15 Questions
What is the primary mode of transmission of Bordetella pertussis?
Droplet infection through respiratory droplets
What is the typical clinical manifestation of pertussis in young children?
Severe cough often ending in vomiting, cyanosis, and loss of oxygen exchange in severe cases
How does Bordetella pertussis modulate the host immune response?
Inhibits complement, survives within phagocytes, inhibits recruitment of immune cells, and suppresses antibody production
What is the typical age range for pertussis to occur?
First year of life, young children, and young adults
What is the role of lipooligosaccharide (LOS) in the pathogenesis of pertussis?
LOS inhibits the recognition by surfactant A and inhibits complement
What is the effect of Bordetella pertussis on respiratory epithelial cells?
Adherence to and destruction of ciliated cells, leading to ciliary stasis and mucous accumulation
What is the significance of the catarrhal stage of pertussis?
Maximum communicability during this stage
What is the characteristic of Bordetella pertussis growth?
Slow-growing and requires selective media for primary isolation
What is the primary cause of whooping cough, and how does it affect the respiratory tract?
The primary cause of whooping cough is the bacteria Bordetella pertussis, which grows on the surface of the respiratory tract, producing a powerful toxin that kills ciliated respiratory epithelia, leading to damage and swelling of the airway.
What are the symptoms of whooping cough in infants, and how do they differ from those in older children?
In infants, the symptoms of whooping cough may include apnea and difficulty breathing, whereas in older children, it is characterized by a persistent cough, often referred to as the '100 days cough'.
What is the recommended treatment for whooping cough, and why is early treatment crucial?
The recommended treatment for whooping cough includes antibiotics such as Erythromycin, which should be started early to reduce the severity of the disease and prevent further spread.
What is the purpose of vaccinating pregnant women against whooping cough, and how effective is it in protecting infants?
Vaccinating pregnant women against whooping cough helps to protect their infants, with a 90% effectiveness rate in preventing the disease.
Why is it important to boost the immunity of individuals in contact with infants, and how does this prevent the spread of whooping cough?
Boosting the immunity of individuals in contact with infants helps to prevent the spread of whooping cough, as immunity to the disease fades quickly, and those in close contact with infants are at higher risk of transmission.
What is the characteristic of the flagellae of the genus Bordetella, and how many species are motile?
The genus Bordetella has 8 species, with 4 species having motile peritrichous flagellae.
What is the composition of the vaccine against whooping cough, and how does it work?
The vaccine against whooping cough is an acellular vaccine made from inactivated toxin, which helps to prevent the disease by inducing immunity against the toxin.
Study Notes
Pertussis (Whooping Cough)
- A common respiratory illness affecting all age groups, with infants being at particular risk.
- Caused by the bacterium Bordetella pertussis, which grows on the surface of the respiratory tract and produces a powerful toxin that kills ciliated respiratory epithelia.
Pathogenesis
- The bacterium is inhaled and contracts with respiratory epithelium, adhering to and destroying ciliated cells.
- This leads to ciliary stasis, mucous not being cleared, and tissue necrosis.
- The bacterium modulates the host immune response by:
- Inhibiting recognition of lipooligosaccharide (LOS) by surfactant A (SPA)
- Inhibiting complement
- Surviving within phagocytes and limiting phagocytosis
- Inhibiting recruitment of immune cells and lymphocytes
- Suppressing antibody production
Clinical Manifestation
- In young children, pertussis typically presents with:
- Runny nose, fever, and a slight cough in the early stages, which may not be suspected as pertussis
- A severe cough often ending in vomiting, and cyanosis in severe cases due to reduced oxygen exchange
- In young adults, pertussis may present as a chronic cough due to loss of vaccine-induced immunity
Epidemiology
- Pertussis is highly contagious and spread through droplet infection.
- The reservoir of infection is humans, and transmission occurs through respiratory droplets.
- The communicability of pertussis is maximum during the catarrhal stage, with a secondary attack rate of up to 80%.
Treatment and Prevention
- Treatment typically involves:
- 24-hour care and respiratory support for infants
- Administration of steroid or salbutamol to reduce severity
- Erythromycin for 2 weeks, which should be started early to reduce infectivity to siblings
- Prevention involves:
- Vaccination with an acellular vaccine made from inactivated toxin
- Recommendation for all pregnant women to get a booster late in pregnancy (90% protective for infants)
- Boosting of all individuals in contact with infants, as immunity fades quickly
Learn about Pertussis, a common respiratory illness affecting all age groups, particularly infants. Understand its causes, symptoms, and effects on the respiratory tract.
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