Japanese encephalitis prevention — DTM&H MCQ

Correct answer: E — Japanese encephalitis vaccination plus mosquito avoidance

The correct answer is E, Japanese encephalitis vaccination plus mosquito avoidance. This traveller has the classic high-risk profile for JE: an 8-week rural stay in Southeast Asia during the rainy (transmission) season, with evening fieldwork near pig farms and rice paddies, the exact ecological niche of the Culex mosquito vector and its amplifying hosts (pigs and wading birds). Current UK travel health guidance recommends JE vaccination for travellers staying a month or more in a JE-risk area during transmission season, and for those whose planned activities (fieldwork, camping, dusk-to-dawn outdoor exposure) raise risk even on shorter trips. Because IXIARO does not eliminate mosquito-borne transmission risk from other arboviruses (dengue, chikungunya) or reduce bite frequency, mosquito bite avoidance measures (repellents, nets, clothing) remain mandatory alongside vaccination. Why the other options are wrong: B, Oral cholera vaccine instead of mosquito precautions: Cholera vaccine addresses a faeco-oral risk, not the vector-borne encephalitis risk defined by this rural, pig-farm, evening-exposure scenario; substituting it for mosquito precautions ignores the actual transmission route described. C, No vaccine because exposure is rural: This inverts the guidance; rural exposure with prolonged stay and night-time fieldwork is precisely the indication that raises risk enough to warrant vaccination, not a reason to withhold it. D, Doxycycline for viral encephalitis prevention: Doxycycline is an antibacterial used for malaria chemoprophylaxis and cannot prevent a viral flavivirus infection such as JE; it has no antiviral activity. E, Rabies vaccine as the sole arboviral measure: Rabies vaccine protects against a lyssavirus transmitted by mammalian bites, not an arthropod-borne infection, so it cannot serve as an arboviral protective measure and is irrelevant to the mosquito exposure described. Key point: Prolonged (one month or more) rural stays with dusk-to-dawn outdoor exposure near rice fields and pigs mandate JE vaccination combined with mosquito bite avoidance, since neither measure alone covers the full risk.

Reference: NaTHNaC (TravelHealthPro), Japanese Encephalitis factsheet, National Travel Health Network and Centre, UK; https://travelhealthpro.org.uk/factsheet/55/japanese-encephalitis