How does a tick transmit piroplasmosis? - briefly
When a tick attaches and feeds, it injects sporozoites from its salivary glands into the host’s bloodstream. The parasites then invade red blood cells, multiply, and produce piroplasmosis.
How does a tick transmit piroplasmosis? - in detail
Ticks act as vectors for piroplasm parasites through a series of biological processes that begin when an unfed nymph or adult attaches to a vertebrate host. During the blood meal, the parasite present in the host’s erythrocytes is ingested along with the blood. Inside the tick’s midgut, piroplasms undergo sexual reproduction, forming zygotes that develop into kinetes. These motile stages cross the midgut epithelium, enter the hemocoel, and migrate to the salivary glands.
In the salivary glands, kinetes differentiate into sporozoites, the infective form that will be transmitted to the next host. When the tick resumes feeding, sporozoites are released with the saliva into the host’s bloodstream, where they invade erythrocytes and initiate the disease cycle.
Key biological features of this transmission pathway include:
- Acquisition: Parasite uptake occurs during any feeding stage on an infected animal.
- Transstadial persistence: The pathogen survives the molt from larva to nymph and from nymph to adult, ensuring continuity across developmental stages.
- Salivary gland colonization: Migration to and multiplication within the glands are essential for successful inoculation.
- Transovarial passage (in some species): Female ticks can transmit the parasite to their offspring, establishing a reservoir within the tick population.
- Feeding behavior: Prolonged attachment increases the volume of saliva delivered, raising the probability of successful infection.
The efficiency of transmission depends on tick species, the density of sporozoites in the salivary glands, and the duration of attachment. Control strategies focus on interrupting any of these steps—preventing tick attachment, reducing tick populations, or targeting the parasite’s development within the vector.