View Full Test Report

Method for the Reduction of mosquitoes
vectors of West Nile virus and Dengue fever
Gerardo Ulíbarri, PhD
Sept. 2013
What are mosquitoes good for?
• Food for other animals/insects
• As Larva or adulto mosquitoe
• Good virus/parasite wells
• Vectors of viruses/ parasites
Some of the illnesses that
mosquitoes can transmit to humans
• Yellow Fever (Aedes aegypti)
• Dengue Fever (Aedes albopictus/aegypti)
• Malaria (Anopheles gambiae)
• West Nile virus (Culex pipiens)
• Lymphatic filariasis (elephantiasis)
• River blindness
Some of the illnesses that
mosquitoes can transmit to animals
Encefalitis Equina del Este (Aedes vexans)
Encefalitis Equina del Oeste (Culex/Culiseta)
Malaria aviar (Culex quinquefasciatus)
Virus del Oeste del Nilo (Culex spp)
3561 different species of mosquitoes around the world
http://www.mosquitocatalog.org/default.aspx
 México 224
 Continental United States 166
 Canada 74
Walter Reed Biosystematics Unit (WRBU), Division of
Entomology, Walter Reed Army Institute of Research
(WRAIR), Silver Spring, Maryland, USA.
3561 different species of mosquitoes around the world
 Anopheles spp.
 Aedes / Ochlerotatus spp.
 Culex spp.
478
206
789
México
 Anopheles spp.
 Aedes / Ochlerotatus spp.
 Culex spp.
26
25
58
The mosquito reproductive cycle
http://commons.wikimedia.org/wiki/File:Culex_mosquito_life_cycle_es.svg
•
Mosquitoes undergo
metamorphological
changes
•
Only females need
blood to develop
their eggs
•
Three days after
biting, the female can
lay from 3-300 eggs
•
In 48 hours larva can
emerge from the eggs
•
Larva needs air to
survive
•
Adults emerge after 2
days in pupa state
El ciclo de reproducción del mosco
http://commons.wikimedia.org/wiki/File:Culex_mosquito_life_cycle_es.svg
•
It needs from 4-6
days to go from egg
to adult, dependent
on Temperature
•
Larva can survive in
only 1 cm of water
•
Eggs of some species
can survive for years
in drought
•
Some eggs can
support very low
temperatures
•
There are mosquitoes
that prefer humans
(antropophilic) to
other animals for
blood.
Methods used to control or reduce mosquitoes
1) Biological
2) Physical
3) Chemical
9
Methods used to control or reduce mosquitoes
1) Biological:
Uses natural predators of the mosquito

Mosquito Fish (Gambusia affinis)

Bacteria: Bacillus thurigiensis israelensis (Bti)

Bacillus sphaericus

Dragon Fly

Genetically modified mosquitoes
Life history variation of invasive mosquitofish (Gambusia holbrooki) along a salinity gradient. C Alcaraz, E Garcıa-Berthou. BIOLOGICAL CONSERVATION 139 (2007) 83–92.
Bacillus sphaericus as a mosquito pathogen: properties of the organism and its toxins. P Baumann, M A Clark, L Baumann, and A H Broadwell. Microbiol Rev. 1991 September; 55(3): 425–436.
10
Insects and animals that feed on mosquitoes
11
Methods used to control or reduce mosquitoes
1) Physical:

Layer of oil in water surface

Water container coverts

Adult Traps

Carbon dioxide, water steam and heat

Photonic fence (micro laser)

Lethal Ovitraps (use insecticide)

Bed nets

Clean Patio
12
http://www.educasocial.com.uy/demo/mod/file/download.php?file_guid=1039
13
Methods used to control or reduce mosquitoes
1) Chemistry: pesticides




Organochlorinated
Organo-phosphates
Carbamates
Piretotroids
Neurotoxicity: prolonged activation of
Sodium channels causing depolarization
sustained depolarization in neurones,
producing muscular spams.
Teratogenicity: abnormal fetus development
DDT: Inhibits shell formation in bird eggs.
-DDT
dichlorodiphenyltrichloroethane Carbaryl
Malathion
Permetrine
14
Methods used to monitor the presence of
mosquitoes vectors of disease
How is it determined when is the right moment
to spray pesticides
15
CDC Light traps
(Centers for Disease Control and Prevention)
(www.cdc.gov/)
CDC Light Traps
•Traps only adult
mosquites and other inects
•Mainly females
•Uses light and CO2 to
attract the insects
•Problems
•There is no selectivity
•High cost of operation
•~$15 dollars per night /per
16
trap
Larval deep
www.keysmosquito.org/larvicides_treatments.html
•Problems
•Every pond ahs to be
verified independently
www.ocvcd.org/mosquitoes2.php
•High operative cost
(labor)
17
Human Bait
news.cals.wisc.edu/newsDisplay.asp?id=1771
...
•Problems
•Only anthropophagic
mosquitoes are trapped
www.trevorwilliams.info/Mosquitoes_blackflies
•Dilemma with the ethic of
using humans as bait
18
Gravid y Ovitraps
www.ocvcd.org/mosquitoes2.php
•Problems
•Very selective. Attraction
depends on solution used
•Only attracts gravid
females
www.fehd.gov.hk/.../2002/calendar-photo5.html
•Problems
•Very selective, Attraction depends
on the solution used
19
•Only collects eggs/larvae
West Nile virus-The North America Problem
20
Culex spp – Main vectors of the West Nile virus
http://www.madrimasd.org/blogs/virusemergentes/2012/10/el-avance-de-los-flavivirus-emergentes-y-reemergentes/
21
22
www.usgs.gov/125/articles/images/wnv_map.jpg
http://www.cdc.gov/westnile/resources/pdfs/cummulative/99_2012_CasesAndDeathsClinicalPresentationHumanCases.pdf
West Nile virus infections
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
US
62
21
66 4156 9862 2539 3000 4269 3630 1356 720 1021 712 1590
Canada
414 1481 25 225 151 2215 36
13
5
101 62
24
Mosquito Behaviour
Mosquito behaviour is mainly influenced by a series of olfactory
stimuli.
25
W Takken, and B G Knols. (1999). Annu. Rev. Entomol. 44, 131-157.
Odorant Binding Proteins (OBP)
• Water-soluble globular
proteins with exposed
hydrophilic groups
• Located in the lymphatic
space surrounding the
sensory neurons
• Transport the hydrophobic
odorant molecules through
the aqueous lymph to the
odorant receptors.
Proteina tipo-G acoplada a receptores (G-PCR)
• Seven transmembrane
helical proteins
• Residing on the dendritic
membrane of the olfactory
sensory neurons
• Activated when bound to
OBP which in turn activates
the olfaction signal
Receptor del olor 7 (Or‐7)
• Identificado y caracterizado en varias especies de
mosquitos:
Anopheles gambiae (AgOr7),
Aedes aegypti (AaOr7),
Culex quinquefasciatus (CqOr7)
• CqOr7 fue identificado en Marzo de 2006 por el
equipo del Dr. Zwiebel, el mismo grupo que
secuencio el genoma del mosco Anofeles. (Xia and
Zwiebel, 2006).
Xia, Y. & Zwiebel, L. J. Insect Biochem Mol Biol 36, 169‐76 (2006)
28
Modified Ovitrap
Bacteral fermentation
H 2O
http://www.youtube.com/watch?v=VwIqGbhq4T8
Mosquito laying eggs, eggs hatching (#311)
nature1upclose·
29
Culex egg rafts on modified ovitrap
30
Modified Ovitrap
Egg Raft
www.qac.org
Pupa
Larva
31
Field studies
We have found up to 89 rafts in one night study
(~26,000 eggs)
What is the secret?
Initially, the mosquitoes are attracted to the ovitrap by the natural concoction.
The apical part (superior) of each egg contains a chemical compound which
serves a signaling to oviposition to new comers (attractant) for the Culex spp.
34
34
S
u
d
b
u
r
y
O
v
i
t
r
a
p
Day
Temperature (oC)
Relative Humidity (%)
# of Egg Raft / Day
Max.
Mean
Min.
1
24.4
18.45
12.5
87.42
41
2
27.9
22.15
16.4
73.96
146
3
30.3
24
17.7
70.88
52
4
31.6
25.05
18.5
59.54
67
5
31.4
24.85
18.3
66.21
33
6
31.4
25.05
18.7
62.08
30
14
29.4
22.9
16.4
90.25
47
15
22.8
19.7
16.6
70.58
30
16
25.5
21.7
17.9
91.38
103
17
29.3
23.2
17.1
77.29
116
18
21.7
18.3
14.9
70.21
165
19
22.2
17.85
13.5
80.33
65
20
27.5
22.8
18.1
89.88
52
21
33.2
27.2
21.2
81.38
119
Total
2007
Average
91
S
u
d
b
u
r
y
Average eggs in a raft (Sudbury)
= 270 (Culex pipiens/restuans)
O
v
i
t
r
a
p
An average of 25,804 eggs per day
In the first field study 2007 rafts were
collected in 21 days = 541,890 eggs
Using only 3 modified ovitraps
2007 Field study
150 modified ovitraps were used in 12 different sites
Field study was run from 1st of June to the 30 of August
• 11196 rafts were colected in 90 days
• 870 rafts per week
• 3,358,800 eggs destroyed!
37
If one estiamtes a 20% of the eggs hatching producing
females capable of laying eggs;
In the first two weeks they will produce:
(870)(2)(270)=469,800 x 0.2= 93,960 females
If each lays eggs once; 25,369,200 eggs potentially
produced
In Only Two weeks
But, does this really cause a
reduction of mosquitoes?
CDC Light Trap
44
N
Artificial Breeding
Ovitrampa
modificada
Pools
1
4
7
4
10
2
5
4
4
8
11
3
4
6
9
4
12
4
39
40
Comparative study between a test site using modified ovitraps and two control sites without ovitraps, in Sudbury
100
Adult Culex mosquitoes
per trapping event
90
80
70
60
50
40
30
20
10
0
1
2
3
4
5
6
7
8
9
10
Sudbury control
1
9
4
24
10
78
74
89
52
44
Long Lake
2
1
3
5
1
2
2
0
0
0
Collection of adult mosquitoes was done using the standard CDC light traps on each site
41
O
O
H
O
erythro‐6‐Acetoxy‐5‐hexadecanolide
Attractiveness
Ovitrap
B.R. Laurence and J.A. Pickett J. Chem. Soc, Chem. Commun. 1982 p. 59-60
Dump
solution
fehd.gov.hk
Rafts
Bacterial
fermentation
Time
ABP
Attractiveness
O
Filter
solution
Rafts
Bacterial
fermentation
Time
42
Do the modified ovitraps work as well
with other species?
A female mosquito (Anopheles gambiae) feeding
Photo courtesy Centers for Disease Control & Prevention,
photographer Jim Gathany
(http://home.howstuffworks.com/mosquito-magnet1.htm)
Aedes aegypti
(http://en.wikipedia.org/wiki/Aedes)
Dengue Regional Information: Number of Cases-2013
http://www.paho.org/hq/index.php?option=com_content&view=article&id=264&Itemid=363&lang=en
Estado del estudio en Pentatlán, Gro, México.
Inicio : primera semana de Febrero hasta Ultima semana de Agosto 2013
(30 semanas de estudio)
Modified Ovitrampa
Aedes eggs on a paper pellon
Photo of Aedes mosquitoe eggs on paper pellon
Semana
Atrayente
Control
Huevo destruido
1
4575
1048
5623
17
3763
723
4486
2
6643
481
7124
18
3005
621
3626
3
7076
785
7861
19
2695
690
3385
4
6515
665
7180
20
3552
713
4265
5
5617
776
6393
21
2802
624
3426
6
4502
896
5398
22
4799
806
5605
9000
7
4001
503
4504
23
4134
820
4954
8
5744
602
6346
24
4640
876
5516
9
8870
704
9574
25
4921
910
5831
11
4769
494
5263
27
4599
1094
5693
12
2622
368
2990
28
4184
808
4992
13
2425
553
2978
29
4763
855
5618
14
3887
668
4555
30
3959
889
4848
15
4653
430
5083
16
4664
606
5270
31
7304
1013
8317
32
7119
1220
8339
Total Atractant= 40 ovitrampas
Control = 10 ovitrampas
Atrayente
Control
8000
Total eggs collected
10
7570
1180
8750
26
5217
1151
6368
155,589
24,572
180,161
7000
6000
5000
4000
3000
2000
1000
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Week
Total number of Aedes mosquito eggs collected during the field study in Petatlán, Gro
31
Semana
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Atrayente/ovitrampa
131
190
202
186
160
129
108
144
222
189
119
66
61
97
116
117
Control/ovitrampa
70
32
52
44
52
60
75
105
70
118
49
37
55
67
43
61
Semana
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Atrayente/ovitrampa
94
75
67
89
70
120
103
116
123
130
115
105
119
99
183
178
Control/ovitrampa
72
62
69
71
62
81
82
88
91
115
109
81
86
89
101
122
Average eggs collected per ovirap
during the study (32 weeks)
250
Control/ovitrap
Attractant 126
Eggs collected per ovitrap
Attractant/ovitrap
Control 74
200
150
100
50
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Week
Total number of Aedes mosquito eggs collected during the field study in Petatlán, Gro
30
31
Semana/mes
Control / ovitrampa
En lugar del estudio
Atrayente / ovitrampa
En lugar ajeno al
estudio
Tercera Cuarta Primera Segunda Tercera
Junio Junio
Julio
Julio
Julio
18
3
0
20
Cuarta
Julio
Primera
Agosto
Segunda
Agosto
Tercera
Agosto
Cuarta
Agosto
Quinta
Agosto
13
17
11
2
8
18
12
29
79
104
97
71
63
37
120
Eggs collected per ovitrap
100
80
60
Control / ovitrampa en lugar del estudio
40
Atrayente / ovitrampa en lugar ajeno al estudio
20
0
Week
In Red-Egg couunt using traditional ovitraps with attractant solution (Downtown Petatlan)
In Blue-egg count using traditional ovitraps, where the modified ovitraps were located.
E
F
M
A
M
J
J
A
S
O
N
D
Atrayente/ovitrampa‐Gua
71
273
308
877
744
1135
1555
371
350
300
256
240
Control/ovitrampa‐Gua
37
109
172
276
137
245
407
164
205
206
113
103
Atrayente/ovitrampa‐Pet
709
568
596
485
231
462
568
Control/ovitrampa‐Pet
199
291
60
298
202
341
480
Atrayente/ovitrampa‐Gua
1800
Control/ovitrampa‐Gua
Atrayente/ovitrampa‐Pet
Control/ovitrampa‐Pet
1600
1400
1200
1000
800
600
400
200
0
E
F
M
A
M
J
J
A
S
O
N
D
Comparative Field studies between Petatlán, Gro, México in 2013 (Green)and a field study
in Zayaxche, Guatemala en 2010 (Blue). Observe that the count does not go up during the
rainy season in Mexico (July-Sept).
Conclusion:
• The modified ovitraps reduce the presence of the adult Culex spp. mosquito vector of the
West Nile virus in above 80% when a Culex-specific attractant solution is used. The
solution that has been used is based on a known bacterial/yeast fermentation of natural
plants and a few other attractant ingredients.
• The modified ovitraps maintain low the population of the Aedes spp. mosquitoes, vectors
of the dengue virus, even during the rainy season. The difference of adult mosquitoes
between the site with modified ovitraps and a site with no ovitraps is approx. of 60-70%
(to be verified). The attractant solution has been develop exclusively for the Aedes type
of mosquitoes.
• Modified ovitraps are being studied with different attractant solution in Zayaxche, Peten,
Guatemala against the malaria mosquitoes by the team of Jacobo Rojas y Valentín
Salazar from the local Health Unit.