# From flyways to foci: a systematic review and meta-analysis on the role of birds in the maintenance and global dispersal of ticks and tick-borne pathogens

## TL;DR

Birds play a key role in spreading ticks and tick-borne diseases globally, especially through migration, but more research is needed in under-studied regions like Asia.

## Contribution

This study provides the first global synthesis of bird-associated ticks and pathogens, revealing their epidemiological roles and highlighting surveillance gaps.

## Key findings

- Birds host 185 tick species and 102 tick-borne pathogens, with 53.9% of pathogens being zoonotic.
- Passeriformes (songbirds) host the most tick diversity, while Galliformes have the highest infestation prevalence.
- Asia is significantly underrepresented in tick surveillance despite its high pathogen diversity.

## Abstract

Birds (Aves) are considered to play important roles in the dissemination of ticks and tick-borne pathogens, yet the global extent of their contribution to vector maintenance and long-distance dispersal remains poorly quantified. This study provides a comprehensive global synthesis of bird-associated ticks (BATs) and bird-associated tick-borne pathogens (BATBPs) to characterize the epidemiological roles of birds and assess the resulting public health and biosecurity risks.

We systematically searched multiple bibliographic databases and GenBank up to February 2025 in accordance with Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Field-based studies reporting bird–tick–pathogen associations were included. Thematic maps showing the geographical distributions of birds, BATs, and BATBPs were produced in ArcGIS, and pooled infestation prevalence was estimated via logit-transformed random-effects meta-analysis with the Hartung–Knapp adjustment.

Our synthesis of 772 studies and 86 molecular records identified 185 BAT species and 102 BATBPs across 34 avian orders, representing 77.3% of all global orders. Within the BATBP spectrum, 53.9% are zoonotic, and 99 tick species have documented records of human-biting. Passeriformes (songbirds) hosted the greatest tick diversity (129 species), while Galliformes exhibited the highest pooled infestation prevalence (17.6%; n = 29 studies, m = 18,746 birds). Globally, allochthonous tick records showed relatively high spatial overlap with the Black Sea–Mediterranean and East Atlantic flyways. Critically, we identified a profound surveillance imbalance in Asia, which accounts for only 6.5% of sampling coordinates (26/397 sites) despite exhibiting a high diversity of emerging pathogens.

Birds serve as important contributors to global tick-borne disease epidemiology through local vector maintenance and intercontinental bio-dispersal. They support tick feeding and life-cycle completion and may disperse ticks during migration, facilitating population establishment in new areas. Molecular evidence indicates that birds carry a broad spectrum of tick-borne pathogens; however, the available evidence is largely observational, and experimental validation is required to clarify reservoir competence and transmission. Strengthening integrated One Health surveillance of high-risk hubs, particularly in data-deficient regions such as Asia, is essential to mitigate spillover risk at shifting ecological and migratory interfaces.

The online version contains supplementary material available at 10.1186/s13071-025-07238-4.