Detection of Chlamydophila psittaci from feral pigeons in environmental samples: problems with currently available techniques

Abstract

Chlamydophila psittaci (Lillie, 1930) Everett et al., 1999, the pathogenic agent of human ornithosis, is widespread in feral pigeon populations and many cases of transmission from feral pigeons to humans have been reported. The aim of the present study was to detect C. psittaci in environmental samples to find out more about possible transmission routes and, therefore, to assess the zoonotic risk for humans. Fecal samples were collected from nest boxes in a feral pigeon loft. Additionally, samples were taken from the feather dust film covering the water surface of public fountains where pigeons regularly bathe. The samples were tested for the presence of chlamydial antigen using an antigen enzyme-linked immunosorbent assay to prove shedding of C. psittaci by feral pigeons. This test detects a genus specific lipopolysaccharide in the outer membrane of the chlamydial bacteria. Samples were tested using the IDEIA PCE Chlamydia Test kit (DakoCytomation) and positive results were verified with IDEIA Chlamydia Blocking Reagents (DakoCytomation). The IDEIA PCE Chlamydia Test yields a high proportion of positive results. However, when IDEIA Chlamydia Blocking was performed, most of the positive results turned out to be negative or could not be interpreted. We conclude that antigen-enzyme-linked immunosorbent assay tests are not suitable for detecting C. psittaci in environmental samples. Previous publications where no blocking test was used should be reconsidered critically.

Risk factors associated withChlamydia psittaciinfections in psittacine birds and bird handlers

“…). Asymptomatic infected birds intermittently shed the organism in their secretions and droppings (Geigenfeind and Haag‐Wackernagel ), posing a threat to human health. Human infections usually occur directly through contact with infected birds or indirectly through bird secretions and droppings (Harkinezhad et al .…”

Chlamydiosis in farmed chickens in Slovakia and zoonotic risk for humans

“…The families Psittacidae (cockatoos, parrots, parakeets and lories) and Columbiformes (pigeons) seem to be especially affected. This pathogen is also prevalent in wild birds, pet birds and the pet bird and poultry trades, causing economic losses to the poultry industry [4].…”

Chlamydia psittaci exposure in pet birds

“…They may lead to a wide range of clinical manifestations including ocular, pulmonary, genital, articular and intestinal illness, but very often they induce persistent, chronic, or subclinical infections (Rodolakis & Yousef Mohamad, 2010). Psittacosis is a well-known disease caused by Chlamydia psittaci (Rohde et al , 2010), which is prevalent in poultry, pet birds and wild birds, and causes economic losses to the poultry industry and the pet trade (Geigenfeind & Haag-Wackernagel, 2010). As far as the transmission of Chlamydia psittaci strains from birds to humans is concerned, veterinarians and the owners of pet birds have been reported to face a particular risk (Evans, 2011).…”