Ecology of Anopheles mosquito and transmission of malaria and lymphatic filariasis in rural-suburban

settings in rice growing areas, Côte d’Ivoire www.csrs.ch Dr. Julien Zahouli 30.6.18

: Centre Suisse de Recherches Scientifiques (CSRS)

: Abidjan, Côte d’Ivoire

: Research & Development

: www.csrs.ch

Institution

City & Country

Department

Website

: ANH 2019, Hyderabad, India

: The Westin Mindspace Hotel

: Session 6B ; Ballroom 1

: June 27, 2019 ; 2:10 pm - 3:30 pm

Conference

Place

Session & Room

Date & Time

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CONTENT

Introduction

Methods

Results & Discussion

Conclusions

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019

INTRODUCTION

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3

INTRODUCTION

Côte d’Ivoire

Malaria & lymphatic filariasis (LF)

• Malaria: 450,000 deaths/y, FL: 120 million cases/y (Sub-Sahar. Africa)

Vectors

• Anopheles gambiae mosquito

Parasites

• Plasmodium falciparum

• Wuchereria bancroftiZahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019

Rice growing

An. gambiae

P. falciparum W. bancrofti

• Prevalent: Rural/suburban in rice growing areas

Diseases

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INTRODUCTION

Aim

Specific objectives

To assess the ecology of An. gambiae and the transmission of Plasmodium

and Wuchereria along a rural-urban gradient in irrigated rice growing areas

Species composition of mosquitoes & dynamics of An. gambiae;

Biting & resting behaviours of An. gambiae females;

Transmission of P. falciparum & W. bancrofti by An. gambiae.

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019

METHODS

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Adult mosquito collectionMosquito larvae collection

4

3 21

Laboratory treatment

PCR techniqueRice development cycle

METHODS

P. falciparum W. bancrofti

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019

RESULTS & DISCUSSION

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Dominance of Anopheles genus & An. gambiae species

Mosquito genera

Anopheles species

Rural Suburban

RESULTS & DISCUSSION

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019

n = 10,312

19 species

n = 7,662

14 species

n = 7,193

5 speciesn = 6,762

6 species

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0

50

100

150

200

250

Bit

e/p

erso

n/n

igh

t Rural

Suburban

9

An. gambiae abundance correlated to rice field development stage

RESULTS & DISCUSSION

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019

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10

0

2

4

6

8

10

12

14

16

No

mb

re d

e p

iqû

res/

ho

mm

e/h

eu

re (

p/h

/h)

Tranches horaires

Abokro

Extérieur

Intérieur

Global

Divergences in An. gambiae biting behaviours: Challenge for LLINs?

Endophagy = 67.4% ; Exophagy = 32.6% ; LLINs: Yes Endophagy = 49.3% ; Exophagy: 50.7% ; LLINs: no?

Rural Suburban

RESULTS & DISCUSSION

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019B

ite/

per

son

/ho

ur

(b/p

/h)

Bit

e/p

erso

n/h

ou

r (b

/p/h

)

Outdoor

Indoor

OverallOutdoor

Indoor

Overall

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0

10

20

30

40

50

60

70

80

90

100

Ta

ux

de

pa

rtu

rité

ho

rair

e (

TP

)

Tranches horaires

Abokro

Nullipares

Pares

0

10

20

30

40

50

60

70

80

90

100

Ta

ux

de

pa

rtu

rité

ho

rair

e (

TP

)

Tranches horaires

Yaokoffikro

Nullipares

Pares

Difference in the temporal distribution of An. gambiae parity rate

Parturity rate = 75.8% Parturity rate = 84.5%

Rural Suburban

RESULTS & DISCUSSION

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019

Period (hours) Period (hours)

Nulliparous

Parous

Nulliparous

Parous

Parr

ity

rate

(%

)

Pari

ty r

ate

(%

)

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P. falciparum & W. bancrofti transmitted by An. gambiae

Heterogeneous biting & resting behaviour in An. gambiae

Endophagic rate (%) Exophagic rate (%) Indoor resting density (f/b/d)

Rural 67.4 32.6 14.9

Suburban 49.3 50.7 2.9

%: percentage f/c/j: female/bedroom/day d: day

Biting rate (b/p/n) P. falciparum EIR (ib/p/n) W. Bancrofti IR (%)

Rural 92.2 6.5 0.34

Suburban 99.0 6.4 0.53

b/p/n : bite/person/night ib/p/y : infectd bite/person/night EIR: entomological inoculation rate IR: Infection rate

RESULTS & DISCUSSION

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019

CONCLUSIONS

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Conclusion, Perspectives & Recommendations

Results

An. gambiae abundanceP. falciparum

W. bancrifti

Entomo/Epidemilogy Urbanism

Health sector Urbanism sector

Integrated Vector Management (IVM)

Rice growing

Research

Intervention

Interdisciplinarity

Transdisciplinarity

Multisectoriality

Outcomes

An. gambiae behavioursUrbanisation

Agriculture

Agricult. sector

Malaria & LF ?

CONCLUSIONS

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019

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ACKNOWLEDGEMENT

Zahouli et al. 2019. Côte d’Ivoire: Anopheles, malaria, lymphatic filariasis & irrigated rice growingANH 2019