What is the preferred method for detecting larvae of Aelurostrongylus abstrusus in cats?

The preferred method for detecting larvae of Aelurostrongylus abstrusus, which is a lungworm affecting cats, is the Baermann examination of feces. This method is specifically designed to isolate and identify certain types of lungworm larvae from fecal samples. The Baermann technique uses the principle of gravity to allow the larvae, which are motile, to migrate out of the solid fecal matter into a liquid medium, making it easier to visualize them under a microscope.

In contrast, fecal flotation is not as effective for lungworm larvae because the larvae do not float to the surface in the same way that eggs do, making it less reliable for detection. Blood smear analysis focuses primarily on blood-borne parasites and will not provide information about gastrointestinal or respiratory parasites like Aelurostrongylus abstrusus. Endoscopy is an invasive procedure typically used for direct visualization and retrieval of samples from the gastrointestinal tract, which is not necessary for identifying lungworm larvae. Thus, the Baermann method is the most suitable and effective choice for detecting this specific parasite in cats.