Neisseria meningitides outbreak-Harenabuluk District, Ethiopia,2011 Yembo Gole Ejeta1, Fikire Bulti2 an Kebabe Tolasa3

1Addis Ababa University, 2Oromia Health Bureaus,3Madawalabu University

Introduction

Acknowledgements

Results

Ethiopia •Within the "meningitis belt" of Sub-Saharan Africa•Neisseria meningitides(NM) outbreaks occur yearly• with >3000 cases/year and 1.4-8.5% case fatality rate

•February 2011, a cluster of suspected meningitis cases in Harenabuluk; outside the classical meningitis belt areas

• Investigated to confirm the outbreak, identify etiologic agent, determine risk factors, and establish control measures

FETPEthiopia

Methods

• Descriptive study followed by case-control study• Introduced identical structured questionnaires to both patients and controls

•Case was a person from Harenabuluk in which NM was isolated by bacterial culture from cerebrospinal fluid between 02/02/-17/03/2011

• Selected age and sex matched controls from the neighbor of patients in the ratio of 1:1

•Adjusted odds ratios (AOR) with 95% of confidence interval (CI)

•Bivariate and multivariate analysis logistic regression • Collected laboratory specimens from 49 patients•Collected meteorological data

Results• Forty-nine cases identified in the outbreak •Median age of 12 years(range,1-60years)•Sixty (62%) were female •Observed highest attack rate ( 115/10,000) among 20-29 years old (Table1)

•This was NM outbreak caused by serogroup A•The outbreak showed two unusual characteristics•Geographical location outside the meningitis belt and high age specific AR among 20-29 years

•The occurrence of the outbreak and the identified meningitis risk factors, demonstrate that meningitis outbreaks are possible in all situations once the NM has been introduced

•Our recommendations led to start vaccination (1-30 age groups) and active surveillance with monthly community health education on meningitis and its risk factors.

Conclusions

Map 1: Site of Meningitis outbreak-Harenabuluk, Ethiopia,2011

•Laboratory analysis showed that all 49 patients were positive for NM serogroup A

•Harenabuluk District experienced extended drought

27 28 29 30 31 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Jan-11 Feb-11 Mar-11

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Date of onset

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We would like to thank the staff from the Oromia Regional Health Bureau, Madawalabu University and Bale Zone Health Department who participated in this investigation

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Table2: Bivaiate analysis results-Harenabuluk,Ethiopia,2011

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Figure 1: Meningitis case by date of onset, Harenabuluk, Ethiopia, 2011

Table1: Meningitis attack rate and case fatality rate by age group-Harenabuluk, Ethiopia,2011

Age

group

s

Populati

on

Number of cases

(%) of the total

cases (N=49)

Attack

rate /

10,000

Deaths Case

fatality

rate / 100

0-4 2317 14(29.17) 60.42 0 0

5-14 1951 18(37) 92.29 2 11.11

15-29 1210 14(27.08) 115.7 4 29

30+ 2541 3(6.25) 11.8 0 0

Total 8019 49(100) 61.1 6 8.16

Exposure Proportion exposedOdd

ratio

95%

confidence

interval

Cases (n %)Control (n

(%)

Having no ventilation 31(63.3) 10(24.4) 8.3 3.2-10.6

Attendance at Koran teaching 39(79.6) 19(38.8) 7.2 4.1-13.2

Having kitchen in the living room 42(85.7)

26(5.3)

6.3 1.9-1-12.1

Living in one house with more than 4 peoples 40(81.6) 26(53.1) 5.9 1.6-12

Sharing bedroom with more than two people 37(75.5) 19(38.8) 4.8 2.0-11.6

Exposure to dusty environment 34(69.4) 26(53.1) 4 1.1-4.5

Contact history with case-patient 30(62.5) 18(67.5) 2.7 1.2-6.3

Sharing house with animals 44(89.8) 43(87.8) 1.9 2.1-7

Travel history 14(28.6) 9(18.4) 1.8 2-4-12

• Bivariate analysis identified nine risk factors (Table2)• Four risk factors remained associated in logistic regression (Table3)

Exposure Proportion exposed

Odd

ratio

95%confide

nce interval

Cases (n %))

Control (n

(%))

Having no ventilation 31(63.3) 10(24.4) 6.7 2.7-16.6

Attendance at Koran teaching 39(79.6) 19(38.8) 6.1 2.5-15.2

Having kitchen in the living room 42(85.7)26(5.3)

5.3 2-13

Living in one house with more than 4 peoples 40(81.6) 26(53.1) 3.9 1.6-11

Table3. Logistic regression analysis results-Harenabuluk, Ethiopia, 2011