During the monsoon season, a 6-year-old child from rural Uttar Pradesh presents with fever and altered sensorium. CSF shows mild lymphocytic pleocytosis with normal sugar. Japanese encephalitis is confirmed serologically. In the natural transmission cycle of this virus, the principal vertebrate amplifying host, while man acts only as a dead-end host, is:
- A Pigs ✓
- B Dogs
- C Cattle
- D Rodents
Correct answer: A. Pigs
Explanation
Japanese encephalitis virus circulates between Culex mosquitoes (chiefly Culex tritaeniorhynchus, breeding in rice paddies) and vertebrate amplifying hosts. Pigs develop high-titre, prolonged viraemia after infection without disease, making them the key amplifying hosts; wading birds such as pond herons also amplify the virus. Man develops viraemia too low and brief to infect mosquitoes and is a dead-end host. Cattle are not competent amplifiers, which is why locating piggeries away from dwellings is a control measure.
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.