Super-Sterile Aedes aegypti for Controlling
Dengue and Zika Diseases
Presenter: Dr. Pattamaporn Kittayapong
Centre of Excellence for Vectors and Vector-Borne Diseases Faculty of Science, Mahidol University ar Salaya, Nakhon Pathom 73170, Thailand
Dengue and Zika Situation
• -Proteobacteria • Endosymbiont in arthropods • Potential use as biological
control of disease vectors
Cellular examination of the bacteria Wolbachia on reproductive mechanisms of the fruit fly D. melanogaster. In this image, DNA is labeled green, and Wolbachia are red. Photo credit to UCSC
Alternative Vector Control Using Wolbachia
Introduction to Wolbachia:
Wolbachia Influence on Host Reproduction
Ref.: Werren, J. H., Baldo, L., & Clark, M. E. (2008). Wolbachia: master manipulators of invertebrate biology. Nature Reviews Microbiology, 6(10), 741–751. https://doi.org/10.1038/nrmicro1969
Aedes aegypti Wolbachia-free, major vector of dengue viruses
Aedes albopictus Wolbachia-infected; minor vector of dengue viruses
Wolbachia in Mosquitoes
Unique Characteristics of Wolbachia
Ref.: McGraw, E. A., & O’Neill, S. L. (2013). Beyond insecticides: new thinking on an ancient problem. Nature Reviews Microbiology, 11(3), 181–193. https://doi.org/10.1038/nrmicro2968
Wolbachia as Population Replacement
Release both males and females
Wolbachia as Population Suppression
Super-Sterile Mosquitoes
Wild Mosquitoes
Release Period
Suppression of Wild Mosquito Population Wild Mosquito Population Release of Super-Sterile Mosquitoes
Release only males
Wolbachia-induced incompatibility Sterile Insect Technique Super-sterile male
Super-Sterile Mosquito Concept
5. Blood-feeding of mated Wolbachia-transinfected Aedes aegypti females
3. Direct microinjection of Wolbachia into Aedes aegypti females
2. Extraction of Wolbachia from ovaries of Aedes albopictus females
6. Egg laying and rearing progeny of Wolbachia-transinfected Aedes aegypti females 1. Remove ovaries from Aedes albopictus females
collected from rubber plantations
4. Mating of Wolbachia–transinfected Aedes aegypti females with normal males in a mosquito cage
Step 1: Development of Wolbachia-Transinfected Aedes aegypti
We have developed Wolbachia-super-infected Aedes aegypti lines for the pilot
Aedes vector suppression trial in Thailand.
Thai Wolbachia-Transinfected Aedes aegypti line was successfully established
1. Select only male pupae from the rearing colony using glass separators
5. Mating competitiveness test in irradiated Aedes aegypti males
3. Test of sterility in irradiated Aedes aegypti males
2. sterilization of male pupae using radiation (70 Gy for 45 sec. per 500 pupae)
4. Test of sterility in irradiated Aedes aegypti females
Step 2: Sterilization of Wolbachia-Transinfected Aedes aegypti using Radiation
Source: Kittayapong et al., unpublished data
IRRADIATED FEMALES IRRADIATED MALES
92% Sterile
(7.84% hatched eggs)
Mating with normal females
100% Sterile
(0% hatched eggs)
Mating with normal males
100% Sterile
(0% hatched eggs)
100% Sterile
(0% hatched eggs)
50 Gy 70 Gy 50 Gy 70 Gy
(n=18) (n=27) (n=27) (n=27)
Completed Sterility of Wolbachia-Transinfected Aedes aegypti
From Laboratory to Field Application
Plaeng Yao District, Chachoengsao Province, Eastern Thailand
12 km
500-800 m
= Sampling houses = Houses located in study areas
GIS Map of Pilot Release Site
Several health education meetings and focus group discussion were organized.
Community Engagement Activities
A total numbers of 64 news articles, 20 TV programs and 3 radio interviews were released to inform and educate the public.
Public Engagement Through Media
School activities and TV interview about the pilot project on the ASEAN Dengue Day
Pilot Project Opening Ceremony on the ASEAN Dengue Day
First Release of Super-Sterile Males on the ASEAN Dengue Day
The opening ceremony of the pilot project was was attended by representatives from 15 countries.
100-200 super-sterile males were released weekly, both indoor and outdoor, in each household using health volunteers
Field Release of Super-Sterile Aedes aegypti Males
Percentage of Aedes aegypti females per house collected by using MosVac aspirators and MosHouse traps
No. released mosquitoes
Zero female
Source: Kittayapong et al., unpublished data
No. released mosquitoes
Significant Reduction of Aedes aegypti Females per House
4.17
3.75
2.27
3.13 2.50
2.78 2.86
0.00
1.67 2.00
0.83 0.00
42,000
63,880
91,000
79,100 87,000
127,000
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
0.00
1.00
2.00
3.00
4.00
5.00
6.00
Jul-2016 Aug-2016 Sep-2016 Oct-2016 Nov-2016 Dec-2016
No
. re
leas
ed
mo
squ
ito
es
Pe
rce
nta
ge (
%)
Collection time (Month)
%Female_Control %Female_Treatment No.released mosquitoes
1.55 1.33 1.40 1.43 1.88 1.69
0.27 0.13 0.14 0.22 0.29 0.22
42,000
63,880
91,000
79,100 87,000
127,000
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
0.00
1.00
2.00
3.00
4.00
5.00
Jul-2016 Aug-2016 Sep-2016 Oct-2016 Nov-2016 Dec-2016
No
. re
leas
ed
mo
squ
ito
es
Pe
rce
nta
ge (
%)
Collection time (Month)
%Female_Control %Female_Treatment No.released mosquitoes
90
11
0
11
0
11
0
11
8
17
0
16
0
19
0
18
0
19
0
18
0
18
0
18
0
17
5
24
6
15
0
22
0
18
0
22
0
22
0
25
0
25
0
25
0
25
0
-40
0
40
80
120
160
200
240
280
-0.20
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
W0 W1 W2 W3 W4 W5 W6 W7 W8 W9 W10 W11 W12 W13 W14 W15 W16 W17 W18 W19 W20 W21 W22 W23 W24
Rai
nfa
ll (x
0.1
mm
)/
No
.re
leas
ed
mo
squ
ito
es
(x1
02 )
Egg
hat
ch r
ate
Collection time (Week)
No.released mosquitoes Rainfall Egg Hatch Rate_Treatment Egg Hatch Rate_Buffer Zone Egg Hatch Rate_Control
Release super-sterile male mosquitoes
Egg hatch rate in treatment, control and buffer zone in Plaeng Yao District, Chachoengsao Province, Thailand
Rainfall
No. released mosquitoes
Source: Kittayapong et al., unpublished data
Sterility Observed by Significant Reduction of Egg Hatch Rate
First to proof-of-concept to suppress natural populations of Aedes aegypti using super-sterile males
Simple and environmental friendly method and could combine with any conventional vector control methods and vaccines
Further research is needed to determine whether the approach has impact on the diseases that these mosquitoes transmit
Conclusion
Koh Chang, Thailand
Siem Reap, Cambodia
Cat Ba, Vietnam
Palawan, Philippines
Bali, Indonesia
Vqng Vieng, Lao PDR
Langkawi, Malaysia
Palawan, Philippines
Koh Chang, Thailand
Vang Vieng, Lao PDR Seam Reap, Cambodia
Yangon, Myanmar
Bali, Indonesia
Langkawi, Malaysia
Cat Ba, Vietnam
Yangon, Myanmar
1. Conduct pilot project in ASEAN countries 2. Build capacity for SIT application in Asia
Way Forward: Pilot Projects in Tourist Spots in SEA
IAEA-TC Project RAS 5066
IDRC/FBLI & WHO/TDR/VES
Mahidol University Research Grant
THANK YOU FOR YOUR ATTENTION!
Acknowledgement
