Animal sources for zoonotic transmission of psittacosis: a systematic review

Abstract

Background: Human psittacosis, caused by Chlamydia (C.) psittaci, is likely underdiagnosed and underreported, since tests for C. psittaci are often not included in routine microbiological diagnostics. Source tracing traditionally focuses on psittacine pet birds, but recently other animal species have been gaining more attention as possible sources for human psittacosis. This review aims to provide an overview of all suspected animal sources of human psittacosis cases reported in the international literature. In addition, for each animal species the strength of evidence for zoonotic transmission was estimated. Methods: A systematic literature search was conducted using four databases (Pubmed, Embase, Scopus and Proquest). Articles were included when there was mention of at least one human case of psittacosis and a possible animal source. Investigators independently extracted data from the included articles and estimated strength of evidence for zoonotic transmission, based on a self-developed scoring system taking into account number of human cases, epidemiological evidence and laboratory test results in human, animals, and the environment. Results: Eighty articles were included, which provided information on 136 different situations of possible zoonotic transmission. The maximum score for zoonotic transmission was highest for turkeys, followed by ducks, owls, and the category 'other poultry'. Articles reporting about zoonotic transmission from unspecified birds, psittaciformes and columbiformes provided a relatively low strength of evidence. A genotypical match between human and animal samples was reported twenty-eight times, including transmission from chickens, turkeys, guinea fowl, peafowl, pigeons, ducks, geese, songbirds, parrot-like birds and owls. Conclusions: Strong evidence exists for zoonotic transmission from turkeys, chickens and ducks, in addition to the more traditionally reported parrot-like animal sources. Based on our scoring system, the evidence was generally stronger for poultry than for parrot-like birds. Psittaciformes should not be disregarded as an important source of human psittacosis, still clinicians and public health officials should include poultry and birds species other than parrots in medical history and source tracing.

A New SNP-Based Genotyping Method for C. psittaci: Application to Field Samples for Quick Identification

“…Six of the successfully amplified samples were collected from duck breeders (16-1264_MJC, 16-1264_JL1, 16-1264_JL2, 2008_A, 2009_A, and 20-3954_C054) and genotyped as group II_duck by PCR-HRM) and three other samples (16-1264_VE, 20-1105_A036, and 20-1105_A039) were genotyped as group III_pigeon by PCR-HRM, in line with the suspected infection source (dust exposure, cleaning of attics). These bird groups are among the common sources of human infection [ 3 ].…”

“…Misdiagnosis and/or inappropriate antibiotic-based treatment can also result in death due to atypical pneumonia. Avian species belonging to the orders Psittaciformes, Galliformes, Anseriformes, and Columbiformes are common sources of infection [ 3 ]. In birds, the clinical presentation may vary considerably and is influenced by the pathogen (genotypes of C. psittaci ) and the host (species, age, health and immunological status).…”

Pmp Repertoires Influence the Different Infectious Potential of Avian and Mammalian Chlamydia psittaci Strains

“…The mare was obviously passing the highly virulent C. psittaci strain 6BC, identical to the 6BC strain present in Australian parrots ( Chan et al, 2017 ; Jelocnik et al, 2017 ). In general, mammals seem to be an accidental host of avian C. psittaci strains ( Harkinezhad et al, 2009 ; Hogerwerf et al, 2020 ). One could argue that all strains isolated from mammals were originally acquired from birds and were therefore “avian strains,” which evolved to “mammalian strains”.…”

“…In these mammals, the infection is mostly latent and the development of clinical disease is possible but rare ( Reinhold et al, 2011 ; Reinhold et al, 2012 ; Knittler and Sachse, 2015 ). In contrast to C. psittaci from infected birds, C. psittaci of mammalian origin does not seem to have a strong zoonotic potential, as only few cases of human transmission from infected mammals have been reported and, in all cases, the primary infection was acquired from infected birds ( Hogerwerf et al, 2020 ). Empiric observations imply that C. psittaci strains from mammalian origin (mammalian strains) have a lower infectious and zoonotic potential, compared to strains from avian origin (avian strains) ( Knittler and Sachse, 2015 ).…”

Clinical characteristics of Chlamydia psittaci pneumonia

“…Here, one case had been fertilized with pigeon manure, one had newly reared chickens at home, one had reared pigeons, and one had a possible indirect environmental contact because her workplace was located upstairs of a farmers’ market (including poultry market areas), consistent with poultry transmissible zoonoses. [ 3 ]…”