Who infected ticks with encephalitis? - briefly
Small mammals, primarily rodents, act as reservoirs that transmit the tick‑borne encephalitis virus to feeding ticks. The virus is acquired by ticks during blood meals from these infected hosts.
Who infected ticks with encephalitis? - in detail
Ticks acquire encephalitic viruses while feeding on infected vertebrate hosts. The primary reservoirs are small mammals that maintain viral circulation without showing severe disease. Typical reservoir species include:
- Peromyscus leucopus (white‑footed mouse)
- Myodes gapperi (southern red‑backed vole)
- Microtus spp. (voles)
- Apodemus sylvaticus (wood mouse)
Many bird species also serve as amplifying hosts, especially passerines that migrate across continents, transporting the virus to new regions. Notable avian contributors are:
- Turdus migratorius (American robin)
- Sturnus vulgaris (common starling)
- Parus major (great tit)
Transmission can occur without simultaneous viremia through co‑feeding, where an infected tick and an uninfected tick attach to the same host skin area, allowing virus passage via localized skin cells. This mechanism sustains the pathogen in tick populations even when host viremia is low.
Human activities that increase contact between ticks and wildlife—deforestation, suburban expansion, and climate‑driven changes in tick distribution—enhance the opportunities for these reservoirs to infect ticks. Consequently, the combination of competent mammalian and avian hosts, co‑feeding dynamics, and ecological disturbances determines which organisms are responsible for introducing encephalitic agents into tick vectors.