Female Aedes.

72 Pages·2010·1.28 MB·English

SOME BEHAVIOURAL AND ECOLOGICAL
ASPECTS OF AEDES MOSQUITOES IN RELATION
TO ARBOVIRUSES TRANSMISSION IN
KHARTOUM STATE (SUDAN)

A thesis submitted to University of Khartoum in partial fulfillment 
of the requirements of M. sc. in Medical Entomology  

                                                            By  
Hind Mohammed Mohammed Khair
B. Sc. Honours in Zoology 2004
University of Khartoum

Supervisor: Dr. El Tegani M.H. Alam

Department of Zoology,
Faculty of Science,
University of Khartoum
April 2010

I
Dedication
I dedicate this work to my
parents, to my brothers &
sisters, to my friends, and
the soul of grandmother
(Noor)

Hind
II
ACKNOWLEDGEMENTS

Iam extremely grateful to my supervisors: Dr. Fathi M.A. El Rabaa, Dr.
El Tegani M.H. Alam and Dr. El Fatih Malik for their kind help and
guidance and for reading the draft manuscript…..
Grateful thanks are due to Dr. El Fatih Malik for funding this
research…. Also grateful thanks are due to Dr. Mubark ElKarsani and
Miss. Rehab El Ageb for carrying out the molecular tests….. Thanks are
due to Dr. Somaya Abu Kashawa for preserving the specimens…..
Thanks are also extended to Mr. Osama Seed Ahmed for his guidance,
financial support and data supply and to Mr. Fayz Taj El Sir for data
supply…. I would also like to thank the staff and head Department of
Geology, Faculty of science, University of Khartoum for their assistance in
soil analysis and also the staff and head Department of Zoology for their
support and adoption of this research…..
Thanks are also extended to Miss. Arwa Hassan for provision of
laboratory equipment…..
At last but not least my thanks and appreciation are extended to my
colleagues: Raiyed M. Awad, Al Abbas M.Abbas, Ahmed Siddig,
Mohamed El Maki, Basheer Hamid and Taha Mansoor for joining the
field trips…..
III
ﺔﺻﻼﺨﻟا

ﺔﻳﻻو ﻲﻓ ﺔﻤﻬﻤﻟا ﺰﻳﺪﻳﻻا ضﻮﻌﺑ عاﻮﻧأ كﻮﻠﺳو ﺔﺌﻴﺑ ﻲﻠﻋ فﺮﻌﺘﻠﻟ ﺔﺳارﺪﻟا ﻩﺬه ﺖﻳﺮﺟا
.ﻞﺟرﻷا تﺎﻴﻠﺼﻔﻣ ﺔﻄﺳاﻮﺑ ﺔﻟﻮﻘﻨﻤﻟا ﺔﻴﺳوﺮﻴﻔﻟا ضاﺮﻣﻸﻟ ﺔﻠﻤﺘﺤﻤﻟا ﺔﺌﺑوﻷا ﺮﻄﺨﺑ ﺆﺒﻨﺘﻠﻟ مﻮﻃﺮﺨﻟا
ﺔﻳﻻو ﻰﻓ ﺮﺒﻤﺘﺒﺳ ﺮﻬﺷ ﺔﻳاﺪﺑ ﻰﺘﺣو ﻮﻴﻟﻮﻳ ﺮﻬﺷ ﺔﻳﺎﻬﻧ ﻦﻴﺑ رﺎﻄﻣﻷا ﻢﺳﻮﻣ ﻲﻓ ﺔﻴﺌﻴﺒﻟا تﺎﺣﻮﺴﻤﻟا ﺖﻳﺮﺟا
Aedes :ﺎﻤهو ﻂﻘﻓ ﺎﺑﻮﺳ ﻪﻘﻄﻨﻣ ﻲﻓ ﺰﻳﺪﻳﻻا ضﻮﻌﺑ ﻦﻣ نﺎﻋﻮﻧ ﺪﺟو .ﺎﺑﻮﺳ ﺔﻘﻄﻨﻤﺑ مﻮﻃﺮﺨﻟا
ﺪﻟاﻮﺗ ﻦآﺎﻣاو كﻮﻠﺳو ﺔﻓﺎﺜآ ﻲﻓ تﺎﻓﻼﺘﺧإ دﻮﺟو ﺔﺳارﺪﻟا تﺮﻬﻇأ . Aedes vittatusو vexans
.ﺔﺳارﺪﻟا ﻊﻗﻮﻣ ﻲﻓ ضﻮﻌﺒﻟا
لﻮﻃا ةﺮﺘﻔﻟ ﺶﻴﻌﺗ ﺔﺳارﺪﻟا ﺎﻬﻴﻠﻋ ﺖﻳﺮﺟا ﻰﺘﻟا ضﻮﻌﺒﻟا عاﻮﻧأ نا ﺔﻴﻠﻤﻌﻤﻟا تﺎﺳارﺪﻟا ﺖﺤﺿوأ
.ضﻮﻌﺒﻟا ءﺎﻘﺑ لﺪﻌﻣو ﺔﻳﺬﻐﺘﻟا عﻮﻧ ﻦﻴﺑ يﻮﻗ طﺎﺒﺗرا ﺪﺟﻮﻳو ضﻮﻌﺒﻟا ﻞﺧاد سوﺮﻴﻔﻟا ﺔﻧﺎﻀﺣ ةﺮﺘﻓ ﻦﻣ
ﻲﻟا 2008 ﺮﺒﻤﻓﻮﻧ ﻦﻴﺑ ﻞﺟرﻻا تﺎﻴﻠﺼﻔﻣ ﺔﻄﺳاﻮﺑ ﺔﻟﻮﻘﻨﻤﻟا تﺎﺳوﺮﻴﻔﻟا تﺎﺣﻮﺴﻣ ﺖﻳﺮﺟأ
يداﻮﻟا ﻲﻤﺣو ﻚﻨﻀﻟا ﻲﻤﺣ ﻲﺳوﺮﻴﻓ دﻮﺟو ﻦﻋ ﻒﺸﻜﻟا ﻢﺗ ﺪﻗو .مﻮﻃﺮﺨﻟا ﺔﻳﻻﻮﺑ 2009 ﺮﻳﺎﻨﻳ
ﻞآ .ﻲﻌﻗاﻮﻟا ﻦﻣﺰﻟا وذ ﻲﻠﺴﻠﺴﻟا ﻞﻋﺎﻔﺘﻟا ﺔﻴﻨﻘﺗ ماﺪﺨﺘﺳﺈﺑ مﺪﻟا ﻲﻠﻋ ﺔﻳﺬﻐﺘﻤﻟا ضﻮﻌﺒﻟا ثﺎﻧا ﻲﻓ عﺪﺼﺘﻤﻟا
يداﻮﻟا ﻲﻤﺣ سوﺮﻴﻓ ﻦﻋ ﻒﺸﻜﻟا ﻢﺗ ﺎﻤﻨﻴﺑ ﻚﻨﻀﻟا ﻲﻤﺣ سوﺮﻴﻔﻟ ﺔﻴﺒﻠﺳ ﺞﺋﺎﺘﻧ تﺮﻬﻇا تﺎﻨﻴﻌﻟا
.Aedes vexans ﻲﻓ عﺪﺼﺘﻤﻟا
ﻰﻤﺣ ﻞﻗاﻮﻧ ﺔﺤﻓﺎﻜﻤﻟ تﻼﻤﺣ ءاﺮﺟا ﺔﺳارﺪﻟا ﻩﺬه ﻦﻣ ﺎﻬﺑ جوﺮﺨﻟا ﻦﻜﻤﻳ ﻲﺘﻟا تﺎﻴﺻﻮﺘﻟا ﻢها
ﻦﻣ ىﺮﺧا عاﻮﻧا ﻞﻤﺸﺗ ﺪﻗ ﻲﺘﻟاو ضﺮﻤﻟا ﻞﻗاﻮﻧ دﻮﺟو ﻦﻋ ﻲﺼﻘﺘﻟاو ﺎﺑﻮﺳ ﺔﻘﻄﻨﻣ ﻲﻓ عﺪﺼﺘﻤﻟا يداﻮﻟا
.ضﻮﻌﺒﻟا ﺮﻴﻏ ﻞﺟرﻻا تﺎﻴﻠﺼﻔﻣ
IV
ABSTRACT 
The  ecology  and  behavior  of  Aedes  species  in  Khartoum  State  were 
investigated to forecast the risk of possible outbreaks in the State during 
the future. Ecological surveys have been conducted during the rainy season 
between the end of July to the beginning of September in Khartoum State 
at  Soba.  Two  species  of  Aedes  mosquitoes  were  found  namely  Aedes 
vittatus  and  Aedes  vexans.  Differences  in  densities,  breeding  sites  and 
behavior were recorded. 
The productivity of breeding sites Aedes mosquitoes was very low because 
diapausing larvae of Ae. vexans usually emerged after rainfall or increase of 
water level and adult emerged 6‐14 days a(cid:332)er complete water removal. 
The results showed very high correlation between the nutrition and the 
number of female Aedes mosquitoes that survived beyond fifteen days. 
Aedes  mosquitoes  survived  under  laboratory  conditions  beyond  the 
incubation period of arboviruses in the mosquitoes.  
Arboviral  surveys  have  been  conducted  between  November  2008,  to 
January 2009, in Khartoum State.  Dengue Fever Virus and Rift Valley Fever 
Virus were detected in a pool of fed female Aedes mosquitoes using Real‐
Time Polymerase Chain Reaction technique.  Aedes vexans pool showed 
negative results for DFV but were positive for RVFV. 
According  to  findings  of  this  study,  vector  control  campaigns  are 
recommended to be carried out at Soba and the areas within the flight 
range of these mosquitoes. Surveillance for vectors can be either for virus 
isolation or for recording the other populations of other biting arthropods. 
V
CONTENTS
Subjects Pag
e
ACKNOWLEDGEMENTS…………………………………………… I
DEDICATION……………………………………………………….... II
ARABIC ABSTRACT…………………………………………………. III
ABSTRACT…………………………………………………………… IV
CONTENTS…………………………………………………………... V
LIST OF TABLES……………………………………………………. VIII
LIST OF FIGURES…………………………………………………… IX
LIST OF PLATES……………………………………………………… X
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CHAPTER ONE
1. INTRODUCTION……………………………………………………… 1
1.2. Objectives of the Study……………………………………………......... 3
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CHAPTER TWO
2. LITERATURE REVIEW…………………………………………… 4
2.1 Mosquitoes……………………………………………………………. 4
2.1.1 Aedes mosquitoes.................................................................................. 4
2.1.2 Aedes aegypti Linnaeus....................................................................... 5
2.1.3 Aedes vittatus Bigot........................................................................... 5
2.1.5 Blood Feeding Behaviour of Aedes Mosquitoes………..…………... 5
2.1.6 Oviposition Behavuior of Mosquitoes…………………………….. 6
2.1.7 Productivity of Larval Habitat……………………………………. 8
2.2 Arboviruses…………………………………………………………… 9
2.2.1 Rift Valley Fever Virus (RVFV)…………………………………….. 11
VI
2.2.1.1 Rift Valley Fever in Sudan…………………………………………... 14
2.2.2 Dengue Fever Viruses (DFV)……………………………..………... 14
2.2.2.1 Dengue Fever in Sudan……………………………………..……....  17
2.3 Real Time PCR Technique………………………………….……... 18
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CHAPTER THREE
3 MATERIALS AND METHODS……………………………….…… 19
3.1 Study Areas……………………………………………………..…….. 19
3.1.1 Khartoum State………………………………………………..…….... 19
3.1.2 Soba…………………………………………………………….….…….. 26
3.2 Adult Mosquito Collection…………………………………….………. 20
3.2.1 Indoors and Outdoors Aspiration…………………………..….……… 20
3.3 Identification of Mosquito Species……………………………….……. 23
3.4 Estimation of Mosquito Emergence Rate…………………….……….. 27
3.5 Estimation of the Density of Mosquito Larvae……………….………. 27
3.6 Estimation of Survival Rate of Adult Mosquitoes…………….……… 30
3.7 Detection of Viruses inside Mosquitoes…….......................................... 32
3.7.1 Grading of Adult Female Mosquitoes………………………….……… 32
3.7.2 Extraction of Virus RNA. …………………………………………….. 32
3.7.3 Preparation for PCR and Amplification for the Detection of DEN
Viruses. ………………………………………………………………… 33
3.7.4 Preparation for the Master Mix. …………………………….……….. 33
3.7.5 Steps of Detection of DEN 1-4 Viruses………………………….….…. 34
3.7.6 Preparation for PCR and Amplification for the Detection of RVF
Viruses. …………………………………………………………..…… 34
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CHAPTER FOUR
4 RESULTS…………………………………………………………..….. 37
4.1 Identification of Larvae………………………………………….…….. 37
4.2 Productivity of Breeding Sites and Emerged Mosquitoes from
VII
Emergance Trap…………………………………………………….….. 37
4.3 The Effect of Food on the Survival Rate of Adult Mosquitoes…….. 39
4.3.1 The Effect of Blood Feeding on the Survival of Adult Female Aedes 39
4.1.2 The Effect of Feeding on Sucrose Solution on the Survival of Adult
Female Aedes ……………………...……………………….…………… 39
4.3.3 The Effect of Starvation on the Survival of Adult Female Aedes…... 39
4.9 Mosquito Collections and Virus Isolations………………..………… 44
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CHAPTER FIVE
5 DISCUSSION……………………………………………………..…….. 49
.
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6 RECOMMENDATIONS………………………………………………. 54
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7 REFRENCES…………………………………………………………... 55

VIII
LIST OF TABLES 
Table Page
Table. 1: Comparison between Numbers of Emerged Males and
Females……………………………….............................….
38
Table. 2: Survival Rate of Female Aedes Mosquitoes Fed on
Blood…………………………………………………………
41
Table. 3: Survival Rate of Female Aedes from Soba Fed on Sucrose
Solution………………………………………………………….
42
Table. 4: The Effect of the Starvation on the Survival of Adult
Females of Aedes ..................…………………………………...
43

IX
LIST OF FIGURES 
Figure Page
Figure 1:  Numbers of Emerged Males and Females Aedes from
Emergence trap………………………........................……… 
38
Figure 2: Survival Rate of Female Aedes Fed on Blood…………........ 41
Figure 3: Survival Rate of Female Aedes Mosquitoes Fed on Sucrose
Solution………………………………………………………..
42
Figure 4: The Effect of the Starvation on the Survival of Adult
Females of Aedes..................…………………………………
43
Figure 5: Real-time PCR for Detection of DF/DHF Viruses inside
Pools of Female Mosquitoes………………………………….
46
Figure 6: Real-time PCR for the Detection of RVF Virus inside Pools
of Female Mosquitoes………………………………………...
46

X