Cholera in Zimbabwe: Epidemiological Bulletin Number 5 Week: 4 Jan 2009- 10 Jan 2009 Foreword This is the 5th epidemiological bulletin to be issued since the onset of a countrywide Zimbabwe cholera epidemic first reported in August, 2008. Bulletins are to be published weekly to coincide with the end of an epidemiological week (Sunday to Saturday). Daily cumulative caseload updates are posted on the OCHA website http://ochaonline.un.org/Default.aspx?alias=ochaonline.un.org/zimbabwe The bulletin provides a weekly overview of the epidemic in Zimbabwe, including province by province data, to inform and improve the continuing public health response. It also provides guidance to agencies on issues relating to data collection, analysis and interpretation, and suggests operational strategies on the basis of epidemiological patterns so far. The WHO Team welcomes feedback and data provided by individual agencies. Given the scope of this epidemic, errors and omissions are inevitable: we will be grateful for any information that helps to rectify these. Please send any comments and feedback to the Cholera Control and Command Centre Email: [email protected]. Toll free number for alert by district and province is 08089001 or 08089002 or 08089000 Mobile number for alerts is 0912 104 257 Source: Ministry of Health and Child Welfare Rapid Disease Notification System 1 Table of contents 1. Introduction 3 1.1. Map and population 3 1.2. Cholera treatment centres (CTC and CTU) 3 2. National Overview 4 2.1. Global picture 4 2.2. Case definition 5 2.3. Number cases and CFR 5 2.4. Attack rates and proportion of cases per district 7 2.5. Community deaths 9 2.6. Conclusion: hot spots for this week 10 3. Surveillance findings by province 10 3.1. Harare 10 3.2. Bulawayo 12 3.3. Mashonaland West 12 3.4. Mashonaland Central 12 3.5. Mashonaland East 13 3.6. Midlands 13 3.7. Masvingo 14 3.8. Manicaland 14 3.9. Matabeleland South 15 3.10. Matabeleland North 15 4. Discussion 16 4.1. Alerts and early warning system 16 5. Acknowledgements 16 Source: Ministry of Health and Child Welfare Rapid Disease Notification System 2 1. Introduction 1.1. Map and population 1.2. Cholera treatment centres (CTC and CTU) There are 172 Cholera Treatment Centres (CTC/CTU) distributed over the country. 74 of the 172 CTC/CTU so 43% of them are run by the MoHCW. The others are receiving support from NGOs and partners. On average, one CTC/CTU is covering a population of 211 046 persons with a noted peak in Harare of 670 928 persons per CTC/CTU. Table 1. Number of CTC/CTU per province, as of Jan 10th, Zimbabwe Average catchment Province Population Number of CTC population per CTC Harare (Harare city+ Chitungwiza) 2,012,784 3 670928 Bulawayo 718,278 1 718278 Manicaland 1,665,451 36 46263 Mash Central 1,056,666 25 42267 Mash East 1,196,772 26 46030 Mash West 1,300,012 35 37143 Masvingo 1,401,672 31 45215 Mat North 748,317 0 - Mat South 693,230 7 99033 Midlands 1,554,058 8 194257 TOTAL 12347238 172 211046 Source: Ministry of Health and Child Welfare Rapid Disease Notification System 3 Figure 2 (map): Location of the cholera treatment center (CTC and CTU) in Zimbabwe, as of 10 Jan 2009 Figure 3(map): Location of the 2 cholera treatment centers (CTC) among Harare city suburbs, as of 10 Jan 2009 Budiriro polyclinics Beatrice hospital 2. National Overview 2.1. Global picture New cholera cases and deaths continue to be reported. The cholera outbreak is not yet under control with nine of ten provinces reported cases for the epidemiologic week 04/1/08 - 10/1/09. To date and as of 10 January 2009, a cumulative total of 37 806 suspected cases and 1912 deaths have been reported to the World Health Organization (WHO), through the Ministry of Health and Child Welfare's (MoHCW) surveillance department. Number of cases have increased from last week as weel as the number of deaths. Case-fatality rates (CFR, the proportion of cases that die of the Source: Ministry of Health and Child Welfare Rapid Disease Notification System 4 disease) based on reported cases increased markedly this week to 6 % (5.9% exactly) similar to the week preceding the Christmas and New year’s holiday, and is still much higher than expected for a cholera outbreak (normally <1%). To date since November 16th 2008, 587 cases per day are reported and 31 persons are dying every day of cholera. This week (4 Jan -10 Jan 2009) nearly half of the deaths (41%) are occurring outside treatments centre suggesting continued problems associated with the unavailability of health care in the country. The highly affected provinces this week are: 1. Mashonaland West (increase cases and CFRs > 5% and high attack rates and 1/3 of the total weekly number of cases) 2. Midlands, (increase cases and CFRs > 5% and high attack rates) 3. Manicaland (CFRs > 5% and high attack rates) 4. Mathebeleland South (increase cases) 5. Chitungwiza (CFRs > 5%) 6. Masvingo (CFRs > 5%) 7. Mashonaland central (increase cases) 2.2. Case definition The cholera control guidelines for Zimbabwe state that the definition of suspected cholera cases is "in an area where there is a cholera epidemic, a patient aged 2 years or more develops acute watery diarrhoea, with or without vomiting". A confirmed cholera cases is “when Vibrio cholerae is isolated from any patient with diarrhoea”. This is adapted/modelled after the WHO case definition for cholera. Including all ages in the case definition somewhat reduces specificity (i.e. more non-cholera childhood diarrhoea cases are included), but essentially does not impede meaningful interpretation of trends. However, teams should monitor any shift in the age distribution of cases, which might indicate a changing proportion of non-cholera cases among patients seen. However, up to this point in the outbreak, we have been collecting data from all patients regardless of age. This is because we collect aggregate data every day which does not include ages. Data is also reported via line lists which do include ages. This information takes more time to come in, but in the future we aim at analysing data by age and separate out the <2 year olds at that point for official reporting. So while respecting the case definition for Zimbabwe, we continue to collect case data for all ages to avoid delay in responding to the current outbreak. 2.3. Number cases and CFR For the week 04/01/09 - 10/1/09, 4594 new cases of cholera were reported, an increase from the 3690 cases reported last week. New deaths from cholera reported this week were 272 (a threefold increase from the 79 of last week). Cases of cholera continue to be reported from 9 of 10 provinces (8 rural provinces and 2 urban provinces-Harare and Bulawayo), although outbreaks are localized by province and vary in their characteristics. Figure 1 demonstrates the cholera cases reported nationwide. This week data provide proof that week 28 Dec-3 Jan (Christmas and New year’s holidays period) was an artefact in the surveillance as this week 4 Jan-10 Jan the number of cases is back to around 6000 cases/week. Case-fatality rates (CFR, the proportion of cases that die of the disease) based on reported cases increased markedly this week to 6 % (5.9% exactly) similar to the week preceding the Christmas and New year’s holiday, and is still far above the <1% target. The CFR for the week 04/10/09 - 10/1/09 is 5.9%, compared to 2.1 % last week. Figure 1 demonstrates CFRs by week nationwide. Source: Ministry of Health and Child Welfare Rapid Disease Notification System 5 Figure 4 : New cholera cases, with case-fatality rates, by week. Zimbabwe, Nov 08 - Jan 09 * For week 7-13 December, gaps in reporting of data were noted. ** For week 28 December 08- 3 January 09, probable under reporting of number of cases and death during the Christmas- New Years holiday period 7,000 10.0 9.0 6,000 8.0 5,000 7.0 6.0 4,000 ** 5.0 Cases CFR Cases * CFR 3,000 4.0 3.0 2,000 2.0 1,000 1.0 0 0.0 16-22 Nov 23-29 Nov 30 Nov - 6 Dec 7-13 Dec 14-20 Dec 21-27 Dec 28 Dec-3 Jan 4-10 Jan The method of calculating CFR at this time and since the beginning of the epidemic is total deaths reported (institutional and community deaths) / total cases reported. This has the same meaning as “lethality”. CFRs vary by district and reflect issues of access to care, quality of care, and underlying prevalence of co-morbid conditions such as HIV/AIDS and malnutrition The number may not accurately reflect the quality of care once admitted to a treatment facility, as deaths in the community (not admitted) have been included in the calculation. But in some districts, they also report cases in the community in the total number of cases so the calculation of the institutional CFR and the comparison between institutional CFR and community CFR are not appropriate. Figure below shows the cumulative number of cholera cases, with the cumulative case-fatality rates since consistent data are collected. Figure 5: Cumulative cholera cases, with cumulative case-fatality rates. Zimbabwe, Nov 08 - Jan 09 40000 6 35000 5 30000 4 25000 Cases 20000 3 CFR 15000 2 10000 1 5000 0 0 22-Nov 29-Nov 6-Dec 13-Dec 20-Dec 27-Dec 3-Jan 10-Jan Source: Ministry of Health and Child Welfare Rapid Disease Notification System 6 On average since November 16th 2008, 587 cases per day and 31 deaths per day are reported with a peak of 819 cases per day in 21-27 Dec 2008 and 52 per day in 14-20 Dec 2008.