ATYPICAL CHLAMYDIACEAE IN WILD POPULATIONS OF HAWKS (BUTEOSPP.) IN CALIFORNIA

Abstract

Chlamydiaceae bacteria infect many vertebrate hosts, and previous reports based on polymerase chain reaction (PCR) assays and serologic assays that are prone to cross-reaction among chlamydial organisms have been used to describe the prevalence of either DNA fragments or antibodies to Chlamydia spp. in wild raptorial populations. This study reports the PCR-based prevalence of Chlamydiaceae DNA that does not 100% match any avian or mammalian Chlamydiaceae in wild populations of hawks in California Buteo species. In this study, multimucosal swab samples ( n = 291) for quantitative PCR (qPCR) and plasma ( n = 78) for serology were collected from wild hawks. All available plasma samples were negative for antibodies using a C. psittaci-specific elementary body agglutination test (EBA; n = 78). For IgY antibodies all 51 available samples were negative using the indirect immunofluorescent assay. The overall prevalence of Chlamydiaceae DNA detection in wild Buteo species sampled was 1.37% (4/291) via qPCR-based analysis. Two fledgling Swainson's hawks ( Buteo swainsoni) and two juvenile red-tailed hawks ( Buteo jamaicensis) were positive by qPCR-based assay for an atypical chlamydial sequence that did not 100% match any known C. psittaci genotype. Positive swab samples from these four birds were sequenced based on the ompA gene and compared by high-resolution melt analysis with all known avian and mammalian Chlamydiaceae. The amplicon sequence did not 100% match any known avian chlamydial sequence; however, it was most similar (98.6%) to C. psittaci M56, a genotype that is typically found in muskrats and hares. Culture and full genome sequence analysis of Chlamydia spp. isolated from diseased hawks will be necessary to classify this organism and to better understand its epizootiology and potential health impact on wild Buteo populations in California.

A Review of Chlamydial Infections in Wild Birds

“…The more recently proposed genotype 1V appears to be associated with the Corvidae family [ 34 , 36 ]. Interestingly, genotype M56 (originally associated with mammals) has recently been found in association with wild raptors [ 34 , 37 ] in Switzerland and the USA.…”

“…In recent years, a mortality event in rosy-faced lovebirds ( Agapornis roseicollis ) prompted screening of wild birds at feeders in Arizona, where several bird species (including feral pigeons, house sparrows, and Inca doves ( Columbina inca )) tested positive for C. psittaci [ 88 ]. There has been some raptor surveillance in the USA; a Chlamydiaceae prevalence of 1.4% was found in wild hawks in the Buteo genus [ 37 ], with the chlamydial species identified later characterised as C. buteonis [ 5 ]. Additionally, C. psittaci and another member of the Chlamydiales, Candidatus Rhabdochlamydia spp., were identified in an osprey ( Pandion haliactus ) and a red-tailed hawk ( Buteo jamiacensis ), respectively [ 75 ].…”

Chlamydia buteonis in birds of prey presented to California wildlife rehabilitation facilities

“…There are relatively few reports of chlamydial infections in raptors in the United States [ 11 – 14 ]. In 1983, C .…”

“…psittaci was cultured from a RTHA in Louisiana with respiratory distress and diarrhea [ 11 , 12 ]. A recent study reported a 1.37% prevalence of chlamydial DNA in free-ranging raptors in northern CA, although anti-chlamydial antibodies using an elementary body agglutination (EBA) assay were not identified in any bird [ 14 ]. In Oregon, 3.6% of raptors at rehabilitation centers were positive for C .…”

Occurrence of Chlamydiaceae in Raptors and Crows in Switzerland

“…Several studies investigating wild birds found chlamydial species that could not be classified but were identified as genetic intermediates between C. psittaci and C. abortus [22][23][24][25][26][27][28][29][30]. One of these intermediates had initially been detected in a red-tailed hawk (Buteo jamaicensis) in the 1990s [31].…”