Epidemiological Risk - Health - Lecture Slides, Slides of Public Health

Download Epidemiological Risk - Health - Lecture Slides and more Slides Public Health in PDF only on Docsity!

New Approaches to

Epidemiological Risk

Assessment Management

One of the most important tasks of modernepidemiology is the effective monitoring,forecasting and management of epidemiologicalsituation and epidemiological risk assessment.Creation of information computer system (ICS)on the basis of epidemiological software andmethods of mathematical modeling is moreeffective strategy of above task solution. It is theimportant auxiliary tool for minimization ofexpenses on prevention of epidemic andliquidation their consequences.

On the other side the Chernobyl disasterand events of September 11, 2001 haveshown that even negligible value of riskcan occur. In this connection widespreadgets understanding that the unique andsingle character of so sophisticatedsubject as epidemic, and especially globalepidemics does not allow in some cases touse correctly the theory of probability forrisk assessment.

There is another approach to risk assessment,which may prove more useful here. In thisapproach the risk estimation is carried out usingthe theory of smooth functions allowing thedetermination of critical parameter values whichdescribe the levels of control system intensitiesand reserve possibilities. The risk is estimated ona degree of the system parameter approximationof the bifurcation values, which characterise thesystem’s transition from one steady state (norm),to another (catastrophe/epidemic).

On the basis of this approach ICS iselaborated for epidemiological taskssolution. It includes the database

of infectious diseases, software for basic

statistics and epidemiological modeling.The distinctive feature of elaborated systemis joining in technological gear software thatallows the different dynamic andoptimization tasks solution.

There are following main tasks: 1. Forecasting of infectious diseases arisingand spreading.2. Risk assessment of epidemic arising andanalyses of efficacy of carry out prophylacticmeasures.3. Decision making support for optimalmeasures elaboration, which permit tominimize the infectious diseases increase andspreading.4. Monitoring of epidemiological situation.

Optimization problems were solved by a methodof casual search. The multicriterion statements of aproblem were considered, to find an optimumcontrol, which would permit to maximize the levelof manufacture and quality of life, on the onehand, and minimize epidemiological risk ofaccidents and level of pollution, on the other. Thiswork also illustrates the above approachapplication to HIV/AIDS risk assessment fordifferent countries using new WHO’s data

Main postulates

. Let us introduce some postulates that we

take as a basis of model elaboration.1.Epidemiological system is aggregate of elements thatcharacterize different aspects of infectious diseases arisingand spreading. Some of these elements belong to anothersystems – ecological, biomedical, and social.2. Epidemiological system has

three steady states

. Using

Guastello [5] idea about organization safety of complicatedsystems

it

is

possible

to

put

forward

a

following

suppositions.

The first

state is characterized by existence of

external

and

internal

safety

(

norm

).

Second

state

is

characterized by only external safety, as internal one isbroken (intermediate state or

preepidemic

).

Third

state

is

characterized by full loss of any safety, as external, sointernal (

epidemic

).

The

mathematical

model

for

epidemiological

risk assessment

The relationship between epidemic safety (X)and above-mentioned parameters aredetermined for butterfly catastropheby following polynomial :

X5 + aX3 + bX2 + cX + d = 0

Algorithm of epidemiological risk assessment.

On

the

base

of

works

dealing

with

methods

of

catastrophes

theory

a

following

algorithm

of

epidemiological risk assessment can be suggested.

Information

characterizing

agents

of

diseases,

population immune status and restoration possibilities,health

care,

environment

impacts

is

inputted

from

modern health care systems (EPID Info 2000, etc).

2. The indices characterizing appropriate group of parameters

are

estimated

by

means

of

developed

mathematical models with the help of inputted data.

Forecasting of infectious diseases arising andspreading.Optimization problems of risk management.

The mathematical model was used to solve some problems of optimum redistribution of resources

with the purpose of minimization of epidemic risklevel and pollution and maximization of lifequality and GNP. The shares of the capital,directed on restoration of resources, on health careand on struggle with pollution were chosen ascontrol parameters..

Optimization task solution and risk assessment

On

Figure 3

the modeling results are shown,

which reflect dynamics of main model variableswith fixed control effects, and with control effectsvarying in the course of time, and also thedynamics of control effects.

Analysis of WHO date on HIV/AIDS risk assessment for different countries

Examine the example of above approach application to HIV/AIDS escalation riskassessment. The WHO data for differentcountries presented at Table 1 wereutilized.

Let us introduce integrated indices

characterizing state of demographic situation(D), economics (E), health care (H) andeducation (E). Using these indices, whichcharacterize degree of the epidemiologicalsystems’ functions violation and theirreserves, above mathematical method of riskassessment may be utilized.