<prompt> A Giemsa stain of a thin peripheral blood smear is prepared. Which of the following cannot be diagnosed?Bartonella henselaeCoxiella burnettiiToxoplasma gondiiEhrlichia chaffeensis  <response>: Ans. B Coxiella burnettiiRef: Jawetzs Medical Microbiology 27th Ed; Page No-347A diagnosis of Coxiella burnettii cannot be done using a Giemsa stain of a thin peripheral smear.The diagnosis of Coxiella burnetii is done mainly by serology which shows a rise in the titer of specific antibodies to C. burnettii.Other Options:Toxoplasma gondii: It can invade any nucleated cell and replicate within cytoplasmic vacuoles by a process called endogony internal budding. The trophozoites stain with Giemsa stain.Bartonella henselae: Invade macrophages and neutrophils which can be seen by Giemsa staining of a peripheral smear.Ehrlichia chaffeensis: They infect circulating leukocytes, erythrocytes and platelets, where they multiply within phagocytic vacuoles, forming clusters known as morulae. They can be seen on peripheral blood smear using Giemsa stain. 