Source: Ministry of Health and Child Welfare Rapid Disease Notification System  1

Cholera in Zimbabwe: Epidemiological Bulletin Number 24 Week 21 (17 - 23 May 2009)

 

Foreword This is the 24th epidemiological bulletin to be issued since the onset of a countrywide Zimbabwe cholera epidemic first reported in August 2008. Bulletins are published weekly to coincide with the end of an epidemiological week (Sunday to Saturday). Daily cumulative caseload updates are posted on the WHO website, http://www.who.int/hac/crises/zwe/en/index.html and http://www.who.int/hac/crises/zmb/sitreps/cholera_daily_updates/en/index.html as well as on the OCHA website http://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.

Acknowledgements

We are very grateful to MoHCW District Medical Officers, Provincial Surveillance Officers, Provincial Medical Directors, Environmental Heath Officers, and MoHCW's department of surveillance, who have helped to gather and share the bulk of the information presented here. Likewise, we acknowledge agencies, including members of the Health and WASH clusters, who have kindly shared their data with our team. MoHCW has recognized and thanked the efforts made by NGOs assisting in the response and providing support to MoHCW cholera treatment centres (MoHCW – 16/12/2008). This document would not have been possible without the contributions of the WHO data management team, who are part of the C4 Cholera Command and Control Centre.

Please send any comments and feedback to the Cholera Control and Command Centre Email: Cholera_Taskforce@zw.afro.who.int.

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  2

1. Figures See also summary tables (annex 1), maps (annex 2) and graphs (annex 3) The case definition can be found in appendix 1 and detailed data by district are shown in appendix 2 Since August 2008 • 55 out of the 62 districts (89%) in the country have been affected by the ongoing cholera epidemic. • 98,343 suspected cholera cases and 4,275 deaths have been reported by 23rd May 2009 to the World

Health Organization (WHO) through the Ministry of Health and Child Welfare's (MoHCW) surveillance department.

• The crude case fatality since the outbreak started stands at 4.3% During week 21 (17th – 23rd May 2009) • 140 new suspected cases were reported compared to 201 cases during week 20 (30.3% decrease). • 2 new deaths were reported compared to 6 during week 20 (66.7% decrease). • The weekly Crude Case Fatality Rate (CFR) decreased from 3.2% to 1.4%, and all (100%) the two

reported deaths were institutional deaths. • The institutional CFR (i-CFR) increased from 0% in week 20 to 1.4% this week. At provincial level • During week 21, compared to week 20, fewer cases were reported in all the country’s provinces. • The highest (weekly) case loads were observed in Harare (62), Masvingo (22) and Manicaland (18)

provinces that accounted for 73% of all the reported cases. (See table 1) • Matabeleland North and Matabeleland South reported no cases for the seventh cumulative week.

Bulawayo also continued to report zero cases this week. • The highest weekly attack rates (cases per 100,000 inhabitants) were observed in Harare (3.3) and

Masvingo Provinces (1.6). (See table 1). The weekly attack rate for Masvingo Province went up from 0.1 in week 20 to 1.6 this week. The weekly attack rates in all the other provinces reduced significantly e.g. the attack rate for Harare decreased from 5.1 in week 20 to 3.3 this week, while that for Midlands Province went down from 4.2 in week 20 to 1.0 case per 100,000 inhabitants this week.

At district level • All the districts that reported high case loads in week 20 showed a decrease in the number of cases

reported this week with cases from Gokwe South district decreasing from 61 in week 20 to 11 cases this week, while cases in Makonde district decreased from 17 in week 20 to 7 cases this week.

• A few districts recorded an increase in the number of new cholera cases, notably Guruve district cases increased from no cases in week 20 to 11 new cases this week while cases for Masvingo district increased from 1 case in week 20 to 16 cases this week. Cases for Chimanimani and Mutare Rural districts also showed marginal increases (by 8 and 6 cases respectively).

• Though Harare City and Chitungwiza continue to report higher numbers of cases, the cholera attack rates in the two districts have continued on a downward trend, e.g. the weekly attack rates for Chitungwiza have come down from 22.4 in week 19 to 14.6 in week 20 and then 7.2 cases per 100,000 inhabitants this week. (See graph 8 in annex 3)

• The two deaths that were reported this week occurred in Chimanimani (1 death) and Gokwe South (1 death) districts, both were institutional deaths.

2. Reporting (annex 1) • The average daily reporting rates remained satisfactory throughout the week, the average weekly

reporting rate increased from 76% in week 20 to 97.7 % this week. (See graph 3 in Annex 1). Poor reporting compliance during the week was observed from Mberengwa district which failed to report on six of the seven days.

• Mudzi district de-notified 31 cases (said to have been over-reported in the previous weeks), while Chiredzi district back reported 11 cases and 9 deaths (these have been excluded from this week’s total case count, although they have been added to the cumulative figures).

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  3

3. Data interpretation The number of new cholera cases and deaths continued on a downward trend in most provinces

indicating that the outbreak is now under control. The reduction in the number of new cases reported from Gokwe South district suggests that the situation in that district is also getting under control, but follow ups and close monitoring is still required.

Districts that reported increases in the number of new cholera cases, namely Guruve, Masvingo, Chimanimani, Chiredzi and Mutare districts, also require close monitoring.

The daily reporting rates by the various districts and provinces remained satisfactory, with an average weekly reporting rate of 97%. The high reporting rate entails that the figures reported for the week reflect a more accurate picture of the cholera incidence in the country, strengthening our evidence that the epidemic is almost contained. The provinces need to be encouraged to continue sending in the reports (including the zero reports).

The bulk of the cases for this week (72.8%) were reported from Harare, Masvingo and Manicaland Provinces.

4. Response

Different organizations continue to support the various technical areas of the cholera control efforts across the country (case management, social mobilization, NFI distribution, drilling boreholes, and trucking of water). This support should be commended and encouraged. The computers donated by the WHO to the MoHCW are now being distributed to the provinces and city health departments, with each getting three desktop computers and two printers. It is hoped that the equipment will further strengthen existing surveillance systems through improved data management.

5. Recommendations

Although the epidemic appears to be coming to an end concerted efforts are still required in the identified areas (hot spots) which continue to report high numbers of cases. In the areas where cholera cases haven’t been reported for some time, the districts and provinces should be encouraged to maintain vigilance, keeping in mind that the major driver of the current epidemic (unavailability of safe water and sanitation) remains a challenge in most parts of the country.

Laboratory surveillance needs to be strengthened, so that there is systematic examination of specimens to confirm cases in new areas as well to ascertain the definite ending of the epidemic.

Partners who are assisting with the rehabilitation of water and sanitation infrastructure should be encouraged to continue with their efforts, even after the current outbreak is controlled. Improved availability of safe water and sanitation (especially in the densely populated urban areas) will reduce the risk of having another cholera outbreak in the near future.

Lastly, social mobilization should continue in all areas so that the communities remain alert to the possibility of another cholera outbreak.

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  4

Annex 1: Summary Tables Table 1: Cholera cases reported during week 21 and the cumulative cases since August 2008, including the attack rates (AR) per 100,000 inhabitants by province in Zimbabwe as of the 23rd of May 2009

 

Affected Number of cases AR per 100,000 Province Populations(a) WEEK 21 Cumulative WEEK 21 Cumulative

Bulawayo 718,278 0 445 0 61 Matabeleland North 351,260 0 1166 0 332 Matabeleland South 331,096 0 5257 0 1588

Mashonaland East 1,317,856 1 6511 0.1 494 Midlands 1,464,537 15 7086 1.0 484

Mashonaland Central 1,056,665 14 10388 1.3 983 Masvingo 1,401,672 22 11690 1.6 834

Manicaland 1,665,450 18 13583 1.1 816 Harareb 1,891,700 62 19476 3.3 1030

Mashonaland West 1,300,012 8 22741 0.6 1749 TOTAL 11,498,526 140 98,343 1.22 855

(a) Cumulative population of affected district only; (b) Includes Harare City and Chitungwiza Table 2: Proportion of deaths outside cholera treatment centers (community deaths) in Zimbabwe, from the 17th August 2008 to the 23rd of May 2009

 

Province No of deaths No of community deaths

Proportion of community death (%)

Harare city* 0 0 0 Chitungwiza 0 0 0

Bulawayo 0 0 0 Mashonaland Central 0 0 0

Mashonaland East 0 0 0 Mashonaland West 0 0 0

Manicaland 1 0 0 Masvingo 0 0 0

Matabeleland North 0 0 0 Matabeleland South 0 0 0

Midlands 1 0 0 Total 2 0 0

*for Harare, deaths outside CTC are irregularly/not reported  

 

 

 

 

 

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  5

 

Annex 2: Maps

Map 1 showing the distribution of the new cholera cases in Zimbabwe by district, Week 21 (17th to 23rd May 2009) 

            

                                                    

 

                                                                                     

Map 2 showing the distribution of cholera deaths by district, week 21 (17th to 23rd May 2009)

 

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  6

Map 3 showing the cumulative cholera attack rates by district in Zimbabwe, 17 August 2008 to 23 May 2009.  

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  7

 

Annex 3: Graphs

Graph 1 showing the trends in the number of Cholera Cases and Deaths reported weekly in Zimbabwe, 17th Aug 2008 to 23rd May 2009.

Graph 2 showing the cumulative number of reported cholera cases by province, 17th August 2008 to the 23rd May 2009.

 

 

        445

1,166

5,257

6,511

7,086

10,388

11,690

13,583

19

Bulawayo 

Mat North 

Mat South

Mash East

Midlands 

Mash Central

Masvingo 

Manicaland 

Harare

Mash West 

Prov

ince

Cas

       

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  8

 Graph 3 showing the number of new cholera cases reported in Zimbabwe each day during week 21 and the daily average reporting rates, 17th to the 23rd May 2009

Graph 4 illustrating trends of the Weekly Crude and Institutional Cholera Case Fatality Rates in Zimbabwe, 7 December 2008 to 23 May 2009.

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  9

Graph 5 showing the number of new Cholera Cases reported by each province in Zimbabwe during week 21 (17th to 23rd May 2009).

Bulawayo Mat North Mat SouthMash EastMidlands 

Mash CentralMasvingo 

Manicaland Harare

Mash West Pr

ovin

ceNumber of new cholera cases, week 21 20

Series1

Graph 6 showing the trends in the number of new cholera cases reported weekly in Chitungwiza, 17th Aug 2008 to 23rd May 2009.

0

50

100

150

200

250

300

4 6 8 0 2 4 6 8 0 2 2 4 6 8 0 2 4

Cum

ula

tive

cas

es t

o w

eek

21

Chitungwiza cholera cases

Cases Reported

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  10

Graph 7 showing the trends in the number of new cholera cases reported weekly from Harare City, 17th Aug 2008 to 23rd May 2009.

0

500

1,000

1,500

2,000

2,500

3,000Num

ber of cases rep

orted

Harare City Cholera Cases

Number of cases

Graph 8 illustrating the decline in the weekly cholera attack rates for Harare City and Chitungwiza, 1st March to 23rd May 2009.

0

10

20

30

40

50

60

70

80

Wee

kly

Atta

ck R

ate

Average Weekly AR, Weeks 10-

Chitungwiza

Harare City

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  11

                                                                                                                                                                                                                                 Graph 9 showing the number of cholera cases reported from Masvingo Province each week from the 1st of November 2008 to the 23rd May 2009.

0

500

1,000

1,500

2,000

2,500

Num

ber o

f Cases

Number of  Cases and Deaths in Masvin

Number of Cases

Number of Death

Slinw

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  12

6. Appendix 1: Case definition

The Zimbabwe cholera state definition states that "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 case is when Vibrio cholerae is isolated from any patient with diarrhoea”. This is adapted from the WHO case definition for cholera.

The inclusion of all ages in the case definition somewhat reduces specificity, that is, inclusion of more non-cholera childhood diarrhoea cases. It, however, does not impede meaningful interpretation of trends. Teams should monitor any shift in the age distribution of cases, which might indicate a changing proportion of non-cholera cases among patients seen.

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  13

7. Appendix 2: Cholera in Zimbabwe: Suspected Cases, Deaths, AR, CFR Epidemiologic Week 20 to 21, 2009  

Province District Week 20

10th – 16th May 2009 Week 21

17th – 23rd May 2009

Cases Deaths AR/100,000 CFR (%) Cases Deaths AR/100,000 CFR(%)

Chitungwiza 50 0 14.6 0 25 0 7.2 0

Harare 45 0 2.9 0 37 0 2.4 0 Harare

Total 95 0 5.1 0 62 0 3.3 0

Bulawayo Bulawayo urban 0 0 0 0 0 0 0 0

Bindura 0 0 0 0 0 0 0 0

Centenary 1 0 0.9 0 1 0 0.9 0

Guruve 0 0 0 0 11 0 3.6 0

Mazowe 0 0 0 0 0 0 0 0

Mt Darwin 2 0 0.9 0 2 0 0.9 0

Rushinga 0 0 0 0 0 0 0 0

Shamva 0 0 0 0 0 0 0 0

Mashonaland Central

Total 3 0 0.3 0 14 0 1.3 0

Chikomba 0 0 0 0 1 0 0.8 0

Goromonzi 0 0 0 0 0 0 0 0

Hwedza 0 0 0 0 0 0 0 0

Marondera 0 0 0 0 0 0 0 0

Mudzi 2 0 1.5 0 0 0 0 0

Murehwa 0 0 0 0 0 0 0 0

Mutoko 0 0 0 0 0 0 0 0

Seke 0 0 0 0 0 0 0 0

UMP 1 0 0.9 0 0 0 0 0

Mashonaland East

Total 3 0 0.2 0 1 0 0.1 0

Chegutu 0 0 0 0 0 0 0 0

Hurungwe 0 0 0 0 0 0 0 0

Kadoma 0 0 0 0 0 0 0 0

Kariba Mahombekombe 0 0 0 0 0 0 0 0

Kariba Rural 0 0 0 0 0 0 0 0

Makonde 17 0 9.2 0 7 0 3.8 0

Mashonaland West

Zvimba 0 0 0 0 1 0 0.4 0

Source: Ministry of Health and Child Welfare Rapid Disease Notification System  14

Total 17 0 1.3 0 8 0 0.6 0

Buhera 0 0 0 0 0 0 0 0

Chimanimani 0 0 0 0 8 1 6.5 12.5

Chipinge 16 0 5.3 0 0 0 0 0

Makoni 0 0 0.3 0 3 0 1.0 0

Mutare 1 1 0.4 100 6 0 2.5 0

Mutare City 3 0 1.7 0 1 0 0.6 0

Mutasa 0 0 0 0 0 0 0 0

Nyanga 0 0 0 0 0 0 0 0

Manicaland

Total 20 1 1.2 5 18 1 1.1 5.6

Binga 0 0 0 0 0 0 0 0

Lupane 0 0 0 0 0 0 0 0

Nkayi 0 0 0 0 0 0 0 0 Matebeleland North

Total 0 0 0 0 0 0 0 0

Beitbridge 0 0 0 0 0 0 0 0

Gwanda 0 0 0 0 0 0 0 0

Umzingwane 0 0 0 0 0 0 0 0

Plumtree 0 0 0 0 0 0 0 0

Matabeleland South

Total 0 0 0 0 0 0 0 0

Bikita 0 0 0 0 0 0 0 0

Chiredzi 0 0 0 0 6 0 2.4 0

Chivi 0 0 0 0 0 0 0 0

Gutu 0 0 0 0 0 0 0 0

Masvingo 1 0 0.4 0 16 0 5.7 0

Mwenezi 1 0 0.7 0 0 0 0 0

Zaka 0 0 0 0 0 0 0 0

Masvingo

Total 2 0 0.1 0 22 0 1.6 0

Chirumhanzu 0 0 0 0 0 0 0 0

Gokwe North 0 0 0 0 4 0 1.8 0

Gokwe South 61 5 19.6 8.2 11 1 3.5 9.1

Gweru City (Mkoba) 0 0 0 0 0 0 0 0

Kwekwe 0 0 0 0 0 0 0 0

Mberengwa 0 0 0 0 0 0 0 0

Zvishavane 0 0 0 0 0 0 0 0

Midlands

Total 61 5 4.2 8.2 15 1 1.0 6.7

GRAND TOTAL

201 6 1.8 3.0 140 2 1.22 1.4