Document 2303
 DOCN  M94A2303
 TI    A mathematical model for HIV transmission among IDU.
 DT    9412
 AU    Yang HM; de Carvalho HB; Massad E; Faculdade de Medicina da Universidade
       de Sao Paulo, Brazil.
 SO    Int Conf AIDS. 1994 Aug 7-12;10(1):335 (abstract no. PC0273). Unique
       Identifier : AIDSLINE ICA10/94370272
 AB    We propose a mathematical model for the estimation of human
       immunodeficiency virus (HIV) prevalence among intravenous drug users
       (IDU) and needles (the injection apparatus), which are the dynamic
       variables of the model. The infection transmission mechanisms are
       assumed to be via both sexual and needle sharing habits. The model
       provides a tool for the estimation of the impact of interventions, like
       the increase of the number of needles and/or the removing rate of
       needles on one hand and the bleaching of the needles on the other, to
       guide public health authorities. The model considers two cases: the
       sexual transmission rate of HIV below or above a certain threshold value
       (or, the existence or not of the disease). In this first case, the model
       provides the threshold values for the IDU density (the number of IDU
       divided by the number of needles) and for the bleaching parameter. In
       the second case, there is no possibility of eradication by the two
       mechanisms of intervention mentioned. Sensitivity analysis shows that
       the increasing of the IDU density by a program of needles distribution
       is more efficient than bleaching the needles. The intervention on IDU
       density or the removing rate of needles has the same effect. The dynamic
       of HIV prevalence in both IDU and needles are also studied by
       introducing a certain amount of infected needles in a previously
       non-infected IDU community. The equilibrium value is reached more
       rapidly when the introduction of infected needles increases. When we
       increase the IDU density or the bleaching parameter values, the dynamic
       variables obey the same rule, that is, there is a time delay to reach
       the equilibrium values. However in the second case this time delay is
       tenfold greater. The dynamic analysis shows that the intervention on the
       bleaching parameter, due to the time delay, seems to be more efficient
       to control the disease, but the intervention on the IDU density is even
       more efficient as shown by sensitivity analysis.
 DE    Brazil/EPIDEMIOLOGY  Human  HIV Infections/EPIDEMIOLOGY/PREVENTION &
       CONTROL/*TRANSMISSION  *HIV Seroprevalence  *Models, Statistical  Needle
       Sharing/*STATISTICS & NUMER DATA  Sex Behavior  Sterilization/STATISTICS
       & NUMER DATA  Substance Abuse, Intravenous/COMPLICATIONS/*EPIDEMIOLOGY
       MEETING ABSTRACT

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).