Classical | Non-classical |
---|---|
• pertussis (type species) | |
• parapertussis | |
• bronchiseptica | • ansorpii |
• avium | |
• broncialis | |
• flabilis | |
• hinzii | |
• holmesii | |
• petrii | |
• sputigena | |
• trematum | |
& 4 other species not associated with human infection |
NB: spp. in underline = not strictly aerobic
| Site | Human URT (we are only reservoir for B.pertussis) | | --- | --- | | Transmission | Airborne droplets | | Risk Factors | <1yrs Children & adolescents Unvaccinated | | Clinical syndromes | NB: Notifiable disease Incubation: 7-10d (range 6-20d)
Features:
Phases of illness
Complications:
Confirmed: Sx of pertussis + 1 of: • +ve Respiratory sample (NPA/NPS/PNS) • +ve Respiratory PCR • anti-pertussis toxin IgG titre >70 IU/ml (serum) or >70 aU (OF) (NB: in the absence of vaccination in the past year)
Epidemiologically linked: Sx of pertussis & was in close contact with Confirmed case within 21d onset of their cough
(Close contact: Household, overnight stay in same room) | | Risk groups (UKHSA 2024) | Group 1: Vulnerable infants A. Unimmunised infants (born <32wks) <2 months old regardless of maternal vaccine status. B. Unimmunised infants (born >32 weeks) <2 months old whose mothers did not receive pertussis vaccine after 16 weeks & >2 weeks before delivery. C. Infants 2 - 5 months, regardless of maternal vaccination status or gestational age at delivery. D. Infants from 5 - 12 months who aren’t fully vaccinated.
Group 2: Individuals who could transmit to Group 1, and haven’t received vaccine in last 5 years (but >7d ago) A. 32+wks Pregnant women B. HCWs who provide close personal care to Group 1 infants & pregnant women. C. People whose work involves regular, close & prolonged contact with Group 1 infants. D. People who share a household with a Group 1 infant. |
Toxin | Seen in | MoA | Effect |
---|---|---|---|
Pertussis Toxin | B.pertussis | AB toxin. | |
Increased intracellular cAMP —> alters signalling. Inhibits G-protein chemokine receptors in cell. | Reduced phagocyte recruitment/chemotaxis. Reduced chemokine synthesis by affected cell | ||
Adenylate cyclase toxin | pertussis, parapertussis, bronchiseptica | RTX toxin. | |
Binds Complement receptor 3 on phagocytes —> Cytotoxic pores —> Ca influx / K+ efflux —> damages cell. Also has IC Adenylate Cyclase activity —> increased cAMP. | Inhibit phagocyte activity | ||
Filamentous hæmagglutinin | pertussis | Attachment factor for adherence to host cells | Biofilm formation |
Pertactin | pertussis, bronchiseptica | Adhesion to epithelial cells | |
Fimbria | An ‘attachment pilus’ | Adherence to cells; biofilm formation | |
Tracheal cytotoxin | pertussis (also N.gonorrhoea, Vibrio fischeri) | Soluble peptidoglycan; damages ciliated cells —> impaired mucus removal from URT —> paroxysmal (whooping) cough | Reduced pathogen removal |
Bug:
Agar: Aerobic