Control of Communicable diseasesRespiratory diseases Lecture4Fourth stage November 18 th 2017 Dr Muslim N Saeed Pertussis Whooping Cough Epidemiology Is an acute communicable infection of the respiratory tract caused by the gramnegative bacterium Bordetella pe ID: 932208
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Slide1
Family & Community Medicine dept.
Control of Communicable diseases-Respiratory diseases
Lecture-4-Fourth
stage
November
18
th
, 2017
Dr. Muslim N.
Saeed
Pertussis
Whooping Cough
Slide3Epidemiology
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
Slide4Susceptibility & 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.
Slide5Susceptibility & 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
Slide6Chain of events
Reservoir
Human
Mode of transmission
Direct contact with respiratory discharge of infected person.
Airborne
Droplet
Incubation
period
6-20 days
Slide7Period 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).
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.
Slide9Clinical 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)
Slide10Diagnosis
Laboratory methods currently available for the identification of
B. pertussis
include,
Culture
polymerase chain reaction (PCR),
direct fluorescent antibody testing, and
serologic antibody testing.
Slide11Prevention 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.
Slide12Prevention
DPT whole cell vaccine
DTaP a cellular preparation
Iraq DPT
2 months
4 months
6 months
18 months first booster
school entry second booster
Slide13Prevention 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.
Slide14Prevention 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
.
Slide15Control
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.
Slide16Control 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.
Slide17Control 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)
Slide18Persons 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)
Slide19Control 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.
Slide20Epidemic 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.
Slide21Diphtheria
Slide22Epidemiology
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.
Slide23Epidemiology
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.
Slide24Chain of events
Reservoir is Human
Mode of transmission
Direct contact with patients or carriers
Indirect
Articles
Raw milk
Incubation period 2-5 days
Slide25Chain 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.
Slide26Chain 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.
Slide27Clinical 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.
Slide28Diagnosis
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.
Slide29Prevention
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.
Slide30Prevention 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.
Slide31Prevention 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
Slide32Control
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
Slide33Control 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)
Slide34Control 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
Slide35Epidemics 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.
Slide36Thanks