# Ectoparasites enhance survival by suppressing host exploration and limiting dispersal

## TL;DR

Ectoparasites manipulate host behavior by altering brain activity, reducing exploration and dispersal to improve their own survival.

## Contribution

The study identifies microglial activation in the prefrontal cortex as a novel mechanism by which ectoparasites influence host behavior.

## Key findings

- Ectoparasites activate microglia in the prefrontal cortex of mice, altering GABAergic neurons.
- Host exploration and dispersal decrease in striped hamsters due to ectoparasite influence.
- Behavioral changes help parasites avoid environmental pressures and improve fitness.

## Abstract

Parasites enhance their fitness by manipulating host dispersal. However, the strategies used by ectoparasites to influence host movement and the underlying mechanisms remain poorly understood. Here, we show that ectoparasites alter metabolic activity in specific brain regions of mice, with evidence pointing to a potential role for microglial activation in the prefrontal cortex. This activation appears to contribute to synaptic changes and altered neuronal differentiation, particularly in GABAergic neurons. Consequently, exploratory behavior decreases—an effect likely mediated through the skin–brain axis. In both indoor and field experiments with striped hamsters, ectoparasites reduce host exploration and modify their dispersal patterns. This behavioral shift ultimately restricts the host’s distribution, enabling parasites to avoid environmental pressures. Our findings reveal that ectoparasites limit host dispersal to improve their own fitness, offering key insights for parasite control strategies that promote health and preserve ecological stability within the One Health framework.

Ectoparasites activate prefrontal microglia via the skin–brain axis, damaging GABAergic neurons and reducing host exploration. This limits host distribution and may help ectoparasites avoid environmental pressures.