Bordetella Pertussis

Question 1

Pertussis

Answer 1

Aka whooping cough

Pertussis is a highly contagious infectious disease.
It is known as whooping cough because of its characteristic cough.

Question 2

History of Pertussis

Answer 2

China- cough of 100 days 7th Century
Sydenham-cough in Latin in 1679

Question 3

What causes Pertussis

Answer 3

Bordetella pertussis
But some cases caused by other species of Bordetella

Question 4

Charateristics of Bordetella Species

Answer 4

Isolated by Bordet and Gengou (Belgian microbiologists) in 1906
Causes 86-95% of whooping cough cases
Strictly human pathogen

Question 5

Characteristics of Bordetella Para-pertussis

Answer 5

Isolated in 1930’s
Seen in sheep and man, causing atypical respiratory infection or pertussis in man

Question 6

Bordetella bronchiseptica

Answer 6

Isolated in 1910
Enzootic in pigs, dogs (kennel cough), rabbits (sniffles), cats, rodents; rare in man (usually with
animal exposure, often in immunosuppressed patient)

Question 7

Bordetella Holmesii

Answer 7

Isolated in 1983
Occasionally causes pertussis in man; bacteremia seen, with asplenia a risk factor

Question 8

Fastidious: exam

Answer 8

hard to grow w/ special medica required (Bordet-Gengou agar)

Question 9

Bordetella Pertussis- species name and feature Exam

Answer 9

1) Fastidious: hard to grow w/ special media required (Bordet-Gengou agar)
2) Gram Negative
3) Pleomorphic= vary in size and shape
4) cocobacillus

Question 10

Bordetella Pertussis molecule feature 1

Answer 10

Pertussis toxin: causes leukocytosis and lymphocytosis with obstruction of small pulmonary vessels, causing pulmonary hypertension

Question 11

Bordetella Pertussis molecule feature 2

Answer 11

Filamentous hemagglutinin (FHA): part of cell wall, highly immunogenic; involved with attachment

Question 12

Bordetell pertussis molecule feature 3

Answer 12

3) Adenylate cyclase toxin: An enzyme that allows B. pertussis to evade nitric oxide killing in macrophages
4) Pertactin (PRN): Outer membrane protein; resists neutrophil-mediated clearance
5) Tracheal cytotoxin: Damages respiratory epithelial cells

Question 13

Transmission of Bordetella pertussis. Exam

Answer 13

Respiratory droplets
Cause 12-17 secondary cases in susceptible population

Question 14

In which stage is the most infectious of Bordetella pertusis?

Answer 14

Catarrhal stage -most infectious
* but transmission most efficient during- paroxysmal stage

Question 15

When does the transmission of Bordetella pertussis most effective?

Answer 15

transmission is most efficient during the paroxysmal stage

Question 16

True or false
the patient is with BP is Not infectious after 5 days of effective antimicrobial therapy

Answer 16

True

Question 17

What is the modes of transmission of Pertussis?

Answer 17

respiratory droplets

Question 18

The modes of pathogenesis of Pertussis

Answer 18

1) Attachment of bacteria to respiratory epithelial cells
2) Production of toxins that injure respiratory epithelial cells, disrupt phagocytosis
Inflammation of the respiratory tract
3) Elevation of the white count, with obstruction of the small pulmonary vessels causing pulmonary hypertension
4) Invasion of the alveolar macrophages and ciliated epithelial cells (intracellular bacteria in both

Question 19

Incubation period of Pertussis : exam

Answer 19

Incubation period is 7-10 days on average (range 5-28 days) but illness lasts 6-12 weeks

Question 20

Stages of Pertussis

Answer 20

1) Catarrhal stage 2) Paroxysmal stage 3) convalescent stage

Question 21

Catarrhal stage

Answer 21

● 1-2 weeks in duration
● Nasal congestion, rhinorrhea, lacrimation, conjunctival injection, sore throat, malaise, mild cough - respiratory secretions is most infectious in this stage

Question 22

Paroxysmal stage

Answer 22

2-6 weeks in duration
● Paroxysms of cough, with 5-10 coughs in expiration, then sudden inspiratory whoop
● Worse at night; may lead to vomiting - the most transmission effective in this stage

Question 23

Convalescent stage

Answer 23

1-12 weeks
● Slow resolution of the cough

Question 24

Severity of illness and age - Infants

Answer 24

Can have life-threatening illness, especially if 3 months of age or younger –> that is why pregnant women needs vaccine
● One-half of infants with pertussis require hospitalization
● Of the hospitalized infants, 68% have apnea, 23% develop pneumonia, 1.2% have
seizures, 0.9% have encephalopathy. Some can develop pneumothorax, subdural
hematoma, rectal prolapse, pulmonary hypertension
● The fatality rate is 1-3% in neonates

Question 25

Severity of Illness and age- adolescents and adults Bordetella pertussis

Answer 25

May be asymptomatic, and, if symptomatic, often do not have whooping, ● Cough (prolonged) and sweats are common ● Often go undiagnosed ● 3% require hospitalization, with the hospitalization rate 14.8% in those over 65 ● Weight loss, syncope, rib fractures, subdural hematoma, pneumothorax, rectal prolapse, encephalopathy may be seen

Question 26

Diagnosis of Pertussis

Answer 26

The bacterium may be cultured during the first 2 weeks of cough on selective media (Bordet-Gengou agar). ● PCR testing has become the standard for diagnosis. ● ELISA with a high IgG or IgA to Pertussis toxin is diagnostic, but should not be used if there has been vaccination in the previous 12 months

Question 27

Treatment of Pertussis

Answer 27

Azithromycin or trimethoprim/sulfamethoxazole ● Supportive care with humidified oxygen ● Exchange transfusion to lower the WBC has been used

Question 28

Vaccination of Pertussis : DTwP Exam

Answer 28

DTwP ● Whole cell vaccine, developed in the late 1940s ● Commonly caused a severe local reaction, fever, drowsiness, and crying ● Has not been used since 1997.

Question 29

Vaccination- Acellular Vaccines

Answer 29

Accomplished with DTaP in children, Tdap in adolescents and adults. Note Tdap has lower amounts of d and p antigens ● Fewer side effects, but with decreased durations of efficacy compared to the cellular vaccines.

Question 30

Vaccination Schedule for Pertussis : DTaP Exam

Answer 30

DTaP is given ● at 2, 4, 6, 15-18 months ● at age 4-6 years.

Question 31

Vaccination Schedule for Pertussis : Tdap Exam

Answer 31

Tdap is given ● at 11-12 years of age ● at age 19 if not given at age 11-12 ● every 10 years thereafter ● to all pregnant women during weeks 27-36 of gestation ● to all close caregivers of infants (cocooning practice)

Question 32

Incidence of Pertussis

Answer 32

In the U.S. there was a peak in the incidence in 1934 (250,000 cases), with a nadir in 1976 (1010 cases). There has been an increase in the number of cases since the 1970s, with 330,000 cases reported from 2000-2016 in the U.S. Worldwide there are 30-50 million cases each year of pertussis, with 300,000 deaths, mostly in infants and unvaccinated children.

Question 33

Why the Resurgence of Pertussis?

Answer 33

The switch from the whole cell vaccine to acellular vaccine led to more rapidly waning immunity and more cases.

Question 34

What do we need to combat pertussis

Answer 34

We need a vaccine that is effective and with lifelong or long-lasting immunity.

Question 35

Why the resurgence of Pertussis - adolescents

Answer 35

In outbreak analyses among adolescents who had received only acellular vaccine, Tdap was 73% effective after one year, 34% at 2-4 years.

Question 36

Exam: Neither natural infection nor vaccination confer lifelong immunity with Pertussis

Answer 36

true