BOOKS OF RtfiDIfGS - PAHO/WHO

MANACGEIttI SC'IEN.'t
Vol. 2Z. No. 4, F,-cemnhr. 197'
Pr,*,t in C'.S.A.
-90 -
A COMPUTER SIMUILATION MODEL FOR THE
CONTROL OF RABI31S IN AN UJ13AN AREA OF
COLOMBIA*t
RAII'H R. FRI-tl CI¡S; AND JUAN PRAW §)A
A siminulation itilItJl is develhq>ed Jcs.ribIing ihie itr:ai.llesiloll o ca ;iitic f;-lllsv: witvaill ;¿liJ
between 116 spaiially distribuied barrios (ncighborhoods) in Calli Colombia. The discrete
time. dynamic model considers both discrete randomni variables (incubation and infective
periods. appearance and movemitent of rabid dogs through the city. ete.) and delerministic
vatriables (Jc¡nogr:iphlic ouipuiluenis of harrio cainii¡ populalailions). V:hlties for tIh ilrnp
variables were aequired throuigh field observalions, other Colombian sources. and a review of
the literature. Vanriots caniine vaccinatlion slrategies were tested in the model over a Ien-vear
planning horizon for liheir cost-cefeetiveness with regard to ihe prevention of canine rabies.
The model is reommnended to ¡he l>an Amnerican Hlealth Organization lo he used a. an
interactive gaminiug nilel to aid heali ll sysiClmli i;al:igers il (C'ali. C'thlolulia ¿aind inl otller l.;liiii
American cities in seliedulilg I(he
cost-effective mnanner.
tine and locations of vaccination teams in a more
1. hlilrOdtl¢mlion¡
The problem of rabies has bcen with man for many years. Celsus. as far back as the
first century A.D.. described the infection in man and observed that the disease is
transmitted by the bite of a rabid animal. Since then. it has been shown that rabies is
a viral infection of ¡he nervous systemi primirily of warm-bloolded aninials. anid is
invatriably fatal once ¡ihe virus has infected the body 120]. 1331.
In the last twenty years. the United States has rid its urban dog populations of this
disease but the problem still lingers in wildlife. namely skunks and foxes [35]. Since
man has his closcst conilct with urban animials. the climination of rabies fronm dogs
has reduced human rabies in the United Sidtes lo one or two cases per ycar.
Unfortunately. South anid Central American countries have not liad simiilar success
[251. Since other diseases compete for allocations within the health budget, rabies
control programis have not always rceeived ¡he funds necessary to climilnate the
problem in urban areas (2].
The World Health Organization feels that the vaccination of dogs is one of the most
important methods for controlling rabies in cities and many immunization campaigns
have proven thc efficacy of this approachi [41]. In addition. they recomnmend that stray
dogs be euthanized in order lo decrease ihe canine density in the streets to such a
point that there is little opportunity for rabies transmission. The collection and
subsequent lilliidg of stray dogs. however, is highly unpopular as evidenced by the
disdain shown throughout the world toward the neighborhood dog catcher. The
assumption is made by the authors t. ,t in Colombia' a democracy with a history of
internal violence, a caninc euthanasia campaign would be politically unacceptable.
Therefore. the scope of our analytical effort'is liniited to a control program fcaturing
different vaccination policies.
Processed by Professor William W. Cooper, Departmental Editor for Public Aminiinstration and
Associate Editor E. S. Savas: received Ociober 1974.
t This research study was supported by the Tulane University Intlernational Center lor Medical Rcecarch
and Training. Grant AI-10050 from the National Institute of Allergy and Infectious Diseases. National
Institutes of Health, Unitei Siates Public llealth Scrvicc, Washington. D. C.
: I.ouisiana Stale University Medical School.
f Natiounal Company ol Basic ('omnoditicis (CONASUI>O). Mexico andt National Politemc lutie Institutc
Mexico.
. . Copyrtght £ 1975, The Institute of stani$;omcnt Sclencem