From 15 August 2015 through 7 January 2018, 33 421 cases including 542 deaths (case fatality rate = 1.62%) have been reported across all 26 regions of the United Republic of Tanzania (Tanzania mainland and Zanzibar). Tanzania mainland has reported 86% of the total cases in this outbreak. Children under five years old accounted for 11.4% of cases. Since the beginning of the outbreak over 7000 specimens have been tested for cholera and 47% were positive for Vibrio cholerae by culture.

From 1 January 2017 through 31 December, 4985 cases including 99 deaths have been reported in Tanzania Mainland and Zanzibar. The number of cases as well as geographical spread of cholera has markedly reduced compared to the two previous years. During the same period in 2016, 14 547 cases and 225 deaths were reported for Tanzania mainland and Zanzibar. In 2017, the highest number of cases was reported from Mbeya Region during week 31 (week starting 31 July 2017) and from Songwe Region during week 43 (week starting 23 October 2017). Between weeks 49-52, Uvinza, Songwe and Nyasa districts reported the highest number of cases.

The resurgence of cases in Kigoma, Manyara, Dodoma, Mbeya and Dar es Salaam regions, and Ruvuma and Rukwa regions reporting cases for the first time since the beginning of the outbreak reflects the persisting risk for a cholera upsurge in many other regions. Zanzibar has reported no cases since the last case was reported on 11 July 2017, however high population movement to and from Tanzania Mainland still poses a risk of spread to Zanzibar.

Figure 1: Number of cholera cases in Tanzania mainland reported by week of illness onset from 1 January through 7 January between 2015-2018.

Public health response

The following public health measures are currently being implemented:

• The Ministry of Health (MoH) is collaborating with WHO and other partners (UNICEF and the United States Center of Disease Control and Prevention (CDC)) to implement and monitor cholera control activities through the National Task Force.
• On 15 December 2017, the National Cholera Response Plan has been reviewed and validated by the MoH and stakeholders.
• Cholera National Task Force meeting was conducted on Friday 29 December 2017 and agreed to deploy a team to assist Uvinza District to respond to the acute upsurge of cholera cases.
• The MoH deployed a national rapid response team to Ruvuma Region which reported cases for the first time at the end of November 2017.
• Community sensitization and awareness through local radio, television and social media is ongoing.
• UNICEF is supporting the promotion and distribution of aqua tabs for household level water treatment and safe storage in the affected households.
• Zanzibar is progressing to develop a ten year cholera elimination plan.
• Initiation of exchanges for reinforcing the cross-border preparedness and response actions.

For more information about Cholera, please visit http://www.who.int/csr/don/12-january-2018-cholera-tanzania/en/