Controling communicable diseases pdf - د. ناديا

Programs for controlling

communicable disease

Dr. Nadia Aziz
C.A.B.C.M
Department of community medicine

1- Explain the factors interaction that cause the

diseases.

2- Explain the mode of transmission of disease.

3- Discuss the levels of prevention of diseases.

4- Definitions encountered in the controlling of

communicable diseases.

5- Explain the classes of reporting of communicable

diseases

Objectives

Human disease does not arise in vacuum. I t results

from an interaction of the

host

(a person), the

agent

( e.g. a bacterium)& the

environment

(e.g.

contaminated water supply).

Virtually all diseases result from interaction of

genetic

and

environmental

factors, with the exact

balance differing for different diseases.

Introduction

HOST

ENVIR ONMENT

AGENT

VECTO
R

1-Direct (person to person)

2-Indirect

a-Common vehicle

- single exposure

- multiple exposures

- continuous exposures

b- Vector

Modes of transmission of disease

Primary prevention

An action taken to prevent the development

of a disease in a person who is well &

does not

have the disease

question.

Levels of prevention of disease

Secondary prevention

Identification of people who have

already

developed a disease

, at an early stage in the

diseases natural history, through screening &

early intervention.

Levels of prevention of disease

Tertiary prevention

The

prevention of complications

such as

disability.

L evels of prevention of disease

Identification

: presents the main

clinical

features

of the disease and

differentiates

from others that may have a similar clinical

picture. Also noted are those

laboratory tests

most commonly used to identify or confirm the

etiological agent.

Control of disease

Infectious agent

: identifies the

specific

agent

or agents causing the disease; classifies

the agent(s); and may indicate its (or their)

important

characteristics.

Control of disease

Occurrence

: provides information on

where

the disease is known to occur and in

which

population

groups it is most likely to occur.

Information on past and current outbreaks may

also be included.

Control of disease

R eservoir

I ndicates any person, animal, arthropod, plant, substance

or combination of these,

in which an infectious agent

normally lives and multiplies

, on which it depends

primarily for survival, and where it reproduces itself in

such a manner that it can be transmitted

to a susceptible host.

Control of disease

Mode of transmission

Describes the

mechanisms

by which the

infectious agent is spread to humans.

a) Direct

b) Indirect

Control of disease

Incubation period

Is the time interval between

initial contact

with the infectious organism and the

first

appearance of symptoms

associated with the

infection.

Control of disease

Period of communicability

Is the time during which an infectious agent

may be transferred directly or indirectly

from

an infected person to another person

, from an

infected animal to humans, or from an infected

person to animals, including arthropods.

Control of disease

Susceptibility

: (including immunity) provides

information on human or animal populations at

risk of

infection

, or that are

resistant

to either infection or

disease. Information on subsequent immunity

consecutive to infection is also given.

Control of disease

Methods of control

: are described under the

following headings:

Preventive measures

: for individuals and groups.

Control of patient, contacts and the immediate

environment

Control of disease

measures designed to

prevent further spread

of the

disease from infected persons,

and specific

best current treatment

minimize the period of communicability

and to

reduce

morbidity and mortality

R ecommendations for isolation of patients depend first

on “

universal precautions’

’

Control of patient, contacts and the

immediate environment:

The I HR ( 2005) are designed to prevent, protect

against, control, and provide a

public health response

to the international spread of disease

in ways that are

commensurate with, and restricted to, public health

risk, and which avoid unnecessary interference with

international traffic and trade.

Communicable disease control &

international health regulations

The IHR ( 2005) are also designed to tak e into account

environmental factors

that increase the risk for

infections including:

1-Intensified human encroachment on natural

environments.

2-Increasing urbanization and crowding of human

populations.

International health regulations

(IHR )

3-Climatic alterations that lead to changes in vector

density and geographical distribution.

4-The continuing extension of international travel and

global trade, including food products.

5-Changing animal husbandry practices.

6-The changing patterns of drug resistance.

International health regulations

(IHR)

The IHR ( 2005) depends heavily on

global surveillance

alert

and

response activities

, which aim to support

countries and the international community in

identifying and responding to emerging public health

risk .

International Health R egulations

(IHR )

The process of global surveillance involve the

systematic

collection

of information from

many different sources, its

assessment,

and

taking

prompt public health action

based on

the conclusion.

Surveillance under IHR (2005)

The events that are to be notified are effectively

defined by four criteria :

1-whether the event has a

serious public health impact.

2-whether the event is

unusual

or unexpected.

3-whether the event risks

spreading internationally

4-wehther the event risks

resulting in restrictions on

international trade and or travel.

Notification

Accordingly, even

one case

of these diseases must

be notified to WHO.

These diseases are as follows:

Smallpox

Poliomyelitis

due to wild-type poliovirus.

Human influenza

caused by a new subtype (e.g.

H1N1in human)

-Severe acute

respiratory syndrome

(SARS).

Notification

Case reports

: Case reporting provides

diagnosis

age

sex

and

date of onset

for each person with the disease.

Sometimes it includes

identifying information

such as

the name and address of the person with the disease.

Additional information such as

treatment

provided and

its duration are required for certain case reports.

REPORTING OF

COMMUNICABLE DISEASES

Outbreak reports

: Outbreak reporting provides

information about an

increase above the expected

number of persons with a communicable disease

that

may be of public concern.

The specific disease may not be included in the list of

diseases officially reportable, or it may be of unk nown

etiology if it is newly recognized or emerging.

REPORTING OF

COMMUNICABLE DISEASES

National guidelines and legislation indicate

which

type of outbreak

must be reported,

who is

responsible

for reporting, the

format

for reporting,

and

how case reports are to be entered

into and

forwarded within the national system.

If there is a requirement for international case

reporting, national governments report to WHO.

REPORTING OF

COMMUNICABLE DISEASES

In general, outbreak reporting is required by the

most rapid means of communication

available.

R EPOR TING OF

COMMUNICABL E DISEASES

Class 1

: Case report required

internationally

to WHO by

the International Health Regulations or as a disease

under surveillance by WHO.

Diseases under surveillance by WHO include:

louse-borne

typhus fever

relapsing fever

meningococcal meningitis

paralytic poliomyelitis

malaria

tuberculosis

HIV/AIDS

influenza

and

SARS

Classes of reporting

Case report is required to the WHO through the

national health authority

. Collective outbreak reports

including the number of cases and deaths may be

requested on a

daily

weekly

basis for diseases with

outbreak potential such as influenza.

Classes of reporting

Class 2

: Case report regularly required wherever the

disease occurs

Diseases of

relative urgency

require reporting either

because

identification of contacts

is required or

because the

source of infection

must be known in

order to begin control measures.

Classes of reporting

National health authorities generally require

reporting of the

first recognized case

in an area or

the

first case outside the limits

of a known affected

local area by the most rapid means available,

followed by weekly case reports—examples include

diseases under surveillance by WHO

typhoid fever

and

diphtheria.

Classes of reporting

Class 3

Selectively reportable

in recognized endemic

areas

R eporting may however be required by reason of

undue

frequency

or severity, in order to stimulate control

measures or

acquire

essential epidemiological

data. Examples of

diseases in this class are

scrub typhus

schistosomiasis

Classes of reporting

Class 4

: Obligatory

report of outbreak s only

, no case

report required

Many countries require reporting of outbreak s to

health authorities by the most rapid means. Information

required includes number of cases, date of onset,

population at risk and apparent mode of spread.

Examples are

staphylococcal foodborne intoxication

and outbreak s of an unidentified etiology.

Classes of reporting

Class 5

: Official report

not ordinarily justifiable

Diseases in this class

occur sporadically

or are

uncommon, often

not directly transmissible

from

person to person or of an epidemiological nature

that offers

no practical measures

for control

( common cold).

Classes of reporting

Thank you