29 February 2012

Lassa fever in Nigeria - update

 

This replaces the information posted on Lassa fever in Nigeria on 03 February 2012.

 

The outbreak of Lassa fever in Nigeria, first reported in January 2012, is continuing. As of 17 February, the Nigerian Federal Ministry of Health has reported 397 cases with 87 of these confirmed as Lassa fever [1]. A total of 40 deaths have also been reported, including six health workers: two doctors and four nurses [2].

Cases have been reported from 12 states: Anambra, Borno, Ebonyi, Edo, Gombe, Lagos, Nassarawa, Ondo, Plateau, Rivers, Taraba and Yobe. The States of Edo, Nassarawa and Plateau are known to be endemic for Lassa fever and it is from these states that the cases in Lagos, Rivers and Yobe originated [2].

The Nigerian Federal Ministry of Health has deployed a rapid response team to affected areas to enhance surveillance, verify cases, support treatment and trace contacts [1]. In addition, the International Federation of Red Cross and Red Crescent Societies are supporting the Nigerian Red Cross Society in delivering assistance to 15,000 households. Volunteers will carry out community activities to highlight good hygiene and sanitation and the importance of case detection to help control disease spread [3].

Lassa fever

 

Lassa fever, named after the town in northeastern Nigeria where the disease was first described, is an acute viral haemorrhagic fever caused by Lassa virus, a member of the Arenavirus family. Lassa fever is also endemic in Guinea, Liberia and Sierra Leone. In recent years, there is evidence of infection in the Central African Republic, Mali and Senegal.

Lassa fever is usually transmitted to humans after broken skin or mucous membranes are contaminated with urine or droppings from rats living near rural homes in endemic countries. Person to person transmission can occur after direct contact with body fluids of infected individuals, usually in hospital or healthcare settings.

A total of 12 imported cases of Lassa fever have been reported in the UK since 1970, including five from Nigeria [4]. The two most recent cases occurred in 2009, in travellers who had returned from Nigeria and Mali [5, 6].

Advice for travellers:

Lassa fever is a rare risk for travellers [7, 8]. Travellers at greater risk include those living or working in endemic areas, particularly healthcare or humanitarian aid workers, or those undertaking rural pursuits (e.g. camping) or work activities, where contact with rodents may be more likely [8].

There is no vaccine to protect against Lassa fever. Travellers to endemic countries should avoid contact with rodents. Rodent populations can be reduced by clearing rubbish around dwellings, and preventing rodent access into buildings.

Healthcare workers should use personal protection measures when caring for persons suspected to have Lassa fever. See WHO guidelines which are designated for use in endemic settings: Infection control for viral haemorrhagic fevers in the African health care setting.

 

Advice for Health Professionals:

 

Health professionals who suspect Lassa fever in a returned traveller must contact the Health Protection Agency’s Duty Doctor for advice on 020 8200 4400 as a matter of urgency.

More information about Lassa and other viral haemorrhagic fevers (including UK Guidance for Management and Control) is available from the Health Protection Agency.

References

1. Federal Ministry of Health, Nigeria. Federal Government Inaugurates Lassa fever Rapid Response Committee. 24 February 2012. [Accessed 29 February 2012]. Available at: http://www.fmh.gov.ng/index.php/component/content/article/913-fg-inaugurates-lassa-fever-rapid-response-committee
2. Federal Ministry of Health, Nigeria. 12 States Affected with Lassa Fever – Minister of State Health. 22 February 2012. [Accessed 29 February 2012]. Available at: http://www.fmh.gov.ng/index.php/component/content/article/912-12-states-affected-with-lassa-fever-minister-of-state-health
3. International Federation of Red Cross and Red Crescent Societies. Disaster relate emergency fund (DREF). Nigeria: Lassa fever. 4 February 2012. [Accessed 29 February 2012]. Available at: http://www.ifrc.org/docs/appeals/12/MDRNG012.pdf
4. Health Protection Agency. Table of imported confirmed cases of Lassa fever in UK since 1970. [Accessed 29 February 2012]. Available at: http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/

LassaFever/GeneralInformation/lassa005Historical

ableImportedConfirmedLassaCase
5. NaTHNaC. Imported case of Lassa fever in the United Kingdom, 30 January 2009. [Accessed 29 February 2012]. Available at: https://www.nathnac.org/pro/clinical_updates/Lassa_300109

htm.htm
6. Health Protection Agency. Patient dies from Lassa fever at a London hospital, 17 February 2009. [Accessed 29 February 2012]. Available at: http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPA

web_C/1234946215137?p=1231252394302
7. Health Protection Agency. Lassa Fever Africa. [Accessed 29 February 2012]. Available at: http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/

LassaFever/EpidemiologyRiskMaps/lassaafrica/
8. Beeching NJ, Fletcher TE, Hill DR, Fletcher TE. Travellers and viral haemorrhagic fevers: what are the risks? Int J Antimicrob Ag. 36 (S1):S26-S35, 2010.

 

Links:

 

Health Protection Agency: Lassa fever – Questions and Answers.

NaTHNaC: Outbreak Surveillance