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Chemical control of vampire bats

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Title:
Chemical control of vampire bats
Creator:
Mitchell, G. Clay.
Burns, Richard J.
United States. Bureau of Sport Fisheries and Wildlife.
United States. Agency for International Development.; Bureau for Technical Assistance.
Mexico. Secretaria de Agricultura y Ganaderia.
Denver Wildlife Research Center.
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Denver
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U.S. Bureau of Sport Fisheries and Wildlife, Wildlife Research Center,
Publication Date:
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English
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ii, 37 leaves : ill. ; 27 cm.

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Vampire bats.
Cattle -- Latin America

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On cover: Denver Wildlife Research Center, U.S. Bureau of Sport Fisheries, in cooperation with Instituto Nacional de Investigaciones Pecuarias, Secretaria de Agricultura y Ganaderia, Gobierno de Mexico ; Office of Agriculture and Fisheries, Bureau of Technical Assistance, U.S. Agency for International Development.
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Includes bibliographical references.
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Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.

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Full Text
CHEMICAL CONTROL
OF VAMPIRE BATS
DENVER WILDLIFE RESEARCH CENTER
U.S. BUREAU OF SPORT FISHERIES AND WILDLIFE in cooperation with
INSTITUTO NACIONAL DE OFFICE OF AGRICULTURE
INVESTIGACIONES PECUARIAS AND FISHERIES
SECRETARIA DE AGRICULTURA BUREAU OF TECHNICAL ASSISTANCE
Y GANADERIA
U.S. AGENCY FOR
GOBIERNO DE MEXICO INTERNATIONAL DEVELOPMENT




CHEMICAL CONTROL OF
VAMPIRE BATS
G. Clay Mitchell and Richard J. Burns
U.S. Bureau of Sport Fisheries and Wildlife
Wildlife Research Center
Denver, Colorado 80225
May 1973




CONTENTS
Page
Introduction ................................................... 1
Identification of the Vampire Bat ............................. 3
The Chemical Control Compound ................................. 5
Toxicity for Humans and Antidote ......................... 8
Toxicity for Cattle and Antidote ......................... 8
Control by Treating the Vampire Bat ........................... 8
Catching Vampire Bats .......... .............. 9
Treating Vampire Bats .......... ... ................... 12
Precautions .............................................. 16
Control by Treating the Cattle ................................ 18
When to Treat ............................................ 18
Haw to Treat ............................................. 19
Precautions .............................................. 21
Advantages and Disadvantages for Each Control Method .......... 22
Treating the Bats ........................................ 22
Advantages ........................................... 22
Disadvantages ....................................... 22
Treating the Cattle ......... I .............................. 23
Advantages ........................................... 23
Disadvantages ....................................... 23
Control Evaluation ............................................ 23
Pre-control Evaluation ................................... 23
Post-control Evaluation .................................. 27
The Use of Rabies Vaccines in Conjunction with
Control of Vampire Bats ..................................... 27
If Vampire Bats Are Controlled, Why Vaccinate? ........... 27
If Cattle AreVaccinated, Why Control? ................... 29
i




CONTENTS Continued
Page
Proposed Agency for International Development and
Denver Wildlife Research Center Assistance
in the Future ............................. o.............o.......29
Literature Cited .....................o............................31
Appendix A Diphenadione Dosage Scale for Cattle.................32
Appendix B Special Equipment....................................35
Appendix C Recommended Selected Readings......................... 37




INTRODUCTION
Vampire bats attack and feed on the blood of man and animals
throughout most of Latin America. The calf shown (Fig. 1) has at least 10 fresh vampire bat bites and has lost approximately 250 ml of blood to the feeding bats. Also, additional blood has been lost because blood continues to flow from wounds after bats finish feeding. Blood loss, however, represents only one problem caused by-vampire bats, because their feeding habits have the potential of spreading rabies and their bites provide avenues for many other kinds of infections.
Great numbers of livestock live within the geographic range of the vampire bat, which extends from Northern Mexico to Central Argentina. Many of these domestic animals suffer nightly attacks from vampire bats. The calf shown lives in a rabies-free area; therefore, it will not die from the disease, but many animals are not so fortunate. Annual losses attributed to vampire bat-transmitted rabies in Latin America are estimated at about one-half million head for bovines, and at about 2 million head for all kinds of livestock (see Constantine 1970, p. 374, for review).
Because of the great loss of livestock to rabies, most Latin
American countries have, at one time or another, attempted to reduce vampire bat populations. The methods used included gassing, poisoning, dynamiting, and smoking bats out of caves. These attempts proved to be expensive, sometimes ineffective, and most important, not specific
1




Fig. 1. Calf with multiple vampire bat bites on face, ears, and neck.




for vampire bats. As a result, many other species of bats and cavedwelling creatures were indiscriminately killed. Now, however, inexpensive, safe, and selective methods have been developed for controlling vampire bat populations.
In this pamphlet, we describe two methods of controlling vampire bats that were developed by the U.S. Bureau of Sport Fisheries and Wildlife. Research was conducted at the Denver Wildlife Research Center, Denver, Colorado, and at the Instituto Nacional de Investigaciones Pecuarias, Mexico City, Mexico. Field work was done cooperatively in Mexico (Fig. 2). Funds for the project were provided by the United States Agency for International Development PASA RA(ID) 1-6 7.
IDENTIFICATION OF THE VAMPIRE BAT
There are many different kinds of bats, but only the vampire bat feeds on blood and is the major vector of livestock rabies in Latin America. Therefore, only vampire bats should be treated with the control compound. Bats other than vampires feed on such things as nectar, fruit, and insects. These bats are beneficial to man because they pollinate plants, disseminate fruit seeds, and destroy insects, so they should not be harmed.
Vampire bats may be separated from beneficial bats by carefully observing the following characteristics of vampire bats:
(A) Color: Dark grayish-brown on upper parts, underparts paler.
3




4k
Fig. 2. Preparing to mark vampire bat for studies carried out during
the research phase of the project to control vampire bats.




(B) Tail: Absent, only has a narrow skin membrane around inside
back of legs.
(C) Thumb: Long with three obvious joints, and larger than in
most other bat species. Thumbs extend forward from the center
of the wings of bats.
(D) Face: Nose, a wrinkled mass with no nose leaf. Eyes, large
and dark brown.
(E) Teeth: Upper incisors, and upper and lower canine teeth,
large. All others are extremely small and usually not seen
unless you examine the mouth carefully.
(F) Ears: Relatively small and pointed.
Please note carefully the above characteristics of vampire bats in Figures 3 and 4. Figure 3 shows a vampire bat with his wings folded walking on the ground, and Figure 4 shows a vampire bat in flight.
THE CHEMICAL CONTROL COMPOUND
The control methods described in this pamphlet utilize an anticoagulant called diphenadione*. Diphenadione used as described has effectively reduced vampire bat populations in problem areas without harming other animals. Low doses of the chemical are sometimes used in human medicine to reduce blood clotting. Diphenadione is stable
*Reference to trade names does riot imply endorsement of commercial products by the United States Federal Government.
5




Fig. 3. Vampire bat walking with wings folded showing frontal view of face
(Courtesy Nicandro Gomez, USIS, U.S. Embassy, Mexico City, Mexico).




Fig. 4. Vampire bat in flight showing side view (profile) of face.
(Courtesy J. Scott Altenback, Colorado State University,
Ft. Collins, Colorado)




in heat to 1450 C and does not decompose readily. The compound should be stored in a cool place, but refrigeration is not necessary; also, it is a lethal agent so it should be stored in a safe place. Toxicity for Humans and Antidote
Diphenadione is relatively nontoxic to humans. An average adult (70 kilograms) using diphenadione as medication can take up to 30 milligrams daily; consequently, chances of poisoning from ingesting the control compound are very slight. However, in case of accidental human poisoning, immediately consult a medical doctor. The antidote for diphenadione in humans is vitamin K1.
Toxicity for Cattle and Antidote
The dose level of diphenadione injected into cattle for vampire bat control is 1 milligram per kilogram of body weight of the bovine. But up to 5 milligrams per kilogram has been experimentally injected in cattle without producing poisoning, so there is a wide margin for error. Nevertheless, should a massive overdose accidently occur, consult a veterinarian. The antidote for diphenadione in cattle is vitamin K2.
CONTROL BY TREATING THE VAMPIRE BAT
Control by treating vampire bats should be done at corrals where the bats are attacking livestock. The control is done by:
8




(A) Cat ching bats in mist nets placed outside corrals.
(B) Removing carefully all bats from the .nets.
(C) Identifying the vampire bats and placing them in a cage.
Release all other kinds of bats.
(D) Treating the vampire bats with diphenadione paste and
releasing them.
Catching Vampire Bats
To catch vampire bats at corrals, mist nets should be set outside the corrals about 1 meter away from the fences (Fig. 5). Mist nets have a body of fine nylon thread with support cords running the full length of the net. The long cords have heavy tie cords at each end which are used for fastening the net to support poles. The nets should be set from ground level up to about 2 meters high on poles about 2.5 meters long. The longitudinal cords should be pulled tight, but the net body should be left very loose (Fig. 6). When bats strike a net set as described, they become entangled easily. If the net body is set too tight, the bats will simply bounce off and escape.
Mist nets pick up debris and tangle very easily. Hence, they must be handled very carefully. Do not let the nets fall to or drag along the ground when they are being set or removed. Clear brush, tall grass, and low tree branches away from a strip 2 meters wide along the corral fence where nets are to be set, then set the nets down the center of the clean strip.
9




Fig. 5. Mexican biologist showing proper way to set mist nets outside
of a corral.
10




Fig. 6. Mist net set with net body loose. Note top tie cord has another cord used to tie
all ends together and to mark top of net. (From Bats and Bat Banding, Bureau of
Sport Fisheries and Wildlife Resource Publication 72)




When trapping is completed for the night, carefully clean all debris, insects, etc., from the nets and store the nets carefully in plastic bags. If the nets are not completely cleaned before packing into the bags, they will tangle badly and it will be very difficult to use them again. Also, it is helpful to fasten the heavy cord ends (which attach to the poles) together and to somehow mark the first tie-cord so it can be recognized when nets are to be reused (Fig. 7).
Treating Vampire Bats
After removing all the bats from the nets (Fig. 8) and placing the vampires in a cage, take down the nets and store them as described previously. Now treat the vampire bats with diphenadione paste and release them.
Two persons should work together when treating the vampire bats. One person should hold a bat securely by both wings while the other person applies about 1.5 cc of the control paste to the back of each bat. The paste should be spread evenly over the entire surface of the bat's back (Fig. 9). Release each vampire bat immediately after it has been treated.
The number of vampire bats that should be treated at a corral varies
considerably, and depends on local habitat conditions. We suggest that you treat one vampire bat for each five that you estimate are attacking the cattle herd. The estimate can be made by counting carefully the number of fresh vampire bat bites on the attacked herd very early in the morning. Generally, you can expect that each fresh bite seen represents one vampire
12




Fig. 7. How to close and fold a mist net for proper storage. Both ends should be tied as
shown in the diagram. (Courtesy AID/RTAC, U.S. Embassy, Mexico City, Mexico)




4:
Fig. 8. Captured vampire bats ready to be removed and treated with the diphenadione paste.




LIl
Fig. 9. This vampire bat has just been treated with the diphenadione paste and is ready to release.




bat attackingthe herd. Remember, treating one out of five is only an average, and if you find that in some areas this treatment level. is not sufficient to give at least a 90 percent reduction in vampire bat bites, you should probably treat each vampire bat captured in the area in the future.
Treated vampire bats will return to their roost (Fig. 10) and spread the control compound to other members of the colony. One treated, released vampire bat, under ideal conditions, may contaminate up to 20 of his fellow-vampire bats. Since vampire bats form compact colonies separated from other kinds of bats, even other bats that live in the same roost, this technique is specific for vampire bats.
Vampire bats usually feed during the darkest hours of the night: before moonrise, after moonset, when it is cloudy, etc.; so you can save a great deal of time by planning to trap the bats when it is darkest. The dark period of the moon is quite variable, and you should either watch the moon carefully or purchase a book telling when the moon rises and sets in your work area. It is most convenient to trap when the moon rises at about 10:00 to 11:00 p.m.; then trapping can be done between dark and about 10:30 p.m. Precautions
Everyone handling bats of any species should first take a preexposure series of anti-rabies injections. Consult a local medical doctor about where to get the injections. When handling vampire bats,
16




Fig. 10. Vampire bats roost in caves in tightly packed groups. This close body contact helps
to pass the topically applied control compound from one carrier to many others.




very heavy leather gloves are necessary to protect against bat bites and possible infections.
Finally, if vampire bats in the problem area roost in water wells used by people for drinking, this method of control should not be used. In areas where the bats roost in wells, you should control them by injecting livestock, or by trapping and destroying the bats. Also, in very humid areas, vampire bats may roost in abandoned houses or other buildings. After treatment, most vampires will die in their roost, and extreme precaution should be taken not to be bitten and not to let other animals consume dead or dying bats. If you find dying vampires in a house or abandoned building, destroy them. Do not touch the bats, but kill them with a stick or other long object. Bury the carcasses deep enough so that dogs, pigs, etc., cannot uncover and eat the remains.
CONTROL BY TREATING THE CATTLE
Diphenadione has the characteristic of being relatively nontoxic to cattle but extremely toxic to vampire bats, and this is the basis for control by injecting the chemical into cattle. Vampire bats feeding on the treated cattle receive lethal doses while the cattle remain unharmed.
When to Treat
First, it must be determined whether cattle should be treated.
This is done by counting fresh bites. If the biting incidence is low
18




capturing and treating the bats could be less expensive, and less time-consuming, than treating the cattle. If biting is sufficiently high, then assess the climatic and lunar conditions. Many vampire bats may not feed when the moon is full, so treating cattle at this time of the month should be avoided. Also, rain and cold weather appear to suppress normal foraging behavior of vampire bats, and treatment should not be done during these climatic conditions, if possible. How to Treat
The cattle should either be tethered or herded into a chute. Count and record the number of fresh bites. Then estimate the weight of the bovine to be treated. The amount of drug injected is based on the body weight of the animal to be treated. Inject 1 milligram of drug per kilogram body weight of the bovine. The weight can be determined by measuring the heart girth with a body-weight tape or can be estimated visually. Appendix A shows how much drug to inject based on the heart girth or weight of the animal. Slightly more than 1 milligram per kilogram can be injected, and i't is not dangerous for the bovine; up to 5 milligrams per kilogram have been given to cattle without producing signs of poisoning. However, do not deliberately inject more than 1 milligram per kilogram; this would raise the cost of the operation and reduce the margin of safety.
A thick liquid form of diphenadione is injected into the rumen compartment of the stomach (Fig. 11). If the drug is injected under
19




Ai
Fig. 11. Injecting diphenadione into rumien compartment of a cow's stomach. Note
injection should be made in the area of the triangle drawn on the cow.




the skin or in the muscles, it may not circulate in the blood as well and may not be as effective in controlling vampire bats. Any vampire bat that bites and feeds normally from a properly treated animal, within 72 hours after treatment, receives a lethal dose of the drug. After 72 hours, enough of the drug has been eliminated from the treated animal so that the bats are no longer killed.
Any standard syringe can be used for the injection, but we have found that an automatic syringe greatly facilitates the operation. Appendix B tells where to purchase automatic syringes. Use 14-gauge, 1-1/2-inch disposable, luer-lock-type needles for the intraruminal injections.
Precautions
(A) Diphenadione can be injected into all breeds of cattle, but
should not be injected into other domestic animals.
(B) The drug may be injected into lactating cattle and the milk
is safe for calves to drink. (Studies with humans have not
been done.)
(C) One week after injecting diphenadione, nearly all of the
chemical will be gone from the treated animal. However,
as an extra safety measure, treated animals should not be
slaughtered for food for 30 days.
(D) Cattle should not be treated more often than every 30 days,
but such frequent treatment should not be required. Proper
21




treatment should produce control of vampire bats for at least
6 months, and in many cases for 1-2 years or longer.
ADVANTAGES AND DISADVANTAGES FOR EACH CONTROL METHOD Treating the Bats
Advantages.--Control by treating vampire bats can be used around all kinds of domestic animals, whereas only bovines should be injected. Treating captured vampire bats is usually more effective for fast, more complete control. A trained team is required and the team can move into an area and quickly reduce the vampire bat population. If there is a rabies outbreak, time and completeness of control in the problem area may be critical in containing the rabies spread. A wide-scale injection control program will usually be slower. Treating bats is less expensive than treating cattle because the bats require less chemical. For example, properly treating a vampire bat costs approximately 3 cents and may kill up to 20 others. But treating a 300-kilogram bovine costs approximately 10 cents and will kill only the bats that feed on the treated animal (usually only one to five vampire bats).
Disadvantages.--Capturing and treating vampire bats requires special equipment (mist nets, lights, heavy gloves) and working at night. Members of a control team must be trained in bat identification to prevent treating beneficial bats, and must be vaccinated against rabies to reduce the possibility of contracting the disease.
22




Treating the Cattle
Advantages.--Injecting cattle eliminates direct contact with all species of bats. Since the syringe is a basic part of a veterinarian's equipment, there may be no need to purchase special equipment; except possibly the 14-gauge, 1-1/2-inch needles.
Disadvantages.--Injecting cattle requires chute facilities for best results. It may be more expensive and time-consuming than treating the bats. All the vampires in a given colony may not feed on the treated cattle; hence, a smaller proportion of the vampire bat population may be killed. The injection method should be used only on cattle.
CONTROL EVALUATION
Pre-control Evaluation
There are situations where the cost of controlling vampire bats
may not be justified by their damage, and in other situations only one treatment method may be economical. To determine whether to treat, which method to use, and the most efficient scheduling of your time, each problem must be evaluated in advance. Form I is a proposed data sheet for pre-evaluation. All the information on the form can usually be collected by an extension agent or given by an interested rancher (see Form I).
Bite counts should be made as early in the morning as possible. When examining the cattle for fresh bites, look everywhere (Fig. 12),
23




er
,All
001.
Fig. 12. Vampire bats bite cattle almost anywhere. Here a vampire is
biting a cow on the foot (fetlock) area. (Courtesy Nicandro
Gomez, USIS, U.S. Embassy, Mexico City, Mexico)
24




but closely examine the neck, axillae and tail; vampires sometimes prefer to bite in these areas. A fresh bite may still be oozing blood or will be a fresh concave hole. Examine black cattle in particular, because vampires sometimes prefer to bite the dark animals in a herd.
The type of facilities available are very important in determining which control method to use. Corralsfor cattle are usually required if vampire bats are being captured and treated; chutes facilitate injecting cattle. It is important that the facilities be close to the area where cattle are being heavily bitten to insure successful results.
Under "Miscellaneous" on Form I, several items will assist you in determining how and when to control:
(A) Type of cattle: Dairy cattle are usually easier to inject
than beef cattle; and management practices, that may influence
control measures, are quite different.
(B) Rainy season: If there is a defined wet and dry season, then
treating during the dry season is usually easier.
(C) Variation in biting: In some areas of South America, vampire
bats apparently migrate at certain times of the year. Control
should be conducted when biting incidence is highest.
(D) Number of livestock: The size of the herds may influence which
control method you choose for convenience or economic reasons.
25




FORM I
Date
Ranch:
Owne r:
Location:
No. of cattle checked for fresh bites: (check in morning) No. of fresh bites: Facilities
a) Corrals (size and No.)
b) Chutes
c) Distance cattle are from these facilities when being bitten
Miscellaneous
a) Type of livestock (Dairy or Beef cattle):
b) Total number of livestock:
c) Rainy season:
d) Seasonal variation in biting:
e) Topography:
f) Vampires roost in:
Notes:
26




(E) Topography: The physical features of the area will help in
determining where the bats live and their possible flight
paths. This may be important for effective trapping.
(F) Where vampires roost: If vampire bats roost in water wells
used by people for drinking, then only the injection method
should be used. There is a possibility that treated bats
may contaminate drinking water, so be very cautious. Post-control Evaluation
Form II can be used for control and follow-up data. Such data are important for evaluating the success of control efforts, and valuable in determining when control should be repeated.
If a central vampire bat control office is established, Form II should be forwarded to that office for filing. It is requested that copies of these forms also be sent to the authors in Denver, Colorado, where a vampire bat control surveillance center will be located.
THE USE OF RABIES VACCINES IN CONJUNCTION WITH CONTROL OF VAMPIRE BATS
If Vampire Bats Are Controlled, Why Vaccinate?
All vampire bats will not be killed by using either of the described control methods; hence, there will always be the possibility of cattle being infected with rabies if they are not vaccinated. As a precaution, it is recommended that livestock be vaccinated against rabies even if
27




FORM II
Before treatment C rAfter treatment
Control
Livestock Freshl method used Livestock Fresh Rdcin
Ranch and Date examined bites and number of Date of examined i bites in biting
Location (No.) (No.) animals treated evaluation (No.) (No.) (%)
00I
, I
I I
I I
1. __ t .
_ ___ __ _




vampire bat populations have been reduced in your area. Rabies is carried by many animals besides vampire bats. Vaccination is especially important if expensive individual animals such as purebred bulls or thoroughbred horses are involved.
If Cattle Are Vaccinated, Why Control?
Losses caused by vampire bats can be divided into two categories; direct losses and indirect losses. In Latin America direct losses by death of livestock from rabies are estimated to exceed 100 million dollars; but indirect losses, including malnutrition, approach 250 million dollars (see Constantine 1970, p. 374, for review). Treating livestock with antirabies vaccines does nothing to alleviate indirect losses, and vampire bat population reduction may be required in problem areas.
PROPOSED AGENCY FOR INTERNATIONAL DEVELOPMENT
AND DENVER WILDLIFE RESEARCH CENTER ASSISTANCE IN THE FUTURE
The AID-supported PASA RA(ID) 1-67 will provide for future advisory or consultive services in organizing and developing vampire bat control programs on a selective basis.
AID/DWRC will also assist in the recruitment of vampire bat control specialists for longer term projects. This may be accomplished through mission- or country-supported Task Orders to the existing PASA, by direct hire, or by contract.
29




AID/DWRC also plans to continue to co-support workshops as appropriate and to provide assistance in the placement of participant trainees at the Center or at other suitable institutions.
30




LITERATURE CITED
Constantine, Denny G. 1970. Bats in relation to the health, welfare,
and economy of man. In Biology of Bats, Vol. II. William A.
Wimsatt [ed.], Academic Press, New York and London, pp. xv + 477.
31




Appendix A
DIPHENADIONE DOSAGE SCALE FOR CATTLE
Estimated body Diphenadione dosage
Heart girth weight (1.0 mg/kg)*
(inches) (ibs) (kgs) Number of milliliters
31 100 45.4 0.9
32 106 48.2 1.0
33 116 52.7 1.1
34 130 59.1 1.2
35 141 64.1 1.4
36 150 68.2 1.4
37 164 74.5 1.5
38 177 80.4 1.6
39 192 87.3 1.7
40 207 94.1 1.9
41 222 100.9 2.0
42 238 108.2 2.2
43 255 115.9 2.3
44 273 124.1 2.5
45 290 131.8 2.6
46 308 140.0 2.8
47 329 149.5 3.0
* Rate applies for usual injectable formulations containing 50 milligrams of diphenadione per milliliter of compound.
32




Appendix A Continued
Estimated body Diphenadione dosage
Heart girth weight (1.0 mg/kg)*
(inches) (lbs) (kgs) Number of milliliters
48 349 158.6 3.2
49 371 168.6 3.4
50 392 178.2 3.6
51 414 188.2 3.8
52 438 199.1 4.0
53 462 210.0 4.2
54 486 220.1 4.4
55 511 232.3 4.6
56 537 244.1 4.9
57 564 256.4 5.1
58 591 268.6 5.4
59 620 281.8 5.6
60 649 295.0 5.9
61 678 308.2 6.2
62 709 322.2 6.4
63 739 335.9 6.7
64 772 350.0 7.0
65 804 365.4 7.3
66 836 380.0 7.6
67 871 395.9 7.9
68 905 411.4 8.2
33




Appendix A Continued
Estimated body Diphenadione dosage
Heart girth weight (1.0 mg/kg)*
(inches) (ibs) (kgs) Number of milliliters
69 941 427.7 8.6
70 977 444.4 8.9
71 1,013 460.4 9.2
72 1,051 477.7 9.6
73 1,089 495.0 9.9
74 1,129 513.2 10.3
75 1,169 531.3 11.0
76 1,207 548.6 11.0
77 1,249 567.7 11.3
78 1,2.88 585.4 11.7
79 1,334 606.4 12.1
80 1,374 624.5 12.4
81. 1,418 644.5 12.9
82 1,463 665.0 13.3
83 1,508 685.4 13.7
84 1,557 707.7 14.1
85 1,603 728.6 14.5
86 1,650 750.0 15.0
87 1,699 772.3 15.4
88 1,747 794.1 15.8
89 1,798 817.3 16.3
34




Appendix B
SPECIAL EQUIPMENT
Mist Nets
There are many types and sizes of mist nets. For capturing vampire bats we recommend: Length, 6 or 12 meters; height, about 2 meters; mesh, 36 millimeters; shelves, 4. Mist nets can be purchased from the following suppliers:
E. A. Bergstrom Northeastern Bird Banding Association 37 Old Brook Road West Hartford, Connecticut 06117 U.S.A.
Bleitz Wildlife Foundation 5334 Hollywood Boulevard Hollywood, California 90027 U.S.A.
W. B. Davis
712 Mary Lake Drive Bryan, Texas 77803 U.S.A.
Automatic Syringe. Vaccinating Outfit and Needles
An automatic syringe we have used:
Vaco Pistol Grip Automatic Syringe Shikles Automatic Syringe Filler Shikles Vaccinating Bag \Needles, 14 gauge, 1-1/2 inch disposable, luer-lock-type. These items can be purchased from many veterinary supply houses.
35




A small, disposable automatic syringe may be useful for small herds. We have used: Wellcome Disposable 5-mi Automatic Syringe The Wellcome syringe can be purchased from: Schmidt and Allen Livestock Equipment 4699 Marion Street Denver, Colorado 80216
36




Appendix C
RECOMMENDED SELECTED READINGS
The following publications give more details on the history of vampire bat control, and on the development of the new selective methods for reducing vampire bat populations. Flores Crespo, Raul, Samuel B. Linhart, Richard J. Burns, and G. Clay
Mitchell. 1972. Foraging behavior of the common vampire bat
related to moonlight. J. Mammal., 53(2):366-368.
Linhart, Samuel B., Raul Flores Crespo, and G. Clay Mitchell. 1972.
Control of vampire bats by topical application of an anticoagulant,
Chlorophacinone. Boletin De La OSP (English Edition), Vol. VI,
No. 2, 31-38.
Mitchell, G. Clay, Richard J. Burns, Raul Flores Crespo, and Salvador
Said Fernandez. 1973. Vampire bat control, 1934-1971. Tecnica
Pecuaria En M~xico (in press).
Thompson, R. Dan, G. Clay Mitchell, and Richard J. Burns. 1972.
Vampire bat control by systemic treatment of livestock with an
anticoagulant. Science, 177:806-808.
37




Full Text

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CHEMICAL CONTROL OF VAMPIRE BATS G. Clay Mitchell and Richard J. Burns U.S. Bureau of Sport Fisheries and Wildlife Wildlife Research Center Denver, Colorado 80225 May 1973



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very heavy leather gloves are necessary to protect against bat bites and possible infections. Finally, if vampire bats in the problem area roost in water wells used by people for drinking, this method of control should not be used. In areas where the bats roost in wells, you should control them by injecting livestock, or by trapping and destroying the bats. Also, in very humid areas, vampire bats may roost in abandoned houses or other buildings. After treatment, most vampires will die in their roost, and extreme precaution should be taken not to be bitten and not to let other animals consume dead or dying bats. If you find dying vampires in a house or abandoned building, destroy them. Do not touch the bats, but kill them with a stick or other long object. Bury the carcasses deep enough so that dogs, pigs, etc., cannot uncover and eat the remains. CONTROL BY TREATING THE CATTLE Diphenadione has the characteristic of being relatively nontoxic to cattle but extremely toxic to vampire bats, and this is the basis for control by injecting the chemical into cattle. Vampire bats feeding on the treated cattle receive lethal doses while the cattle remain unharmed. When to Treat First, it must be determined whether cattle should be treated. This is done by counting fresh bites. If the biting incidence is low 18



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capturing and treating the bats could be less expensive, and less time-consuming, than treating the cattle. If biting is sufficiently high, then assess the climatic and lunar conditions. Many vampire bats may not feed when the moon is full, so treating cattle at this time of the month should be avoided. Also, rain and cold weather appear to suppress normal foraging behavior of vampire bats, and treatment should not be done during these climatic conditions, if possible. How to Treat The cattle should either be tethered or herded into a chute. Count and record the number of fresh bites. Then estimate the weight of the bovine to be treated. The amount of drug injected is based on the body weight of the animal to be treated. Inject 1 milligram of drug per kilogram body weight of the bovine. The weight can be determined by measuring the heart girth with a body-weight tape or can be estimated visually. Appendix A shows how much drug to inject based on the heart girth or weight of the animal. Slightly more than 1 milligram per kilogram can be injected, and i't is not dangerous for the bovine; up to 5 milligrams per kilogram have been given to cattle without producing signs of poisoning. However, do not deliberately inject more than 1 milligram per kilogram; this would raise the cost of the operation and reduce the margin of safety. A thick liquid form of diphenadione is injected into the rumen compartment of the stomach (Fig. 11). If the drug is injected under 19



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bat attackingthe herd. Remember, treating one out of five is only an average, and if you find that in some areas this treatment level. is not sufficient to give at least a 90 percent reduction in vampire bat bites, you should probably treat each vampire bat captured in the area in the future. Treated vampire bats will return to their roost (Fig. 10) and spread the control compound to other members of the colony. One treated, released vampire bat, under ideal conditions, may contaminate up to 20 of his fellow-vampire bats. Since vampire bats form compact colonies separated from other kinds of bats, even other bats that live in the same roost, this technique is specific for vampire bats. Vampire bats usually feed during the darkest hours of the night: before moonrise, after moonset, when it is cloudy, etc.; so you can save a great deal of time by planning to trap the bats when it is darkest. The dark period of the moon is quite variable, and you should either watch the moon carefully or purchase a book telling when the moon rises and sets in your work area. It is most convenient to trap when the moon rises at about 10:00 to 11:00 p.m.; then trapping can be done between dark and about 10:30 p.m. Precautions Everyone handling bats of any species should first take a preexposure series of anti-rabies injections. Consult a local medical doctor about where to get the injections. When handling vampire bats, 16



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the skin or in the muscles, it may not circulate in the blood as well and may not be as effective in controlling vampire bats. Any vampire bat that bites and feeds normally from a properly treated animal, within 72 hours after treatment, receives a lethal dose of the drug. After 72 hours, enough of the drug has been eliminated from the treated animal so that the bats are no longer killed. Any standard syringe can be used for the injection, but we have found that an automatic syringe greatly facilitates the operation. Appendix B tells where to purchase automatic syringes. Use 14-gauge, 1-1/2-inch disposable, luer-lock-type needles for the intraruminal injections. Precautions (A) Diphenadione can be injected into all breeds of cattle, but should not be injected into other domestic animals. (B) The drug may be injected into lactating cattle and the milk is safe for calves to drink. (Studies with humans have not been done.) (C) One week after injecting diphenadione, nearly all of the chemical will be gone from the treated animal. However, as an extra safety measure, treated animals should not be slaughtered for food for 30 days. (D) Cattle should not be treated more often than every 30 days, but such frequent treatment should not be required. Proper 21



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(A) Cat ching bats in mist nets placed outside corrals. (B) Removing carefully all bats from the .nets. (C) Identifying the vampire bats and placing them in a cage. Release all other kinds of bats. (D) Treating the vampire bats with diphenadione paste and releasing them. Catching Vampire Bats To catch vampire bats at corrals, mist nets should be set outside the corrals about 1 meter away from the fences (Fig. 5). Mist nets have a body of fine nylon thread with support cords running the full length of the net. The long cords have heavy tie cords at each end which are used for fastening the net to support poles. The nets should be set from ground level up to about 2 meters high on poles about 2.5 meters long. The longitudinal cords should be pulled tight, but the net body should be left very loose (Fig. 6). When bats strike a net set as described, they become entangled easily. If the net body is set too tight, the bats will simply bounce off and escape. Mist nets pick up debris and tangle very easily. Hence, they must be handled very carefully. Do not let the nets fall to or drag along the ground when they are being set or removed. Clear brush, tall grass, and low tree branches away from a strip 2 meters wide along the corral fence where nets are to be set, then set the nets down the center of the clean strip. 9



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(B) Tail: Absent, only has a narrow skin membrane around inside back of legs. (C) Thumb: Long with three obvious joints, and larger than in most other bat species. Thumbs extend forward from the center of the wings of bats. (D) Face: Nose, a wrinkled mass with no nose leaf. Eyes, large and dark brown. (E) Teeth: Upper incisors, and upper and lower canine teeth, large. All others are extremely small and usually not seen unless you examine the mouth carefully. (F) Ears: Relatively small and pointed. Please note carefully the above characteristics of vampire bats in Figures 3 and 4. Figure 3 shows a vampire bat with his wings folded walking on the ground, and Figure 4 shows a vampire bat in flight. THE CHEMICAL CONTROL COMPOUND The control methods described in this pamphlet utilize an anticoagulant called diphenadione*. Diphenadione used as described has effectively reduced vampire bat populations in problem areas without harming other animals. Low doses of the chemical are sometimes used in human medicine to reduce blood clotting. Diphenadione is stable *Reference to trade names does riot imply endorsement of commercial products by the United States Federal Government. 5



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LIl Fig. 9. This vampire bat has just been treated with the diphenadione paste and is ready to release.



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AID/DWRC also plans to continue to co-support workshops as appropriate and to provide assistance in the placement of participant trainees at the Center or at other suitable institutions. 30



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treatment should produce control of vampire bats for at least 6 months, and in many cases for 1-2 years or longer. ADVANTAGES AND DISADVANTAGES FOR EACH CONTROL METHOD Treating the Bats Advantages.--Control by treating vampire bats can be used around all kinds of domestic animals, whereas only bovines should be injected. Treating captured vampire bats is usually more effective for fast, more complete control. A trained team is required and the team can move into an area and quickly reduce the vampire bat population. If there is a rabies outbreak, time and completeness of control in the problem area may be critical in containing the rabies spread. A wide-scale injection control program will usually be slower. Treating bats is less expensive than treating cattle because the bats require less chemical. For example, properly treating a vampire bat costs approximately 3 cents and may kill up to 20 others. But treating a 300-kilogram bovine costs approximately 10 cents and will kill only the bats that feed on the treated animal (usually only one to five vampire bats). Disadvantages.--Capturing and treating vampire bats requires special equipment (mist nets, lights, heavy gloves) and working at night. Members of a control team must be trained in bat identification to prevent treating beneficial bats, and must be vaccinated against rabies to reduce the possibility of contracting the disease. 22



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Fig. 6. Mist net set with net body loose. Note top tie cord has another cord used to tie all ends together and to mark top of net. (From Bats and Bat Banding, Bureau of Sport Fisheries and Wildlife Resource Publication 72)



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4k Fig. 2. Preparing to mark vampire bat for studies carried out during the research phase of the project to control vampire bats.



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Appendix A -Continued Estimated body Diphenadione dosage Heart girth weight (1.0 mg/kg)* (inches) (lbs) (kgs) Number of milliliters 48 349 158.6 3.2 49 371 168.6 3.4 50 392 178.2 3.6 51 414 188.2 3.8 52 438 199.1 4.0 53 462 210.0 4.2 54 486 220.1 4.4 55 511 232.3 4.6 56 537 244.1 4.9 57 564 256.4 5.1 58 591 268.6 5.4 59 620 281.8 5.6 60 649 295.0 5.9 61 678 308.2 6.2 62 709 322.2 6.4 63 739 335.9 6.7 64 772 350.0 7.0 65 804 365.4 7.3 66 836 380.0 7.6 67 871 395.9 7.9 68 905 411.4 8.2 33



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Fig. 3. Vampire bat walking with wings folded showing frontal view of face (Courtesy Nicandro Gomez, USIS, U.S. Embassy, Mexico City, Mexico).



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Fig. 4. Vampire bat in flight showing side view (profile) of face. (Courtesy J. Scott Altenback, Colorado State University, Ft. Collins, Colorado)



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Appendix A -Continued Estimated body Diphenadione dosage Heart girth weight (1.0 mg/kg)* (inches) (ibs) (kgs) Number of milliliters 69 941 427.7 8.6 70 977 444.4 8.9 71 1,013 460.4 9.2 72 1,051 477.7 9.6 73 1,089 495.0 9.9 74 1,129 513.2 10.3 75 1,169 531.3 11.0 76 1,207 548.6 11.0 77 1,249 567.7 11.3 78 1,2.88 585.4 11.7 79 1,334 606.4 12.1 80 1,374 624.5 12.4 81. 1,418 644.5 12.9 82 1,463 665.0 13.3 83 1,508 685.4 13.7 84 1,557 707.7 14.1 85 1,603 728.6 14.5 86 1,650 750.0 15.0 87 1,699 772.3 15.4 88 1,747 794.1 15.8 89 1,798 817.3 16.3 34



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CONTENTS Page Introduction ................................................... 1 Identification of the Vampire Bat ............................. 3 The Chemical Control Compound ................................. 5 Toxicity for Humans and Antidote ......................... 8 Toxicity for Cattle and Antidote ......................... 8 Control by Treating the Vampire Bat ........................... 8 Catching Vampire Bats .......... .............. 9 Treating Vampire Bats .......... ... ................... 12 Precautions .............................................. 16 Control by Treating the Cattle ................................ 18 When to Treat ............................................ 18 Haw to Treat ............................................. 19 Precautions .............................................. 21 Advantages and Disadvantages for Each Control Method .......... 22 Treating the Bats ........................................ 22 Advantages ........................................... 22 Disadvantages ....................................... 22 Treating the Cattle ......... I .............................. 23 Advantages ........................................... 23 Disadvantages ....................................... 23 Control Evaluation ............................................ 23 Pre-control Evaluation ................................... 23 Post-control Evaluation .................................. 27 The Use of Rabies Vaccines in Conjunction with Control of Vampire Bats ..................................... 27 If Vampire Bats Are Controlled, Why Vaccinate? ........... 27 If Cattle AreVaccinated, Why Control? ................... 29 i



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Treating the Cattle Advantages.--Injecting cattle eliminates direct contact with all species of bats. Since the syringe is a basic part of a veterinarian's equipment, there may be no need to purchase special equipment; except possibly the 14-gauge, 1-1/2-inch needles. Disadvantages.--Injecting cattle requires chute facilities for best results. It may be more expensive and time-consuming than treating the bats. All the vampires in a given colony may not feed on the treated cattle; hence, a smaller proportion of the vampire bat population may be killed. The injection method should be used only on cattle. CONTROL EVALUATION Pre-control Evaluation There are situations where the cost of controlling vampire bats may not be justified by their damage, and in other situations only one treatment method may be economical. To determine whether to treat, which method to use, and the most efficient scheduling of your time, each problem must be evaluated in advance. Form I is a proposed data sheet for pre-evaluation. All the information on the form can usually be collected by an extension agent or given by an interested rancher (see Form I). Bite counts should be made as early in the morning as possible. When examining the cattle for fresh bites, look everywhere (Fig. 12), 23



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Ai Fig. 11. Injecting diphenadione into rumien compartment of a cow's stomach. Note injection should be made in the area of the triangle drawn on the cow.



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(E) Topography: The physical features of the area will help in determining where the bats live and their possible flight paths. This may be important for effective trapping. (F) Where vampires roost: If vampire bats roost in water wells used by people for drinking, then only the injection method should be used. There is a possibility that treated bats may contaminate drinking water, so be very cautious. Post-control Evaluation Form II can be used for control and follow-up data. Such data are important for evaluating the success of control efforts, and valuable in determining when control should be repeated. If a central vampire bat control office is established, Form II should be forwarded to that office for filing. It is requested that copies of these forms also be sent to the authors in Denver, Colorado, where a vampire bat control surveillance center will be located. THE USE OF RABIES VACCINES IN CONJUNCTION WITH CONTROL OF VAMPIRE BATS If Vampire Bats Are Controlled, Why Vaccinate? All vampire bats will not be killed by using either of the described control methods; hence, there will always be the possibility of cattle being infected with rabies if they are not vaccinated. As a precaution, it is recommended that livestock be vaccinated against rabies even if 27



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Appendix C RECOMMENDED SELECTED READINGS The following publications give more details on the history of vampire bat control, and on the development of the new selective methods for reducing vampire bat populations. Flores Crespo, Raul, Samuel B. Linhart, Richard J. Burns, and G. Clay Mitchell. 1972. Foraging behavior of the common vampire bat related to moonlight. J. Mammal., 53(2):366-368. Linhart, Samuel B., Raul Flores Crespo, and G. Clay Mitchell. 1972. Control of vampire bats by topical application of an anticoagulant, Chlorophacinone. Boletin De La OSP (English Edition), Vol. VI, No. 2, 31-38. Mitchell, G. Clay, Richard J. Burns, Raul Flores Crespo, and Salvador Said Fernandez. 1973. Vampire bat control, 1934-1971. Tecnica Pecuaria En M~xico (in press). Thompson, R. Dan, G. Clay Mitchell, and Richard J. Burns. 1972. Vampire bat control by systemic treatment of livestock with an anticoagulant. Science, 177:806-808. 37



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A small, disposable automatic syringe may be useful for small herds. We have used: Wellcome Disposable 5-mi Automatic Syringe The Wellcome syringe can be purchased from: Schmidt and Allen Livestock Equipment 4699 Marion Street Denver, Colorado 80216 36



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Fig. 10. Vampire bats roost in caves in tightly packed groups. This close body contact helps to pass the topically applied control compound from one carrier to many others.



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vampire bat populations have been reduced in your area. Rabies is carried by many animals besides vampire bats. Vaccination is especially important if expensive individual animals such as purebred bulls or thoroughbred horses are involved. If Cattle Are Vaccinated, Why Control? Losses caused by vampire bats can be divided into two categories; direct losses and indirect losses. In Latin America direct losses by death of livestock from rabies are estimated to exceed 100 million dollars; but indirect losses, including malnutrition, approach 250 million dollars (see Constantine 1970, p. 374, for review). Treating livestock with antirabies vaccines does nothing to alleviate indirect losses, and vampire bat population reduction may be required in problem areas. PROPOSED AGENCY FOR INTERNATIONAL DEVELOPMENT AND DENVER WILDLIFE RESEARCH CENTER ASSISTANCE IN THE FUTURE The AID-supported PASA RA(ID) 1-67 will provide for future advisory or consultive services in organizing and developing vampire bat control programs on a selective basis. AID/DWRC will also assist in the recruitment of vampire bat control specialists for longer term projects. This may be accomplished through missionor country-supported Task Orders to the existing PASA, by direct hire, or by contract. 29



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for vampire bats. As a result, many other species of bats and cavedwelling creatures were indiscriminately killed. Now, however, inexpensive, safe, and selective methods have been developed for controlling vampire bat populations. In this pamphlet, we describe two methods of controlling vampire bats that were developed by the U.S. Bureau of Sport Fisheries and Wildlife. Research was conducted at the Denver Wildlife Research Center, Denver, Colorado, and at the Instituto Nacional de Investigaciones Pecuarias, Mexico City, Mexico. Field work was done cooperatively in Mexico (Fig. 2). Funds for the project were provided by the United States Agency for International Development PASA RA(ID) 1-6 7. IDENTIFICATION OF THE VAMPIRE BAT There are many different kinds of bats, but only the vampire bat feeds on blood and is the major vector of livestock rabies in Latin America. Therefore, only vampire bats should be treated with the control compound. Bats other than vampires feed on such things as nectar, fruit, and insects. These bats are beneficial to man because they pollinate plants, disseminate fruit seeds, and destroy insects, so they should not be harmed. Vampire bats may be separated from beneficial bats by carefully observing the following characteristics of vampire bats: (A) Color: Dark grayish-brown on upper parts, underparts paler. 3



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INTRODUCTION Vampire bats attack and feed on the blood of man and animals throughout most of Latin America. The calf shown (Fig. 1) has at least 10 fresh vampire bat bites and has lost approximately 250 ml of blood to the feeding bats. Also, additional blood has been lost because blood continues to flow from wounds after bats finish feeding. Blood loss, however, represents only one problem caused by-vampire bats, because their feeding habits have the potential of spreading rabies and their bites provide avenues for many other kinds of infections. Great numbers of livestock live within the geographic range of the vampire bat, which extends from Northern Mexico to Central Argentina. Many of these domestic animals suffer nightly attacks from vampire bats. The calf shown lives in a rabies-free area; therefore, it will not die from the disease, but many animals are not so fortunate. Annual losses attributed to vampire bat-transmitted rabies in Latin America are estimated at about one-half million head for bovines, and at about 2 million head for all kinds of livestock (see Constantine 1970, p. 374, for review). Because of the great loss of livestock to rabies, most Latin American countries have, at one time or another, attempted to reduce vampire bat populations. The methods used included gassing, poisoning, dynamiting, and smoking bats out of caves. These attempts proved to be expensive, sometimes ineffective, and most important, not specific 1



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FORM II Before treatment C rAfter treatment Control Livestock Freshl method used Livestock Fresh Rdcin Ranch and Date examined bites and number of Date of examined i bites in biting Location (No.) (No.) animals treated evaluation (No.) (No.) (%) 00I I I _ I I I 1. __ t _ ___ __ ._ _ _



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When trapping is completed for the night, carefully clean all debris, insects, etc., from the nets and store the nets carefully in plastic bags. If the nets are not completely cleaned before packing into the bags, they will tangle badly and it will be very difficult to use them again. Also, it is helpful to fasten the heavy cord ends (which attach to the poles) together and to somehow mark the first tie-cord so it can be recognized when nets are to be reused (Fig. 7). Treating Vampire Bats After removing all the bats from the nets (Fig. 8) and placing the vampires in a cage, take down the nets and store them as described previously. Now treat the vampire bats with diphenadione paste and release them. Two persons should work together when treating the vampire bats. One person should hold a bat securely by both wings while the other person applies about 1.5 cc of the control paste to the back of each bat. The paste should be spread evenly over the entire surface of the bat's back (Fig. 9). Release each vampire bat immediately after it has been treated. The number of vampire bats that should be treated at a corral varies considerably, and depends on local habitat conditions. We suggest that you treat one vampire bat for each five that you estimate are attacking the cattle herd. The estimate can be made by counting carefully the number of fresh vampire bat bites on the attacked herd very early in the morning. Generally, you can expect that each fresh bite seen represents one vampire 12



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Appendix B SPECIAL EQUIPMENT Mist Nets There are many types and sizes of mist nets. For capturing vampire bats we recommend: Length, 6 or 12 meters; height, about 2 meters; mesh, 36 millimeters; shelves, 4. Mist nets can be purchased from the following suppliers: E. A. Bergstrom Northeastern Bird Banding Association 37 Old Brook Road West Hartford, Connecticut 06117 U.S.A. Bleitz Wildlife Foundation 5334 Hollywood Boulevard Hollywood, California 90027 U.S.A. W. B. Davis 712 Mary Lake Drive Bryan, Texas 77803 U.S.A. Automatic Syringe. Vaccinating Outfit and Needles An automatic syringe we have used: Vaco Pistol Grip Automatic Syringe Shikles Automatic Syringe Filler Shikles Vaccinating Bag \Needles, 14 gauge, 1-1/2 inch disposable, luer-lock-type. These items can be purchased from many veterinary supply houses. 35



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Fig. 7. How to close and fold a mist net for proper storage. Both ends should be tied as shown in the diagram. (Courtesy AID/RTAC, U.S. Embassy, Mexico City, Mexico)



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Appendix A DIPHENADIONE DOSAGE SCALE FOR CATTLE Estimated body Diphenadione dosage Heart girth weight (1.0 mg/kg)* (inches) (ibs) (kgs) Number of milliliters 31 100 45.4 0.9 32 106 48.2 1.0 33 116 52.7 1.1 34 130 59.1 1.2 35 141 64.1 1.4 36 150 68.2 1.4 37 164 74.5 1.5 38 177 80.4 1.6 39 192 87.3 1.7 40 207 94.1 1.9 41 222 100.9 2.0 42 238 108.2 2.2 43 255 115.9 2.3 44 273 124.1 2.5 45 290 131.8 2.6 46 308 140.0 2.8 47 329 149.5 3.0 Rate applies for usual injectable formulations containing 50 milligrams of diphenadione per milliliter of compound. 32



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CHEMICAL CONTROL OF VAMPIRE BATS DENVER WILDLIFE RESEARCH CENTER U.S. BUREAU OF SPORT FISHERIES AND WILDLIFE in cooperation with INSTITUTO NACIONAL DE OFFICE OF AGRICULTURE INVESTIGACIONES PECUARIAS AND FISHERIES SECRETARIA DE AGRICULTURA BUREAU OF TECHNICAL ASSISTANCE Y GANADERIA U.S. AGENCY FOR GOBIERNO DE MEXICO INTERNATIONAL DEVELOPMENT



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FORM I Date Ranch: Owne r: Location: No. of cattle checked for fresh bites: (check in morning) No. of fresh bites: Facilities a) Corrals (size and No.) b) Chutes c) Distance cattle are from these facilities when being bitten Miscellaneous a) Type of livestock (Dairy or Beef cattle): b) Total number of livestock: c) Rainy season: d) Seasonal variation in biting: e) Topography: f) Vampires roost in: Notes: 26



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in heat to 1450 C and does not decompose readily. The compound should be stored in a cool place, but refrigeration is not necessary; also, it is a lethal agent so it should be stored in a safe place. Toxicity for Humans and Antidote Diphenadione is relatively nontoxic to humans. An average adult (70 kilograms) using diphenadione as medication can take up to 30 milligrams daily; consequently, chances of poisoning from ingesting the control compound are very slight. However, in case of accidental human poisoning, immediately consult a medical doctor. The antidote for diphenadione in humans is vitamin K1. Toxicity for Cattle and Antidote The dose level of diphenadione injected into cattle for vampire bat control is 1 milligram per kilogram of body weight of the bovine. But up to 5 milligrams per kilogram has been experimentally injected in cattle without producing poisoning, so there is a wide margin for error. Nevertheless, should a massive overdose accidently occur, consult a veterinarian. The antidote for diphenadione in cattle is vitamin K2. CONTROL BY TREATING THE VAMPIRE BAT Control by treating vampire bats should be done at corrals where the bats are attacking livestock. The control is done by: 8



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4: Fig. 8. Captured vampire bats ready to be removed and treated with the diphenadione paste.



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but closely examine the neck, axillae and tail; vampires sometimes prefer to bite in these areas. A fresh bite may still be oozing blood or will be a fresh concave hole. Examine black cattle in particular, because vampires sometimes prefer to bite the dark animals in a herd. The type of facilities available are very important in determining which control method to use. Corralsfor cattle are usually required if vampire bats are being captured and treated; chutes facilitate injecting cattle. It is important that the facilities be close to the area where cattle are being heavily bitten to insure successful results. Under "Miscellaneous" on Form I, several items will assist you in determining how and when to control: (A) Type of cattle: Dairy cattle are usually easier to inject than beef cattle; and management practices, that may influence control measures, are quite different. (B) Rainy season: If there is a defined wet and dry season, then treating during the dry season is usually easier. (C) Variation in biting: In some areas of South America, vampire bats apparently migrate at certain times of the year. Control should be conducted when biting incidence is highest. (D) Number of livestock: The size of the herds may influence which control method you choose for convenience or economic reasons. 25



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Fig. 1. Calf with multiple vampire bat bites on face, ears, and neck.



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Fig. 5. Mexican biologist showing proper way to set mist nets outside of a corral. 10



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CONTENTS -Continued Page Proposed Agency for International Development and Denver Wildlife Research Center Assistance in the Future ............................. o.............o.......29 Literature Cited .....................o............................31 Appendix A -Diphenadione Dosage Scale for Cattle.................32 Appendix B -Special Equipment....................................35 Appendix C -Recommended Selected Readings......................... 37



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er ,All 001. Fig. 12. Vampire bats bite cattle almost anywhere. Here a vampire is biting a cow on the foot (fetlock) area. (Courtesy Nicandro Gomez, USIS, U.S. Embassy, Mexico City, Mexico) 24



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LITERATURE CITED Constantine, Denny G. 1970. Bats in relation to the health, welfare, and economy of man. In Biology of Bats, Vol. II. William A. Wimsatt [ed.], Academic Press, New York and London, pp. xv + 477. 31