# Positive Molecular Detection of Rickettsia helvetica in Great Tits From Central Poland

## TL;DR

Great Tits in Poland carry Rickettsia helvetica bacteria, suggesting birds may help spread tick-borne diseases into urban areas.

## Contribution

This study is the first to detect Rickettsia helvetica in great tits in Poland, highlighting birds' role in spreading tick-borne diseases in urban areas.

## Key findings

- Six out of 73 great tits (8.2%) tested positive for Rickettsia spp., with Rickettsia helvetica confirmed via sequencing.
- No ticks collected from the birds tested positive for Rickettsia, indicating birds may be carriers rather than vectors.
- Rickettsia helvetica was detected in all three habitats studied, suggesting widespread presence in urban and suburban areas.

## Abstract

Ticks spread to new habitats via wild mammals and birds, with urban green spaces potentially colonized through bird transportation. Rickettsia is a genus of bacteria that can cause diseases in humans and animals, which is often transmitted by ticks. This study investigated the presence of Rickettsia in the great tit (
Parus major
), a widespread Eurasian passerine bird, and in ticks attached to them. Samples were collected in three locations around Lodz, Poland: a suburban forest, an urban park, and green patches near the city center. Using Nested PCR (polymerase chain reaction), 73 samples of blood from birds and five ticks taken from great tits (attached to them) were tested for the presence of Rickettsia DNA. Six birds (8.2%) tested positive for Rickettsia spp., with detections across all locations. Sequencing confirmed the presence of
Rickettsia helvetica
, a known zoonotic species. None of the ticks tested positive for Rickettsia. These findings indicate that synanthropic bird species, like the great tit, may play a role in spreading Rickettsia bacteria into urban areas. This study highlights the potential importance of birds in the ecology of tick‐borne diseases in urbanized environments.

Great Tits were trapped in central Poland from three different habitats: a suburban forest, an urban park, and green patches near the city center.
Ixodes ricinus
species and samples of birds blood were collected from birds. Blood samples and ticks were molecularly tested for the presence of Rickettsia. Tick infestation was low at 5.5%. Prevalence of Rickettsia spp. was 8% in Great Tits' blood, and there were no differences between study places. None of the ticks tested positive for Rickettsia. Sequencing indicated the presence of
Rickettsia helvetica
.