Questions: Which of the following causes a severe type of pneumonia only found in individuals with compromised immune systems such as AIDS patients? A) pneumocystis B) tuberculosis C) toxoplasmosis D) Streptococcus

The answer is the first one (A): pneumocystis.

Explanation for each option:

A) Pneumocystis: Pneumocystis pneumonia (PCP) is a severe type of pneumonia caused by the fungus Pneumocystis jirovecii. It is particularly common in individuals with compromised immune systems, such as those with AIDS. This makes it the correct answer.

B) Tuberculosis: While tuberculosis (TB) can cause pneumonia and is more common in individuals with weakened immune systems, it is not exclusive to them and can affect anyone. TB is caused by the bacterium Mycobacterium tuberculosis.

C) Toxoplasmosis: Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii. It can cause severe complications in immunocompromised individuals, but it does not typically cause pneumonia.

D) Streptococcus: Streptococcus pneumoniae is a common cause of bacterial pneumonia in the general population, not just in immunocompromised individuals. It can affect anyone, regardless of their immune status.

Summary: Pneumocystis pneumonia (PCP) is specifically associated with individuals who have compromised immune systems, such as AIDS patients, making option A the correct answer.