How does a tick acquire encephalitis virus? - briefly
Ticks acquire the virus during a blood meal from an infected vertebrate, usually a small mammal that serves as a reservoir; the pathogen then multiplies in the tick’s salivary glands, enabling transmission to subsequent hosts. Subsequent feeding on other animals spreads the infection within the tick population.
How does a tick acquire encephalitis virus? - in detail
Ticks become carriers of the encephalitis virus through a series of well‑documented mechanisms. The virus resides primarily in small mammals such as rodents, which serve as natural reservoirs. When a larval or nymphal tick attaches to an infected host, it ingests blood containing viral particles. The virus then penetrates the tick’s midgut epithelium, replicates within salivary glands, and remains viable throughout the tick’s subsequent developmental stages—a process known as transstadial transmission.
Key pathways of acquisition include:
- Feeding on viremic hosts – larvae, nymphs, and adults acquire the pathogen during blood meals from animals with circulating virus.
- Co‑feeding transmission – adjacent ticks feeding simultaneously on the same host exchange virus without the host developing systemic infection.
- Transovarial passage – infected female ticks can transmit the virus to their offspring, maintaining the pathogen in tick populations even in the absence of vertebrate reservoirs.
Environmental factors such as temperature, humidity, and host density influence the likelihood of successful infection. Warmer climates accelerate tick development, increasing the frequency of blood meals and thereby raising transmission opportunities. High host density provides more feeding occasions, enhancing viral circulation within the ecosystem.
After infection, the virus persists in the tick’s salivary glands, enabling transmission to new hosts during subsequent feedings. This cycle sustains the enzootic focus of encephalitis virus and underlies its spread to humans and domestic animals.