Hedgehog study finds health link to ticks

Ticks can severely weaken hedgehogs and cause anaemia, and the mammals are in decline in Britain and now on the protected species list.

A team led by Dr Toni Bunnell and including Dr Jorg Hardege and Dr Thomas Breithaupt from the University’s Department of Biological Sciences looked at a sample of sick and healthy hedgehogs and found that healthy animals were significantly less likely to carry ticks than sick ones.

The ecological survey, involving 226 wild hedgehogs, found that ticks choose their “host” based on odour linked to a hedgehog’s health status.

The tick is associated predominantly with hedgehogs but is occasionally found on dogs, cats and even humans.

Ticks are attracted to hosts from a distance by different stimuli including vibrations, body heat and odour.

Since hedgehogs have no specialised skin glands, odour sources that attract hedgehog antagonists from a distance are limited to footprints and faeces.

The compound indole, an aromatic organic compound, is likely to be involved in the attraction of ticks to sick hedgehogs as it was the only major compound found to exist in significantly higher amounts in faecal odour from sick hedgehogs compared with healthy ones.

Ticks were attracted to synthetic indole and also showed a preference for faeces from sick, as opposed to healthy, hedgehogs, the research found.

Dr Bunnell said: “This study sheds light on the mechanisms of parasite host interaction between ticks and hedgehogs. Future studies will aim to identify the chemical compounds possibly released by healthy hedgehogs.”

The study is published in the current edition of Chemical Ecology.