fever
Please note that the data reflects the routine reports i.e. all suspected cases including the laboratory positive and negative cases
1.1. Up to 3 suspected cases of Lassa fever with one Laboratory confirmed were reported from two LGAs (Anambra and Ogun States) in week 23, 2017 compared with zero case at the same period in 2016.
1.2. Laboratory results of the 3 suspected cases were one positive (Anambra - 1) and 2 negatives (Ogun - 2).
1.3. Between weeks 1 and 23 (2017), 301 suspected Lassa fever cases with 65 laboratory confirmed cases and 49 deaths (CFR, 16.28 percent) from 60 LGAs (22 States) were reported compared with 717 suspected cases with 71 laboratory confirmed cases and 87 deaths (CFR, 12.15 percent) from 125 LGAs (27 States) during the same period in 2016 (Figure 1).
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 (Interim National Viral Haemorrhagic Fevers Preparedness guidelines and Standard Operating Procedures for Lassa fever management)
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 and updating of VHF case-based management database
1.5.8. Confirmed cases are being treated at identified treatment/isolation centers 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. States are enjoined to intensify surveillance and promote Infection, Prevention and Control (IPC) measures in health facilities.

Table of cases as of 16 Jun 2017
Cases during week 23: 3 cases, deaths 0
Cumulative weeks 1- 23: 301, deaths 49

[Cases by state not given in thei Epidemiological Report]

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

[During week 23, there were just 3 new suspected cases. 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

Once again, Dr Olutayo Olajide Babalobi is thanked for sending in the above Epidemiological Report.

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

A HealthMap/ProMED-mail map can be accessed at:]

See Also

Lassa fever - West Africa (24): Nigeria 20170626.5130588
Lassa fever - West Africa (23): Nigeria (ON) 20170622.5124247
Lassa fever - West Africa (22): Nigeria (AN) 20170620.5118831
Lassa fever - West Africa (21): Nigeria 20170617.5112720
Lassa fever - West Africa (20): Nigeria 20170607.5088880
Lassa fever - West Africa (19): Nigeria 20170604.5082193
Lassa fever - West Africa (18): Nigeria 20170530.5070103
Lassa fever - West Africa (17): Nigeria 20170513.5033800
Lassa fever - West Africa (16): Nigeria (BA) 20170412.4967018
Lassa fever - West Africa (15): Nigeria (KO) 20170404.4947996
Lassa fever - West Africa (14): Nigeria 20170402.4943005
Lassa fever - West Africa (13): update 20170328.4931422
Lassa fever - West Africa (12): Nigeria 20170327.4929174
Lassa fever - West Africa (11): Nigeria 20170319.4911462
Lassa fever - West Africa (10): Benin, Togo, Burkina Faso 20170312.4896305
Lassa fever - West Africa (09): Nigeria (BO) 20170302.4875164
Lassa fever - West Africa (08): Benin 20170301.4872702
Lassa fever - West Africa (07): Nigeria (BA) 20170225.4864837
Lassa fever - West Africa (06): Nigeria 20170225.4862689
Lassa fever - West Africa (05): Nigeria (NA) 20170215.4842179
Lassa fever - West Africa (04): Liberia 20170209.4827934
Lassa fever - West Africa (03): Nigeria (RI) 20170122.4782917
Lassa fever - West Africa (02): Nigeria (NA) 20170118.4773375
Lassa fever - West Africa (01): Nigeria (OG) 20170101.4735363