Family & Community Medicine dept. - PowerPoint Presentation

Slide1

Family & Community Medicine dept.

Control of Communicable diseases-Respiratory diseases

Lecture-4-Fourth

stage

November

18

th

, 2017

Dr. Muslim N.

Saeed

Slide2

Pertussis

Whooping Cough

Slide3

Epidemiology

Is

an acute, communicable infection of the respiratory tract caused by the gram-negative bacterium, Bordetella pertussis

.

Whooping cough is a disease of infants and pre-school children.

The highest incidence found before the age of 5 years.

Outbreaks occur periodically every 3-4 years.

Marked decline has occurred in incidence & mortality rates during the last four decades in communities with active immunization program, good nutrition and good medical care

Slide4

Susceptibility & resistance

In non immunized susceptibility is universal.

Highest incidence is in

infants

.

School children are often act as a source of infection

for younger siblings at home

Incidence, mortality and morbidity are higher in females than males.

There is no maternal immunity.

One attack confers long immunity although second attacks can occasionally occur.

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Susceptibility & resistance

Cases in previously immunized adolescents and adults occur because of waning immunity.

Protection produced by the vaccine is greater against severe disease & begins to wane after about 3 years

Active immunization after exposure is not protective but it is not contraindicated

Slide6

Chain of events

Reservoir

Human

Mode of transmission

Direct contact with respiratory discharge of infected person.

Airborne

Droplet

Incubation

period

6-20 days

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Period of communicability

Patient not treated with proper antibiotic

onset of typical paroxysm

Either early in the or 3weeks after

Catarrhal stage

In treated patient with erythromycin

5 days after the onset of therapy.(Pt is non-infectious).

Slide8

Clinical features

Catarrhal phase

:

is characterized by rhinorrhea, lacrimation, malaise, and cough that is mild and nonproductive. low-grade fever may also be present. This phase lasts between a few days and 1 week

Paroxysmal phase

:

cough becomes more severe and frequent and eventually paroxysmal where five or more forceful coughs occur in a single episode; this phase usually lasts for 1-2 months or longer

.

Young

infants, partially

vaccinated children, adolescents and adults often do not exhibit the whoop or cough

paroxysm.

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Clinical features

Convalescent

phase:

The

cough becomes less frequent and milder. This phase may last another 1-2 weeks or

longer

Complications

Respiratory (bronchitis, otitis media ,bronchopneumonia,pneumothorax)

Subcojuctival hemorrhage

epistaxis

CNS (convulsion, encephalitis)

Slide10

Diagnosis

Laboratory methods currently available for the identification of

B. pertussis

include,

Culture

polymerase chain reaction (PCR),

direct fluorescent antibody testing, and

serologic antibody testing.

Slide11

Prevention and control

1.Public education

Danger of the disease.

Importance of immunization.

Adherence to the immunization schedule

2.Immunization

is recommended with 3 doses of vaccine consisting of a suspension of killed bacteria with diphtheria & tetanus.

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Prevention

DPT whole cell vaccine

DTaP a cellular preparation

Iraq DPT

2 months

4 months

6 months

18 months first booster

school entry second booster

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Prevention cont.

Side effects of vaccination

Fever.

Local redness and swelling at site of injection.

Anaphylaxis ( first 24 hours)

Collapse, shock like stat.

Persistent crying >3

hours.

Seizures.

Encephalitis.

Contraindication

Progressive neurological disease

Previous anaphylaxis or encephalopathy in same patient.

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Prevention cont.

Family history of febrile seizure is not contra- indication.

Mild illness.

Well controlled seizure.

Stable neurological disorders .

Local reactions.

3. Protection of health workers who have been exposed to pertussis cases by using a 14 days course of erythromycin, azithromycin, clarithromycin

.

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Control

Reporting is obligatory

Isolation

Respiratory isolation for

known cases

Suspected cases

should be removed from the presence of infants (especially unimmunized infants)& young children until:

Patient have received at least 5 days of antibiotics.

Those who do not receive antibiotics should be isolated for 3 weeks.

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Control cont.

Contacts

Inadequately immunized household contacts <7 years should be excluded from Schools for 21 days after exposure or until the case and contacts have received 5 days course of antibiotics

.

Verification of immunization status up to date.

Passive immunization is not effective.

Initiation

of active immunization following recent exposure is not

effective.

Close

contacts <7 years who have not receive 4 DTP doses; or have not received a DTP dose within 3 years should be given a booster dose as soon

as possible

after

exposure.

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Control cont.

Antibiotic prophylaxis

Initiation of postexposure prophylaxis in asymptomatic contacts within 21 days of the onset of cough in the index case can prevent the development of symptoms.

Indications

C

lose contacts.

Individuals at high risk for severe or complicated pertussis.

Regimins

(Erythromycin

for 14

days,Clarithromycin

for 7

days,Azithromycin

for 5

days)

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Persons at high risk for severe or complicated pertussis include

Infants particularly those younger than four months

Persons with immunodeficiency

Persons with underlying medical conditions (chronic lung disease, respiratory insufficiency, cystic fibrosis)

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Control cont.

Specific treatment

Treatment should be initiated within 21 days of start of symptoms

The regimen for antimicrobial treatment is the same as that for prophylaxis

Treatment s

hortens the period of communicability but does not affect symptomatology.

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Epidemic measures

Look for unrecognized & unreported cases.

Accelerated immunization :

1

st

dose 4-6 wk for age

4weeks

2

nd

dose

4weeks

3

rd

dose

Immunization should be completed for those whose schedule is incomplete.

Slide21

Diphtheria

Slide22

Epidemiology

Diphtheria is an acute, communicable disease caused by the gram-positive bacillus

Corynebacterium

diphtheriae

.

Among non immunized populations, diphtheria most often occurs during fall and winter, although summer outbreaks have occurred.

In tropical areas seasonality is less distinct.

Disease spreads more quickly and is more prevalent in poor socioeconomic conditions, where crowding occurs and immunization rates are low.

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Epidemiology

Race No racial differences observed

Sex

No difference has been described for acute infections.

Age

Diphtheria affect children 1-5 years. In countries where wide spread immunization is practiced ,a shift in age incidence has been observed from preschool to school age.

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Chain of events

Reservoir is Human

Mode of transmission

Direct contact with patients or carriers

Indirect

Articles

Raw milk

Incubation period 2-5 days

Slide25

Chain of events

Period of communicability

Unless treated, the period of communicability varies from 14-28 days from the onset of disease.

Carriers may remain infective for longer periods.

A case or carrier may be considered non-communicable when 2 cultures from the nose and throat ,24 hr apart, negative for diphtheria bacilli.

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Chain of events

Susceptibility & resistance

There is maternal immunity which usually lost by age of 6 months.(for infants of immune mothers).

Disease or inapparent infection usually,but not always lead to life long immunity

Toxoid gives prolonged but not life long immunity which wanes with age.

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Clinical features

Respiratory tract form of diphtheria consist of

pharyngo-tonsillar

,

laryngo

-tracheal ,nasal and combination of these forms.

Pharyngo-tonsillar

: sore throat, low grad fever,

O/E mild pharyngeal

erythema

and localized

exudate or grey-black adherent membrane Attempt to remove the membrane result in bleedingLaryngo-tracheal disease most often proceeded by pharyngotonsillar

diphtheria, patient presented with hoarseness of voice and croupy cough.

Slide28

Diagnosis

Clinical

findings

Bacteriological examination

Isolation

of

CoryneBacterium diphtheriae

on cultures confirm the diagnosis

.

In all patients in whom diphtheria is suspected, obtain specimens from the nose and throat (i.e., nasopharyngeal and pharyngeal swab) for culture

.

Isolation of

C .diphtheriae

from close contacts may confirm the diagnosis, even if results of cultures on specimens taken from the patient are negative.

Slide29

Prevention

Educational measures about

the hazards of the disease

and Importance

of

immunization

Active

immunization should be initiated in infancy (DTaP, DTP

)

Children

<7 years of age

(in Iraq)

2 months 1

st

dose

4 months 2

nd

dose

6 months 3

rd

dose

18 moths 1

st

booster dose

4-6 years 2

nd

booster dose

This

schedule does not need to be restarted because of delay in administering the scheduled dose

.

If

pertusis component of DTP is

contra-indicated; use DT form.

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Prevention cont.

Person age 7 years &older

Adult (Td) is usually used (highly purified) for previously unimmunized.

3doses of Td is given,

1

st

,2

nd

doses at 4-8 weeks intervals.

3

rd

dose after 6 months - 1 years after the 2

nd

dose.

Active protection is maintained by giving a dose of Td every 10 years.

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Prevention cont.

Protection of highly risk group;

They should be fully immunized and receive a booster dose every 10 years.

HIV & immunocompromised children should be vaccinated. Use the same schedule

Slide32

Control

Reporting obligatory

Isolation:

Strict

isolation for pharyngeal

type.

Until 2cultures both from nose &throat

taken( not less than 24 hours

apart

after cessation of antibiotic therapy) fail to show the microorganism

.

If there is no

facility;

isolation

may

end after 14 days course of appropriate antibiotic therapy.

Disinfection

Slide33

Control cont.

4-Contacts

7 days surveillance

Cultures from nose &throat

Single dose of benzathin penicillin IM

(600,000units for younger persons < 6years

&

(1.200.000units for older persons)

or

7-10 days course of erythromycin is recommended for all persons with household exposure, regardless of their immunization status

5- specifice treatment (antitoxine and antibiotics)

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Control cont.

Antitoxin

Sensitivity testing

Single daily dose 20000 units for anterior nasal diphtheria to100000 units for extensive disease by IM route for 14 days.

Antibiotics

Procaine penicillin

G (IM) 600000 U for children and 1.2 million U for adults in 2 divided doses)

Recommended duration is 14 days

Slide35

Epidemics measures

Immunize all <5 & highly risk groups . Repeat immunization one month later to provide at least 2 doses to the recipient.

Identify contacts, population at risk.

Carry out special investigation of reported cases to verity diagnosis &to determine biotype & toxigenicity of the organism.

Slide36

Thanks