RABIES TRANSMISSION AND
IN LATIN AMERICA
TRANSMISSION DE RABIA
Y PRODUCTION DE
1974 ANNUAL REPORT
INFORMED ANNUAL 1974
A Cooperative Program
U.S. AGENCY FOR
Bureau of Technical Assistance
Office of Agriculture and Fisheries
U.S. DEPARTMENT OF
Fish and Wildlife Service
Division of Population Regulation Research
Denver Wildlife Research Center
1974 ANNUAL PROGRESS REPORT*
G. Clay Mitchell, Richard J. Burns,
John W. De Grazio and Donald J. Elias
Latin America Ministries of Agriculture
United States -
Agency for International Development (AID)
Fish and Wildlife Service (FWS)
Denver Wildlife Research Center (DWRC)
(Work Unit DF-104.3)
*Results Incomplete and Not for Publication, Release, or Use Without
Authority of the Director, Denver Wildlife Research Center.
A study was continued in Brazil to determine the recovery rates of
vampire bat populations after reductional control. Twenty-seven
months after control, vampire bat populations remained low when
compared to the precontrol populations.
The effects of vampire bat, predation on milk production was studied
Active vampire bat control campaigns were initiated in Brazil,
Colombia,.Guyana, Nicaragua, Panama and Venezuela.
Training sessions were held in Guyana and Ecuador.
Meetings were held with Ministry of Agriculture personnel in Guatemala,
Honduras, El Salvador, Paraguay and Peru.
Five manuscripts were published or are in press.
*This research was conducted with funds provided to the U.S. Fish and
Wildlife Service by the Agency for International Development under
the project "Control of Vertebrate Pests: Rats, Bats, and Noxious
Birds," PASA RA(ID) 1-67.
Annual bovine losses resulting from vampire bat-transmitted rabies
are estimated at approximately 1,000,000 head in Latin America.
Daily loss of blood, mortality of other livestock, and secondary
infections further aggravate the problem.
The original objective of research under this work unit was to
develop techniques for controlling vampire bats. The project began
in June 1968 and was funded by the Agency for International Develop-
ment (AID) and the Mexican Government under a Participating Agency
Service Agreement with the U.S. Fish and Wildlife Service (FWS),
and the Instituto Nacional de Investigaciones Pecuarias (INIP).
Laboratory and field investigations were conducted at the :FWS Vampire
Bat Research Station located at the INIP in Mexico City, Mexico.
The station officially closed in December 1973, after species-specific
control methods were developed.
In 1974 AID continued to fund this program with the objective that
Denver Center biologists would help Latin American countries develop
and initiate control campaigns through training and technical
VAMPIRE BAT CONTROL METHODS
Methods for reducing vampire bat populations developed by this
project are described in the 1971 and 1972 Annual Reports and in
several scientific journals.
Topically Treating Vampire Bats with Diphenadione
Vampire bats are captured with mist nets that are set around corralled
cattle or at cave entrances. Approximately 1.5 cc of a vaseline-
diphenadione mixture is placed on the dorsal surface of each captured
bat and the bat is released. The bats return to their roost, and
because they live in compact colonies, physically pass the chemical
from one to another. The bats die after ingesting the chemical during
Systemically Treating Cattle with Diphenadione
Cattle are injected (intraruminal) with 1.0 milligram of diphenadione
per kilogram of body weight. The drug is absorbed and circulates in
the blood. Any vampire bat that feeds from a properly treated animal,
within 72 hours after treatment, receives a lethal dose of the drug.
Treating all the cattle in a herd gives 90% to 95% reduction in fresh
RECOVERY OF VAMPIRE BAT POPULATIONS AFTER CONTROL
The study was designed to measure how fast vampire bat populations
recover after being reduced by control measures. The time necessary
for vampire bats to reestablish sizeable populations in control areas
will determine how frequently control needs to be repeated.
This study was initiated in 1971 and more details were presented in
the 1971, 1972 and 1973 Annual Reports. The basic procedure was to
count fresh bites on cattle and apply control methods. Postcontrol
censusing was based on fresh vampire bat bites on, the same cattle.
Results and Discussion
Table 1 summarizes data from two ranches near Cabo, Pernambuco, Brazil.
Twenty-seven months after treatment the biting incidence was 80.8%
less than pretreatment counts at Engenho Santo Estavo and 92.5% less
at Engenho Velho.
Table 1. Continuing results from ranches near Cabo, Pernambuco, Brazil, where vampires
were topically treated with Diphenadione
Ranch No. Cattle No. Fresh No. Vampires %
and Date Examined Bites Treated Reduction
Engenho Santo Estavo
Day of treatment 44 73 33
Jan 72 (14 days) 44 0 100
Jan 73 (1 year) 45 4 -94.5
Aug 73 (19 months) 45 4 -94.5
Apr 74 (27 months) 42 14 -80.8
Day of treatment 60 67 54
Jan 72 (14 days) 60 3 95.5
Jan 73 (1 year) 60 6 91.0
Aug 73 (19 months) 60 6 91.0
Apr 74 (27 months) 67 5 92.5
THE EFFECTS OF VAMPIRE BAT CONTROL ON MILK PRODUCTION
Vampire bats are a common predator of cattle in many areas of Latin
America. Though the main problem is that of bat-transmitted rabies,
there is widespread belief that blood letting and harassment of dairy
cattle will lower milk production. Numerous statements to this effect
can be found in the literature, but there is an apparent lack of
documentation to support them. To test this contention, a study was
conducted, in cooperation*with the DWRC Section of Supporting Sciences,
on a dairy farm near Quito, Ecuador.
Fresh vampire bite counts were made prior to treatment for vampire
control and at 30 and 60-day intervals following treatment. Control
was achieved using the systemic method in which 1 mg/kg of diphenadione
is injected into the rumen of the cow (Figure 1). Milk and blood
samples were collected for measurement of various parameters,and milk
production records were obtained for each animal both pre and post
treatment (Figure 2).
Results and Discussion
Vampire predation on the herd was dramatically reduced from an average
of 3.95 bites/cow to 0.12 bites/cow at the end of the 60-day posttreat-
ment period, but milk production remained virtually unchanged from a
pretreatment mean of 28 lbs/cow/day (Figure 3).
Dr. R. Dan Thompson, DWRC, demonstrating how to inject diphacinone near Quito, Ecuador.
Figure 2. Donald J. Elias, AID biologist, checking blood
samples used in a study of effects of the vampire
control procedure on health and production of dairy
cattle in Ecuador.
I 3- \ -- a.
o I 'I
0 10 30 60
Figure 3. Comparison of averages of fresh vampire bites and milk production before and after
Developing Vampire Bat Control Programs
The vampire bat control program, under the direction of Dr. Carlos
Eduardo Autran de Freitas, is part of the national rabies control
program. The program will be incorporated into the existing Infra-
structure of the national campaign against hoof-and-mouth disease.
Vampire bat control and research was initiated this year in northeast
and southern Brazil. In the northeast, control programs were initiated
in the states of Maranhao, Piaui, Ceara, Pernambuco, Alagoas, Sergipe,
and Bahia. Control work has begun in Parana and Santa Catarina in
the south. Approximately $65,000 was allotted by the Ministry of
Agriculture for this program in 1974 with plans to increase funding
In addition to AID-sponsored personnel, other international organiza-
tions have given technical assistance to Brazil. In March 1974,
Drs. Rexford Lord and Jose Rodriguez Torres, Panamerican Zoonosis
Center, Buenos Aires, Argentina, trained 12 veterinarians in the
state of Rio Grande do Sul. The coordinator of animal health programs
in this state reported that they plan a large campaign in 1975.
The Colombians planned to begin a regional program in the northern
states of Guajira and Cesar. In 1971, a rabies outbreak started near
Fonseca, Guajira, and has moved steadily southward into the state of
Cesar. In this area, over 800 cattle valued at $175,000 have died from
vampire bat-transmitted rabies, and deaths continue to be reported.
On a small ranch near San Juan del Cesar, Guajira, 99 of 100 cattle
died in November and December.
The original plan was to create a buffer zone at the front of the
infected area in an attempt to stop rabies from infecting the free
zone. Funding was not available to conduct the work this year, and it
has been rescheduled for early 1975.
The Ministry of Agriculture has appropriated $40,000 for vampire bat
control in 1975. They plan to have large regional campaigns in the
states of Guajira, Cesar, Narino, Caqueta and Antioquia.
Field demonstrations of the control methods were given to Ministry
of Agriculture veterinarians in June. The Ministry plans a state-by-
state evaluation of the problem prior to initiating a control program.
Figure 4. Dr. Surujballi Ramudit explaining to school children that vampire bats actually exist.
This was part of the agricultural display at the national exhibition in Georgetown, Guyana.
AID-trained members of the Nicaraguan national campaign against vampire bats.
Dr. Rodrigo Gonzalez (standing, third from left), Director General of Livestock
Production, coordinates the program.
The Ministry of Agriculture/Guyana, the International Bank of
Reconstruction and Development, and AID/Guyana jointly funded
training in Guyana in October. Demonstrations were given near
Georgetown for veterinarians and near Lethem for cattlemen. In
addition, the Ministry of Agriculture and AID had a display at
the annual National Exhibition held in Georgetown (Figure,4).
The Ministry of Agriculture has begun a regional control program and
intends to fund a national campaign for 1975. The campaign probably
will begin in the Rupununi Region where vampire bat rabies is endemic.
The National Campaign began in March 1974. Nicaragua has appropriated
$570,000 for a 5-year effort ($170,000 for the first year and $100,000
for each year thereafter). Twenty technicians have been assigned to
the campaign and are working in teams of two men to a vehicle (Figure 5).
Nicaragua's campaign can serve as a model for other Latin American
countries. Their organizational chart is illustrated below.
~iallc-5 E6 1
The ten control teams submit weekly reports to the field coordinator.
These reports include ranches worked and follow-up data. The field
director submits a monthly report to the coordinator for tabulation
and statistical analysis.
The 1974 results from the Nicaraguan campaign are summarized in
Table 2. They have been 90% effective in reducing vampire predation.
Projected plans are to finish the campaign in Boaco, Granada and
Rivas before expanding to other departments.
The incidence of human predation apparently is quite high in Nicaragua.
Over 100 Nicaraguans in the town of Granada, most of whom were
children, were bitten by vampire bats this year (Figure 6). The
bats were living in city wells,and personnel from the campaign
eliminated the problem.
Table 2. Statistics of the National Campaign Against Vampire Bats Nicaragua (1974)
Ranches Animals Fresh Vampires Cattle Animals Fresh- Reduction in
Department Visited Examined Bites Treated Treated Examined Bites Fresh Bites (%)
Ranches not evaluated
Ranches not evaluated
Rio San Juan
Dec. not evaluated.
Dec. not evaluated
Ranches treated in Dec. not evaluated
Figure 6. Sra. Lucresia Gomez de Castillo is one of more than 100
citizens of Granada, Nicaragua who were bitten by vampire
bats in the past year. Senora Gomez was sleeping under
mosquito netting when the incident occurred.
Other Central American Countries
Meetings were held with Ministry of Agriculture personnel in Guatemala,
Honduras and El Salvador. The Central American countries have an
agreement with Panama and Mexico to assist each other with agricultural
programs. Since Nicaragua has a well-established campaign, plans are
to have Nicaraguan veterinarians help other Central American countries
develop programs. In February 1975, Nicaraguans will train veterinarians
in Costa Rica.
Panama began a regional control program in the states of Colon and
Panama. In 1975 they plan to expand and have seven control teams
assigned to the seven agricultural sectors in Panama. Each team will
consist of one veterinarian and two assistants. Three additional
teams will initiate a vampire control program in the Darien strip
which borders Colombia. The Ministry of Agriculture has appropriated
$37,000 for the campaign.
Paraguay and Peru
Ministry of Agriculture veterinarians were briefed on the control
methods and developing programs in neighboring countries. Both
countries plan to develop programs next year.
Dr. Rexford Lord, bat specialist of the Panamerican Zoonosis Center,
trained Surinam veterinarians this past year.
Venezuela has a regional campaign in the western part of the country.
1. Burns, R. J. and R. Flores Crespo. 1975. Notes on local
movement and reproduction of vampire bats, Desmodus
rotundus in Colima, Mexico. Southwestern Nat. 19(4):
2. Flores Crespo, R., R. J. Burns, and S. Said Fernandez. 1974.
Evaluacion de una tecnica para el combat de los vampires
en sus refugios. Bol. Ofic. Sanit. Panamer. 76(5): 427-432.
3. Flores Crespo, R. and S. Said Fernandez. 1974. Reduccion de
la dosis de anticoagulante (Difenadiona) para el control de
los vampires. Tecnica Pecuaria en Mexico. No. 24. (in press).
4. Mitchell, G. C., R. J. Burns and A. L. Kolz. 1974. Rastreo del
comportamiento nocturno de los murcielagos vampires por
radiotelemetria. Tecnica Pecuaria en Mexico. No. 24 (in press).
5. Piccinini, R. S., C. G. Araujo and G. C. Mitchell. 1974.
Experimentos realizados com o anticoagulante diphenadiona,
para o combat ao vampire comum, Desmodus rotundus, nos
Estados de Pernambuco y Paraiba, Brazil. Proc. 14th
Congress Brasileiro de Medicina Veterinaria, Sao Paulo,
Brazil, Veterinarias 3(3): 58-59.
Precontrol Data Collection Sheet
Practically every country with an active campaign has collected
precampaign data to determine where to most effectively initiate
the program. Following is a translation of the Colombian data
collection sheet which was distributed to Ministry of Agriculture
veterinarians throughout the country.
Division of Cattle Production
National Animal Health Service
Special Diseases Campaign
In order to plan programs for the control of damage caused by vampire
bats in some cattle ranches of the country, it is necessary to carry
out a general survey to define and locate the problem. Considering
the nature of the Servicio Nacional de Sanidad Animal, this survey
could be carried out within the normal duties of the Sector
The information listed below should be collected as soon as possible
in areas with a history of damage. The cattlemen should be advised
of the technical possibilities of vampire bat control as outlined in
the attached leaflet.
Once the corresponding information has been received and evaluated,
it will be possible to present practical alternatives to go ahead
with the control. The original of this questionnaire must be sent
directly to: Servicio Nacional de Sanidad Animal, Oficinas Nacionales,
Campana gnfermedades Especiales, Apartado Aereo 29743 Bogota. One
copy must be left in the sector office and another sent to the
respective Health Supervisor before November of this year.
General Survey On The Presence Of Vampire Bats
1. Region No. 2. State __3. Municipality___
4. Ranch 5. Owner
6. Total Cattle 7. Total Horses
8. Type of Operation
9. No. of cattle checked the of 1973.
10. No. of cattle that had fresh bites on this date_
PUBLICITY PAMPHLET DISTRIBUTED IN NICARAGUA
Following is a translation of the pamphlet distributed by Ministry
of Agriculture-Nicaragua to announce their national campaign against
MINISTRY OF AGRICULTURE AND LIVESTOCK
NATIONAL CAMPAIGN FOR THE CONTROL OF VAMPIRE BATS
Many cattle in Nicaragua are affected by internal and external parasites.
Among these, one especially worth mentioning is the vampire bat whose
population in this country is very large.
There are more than 100 species of bats in Nicaragua, but only the
species Desmodus rotundus feed on the blood of cattle and is the main
vector of paralytic rabies.
WHAT LOSSES DO VAMPIRES CAUSE IN NICARAGUA?
Vampire bats cause great losses to the cattle industry in Nicaragua.
These losses can be divided into two categories:
1. Direct losses Direct losses are when cattle die from
paralytic rabies. The virus is transmitted by vampire bats.
2. Indirect losses Indirect losses are where vampires take
away nutrients an animal has assimilated. Each vampire laps
30 cc of blood. An additional 20 cc will flow from the wound.
Thus, for each bite, an animal loses an average of 50 cc of
Furthermore, when vampires feed on cattle they cause:
a. Reduced milk production.
b. Retarded development of calves.
c. General weakening of cattle, due to loss of blood.
d. Increased susceptibility to other diseases.
WHAT ARE SOCIAL PROBLEMS CAUSED BY THE VAMPIRES?
Vampires also are a problem to public health. They attack and feed
on rural and urban populations.
WHAT SPECIES DO VAMPIRES ATTACK?
to man, vampires will attack cattle, pigs, horses and
this reason, this serious problem should receive special
The incidence of paralytic rabies is increasing daily:
there were six cases of paralytic rabies.
there were 45 cases of paralytic rabies.
there were 300 cases of paralytic rabies.
WHERE ARE VAMPIRES FOUND IN NICARAGUA AND WHERE DO THEY LIVE?
Vampires can be found throughout the Republic. They live in caves,
wells, hollow trees and tunnels.
HOW CAN YOU TELL IF THERE ARE VAMPIRE BATS ON YOUR RANCH?
It is very easy to determine if you have vampires on your ranch.
Simply look for fresh bites on your animals. These bites are usually
found on the neck, ears, tail and axillae. It is best to examine the
cattle in the morning.
WHAT IS NEEDED TO CONTROL THE VAMPIRE POPULATIONS?
The Ministry of Agriculture and Livestock has dedicated itself to
controlling vampires. Toward this effort the technicians will need:
1. Your information that vampires are found on your ranch.
2. Your permission to place nets around your corrals.
3. Your permission to treat your cattle with a vampiricidal agent.
WHAT METHODS WILL BE USED TO CONTROL THE VAMPIRES?
The Ministry of Agriculture and Livestock will use three methods to
control vampire bat populations.
1. Capture vampires with special nets.
2. Inject a vampiricidal agent intraruminally into cattle.
3. Innoculate cattle with rabies vaccines.
HOW CAN YOU OBTAIN THESE SERVICES?
The Ministry of Agriculture and Livestock wants to provide these
services free of charge to all cattlemen. To obtain the services,
visit one of the Agricultural Extension Agencies where a veterinarian
will provide you with information. You can also get information from
the Ministry of Agriculture and Livestock located at Km 12 of the
North Highway, Managua.