Climate-driven increase in transmission of a wildlife malaria parasite over the last quarter century

Climate warming is expected to influence the prevalence of vector-transmitted parasites. Understanding the extent to which this is ongoing, or has already occurred, requires empirical data from populations monitored over long periods of time, but these studies are sparse. Further, vector-disease research involving human health is often influenced by disease control efforts that supersede natural trends. By screening for malaria parasite infections in a wild population of blue tits (Cyanistes caeruleus) in Northern Europe, over 26 years, we tested whether prevalence and transmission changes were climate-driven. We found that all three malaria parasite genera occurring in blue tits (Haemoproteus, Plasmodium, and Leucocytozoon) have increased significantly in their prevalence and transmission over time. The most common parasite in the study, Haemoproteus majoris, increased in prevalence from 47% (1996) to 92% (2021), and this was a direct consequence of warmer temperatures elevating transm..., , # Data from: Climate-driven increase in transmission of a wildlife malaria parasite over the last quarter century

Dataset DOI: [10.5061/dryad.37pvmcvz2](https://doi.org/10.5061/dryad.37pvmcvz2)

## Description of the data and file structure

Blue tits (*Cyanistes caeruleus*) were sampled from 1996 and 2021 as part of an experimental nest box system used to study their breeding. Age and sex data were obtained for all breeding birds in the study, along with blood samples. DNA was extracted from blood samples and used to identify infections with three different avian malaria genera: *Haemoproteus*, *Plasmodium*, and *Leucocytozoon*. The archived data and code were used to: (1) identify the prevalence and transmission patterns for malaria parasites over the study duration and (2) assess the relationship between warming temperatures and transmission patterns. Additionally, we include information on when eggs hatch (hatch dates) in the study system. 

### Files and variables

#### File: AT_G..., ,