WHO

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.
Geographical