WebMD -- Bacteria on pigeons said to cause more diarrhea than Salmonella

Spanish researchers find two bugs on feral pigeons which cause illness in humans

By Nicky Broyd WebMD Health NewsReviewed by Dr Rob Hicks 22nd June 2010 - A sampling of pigeons captured on the streets of Madrid has revealed the bacteria they carry. Researchers writing in BioMed Central’s open access journal Acta Vetinaria Scandinavica found two bugs that were highly prevalent in the bird population and which cause illness in humans: Chlamydia psittaci and Campylobacter jejuni.

The study

Fernando Esperón from the Animal Health Research Center, in Madrid, worked with a team of researchers to analyse blood and enema samples taken from 118 pigeons caught using gun-propelled nets.The study found extremely high prevalence of bacteria which can be transferred from feral pigeons to humans. Esperón said in news release there was no way to tell if the birds were infected: “This leads to the hypothesis that pigeons act as asymptomatic reservoirs of Chlamydia psittaci and Campylobacter jejuni. These birds may therefore pose a public health risk to the human population.”Since the 1960s, Britain's wild pigeon population has been steadily increasing and feral pigeons have thrived in cities where they’ve found a steady food supply.


Chlamydia psittaci was found in 52.6% of the pigeons captured. It can lead to an infection that varies in severity from a mild flu-like illness to severe pneumonia. Campylobacter jejuni was present in 69.1% of the pigeons captured. It can cause abdominal pain, diarrhoea, fever and general malaise.Although there have been few reports of disease transmission between pigeons and humans the bacteria can be dispersed in the air as very fine droplets or dust particles, or can occur by direct or indirect contact through food and water contamination.According to Esperón, “Thermophilic Campylobacter species are considered the primary pathogens responsible for acute diarrhoea 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 diarrhoea than infection by Salmonella species.”

Article Sources SOURCES:Bio Med news release: Harmful bacteria carried by pigeons

Study: Screening for several potential pathogens in feral pigeons (Columba livia) in Madrid.  Article available at the journal website.