Objective To improve the understanding of pneumocystis carinii pneumonia (PCP) and investigate the role of electron microscopical examination in the diagnosis of PCP.

Because other forms of respiratory infection including PCP are common among HIV-infected people, doctors must be certain of diagnosis before administering antibiotics.

These infections would usually be fought off by a healthy immune system, but a low CD4 cell count means opportunistic infections such as PCP (a type of pneumonia) can be life-threatening.