Outbreak Investigation of

Chikungunia and other febrile Illnesses

Al-Hawtah District, Lahj Governorate

21March – 8 May, 2012

Mohamed A. A. Saleh, MD, Epidemiologist

1st Cohort - FETP

Yemeni International Congress On Infectious Disease

16-18 December 2014 , Sana'a , Yemen

• Chikungunya virus(CHIKV)is an acute viral infection

• Transmitted to humans through bite of an infected

adult female Aedes mosquito

• It is one of the epidemic vector-borne diseases,

recently re-emerged in Asian and African

• First reported case in humans was in Tanzania in

1952

Background

• In Yemen, the CHIKV was first confirmed in Al-

Hodeida governorate in late 2010

• Dengue fever which has a clinical manifestation

similar to CHIKV is also reported from Yemen

• The disease in Yemen occurs yearly in the period

between October to April

Background

• Lahj governorate experienced a major dengue

fever outbreak, notably March and May 2010

• In 18 April 2012, first three cases of CHIKV

reported from Al-Hawtah district, Lahj

governorate

• In 21 April 2012 another 20 cases were reported

• FETP residents asked to investigate the outbreak

Background

Objectives

• Confirm diagnosis of outbreaks

• Describe characteristic of cases

• Recommend control and prevention measures to

local health authorities and help implementation

Methods

• The investigation took place in Al-Hawtah

district between 21 April–8 May,2012

• Active house to house search

• Investigation form used to collect demographic

and clinical data of cases

• Line listing was developed

• 10 blood samples collected and sent to central

lab for CHIKV IgM test

Methods (cont.) Case Definition

• Suspected CHIKV Case

– Acute Febrile Illness and severe joint pain/joint swelling/joint stiffness/arthritis with one of the following sign/symptoms:

• Severe headache

• Retro-orbital pain, Muscle pain, Bone pain

• Rash

AND

– No evidence of haemorrhagic manifestation

– Normal PLT count ( > 100,000 cell/mL)

– Malaria was negative

Methods (cont.) Case Definition

• Probable CHIKV Case

– Met suspected case Chikungunya fever criteria AND one of the following

• epidemiological linkage with confirmed case

• Single positive CHIKV IgM

• Confirmed CHIKV Case

– Met suspected case Chikungunya fever criteria AND one of the following

• Identify CHIK virus by PCR and/or Viral isolation

• Two fold rising of CHIKV IgM from pair serum

Methods (cont.)

• Environmental Survey to look for breeding sites

• Entomological survey to identify the mosquito

and larvae

• Data collected was entered and analyzed using

Epi Info and excel

Results

• A total of 234 CHIK cases met the case definition

• The index case is a child of 14 year age with date

of onset 21 March, 2012

• The attack rate was 7.5 per1000 population

• No deaths occurred among the suspected cases

Fig 1. Distribution of the cases by date of onset, Lahj, Yemen 2012

0

5

10

15

20

25

19

-Mar

21

-Mar

23

-Mar

25

-Mar

27

-Mar

29

-Mar

31

-Mar

02

-Ap

r

04

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r

06

-Ap

r

08

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r

10

-Ap

r

12

-Ap

r

14

-Ap

r

16

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r

18

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r

20

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22

-Ap

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-Ap

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-Ap

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28

-Ap

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30

-Ap

r

02

-May

04

-May

06

-May

08

-May

10

-May

12

-May

No

. of

case

s

days

suspect

confirmed

1st report

Index case

house to house and school health education

indoor fogging

Fig 2. Clinical Manifestation of Chikungunya fever cases

0.4

56

64

95

100

100

0 20 40 60 80 100

bleeding

rash

joints swelling

arthralgia

headache

fever

%

Table 1: Incidence rate of cases by gender and age group

Population No.

cases Incidence per 1000

Gender

M 15876 122 8

F 15253 112 7

Age group

<10 7657 45 6

10-19 6947 44 6

20-29 6762 57 8

30-39 4235 32 8

40+ 5528 56 10

Total 31129 234 8

Fig 3: Location of Chikungunya outbreak in Lahj Governorate

Fig 4: Distribution of the cases by district

209

23

1 0

50

100

150

200

250

Al-Hawtah Tuban Almusamir

No

Cas

es

District

52%

48%

46% 48% 50% 52%

FISH MARKET

OTHER ARIA

Al-Hawtah sub district

Laboratory Results

• Three cases were CHIKV IgM positive (ELISA)

• One case was dengue IgM positive

Environmental Survey

Main container type water reservoir in the household

Entomological Survey

• In 9 sites in Al Hawtah district major containers examined for mosquito breeding site

• In all sites adult Aedes spp mosquito and mosquito larva isolated

Entomological Results Al-hawtah

District Fish

market

No. House Exam. 332 121

House Positive 132 60

House Index (%) 40% 50%

Container Exam 1699 245

Container Positive 217 68

Container Index (%) 13% 28%

Breteau Index (%) 0.20 50%

Actions taken • Integrated meeting with malaria, surveillance,

and education programs

• Met medical and paramedical staff (midwives) in MCHC and Ibn Khaldon hospital

• Met district health office and education directors in Al-Hawtah and Tuban districts

• Met the coordinators of the school health program for health education of students

• In door fogy spray for an entire Al-Hawtah District started

Meeting activities

Training Activities

Indoor fogy spray Activities

Conclusion

• Lahj outbreak is most probably due to CHIKV

• Importation of the CHIKV from another

governorate is likely e.g. fishermen from

Hodeidah

• Control of the outbreaks was successful due to

utilizing an integrated response

Limitations

• No system for integrated planning and action between

different authorities

• Poor laboratory capacities in the country

• Limited CHIKV awareness among physicians and health

workers

• Presence of vector with no intervention measures

• Lack of guideline for Dengue/CHIKV outbreak

investigations

Recommendations

• Strengthen surveillance system throughout

training, guidelines, and financial support

• Ensure intersectional cooperation between

health and other stakeholder

• Provide training for health professionals on early

detection, reporting and treatment of cases

• Increase CHIKV community awareness

Recommendations

• Improve laboratory capacity for rapid outbreak

confirmation

• Decentralize rapid response and strategies for

emergency needs to governorate

• Support school health programs in students’

education for prevention of health problems

Thanks

For Your Attention