Ans. b. Wayson's stain Farmer presents with the features of high fever, painful inguinal lymphadenopathy, vomiting and diarrhea and hypotension. This clinical picture is suggestive of Bubonic plague. Bubonic plague Bubonic plague symptoms can occur within two to six days of being infected by the bacteria Yersinia pestisdeg. If left untreated, symptoms, such as vomiting, abdominal pain, and diarrhea, can progress rapidly to septicemic plaguedeg. Approximately 10 to 20 percent of people with bubonic plague symptoms will also develop symptoms in the lungs. This is called pneumonic plague, and is often fataldeg. Plague Caused by bacteria Yersinia pestisdeg. Animal reservoir for Yersinia pestis: Rodentsdeg Vector: Rat flea (Xenopsylla cheopsisdeg) carries infection from rat to rat and rat to humans Characterized by rapid onset of fever and other systemic manifestations of Gram (-)ve bacterial infections. It is of Bubonic Plague Incubation period 2-7 daysdeg MC type of plague and almost always caused by bite of infected fleadeg. MC site of bubo- femoral, inguinal regiondeg >axillary, cervical. Distinguished from lymphadenitis by its rapid onset, its extreme tenderness, accompanying signs of toxemia and absence of cellulites or obvious ascending lymphadenitis DIC is common and may lead to gangrenedeg. Y. pestis can also be cultured from blood of most bubonic plague patientdeg. Septicemic Plague: Often present with GI symptoms, DIC, multiorgan failuredeg Incubation period 2-7 days Pneumonic Plague Most infectious, most fatal type of plague with incubation period of 1-3 daysdeg Primary pneumonia: Cyanosis is very prominent, with bloody mucoid sputumdeg Secondary pneumonia: Diffuse interstitial pneumonia, less infectious. Diagnosis Yersinia pestis is best demonstrated by polychromatic stains (Wayson, Wright-Giemsadeg). These polychromatic stains accurately highlight bipolar stainingdeg characteristics of these gram negative bacilli