The Bacillus haemophilus causes

Options

A. Influenza
B. Pneumonia
C. A form of meningitis in young children
D. Whooping cough.

Answer

**Step-by-Step Solution:**

1. **Identify the Bacterium**: The question refers to "Bacillus haemophilus," which is more commonly known as "Haemophilus influenzae."

2. **Understand the Characteristics**: Haemophilus influenzae is a gram-negative bacterium and is classified as a facultative anaerobe, meaning it can survive in both the presence and absence of oxygen.

3. **Historical Context**: This bacterium was first identified by Richard Pfeiffer during an influenza epidemic, which provides insight into its association with respiratory diseases.

4. **Recognize the Infections Caused**: Haemophilus influenzae is known to cause several infections, particularly in the upper respiratory tract. It can lead to conditions such as:
- Epiglottitis
- Otitis media (middle ear infection)
- Meningitis, especially in young children

5. **Select the Correct Answer**: Among the options provided, the bacterium is primarily associated with causing influenza. Therefore, the correct answer is that Haemophilus influenzae causes influenza.

**Final Answer**: Haemophilus influenzae causes influenza.

---