A 3-year-old child in Bihar presents with acute onset fever, altered sensorium, and seizures during August. CSF shows lymphocytic pleocytosis with normal glucose. MRI shows bilateral thalamic hyperintensity. Which arbovirus is most likely responsible and what is its transmission cycle?

• A Dengue virus, human-mosquito-human cycle
• B West Nile virus, bird-mosquito-human cycle with humans as amplifying hosts
• C Chikungunya virus, human-mosquito-human cycle
• D Japanese encephalitis virus, pig-mosquito-human cycle with humans as dead-end hosts ✓

Explanation

Japanese encephalitis virus is a flavivirus transmitted by Culex mosquitoes in a zoonotic cycle involving pigs as amplifying hosts and wading birds as reservoirs. Humans are dead-end hosts. JE is endemic in Bihar, Uttar Pradesh, and other parts of India, with peak incidence during monsoon. Bilateral thalamic lesions on MRI are characteristic. Dengue and chikungunya cause human-mosquito-human cycles. West Nile virus uses birds as reservoirs but humans are dead-end hosts, not amplifying hosts.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.