communicable disease

Us:- Waled Amen Moh

Head department, Community Health Nursing

UMST

Communicable Diseases

Introduction

• Communicable Diseases are the major causes of morbidity and mortality.

• Main causes of morbidity and mortality in emergencies are diarrheal diseases, acute respiratory infections, measles and in areas where it is endemic malaria.

Introduction

• Other communicable diseases that have also in the past caused epidemics amongst population affected by emergencies are meningococcal disease, tuberculosis and typhus.

• Malnutrition and trauma are additional causes of illness and death amongst populations affected by communicable diseases.

Definitions

• Communicable Disease is one that can transmitted from one person to another and is caused by an infectious agent that is transmitted from a source or reservoir to a susceptible host.

• Infectious diseases is one that caused by infectious agent.

• Outbreak• o occurrence of new cases of a disease clearly in excess of the• baseline frequency of the disease in a defined community over a• given time period• o point source outbreak: an outbreak due to• exposure of a group of people to a noxious influence that is• common to the individuals in the group• • the exposure is brief and essentially simultaneous, resultant• cases all develop within 1 incubation period of the disease• o propagated outbreak: an outbreak where there are multiple• exposures over a period of time, from host to host• (directly or indirectly), resulting in cases that are not within• 1 incubation period

• Epidemic• occurrence, in a community or region, of a group of illnesses of a• similar nature in excess of normal expectancy• Endemic• habitual presence of a disease or agent within a geographic area• based on the usual prevalence of a given disease within such an area• Pandemic• an epidemic which is worldwide in distribution• Host• person/animal that affords subsistence to an infectious agent• under natural conditions• Carrier• person/animal that harbors a specific infectious agent in the• absence of discernible clinical disease and serves as a• potential source of infection

• Fomite• o contaminated substance (not necessarily a reservoir) serving as• an intermediate means of transport for an infectious agent• Reservoir• o anything (living or inert) in which an infectious agent lives and• multiplies in such a manner that it can be transmitted to a• susceptible host• Vector• o invertebrate animal capable of transmitting an infectious agent• to vertebrates• Virulence• o ability of an infectious agent to cause severe or fatal infections

• IMMUNITY• o active• • altered organism or its product induces a host to produce• antibodies (e.g. natural measles infection or live vaccine)• o passive• • protective antibodies produced by another host which are• introduced into susceptible persons (e.g. natural transplacental• IgG from mother to infant)• o inherent• • endogenous production of antibody• o herd• • expression used to describe immunity of a group or community• • resistance of a group to an infectious agent based on the• immunity of many individuals in the group• • implies transmission interruption when < 100% of group is• immune due to separation of few susceptibles

Transmission of Infectious Agents

Transmission refers to any mechanism by which an infectious agent is spread from a source or reservoir to a person.

– Reservoir.– Mode of infection.– Susceptible host.

Six Factors furthering process• Agent

• Reservoir

• Portal of exit

• Mode of transmission

• Portal of entry

• Susceptible host

Man1=Case:-case can be prevented and controlled by

1-Identification-:

--presentation-: This involves signs and symptoms of this disease.

--Lab finding-: Diagnostic test, or physical examination

--complications That may arise due to this disease .

Reservoir

Case

2-Treatment

3-Isolation -:

this needs to determine communicability period4-Health education-:

About -S&S of complication

-treatment

Man

carrier

2=carrier-:1-Types of carrier

-by type .healthy carrier

.incubatory carrier.convalescence carrier

-by portal of exit.respiratory carrier

.GIT carrier .GUT carrier

2-active detection .Household surveillance for early detection of disease

Man

Reservoir

3-health education

concerning special hygiene and avoid risk factors

4-Quarantine -:

this needs to know Incubation period

Animal(Reservoir)

• Case- Identification- Treatment- Isolation- Extermination

• Carrier

- Type

- Active detection

- Quarantine

- Extermination

Soil (Reservoir)

• Disinfection

Mode of transmission

-Direct--: 1.Direct contact

2.Vertical transmission

3.Droplet infection

4.Animal bite transmission

5.Contact with soil

Indirect

1. Air-borne 2. Vehicle borne3. Vector-borne transmission4. Fomite –borne 5. Hand –borne

Susceptible host

Man 1 -the at risk individual

Systemic diseasesSurgical patientsImmunocompromised individualsGenetic basedOrgan transplantChemotherapyRadiotherapyHIV infection

2-health education-: about vaccination and preventive measures

3-immunization-: if available .

4-prophylaxis-: 5-special protective measures-:

6-legislation-:

Susceptible host

Animals1 -the at risk

2-prophylaxis 3-special protective measures

Emerging Infectious Diseases

Emerging infectious diseases are diseases

that have appeared for the first time or that

have occurred before appeared in

populations where they have not

previously been reported.

Reemerging Infectious Diseases

Reemerging infectious diseases are

familiar diseases caused by well-

understood organisms that were once

under control or declining but now are

resistant to common drugs or gaining

new footholds in the population and

increasing in incidence.

Fundamental principles of Control of

Communicable Diseases

• Rapid Assessment

• Prevention

• Surveillance

• Outbreak Control

• Disease Management

Modern Conditions that Favor the Spread of Infectious

Diseases

1. Global travel

2. Globalization of food supply and centralization of food processing

3. Population growth, increased urbanization and overcrowding

4. Migration due to wars, famines, and natural disasters

Modern Conditions that Favor the Spread of Infectious

Diseases5. Irrigation, deforestation, and

reforestation projects that alter habitats

6. Human behaviors, such as IV drug use and risky sexual behavior

7. Increased use of antimicrobial agents and pesticides

8. Increased human contact with wilderness habitats

Prevention of communicable diseases:- Communicable diseases can be prevented

by appropriate preventive measures which include:

• Good site planning• Provision of basic clinical services• Provision of appropriate shelter• Clean water supply• Sanitation• Mass vaccination against specific diseases• Regular and sufficient food supply• Control of vectors

Primary Prevention

• Increasing the resistance of the host

• Inactivating the agent

• Interrupt the chain of infection • Restricting spread of infection

– isolation – quarantine – segregation – personal surveillance

Secondary Prevention

• Activities targeted at detecting disease at earliest possible time to:

– begin treatment – stop progression – protect others in the community

• Examples of activities: case finding, health screening, health education

Tertiary Prevention

• Limits the progression of disability

• Treatment of symptoms and rehabilitation vary with each specific disease

Surveillance

• Surveillance is the ongoing systematic collection,analysis and interpretation of data in order to plan, implement and evaluate public health intervention.

Surveillance system should be simple, flexible, acceptable.

Outbreak Control

• An outbreak is occurrence of a number of cases of a disease that is unusually large or unexpected for a given place and time.

Outbreaks and epidemics refer to the one and same thing.

Outbreaks in emergency situations can spread rapidly giving rise to high morbidity and mortality rates.

Aim should be to detect and control the outbreak as early as possible.

Steps in the management of a Steps in the management of a communicable disease outbreakcommunicable disease outbreak• Preparation

• Detection

• Response

• Evaluation

Preparation for the outbreakPreparation for the outbreak

• Health coordination meetings

• Strong surveillance system

• Outbreak response plan for each disease

• Stocks of iv fluids, antibiotics and vaccines

• Plans for isolation wards

• Laboratory support


• Detection

• Response

• Evaluation

Detection of outbreakDetection of outbreak

• Surveillance system with early warning system for epidemic prone diseases.

• Inform ministry of health and WHO in case of outbreaks of specific diseases.

• Take appropriate specimens (stool, CSF or serum) for laboratory confirmation.

• Include case in the weekly report.


• Detection

• Response

• Evaluation

Response to the outbreakResponse to the outbreak

• Confirm the outbreak

• Activate the outbreak control team

• Investigate the outbreak

• Control the outbreak


• Detection

• Response

• Evaluation

Evaluation Evaluation

• Assess appropriateness and effectiveness of containment measures.

• Assess timelines of outbreak detection and response.

• Change public health policy if indicated.

• Write and disseminate outbreak report.

Global Disease Eradication Efforts

Methods to accomplish the goal of eradication of diseases include:– immunization and vaccination– drug therapy– community training– health education– national disease surveillance efforts

examples

7 diseases have been targeted for eradication in early 21st century:

– polio– measles– leprosy

– river blindness– Chagas’ disease– guinea worm

disease– lymphatic

filariasis

Nurses’ Role

Community health nurses play an important role with regarded to all population at risk for communicable disease

Nurses concerned with communicable disease

control must • Recognize who at risk • Where the reservoirs and source of infectious

disease agents are located • What environmental factors promote the spread

• What comprise the characteristic of vulnerability of community member and groups-particularly those subject to intervention

• Community health nurses must work collaboratively with other public health professional to establish immunization and educational programs , to improve community infection control policies , and to develop abroad range of services to population at risk

communicable disease

Health & Medicine