Which organism causes whooping cough?

Bordetella pertussis is the causative agent of whooping cough, also known as pertussis. This bacterium is a small, gram-negative coccobacillus that primarily infects the respiratory tract. It attaches to the ciliated epithelial cells of the upper respiratory tract and produces a variety of virulence factors, including toxins that interfere with the function of the respiratory cilia, leading to the severe coughing fits characteristic of the disease, often described as a "whoop" sound when the patient inhales sharply after a series of coughs.

Immunization against Bordetella pertussis has been effective in reducing the incidence of whooping cough, but outbreaks can still occur, especially in populations with lower vaccination rates. Understanding the specific agent of whooping cough is crucial for diagnosis and management, as well as for implementing appropriate public health measures.

The other organisms listed are associated with different conditions. Haemophilus influenzae is known for causing respiratory tract infections and can lead to diseases such as meningitis, while Actinomyces israelii is linked to actinomycosis, a type of bacterial infection that can cause abscesses. Nocardia asteroides is primarily associated with opportunistic infections in