Pigeons captured on the streets of Madrid have turned up positive results on bacterial pathogens, which can cause diarrhoea in humans.
Chlamydophila psittaci and Campylobacter jejuni - the two pathogens found in pigeons, cause more diarrhoea than Salmonella.
"The present study demonstrates the extremely high prevalence of two zoonotic pathogens in feral pigeons in Madrid. At the same time, infection with these pathogens did not appear to be associated with any harmful clinical signs in the birds themselves. This leads to the hypothesis that pigeons act as asymptomatic reservoirs of Chlamydophila psittaci and Campylobacter jejuni. These birds may therefore pose a public health risk to the human population," said Fernando Esperon from the Animal Health Research Center, Madrid, Spain.
The transfer of disease can occur by aerosols, direct contact or indirect contact through food and water contamination.
"Thermophilic Campylobacter species are considered the primary pathogens responsible for acute diarrhea in the world. In fact, in many countries such as England and Wales, Canada, Australia and New Zealand Campylobacter jejuni infection causes more cases of acute diarrhea than infection by Salmonella species," added Esperon.
The study was published in the journal Acta Veterinaria Scandinavica.