This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
Which of the following is true regarding anthrax? 
Select and explain. 
A. McFadyean reaction shows capsule, B. Humans are usually resistant to infection, C. Less than 100 spores can cause pulmonary infection, D. Gram stain shows organism with bulging spores
A: McFadyean reaction shows capsule
Answer: A: McFadyean reaction shows capsule 
Explanation: Ans. is 'a' i.e., McFadyean reaction shows capsuleHumans are usually resistant to infection and Sputum microscopy helps in diagnosis in case of pulmonary anthrax.Stained smears from the local lesion or of blood from clinical samples of human or dead animals often show chains of large gram-positive rods (spores are not in clinical samples). Anthrax can be identified in dried smears by direct immunofluorescence staining techniques.