Plague outbreak control — DTM&H MCQ

Correct answer: D — Prioritise early case detection, antibiotics and flea control

Option D (prioritise early case detection, antibiotics and flea control) is correct because plague outbreak control depends on rapidly identifying and treating human cases while interrupting flea-borne transmission, not on indiscriminate rodent culling. Early antibiotic treatment (streptomycin, gentamicin or doxycycline) dramatically reduces case fatality in bubonic plague and prevents progression to pneumonic disease, which carries a much higher mortality and person-to-person transmission risk. Flea control (insecticide dusting of rodent burrows and affected households) must be applied before or alongside any rodent reduction, because killing rats without first controlling their fleas causes the fleas to abandon dying hosts and seek new blood meals, including humans, amplifying transmission. This sequencing principle is central to WHO outbreak response guidance for endemic plague foci such as Madagascar. Why the other options are wrong: A. Begin rat killing before flea control: this is the classic error; culling rodents first liberates infected fleas that then bite humans, increasing bubonic case numbers rather than reducing them. E. Use chloroquine for household contacts: chloroquine is an antimalarial with no activity against Yersinia pestis; plague chemoprophylaxis for contacts uses doxycycline or ciprofloxacin, not chloroquine. C. Mass vaccinate the district population: no plague vaccine is in routine or emergency programmatic use for outbreak control; historical whole-cell vaccines gave poor efficacy against pneumonic plague and are not deployed for community outbreaks. B. Close water points for 2 weeks: plague is not waterborne, so this measure does nothing to interrupt flea-rodent-human transmission and diverts resources from effective interventions. Key point: control the fleas before the rodents, alongside early diagnosis and prompt antibiotic treatment of cases, to avoid driving infected fleas onto human hosts.

Reference: WHO Fact Sheet: Plague (2023), Prevention and control section, https://www.who.int/news-room/fact-sheets/detail/plague