Disease outbreak - Cholera - Tanzania - 22 April 2016

22 April 2016

The National IHR Focal Point of the United Republic of Tanzania has provided WHO with an update on the ongoing outbreak of cholera.

As of 20 April 2016, a total of 24,108 cases, including 378 deaths, had been reported nationwide. The majority of these cases had been reported from 23 regions in mainland Tanzania (20,961 cases, including 329 deaths).

The overall trend of incident cases has been fluctuating. Between October and December 2015, there was a drastic reduction in the number of new cases reported in several regions (Morogoro, Dar es Salaam, Tanga, Arusha and Singida). From the middle of December 2015 to the end of March 2016, the number of new reported cases started to increase again. Then, since the middle of March, there has been a significant reduction in cases reported in the mainland. For instance, the daily average of incident cases has declined from around 150 in March 2016 to less than 30 in the middle of April 2016.

To date, Zanzibar has reported 3,057 cases, including 51 deaths, from five regions. The majority of the cases are from Unguja Island (1,818 cases, including 38 deaths) while Pemba Island has reported a cumulative total of 1,239 cases, including 13 deaths.

Assessments have shown that the main factors associated with the spread of the infection both in mainland Tanzania and Zanzibar are limited access to safe water and sanitation. Water supply institutions lack the capacity to chlorinate and conduct regular water quality monitoring and assessments. The coverage of improved latrines is also very low. Poor hygienic practices perpetuated by myths and misconceptions, and the lack of sanitation facilities in poor households have also been associated with the outbreak.

Public health response

A multisectoral National Cholera Task Force (comprising the Ministry of Health, WHO, UNICEF, the Centers for Disease Control - CDC, the Red Cross Society and other partners) is providing oversight and coordination for the response to the outbreak. The National Health Sector Cholera Response Plan has been endorsed to guide the response. The task force, which is jointly led by the Government and WHO, has six technical sub-committees: (1) water, sanitation and hygiene (WASH); (2) social mobilization; (3) surveillance; (4) laboratory; (5) case management; and, (6) logistics and administrative. The sub-committees meet on a daily basis to provide updates on the response and the situation in their respective areas of responsibility and closely liaise with the implementing districts. These cholera response coordination structures are replicated at regional and district levels.

The health sector has focused on the following interventions: mobilizing communities to promote personal hygiene, safe water and good sanitation; distributing chlorine for household water treatment and safe storage; conducting routine water sampling and laboratory analysis for contamination; and strengthening of case management in treatment centers and risk management during burial of deceased cholera patients. Extended Primary Health Care (PHC) Committee meetings are held in different regions with participation of Regional Commissioners, Districts Commissioners, other key stakeholders and other local leaders as well as health authorities and workers. Rapid response teams are being deployed to provide field level support to the most affected regions and districts for targeted control initiatives specific to the respective areas.

WHO coordinates partners, provides technical guidance on surveillance and case management as well as water quality monitoring. The Organization has so far mobilized over 25 international public health experts to support the government in various response activities (promotion of safe water, sanitation and hygiene, social mobilization, case management and monitoring, procurement of medicines and supplies, etc.). With WHO and CDC support, a public health emergency operation center (PHEOC) has been made functional to support the coordination of the response interventions. The country office is also supporting the construction of ventilated improved pit latrines and borehole hand pumps in selected hotspot villages.

In November 2015, WHO graded the epidemic as a level 2 emergency on the Emergency Response Framework (ERF) grading scale – the ERF grading scale has three levels. In February 2016, an incident manager was appointed and has been providing support to the response both on the ground and remotely. The Regional Office is providing additional experts for surveillance support at subnational level in the high-risk districts to ensure a sustainable impact.

WHO risk assessment

Although there has recently been an apparent significant decline in the number of reported new cholera cases, the risk of continued spread continues to exist in the country due to (i) the vast geographical distribution of cases, (ii) the persistence of underlying causative factors such as poor access to safe water and sanitation, (iii) sub-optimal surveillance and laboratory capacity in certain districts, (iv) geographical mobility of symptomatic and asymptomatic individuals. Furthermore, the El Nino phenomenon may have also played a part in perpetuating the outbreak. The potential for international spread of this outbreak beyond the borders of Tanzania exists given the high and free mobility between the country and the neighboring countries. Neighboring Democratic Republic of the Congo, Kenya, Malawi, Mozambique, Zambia have also been responding to cholera outbreaks. Additionally, Tanzania harbors busy international seaports and airports which connect the country with many other unaffected countries. WHO continues to monitor the epidemiological situation and conducts risk assessment based on the latest available information.

WHO advice

WHO does not recommend any travel or trade restriction to the United Republic of Tanzania based on the current information available.