This update describes the development, status, and response activities implemented by the humanitarian community of the Acute Watery Diarrhoea outbreak in Somalia. The update follows the structure as proposed in the WHO guidelines for cholera outbreak response. The update is built on surveillance data that health service providers and NGOs transmit on a weekly basis from health facilities and hospitals in South and central Somalia.
1 Epidemiological week No 17: Overall results and outcome
Between 1 January and 27 April 2007, a total of 23 202 cases of clinically diagnosed Acute Watery Diarrhoea (AWD) including 743 related deaths (CFR(1) 3.20) were reported from Central and South Somalia. Cases were reported from 10 regions (Hiiraan, Banadir, Lower and Middle Shabelle, Bay, Gedo, Bakool, Galgudud and Lower Juba and Middle Juba) with an estimated population of 4,089,847; the overall attack rate(2) (AR) is 0.57%.
Note: the sharp decrease of the number of cases since the epidemiological week 15
is mainly related to lack of data from Babadir Region (Mogadishu) due to security reasons.
Figure 1: Distribution of AWD cases, Central and South Somalia, 01 January -27 April 2007
In the last three epidemiological weeks (15 to 17), the trend shows a decrease in the number of reported cases mainly related to a decreased number of reporting units in Mogadishu due to security reasons. In the current week (epidemiological week 17), the reported cases decreased by 14%, in comparison with the previous week (1488 and 1702 respectively). The distribution of AWD cases is shown in figure 1.
The first report of an increase in AWD cases was received form Hiiraan region (not included in the graph) in the first epidemiological week of 2007. After reaching the peak in week 7, cases started to decrease to date (no cases were reported since epidemiological week 12).
In epidemiological week 5, Middle Shabelle region (not included in the graph) reported a similar increase in AWD cases. The number of cases reached the peak in epidemiological weeks 6 and 7 and decreased in the last few weeks.
In the beginning of epidemiological week 6, an increase of AWD cases was reported from Lower Shabelle region. The peak was reached in epidemiological week 10, but a slight decrease was observed in the epidemiologic weeks 11 and 12 with another increase in the epidemiological week 13, followed by a steady decrease in the previous 4 weeks (epidemiological weeks 14-17).
(1) The case fatality rate (CFR) refers to the number of deaths per 100 cases
(2) WHO/EMC/ DIS/97.11”Attack rate of 0.5% would be used for urban areas, 0.2% for rural areas and 1-2% for refugee/displaced populations as a worst case scenario”