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Nigeria: Lassa Fever Outbreak - Jan 2019

Disaster types

On 21 January 2019, the Nigeria Centre for Disease Control (NCDC) declared an outbreak of Lassa fever following an increase in the number of cases. From 01 to 27 January 2019, a total of 213 confirmed cases including 41 deaths were reported from sixteen states (Edo, Ondo, Ebonyi, Bauchi, Plateau, Taraba, Gombe, Anambra, Kaduna, Kwara, FCT, Benue, Rivers, Nassarawa and Kogi States) across 40 Local Government Areas (LGAs). This represents a significant increase in the number of cases reported compared to at the same period in 2018. With the outbreak confirmed, WHO intensified its technical assistance to State and Federal authorities in investigation and response to the outbreak. (WHO, 1 Feb 2019)

The number of confirmed cases reported across Nigeria remains high. In week 6, 2019 (week ending 10 February 2019), 37 new confirmed cases including 10 deaths (case fatality ratio = 27%) were reported from nine states across Nigeria. The majority of cases were reported from Ondo (12) and Edo (10) states. The number of confirmed cases reported in week 6, 2019 represents a slight decrease compared to week 5 when 68 confirmed cases were reported. (WHO, 14 Feb 2019)

The Nigeria Centre for Disease Control (NCDC) has reported a decrease in the number of Lassa fever cases reported weekly in the country. This is following the intensive response to the Lassa fever outbreak declared in Nigeria on the 21st of January 2019...In the last reporting week ending on the 17th February 2019, 25 new confirmed cases of Lassa fever were reported. So far, a total of 355 confirmed cases with 75 deaths have been recorded between January 1st and February 17th, 2019 from 20 states across 57 Local Government Areas. Over the past three weeks, there has been a downward trend in new cases. The number of new cases being reported are lower, compared to the same period during the 2018 outbreak. (Govt, 25 Feb 2019)

Cases of Lassa fever continue to be reported across Nigeria in 2019, with a declining trend since week 10. During week 15 (week ending on 14 April 2019), three new confirmed cases with zero deaths were reported from two states – Edo (one) and Plateau(two). This is the lowest number of cases reported since the beginning of the year, with more than 80 cases reported during the peak of the outbreak in week 4 (week ending on 27 January 2019). From 1 January to 14 April 2019, a cumulative total of 555 confirmed and probable cases with 137 deaths (case fatality ratio 24.7%) have been reported across Nigeria. Eighty-one local government areas across 21 states have reported at least one confirmed case since the beginning of 2019. (WHO, 21 Apr 2019)

Following a joint epidemiological review by the Nigeria Centre for Disease Control (NCDC), the World Health Organisation in Nigeria (WHO Nigeria) and other partners, the NCDC has announced the end of the emergency phase of the 2019 Lassa fever outbreak. (Govt, 30 May 2019)

The Lassa fever outbreak in Nigeria is still ongoing. Since our last report in week 16 of 2019 (week ending 21 April 2019) sporadic cases have continued to be reported across 86 Local Government Areas (LGAs) in 23 states, resulting in a cumulative total of 793 confirmed cases reported between 1 January and 1 December 2019. A significant upsurge in the number of cases was noted in the first three weeks of 2020. Between 1 and 19 January 2020, a cumulative total of 398 suspected cases was reported nationally. (WHO, 26 Jan 2020)

On 25 January, the Nigeria Centre for Disease Control (NCDC) announced the activation of a national emergency operations center (EOC) following an escalation of Lassa fever outbreak across different zones of the country. From 1 to 24 January alone, at least 195 confirmed cases and 29 deaths were recorded across 11 states with the southern Ondo, Edo and Ebonyi states reporting the highest number (89 per cent) of cases. (OCHA, 29 Jan 2020)

The outbreak of Lassa fever in Nigeria continues to propagate, with new states being affected weekly. [...] Between 1 January and 2 February 2020, a cumulative total of 1 226 suspected cases were reported in Nigeria. Among these, a total of 365 confirmed cases were recorded from 74 local government areas (LGAs) in 23 states. (WHO, 09 Feb 2020)

The Lassa fever outbreak in Nigeria continues, with a high incidence of cases and deaths reported and new states being affected. [...] Between 1 January and 23 February 2020, a cumulative total of 2 633 suspected cases were reported across Nigeria. Of these, a total of 689 cases coming from 115 local government areas (LGAs) in 27 states were confirmed, Among the 689 confirmed cases, 118 deaths have occurred, giving a case fatality ratio (CFR) of 17.1% among confirmed cases, which is relatively lower compared to the CFR for the same period in 2019 (21.8%). (WHO, 1 Mar 2020)

Following concerted partners’ response, led by the World Health Organization, the Commissioner for Health, Dr. Salihu Kwayabura has declared an end of Lassa fever outbreak in Borno State. (WHO, 21 Mar 2020)

The Lassa fever outbreak in Nigeria has greatly improved, with only a few sporadic cases being reported. The disease trend has been steadily declining since week 7 (2020) when a peak of 115 confirmed cases (with 18 deaths) were reported. However, in week 16 (week ending 19 April 2020), a total of six new confirmed cases (with no deaths) have been reported, compared to 10 confirmed cases reported in week 15. These new cases reported in week 16 came from three states: Ondo (3), Gombe (2) and Taraba (1). There were six case-patients admitted to treatment centres during the reporting week, and 275 contacts under follow up. No new healthcare worker was reported affected in week 16. From weeks 1-16 of 2020, a cumulative total of 4 475 suspected Lassa fever cases has been reported, of which 969 were laboratory confirmed, including 188 deaths (case fatality ratio among confirmed cases 19.2%). (WHO, 27 Apr 2020)

The Nigeria Centre for Disease Control (NCDC) has declared the emergency phase of the 2020 Lassa fever outbreak over. This is following successive decline in cases below the emergency threshold, and an epidemiological review carried out by NCDC and the World Health Organisation (WHO). (Gov't of Nigeria, 29 Apr 2020)