Webb County, Texas
Tick Activity during 20052008 on the Texas A&M
International Campus
(Webb County, Texas)
Amblyomma cajennense
David L. Beck ,
Josué Zavala,
Fernando Quintana
1
Presentation
Tick Life Cycle
 Tick Collection Methods
 Ticks Identified
 Correlation with Weather Activity
 Future Directions

2
Tick Life Cycle

Tick life cycle includes
three stages:
Six Legged Larval

Eight Legged Nymph

Eight Legged Adult
Image taken from:
http://www.ticktexas.org/ticks/ticks101_develop.htm
J. Zavala
3
Location of Tick Collection
Best
Figure 2:
Satellite Image of TAMIU
4
L. Nunez, D. Beck
Tick Collection Methods

A. Tick CO2 Traps

Tick traps also know as carbon dioxide
(CO2) traps are a white cloth (1m by
0.5m). About 0.25 kg of dry ice is
placed in the center of the cloth. The
trap is set for three hours.

B. Tick Walk/ Drags
C. Collection from
dogs, hogs, deer,
etc.

5
Presentation
Tick Life Cycle
 Tick Collection Methods
 Ticks Identified
 Correlation with Weather Activity
 Future Directions

6
Tick Identification
Identification of each tick
depends on the following
structures: anal groove,
palpi (mouth parts), and the
spiracle.
Each tick is individually
examined under the
microscope.
Figure 8: Tick
Identification
J. Zavala, J. Perez, S. Mata, E. Montalvo, G. Daves
7
Tick Identification: Genera

Note the difference in the anal groove of
the Ixodes and non-Ixodes
Ixodes
Non-Ixodes
Photographs taken by S.J. Upton, Kansas State University
J. Zavala
8
Tick Identification: Genus of
Non-Ixodid ticks
Amblyomma or
Aponomma
Dermacentor
Haemaphysalis
Rhipicephalus or
Boophilus
*Amblyomma eye spots present; Aponomma eye spots absent
*Rhipicephalus with festoons; Boophilus festoons absent
Photographs Taken by S.J. Upton, Kansas State University
J. Zavala
9
Ticks Identified March 2005-Nov 2008
No. Found
No. Found
1. unidentified chigger shown for size comparison.
N/A 11. Amblyomma inornatum Adult Female
16
2. unidentified flea shown for size comparison.
1775 12. Amblyomma inornatum partially engorged Adult Female
3. Amblyomma cajennense Larva
27789 13. Amblyomma maculatum Adult Male
2
4. Amblyomma cajennense full engorged Larva
14. Amblyomma maculatum Adult Female
2
5. Amblyomma cajennense Nymph
19300 15. Dermacentor variabalis Adult Male
62
6. Amblyomma cajennense Adult Male
331 16. Dermacentor variabalis Adult Female
69
7. Amblyomma cajennense Adult Female
210 17. Dermacentor variabalis fully engorged Adult Female
8. Amblyomma cajennense partially engorged Adult Female 18. Haemaphysalis leporispalustris Adult Male
4
9. Amblyomma inornatum Nymph
270 19. Haemaphysalis leporispalustris Adult Female
9
10. Amblyomma inornatum Adult Male
55
Total Speciated
D. Beck, J. Zavala, and other students
52286
10
Tick Species
A. cajennense is the dominant tick.
Tick Species
Amblyomma cajennense
# Collected
% of Total
47629
96.4%
Amblyomma inornatum
1216
2.3%
Amblomma maculatum
8
0.02%
Amblyomma americanum
1
0.002%
Dermacentor albipictus
49
0.1%
Dermacentor variabalis
92
0.2%
1
0.002%
44
0.09%
Dermacentor halli
Haemaphysalis leporispalustris
11
Other Sites
A. inornatum and D. variabilis are more abundant
at other sites.
Table 2: Ticks from other sites
County
Tick Species /
Webb
Site
Amblyomma cajennense
1
2
3
Jim Hogg
4
5
1
2
Maverick
3
1
584
2
6
107
6
1800
0
8
6
Amblyomma inornatum
2
0
0
4
0
566
0
87
13
Amblyomma maculatum
0
0
0
3
0
0
0
3
0
Dermacentor albipictus
7
0
0
0
0
0
0
0
0
Dermacentor variabalis
3
0
1
1
0
88
0
18
5
Haemaphysalis
leporispalustris
0
0
0
1
0
2
0
0
0
12
What is A. cajennense?


Cayenne Tick
Tick likes it warm from 29N to 29 (30 N to 30 S)
 Southern


Texas to Northern Argentina
Lacks cold tolerance – killed by a hard freezes
Host
 Horses,
Cattle, and dogs
 Primates, Anteaters and Peccary (Javelina)
 Medium to large mammals
 HUMANS!!!! Avid feeder on humans.
13
Why does A. cajennense do so well
in South Texas

50% Mortality of Adult ticks (23°C and 85% Relative
Humidity)


507.8-520.0 days
50% Mortality humidity not reported



A. cajennense
A. cajennense
A. americanum
221.0-269.5 days
36-42 days
Under dehydrating conditions (23°C and 35% Relative
Humidity)

A. cajennense
36.7-39.3 days
14
What does A. cajennense transmit






Rocky Mountain Spotted Fever/Brazilian Spotted
Fever
Thai tick typhus
Human ehrlichiosis
Rickettsia amblyomii
Venezuelan equine encephalomyelitis virus
Q fever (Coxiella burnetti)
15
Presentation
Tick Life Cycle
 Tick Collection Methods
 Ticks Identified
 Correlation with Weather Activity
 Future Directions

16
Correlation with weather

Larva





Positive correlation with 3 wk average humidity (p<0.05)
Negative correlation with 3 wk average wind speed (p<0.001)
Negative correlation with maximum wind speed (p<0.05)
Negative correlation with mean temperature (p<0.05)
Negative correlation with 3 wk average mean temperature (not
significant)


17
6.0
5.0
4.0
3.0
2.0
Feb
2008-Jan
Dec
Nov
Oct
Sep
Aug
July
June
May
Apr
Mar
Larval emergence is seen after significant rain events. (Not Significant) 18
12/1/2008
11/1/2008
10/1/2008
9/1/2008
Nov
Oct
Sep
Aug
July
7.0
8/1/2008
8.0
May
3 Week Total Rain - 78041
June
9.0
7/1/2008
10.0
6/1/2008
5/1/2008
4/1/2008
0.0
3/1/2008
0.0
2/1/2008
1.0
1/1/2008
0.5
12/1/2007
1.0
11/1/2007
1.5
10/1/2007
2.0
9/1/2007
2.5
8/1/2007
4.5
Larva
7/1/2007
3 Week Total Rain - 78041
6/1/2007
5.0
Feb
0
5/1/2007
3.0
2007-Jan
120
4/1/2007
40
Mean Ticks per trap
Adult
3/1/2007
3.5
Dec
Nymph
2/1/2007
4.0
Inches of Rain in Preceeding Three Weeks
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
2006-Jan
Dec
Nov
Oct
Sept
Aug
July
Amblyomma cajennense instars
1/1/2007
12/1/2006
11/1/2006
10/1/2006
9/1/2006
8/1/2006
7/1/2006
6/1/2006
5/1/2006
4/1/2006
3/1/2006
2/1/2006
1/1/2006
12/1/2005
11/1/2005
10/1/2005
9/1/2005
8/1/2005
June
May
April
Larva
7/1/2005
6/1/2005
5/1/2005
2005-Mar
Mean Ticks per trap
80
4/1/2005
3/1/2005
2/1/2005
1/1/2005
Inches of Rain in Preceeding Three Weeks
120
Amblyomma cajennense instars
Nymph
80
Adult
40
0
Correlation with weather

Nymph



Positive correlation with 3 wk average cloud cover (p<0.01)
Negative correlation with 3 wk average mean temperature
(p<0.05)
Adults




Negative correlation with 3 wk average humidity (p<0.05)
Positive correlation with 3 wk average Wind Speed (p<0.001)
Positive correlation with wind speed on trap day (p<0.01)
Positive correlation with 3 wk average mean temperature
(p<0.05)
19
10
Negative correlation with 3 wk average mean temperature (p<0.05)
20
12/1/2008
11/1/2008
10/1/2008
9/1/2008
8/1/2008
7/1/2008
6/1/2008
5/1/2008
4/1/2008
2/1/2008
3/1/2008
1/1/2008
12/1/2007
11/1/2007
10/1/2007
9/1/2007
15
8/1/2007
20
7/1/2007
25
35
6/1/2007
30
40
Nov
Oct
Sep
Aug
July
June
May
Feb
2008-Jan
Dec
Nov
Oct
Sep
Aug
July
June
May
Apr
0
5/1/2007
10
Mar
20
4/1/2007
30
100
Feb
40
2007-Jan
50
Mean Number of Nymphs per Trap
60
2/1/2007
3/1/2007
3 Week Average Mean Temperature 78041
Mean Temperature (Degrees Celsius)
Dec
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
2006-Jan
Dec
Nov
Oct
Sept
Aug
July
June
May
April
2005-Mar
Mean Number of Nymphs per Trap
70
1/1/2007
12/1/2006
11/1/2006
10/1/2006
9/1/2006
8/1/2006
7/1/2006
6/1/2006
5/1/2006
4/1/2006
2/1/2006
3/1/2006
1/1/2006
12/1/2005
11/1/2005
10/1/2005
9/1/2005
8/1/2005
7/1/2005
6/1/2005
5/1/2005
35
4/1/2005
2/1/2005
3/1/2005
40
1/1/2005
Mean Temperature (Degrees Celsius)
Amblyomma cajennense Nymph Mean
120
Amblyomma cajennense Nymph Mean
Note: Different Scale
80
60
40
20
0
3 Week Average Mean Temperature 78041
30
25
20
15
10
Larval Emergence
7.0
6.0
5.0
4.0
3.0
2.0
May
Feb
2008-Jan
Dec
Nov
Oct
Sep
Aug
July
June
May
Apr
Mar
21
12/1/2008
11/1/2008
10/1/2008
Nov
Oct
Sep
Aug
July
8.0
9/1/2008
3 Week Total Rain - 78041
June
9.0
8/1/2008
7/1/2008
6/1/2008
0.0
5/1/2008
0.0
4/1/2008
1.0
3/1/2008
0.5
2/1/2008
1.0
1/1/2008
1.5
12/1/2007
2.0
11/1/2007
2.5
10/1/2007
3.0
9/1/2007
4.5
8/1/2007
10.0
7/1/2007
3 Week Total Rain - 78041
6/1/2007
0
5/1/2007
10
Feb
20
4/1/2007
30
2007-Jan
40
100
3/1/2007
50
Mean Number of Nymphs per Trap
60
2/1/2007
3.5
Inches of Rain in Preceeding Three Weeks
4.0
Dec
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
2006-Jan
Dec
Nov
Oct
Sept
Aug
July
June
May
April
Mean Number of Nymphs per Trap
70
1/1/2007
12/1/2006
11/1/2006
10/1/2006
9/1/2006
8/1/2006
7/1/2006
6/1/2006
5/1/2006
4/1/2006
3/1/2006
2/1/2006
1/1/2006
12/1/2005
11/1/2005
10/1/2005
9/1/2005
8/1/2005
7/1/2005
6/1/2005
5/1/2005
4/1/2005
2005-Mar
5.0
3/1/2005
2/1/2005
1/1/2005
Inches of Rain in Preceeding Three Weeks
Amblyomma cajennense Nymph Mean
120
Amblyomma cajennense Nymph Mean
Note: Different Scale
80
60
40
20
0
10
Positive correlation with 3 wk average mean temperature (p<0.05)
22
12/1/2008
11/1/2008
10/1/2008
9/1/2008
8/1/2008
7/1/2008
6/1/2008
5/1/2008
4/1/2008
Dec
Nov
Oct
Sep
Aug
July
June
May
Apr
Nov
Oct
Sep
Aug
July
June
May
Feb
2008-Jan
40
2/1/2008
3/1/2008
1/1/2008
12/1/2007
11/1/2007
10/1/2007
9/1/2007
15
8/1/2007
20
7/1/2007
25
6/1/2007
30
35
5/1/2007
3 Week Average Mean Temperature 78041
4/1/2007
0
Mar
0.5
1
Feb
1
2007-Jan
1.5
Mean Number of Adults per Trap
2
2/1/2007
3/1/2007
40
Mean Temperature (Degrees Celsius)
Dec
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
2006-Jan
Dec
Nov
Oct
Sept
Aug
July
June
May
April
2005-Mar
Mean Number of Adults per Trap
Amblyomma cajennense Adult Mean
1/1/2007
12/1/2006
11/1/2006
10/1/2006
9/1/2006
8/1/2006
7/1/2006
6/1/2006
5/1/2006
4/1/2006
2/1/2006
3/1/2006
1/1/2006
12/1/2005
11/1/2005
10/1/2005
9/1/2005
8/1/2005
7/1/2005
6/1/2005
5/1/2005
35
4/1/2005
2/1/2005
3/1/2005
1/1/2005
Mean Temperature (Degrees Celsius)
2.5
1.2
Amblyomma cajennense Adult Mean
Note: Different Scale
0.8
0.6
0.4
0.2
0
3 Week Average Mean Temperature 78041
30
25
20
15
10
Adults come independent of rain events.
7.0
6.0
5.0
4.0
3.0
2.0
June
May
Feb
2008-Jan
Dec
Nov
Oct
Sep
Aug
July
June
May
Apr
Mar
23
Nov
Oct
11/1/2008
12/1/2008
Sep
10/1/2008
Aug
8.0
9/1/2008
3 Week Total Rain - 78041
July
9.0
8/1/2008
7/1/2008
6/1/2008
5/1/2008
0.0
4/1/2008
0.0
3/1/2008
1.0
2/1/2008
0.5
1/1/2008
1.0
12/1/2007
1.5
11/1/2007
2.0
10/1/2007
2.5
9/1/2007
3.0
8/1/2007
3.5
7/1/2007
4.5
6/1/2007
10.0
5/1/2007
3 Week Total Rain - 78041
4/1/2007
0
Feb
0.5
2007-Jan
1
1
3/1/2007
1.5
Mean Number of Adults per Trap
Amblyomma cajennense Adult Mean
2/1/2007
4.0
Inches of Rain in Preceeding Three Weeks
Dec
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
2006-Jan
Dec
Nov
Oct
Sept
Aug
July
June
May
April
Mean Number of Adults per Trap
2
1/1/2007
12/1/2006
11/1/2006
10/1/2006
9/1/2006
8/1/2006
7/1/2006
6/1/2006
5/1/2006
4/1/2006
3/1/2006
2/1/2006
1/1/2006
12/1/2005
11/1/2005
10/1/2005
9/1/2005
8/1/2005
7/1/2005
6/1/2005
5/1/2005
4/1/2005
2005-Mar
5.0
3/1/2005
2/1/2005
1/1/2005
Inches of Rain in Preceeding Three Weeks
2.5
1.2
Amblyomma cajennense Adult Mean
Note: Different Scale
0.8
0.6
0.4
0.2
0
Conclusion

Larval emergence appears to control the
life cycle of A. cajennense in South Texas.
 Larva
emerge
 3-4 months later the nymphs emerge
 Adults emerge later (usually during the hotter
months).
24
25
Nov
Oct
Sep
Aug
July
June
May
Feb
2008-Jan
Dec
Nov
Oct
0
Sep
0.5
Aug
1
1
July
1.5
Nov
Oct
Sep
Aug
July
June
May
Feb
2008-Jan
Dec
Nov
Oct
Sep
Aug
July
June
May
Apr
Mar
Larva
June
Amblyomma cajennense Adult Mean
May
2.5
Apr
0
Feb
40
2007-Jan
Adult
Mean Ticks per trap
120
Mar
Dec
Nymph
Feb
2
Mean Number of Adults per Trap
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
2006-Jan
Dec
Nov
Oct
Sept
Aug
July
Amblyomma cajennense instars
2007-Jan
Dec
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
2006-Jan
Dec
Nov
Oct
Sept
Aug
June
May
April
Larva
July
June
May
2005-Mar
Mean Ticks per trap
80
April
2005-Mar
Mean Number of Adults per Trap
120
Nymph
Amblyomma cajennense instars
80
Adult
40
0
1.2
Amblyomma cajennense Adult Mean
Note: Different Scale
0.8
0.6
0.4
0.2
0
Presentation
Tick Life Cycle
 Tick Collection Methods
 Ticks Identified
 Correlation with Weather Activity
 Future Directions

26
Tickborne Disease
Detected at TAMIU

We examined 189 A. cajennense for
– spotted fever group
 Borrelia – Lyme, STARI and others
 Ehrlichia – HME, HGE
 Rickettsia
All were negative
 Prevalence would be <4% for these

D. Beck, P. Billingsley, P. Williamson
27
Tickborne Disease
Detected at TAMIU

We examined 102 Dermacentor variabilis
Rickettsia – spotted fever group
 1+ Borrelia – Lyme, STARI and others
 0+ Ehrlichia – HME, HGE
 4+

We detected
4
Rickettsia rhipicephali (2 from a house cat
at a colonia, 2 from TAMIU campus)
 1 Borrelia lonestari
P. Billingsley, P. Williamson, D. Beck
28
2005
2005
Augustin Elizondo
Roberto Flores
Leonardo Nunez
Ruben Sandoval
Fernando Palacios-Bruno
Melissa Vela
Kimberly Witt
Josue Zavala
2006
Marc Andres
C. Alberto Bernal
Leslie Carreon
Eliezar Castenada
Monica Contreras
Francisco Garcia
Alberto Gonzalez, Jr.
2006
Maria Hernandez
Melissa Martin
Larry Miller
Fernando Palacios-Bruno
Jesus D. Perez
Jorge Serrato
Lydia Valenzuela
Melissa Vela
Joey Villereal
Josué Zavala
Arianne Zecca
29
2007
Maxine Caballero
Francisco Garcia
Carlos Gonzalez
Eduardo Gonzalez
Geraldo Gonzalez
Maria Hernandez
Abigail Lovano
Brenda Perez
Jorge Serrato
Leonor Araceli Soto
Cynthia Villareal
Josué Zavala
2008
2009
Maxine Caballero
Eric Montalvo
James Cortez
Jessica Perez
Geofrey Daves
James Cortez
Francisco Garcia
Dania Gomez
Reynaldo Garcia, III
Cesar Cardenas, Jr.
Alissa Gonzalez
Juan Pedro Orozco (MS Biology)
Maria Hernandez
Abigail Lozano
Selina Mata
Ricardo Medrano, Jr.
Eric Montalvo
Jessica Perez
Jorge Serrato
Edna Valadez
Richard Jacobsen (Faculty at LCC)
Juan Pedro Orozco (MS Biology)
Alberto Resendez (MS Biology)
30
Acknowledgments
TAMIU
Thomas C. Vaughan
C. Neal McReynolds
Mike Daniel
Marvin Bennett
University of North Texas
Phillip Williamson
Peggy Billingsley
$$$$
University Minigrants 2005-9
Texas Center Grant 2005, 2006, 2007
Defense Grant # W911NF-04-1-0045
31