Veterinary Microbiology and Immunology exam questions: topics, study tips and free sample questions

Answer: B. This is a tricky question to help you remember that two diseases FORMERLY classified as Ehrlichia have now been RE-classified. The causative organism of equine granulocytic anaplasmosis (a.k.a. anaplasmosis; formerly equine granulocytic ehrlichiosis) was originally classified as Ehrlichia equi, but is now called ANAPLASMA phagocytophilum due to DNA sequencing studies. Do not confuse equine anaplasmosis, a necrotizing vasculitis, with BOVINE anaplasmosis, which primarily causes an anemia with icterus and fever. Another name change occurred with the causative organism of Potomac horse fever (PHF), from Ehrlichia risticii to NEOrickettsia risticii. PHF presents as a febrile colitis/diarrhea, with laminitis 3-5 d after diarrhea in horses of all ages: A big rule out is salmonella (think septicemia/fever + diarrhea).

Answer: C. Pemphigus foliaceus, pemphigus vulgaris, bullous pemphigoid are all examples of type II reactions. Antibody binds antigen on a cell, then the antibody-antigen complex activates complement, causing cell lysis. In general, think of rare, autoimmune skin diseases characterized by varying presentations of ulceration, crusting, pustules, vesicles.

Answer: C. Examples of Type IV diseases include: Contact hypersensitivity-plastic food bowls, or poison ivy in humans, Granulomatous reactions to mycobacteria, Coccidioides , Blastomyces , Histoplasma Lymphocytic choriomeningitis (hamsters, mice), Old-dog encephalitis (Canine Distemper): Autoimmune thyroiditis (has a type II component too) Keratitis sicca (KCS). Type IV immune reactions are cell mediated, sometimes also called delayed hypersensitivity reactions. Typically, think of reactions to organisms that get INSIDE cells. Ie: