Forests harbor more ticks than other habitats: A meta-analysis

With increasing deforestation, questions are being raised about the risk of zoonotic disease to humans. To better assess the role of forest in the emergence of tick-borne diseases, we conducted a meta-analysis of the scientific literature to compare the abundance or diversity of ticks between forest and open habitats (natural or anthropogenic) and a meta-regression to test how tick abundance is influenced by the abundance of their vertebrate hosts in forest habitats.We found that Ixodes ticks were on average more abundant and diverse in forests than in any other nonforested habitats, the difference being more pronounced with mixed deciduous- coniferous than with deciduous forests. At the forest scale, exophilic Ixodes tick abundance was positively influenced by the abundance of their ungulate hosts.Our results suggest that mixed forests represent the habitats with the highest level of tick hazard. However, more studies are needed to assess the risk of transmission of tick-borne diseases in forests, which also depends on the prevalence of pathogens and the exposure of people.

Automated summary

With increasing deforestation, the abundance and diversity of ticks, specifically Ixodes ticks, are found to be higher in forests compared to nonforested habitats. The abundance of ticks in forests is positively influenced by the abundance of their ungulate hosts. However, further studies are needed to assess the risk of tick-borne disease transmission in forests, which depends on pathogen prevalence and human exposure.