LASSA FEVER - SIERRA LEONE (03): (NORTHERN)

Lassa Fever as a Bio-weapon; http://jama.ama-assn.org/cgi/content/full/287/18/2391

LASSA FEVER - SIERRA LEONE (03): (NORTHERN)


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A ProMED-mail post



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Date: Sun 17 Oct 2010

From: Daniel Bausch





re: Lassa fever -- Sierra Leone (02): (NO) 20101008.3662

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We are writing to provide further information regarding the recent postings

on Lassa fever in Sierra Leone:



1. The index case was a 17 year old pregnant woman who delivered at 28

weeks gestational age. Both she and the baby (not a 6 year old) died.

Although she and her family occasionally caught and consumed rodents, there

is no history of her running a "rat meat restaurant".



2. In all, there were 35 identified contacts of this woman and child, but

only 4 developed Lassa fever. All had direct contact with the index case or

secondary cases, and all 4 survived. We have not identified any more cases,

and, since the time from the last known contact of any of the confirmed

cases has now exceeded the 3-week maximum incubation period for Lassa

fever, we do not anticipate more cases related to this particular chain of

transmission.



3. Whether "the disease has migrated from the forest region of the east to

the savannah grasslands of the north" is a very open question. The index

case denied travel to the known endemic area in the east, but it is always

possible that the infection resulted from unrecognized contact from an

infected person coming from the east to her village in Bombali District.

Our zoology team is presently trapping rodents in the home and village of

the index case. Identification of Lassa virus-positive _Mastomys

natalensis_ would confirm the notion that the endemic area has expanded.

However, it should be noted that suspected cases of Lassa fever have been

reported from this area before, but laboratory facilities were not

available at the time to confirm them.



4. There has indeed been a significant increase in reported cases of Lassa

fever in Sierra Leone over the last 9 months or so. However, this

observation largely coincides with the implementation of Sierra Leone's new

policy of providing free care to children under 5 and pregnant and

lactating mothers (). The numbers

of patients seen in hospitals and health clinics sky-rocketed, driving

upward the perceived incidence of virtually every disease that affects

these groups, including Lassa fever. Whether the observed increase in cases

of Lassa fever is purely reflective of the change in policy or also has

concomitant biological determinants is unknown. It should also be noted

that, for reasons unknown, there is significant seasonal and yearly

fluctuation in the incidence of Lassa fever.



--

communicated by:

Foday Dafae, MD

National Disease Surveillance Coordinator, Sierra Leone

Ministry of Health and Sanitation

James Bangura

Lassa Fever Surveillance Coordinator, Eastern Province,

Sierra Leone Ministry of Health and Sanitation

Daniel Bausch, MD, MPH&TM

Director, Tulane University Research and Training Program in the Mano River

Union Countries of West Africa



[ProMED-mail thanks Daniel Bausch and colleagues for these valuable

first-hand observations on the Lassa fever situation in the Northern region

of Sierra Leone, and for correcting some aspects of the previous report.



The HealthMap/ProMED-mail interactive map of Sierra Leone is available at

. - Mod.CP]



[see also:

Lassa fever - Sierra Leone (02): (NO) 20101008.3662

Lassa fever - Sierra Leone: (NO) 20101001.3555

Lassa fever - Nigeria: (KE) 20100519.1656

2009

---

Lassa fever, predictive maps - West Africa 20090428.1605

Lassa fever - Nigeria (07) 20090319.1108

Lassa fever - UK ex Mali (02): fatal 20090313.1036

Lassa fever - Nigeria (06) 20090309.0981

Lassa fever - Nigeria (05) 20090308.0971

Lassa fever - Nigeria (04): control 20090306.0937

Lassa fever - Nigeria (03) 20090305.0913

Lassa fever - Nigeria (02) 20090225.0788

Lassa fever - UK ex Mali: fatal 20090219.0692

Lassa fever - Nigeria 20090218.0669

Lassa fever - UK ex Nigeria (03): fatal 20090130.0414

Lassa fever - UK ex Nigeria (02) 20090124.0308

Lassa fever - UK ex Nigeria 20090123.0296]



.....................cp/msp/sh







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