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

Abstract

Chlamydial infections, caused by a group of obligate, intracellular, gram-negative bacteria, have health implications for animals and humans. Due to their highly infectious nature and zoonotic potential, staff at wildlife rehabilitation centers should be educated on the clinical manifestations, prevalence, and risk factors associated with Chlamydia spp. infections in raptors. The objectives of this study were to document the prevalence of chlamydial DNA shedding and anti-chlamydial antibodies in raptors admitted to five wildlife rehabilitation centers in California over a one-year period. Chlamydial prevalence was estimated in raptors for each center and potential risk factors associated with infection were evaluated, including location, species, season, and age class. Plasma samples and conjunctiva/choana/cloaca swabs were collected for serology and qPCR from a subset of 263 birds of prey, representing 18 species. Serologic assays identified both anti-C. buteonis IgM and anti-chlamydial IgY antibodies. Chlamydial DNA and anti-chlamydial antibodies were detected in 4.18% (11/263) and 3.14% (6/191) of patients, respectively. Chamydial DNA was identified in raptors from the families Accipitridae and Strigidae while anti-C.buteonis IgM was identified in birds identified in Accipitridae, Falconidae, Strigidae, and Cathartidae. Two of the chlamydial DNA positive birds (one Swainson’s hawk (Buteo swainsoni) and one red-tailed hawk (Buteo jamaicensis)) were necropsied, and tissues were collected for culture. Sequencing of the cultured elementary bodies revealed a chlamydial DNA sequence with 99.97% average nucleotide identity to the recently described Chlamydia buteonis. Spatial clusters of seropositive raptors and raptors positive for chlamydial DNA were detected in northern California. Infections were most prevalent during the winter season. Furthermore, while the proportion of raptors testing positive for chlamydial DNA was similar across age classes, seroprevalence was highest in adults. This study questions the current knowledge on C. buteonis host range and highlights the importance of further studies to evaluate the diversity and epidemiology of Chlamydia spp. infecting raptor populations.

Unusual cases of chlamydiosis in psittacine birds

“…The recent discovery of a number of new species of chlamydiae further supports the need to document similarities and differences in diagnostic findings in affected birds. 11,13,16,19,22…”

“…Chlamydia is a genus belonging to the family Chlamydiaceae and encompasses 14 species including C. psittaci , C. avium , C. abortus , C. muridarum , C. suis , C. pecorum , C. trachomatis , C. felis , C. caviae, C. pneumoniae, C. gallinacea, C. ibidis, C. buteonis, and C. poikilothermis. 10,13,19,22,24 Chlamydia are intracellular Gram-negative bacteria that maintain their life cycle in the host cell within a nonacidified vacuole called an inclusion. Unlike other bacteria that solely rely on the host cell’s cytoplasm for free nutrient access, chlamydia import host nutrients across the inclusion membrane.…”

“…C. ibidis and C. buteonis are host specific and affect the African sacred ibis, and Accipitridae and Strigidae raptor families, respectively. 11,13,16,19,22 Chlamydia is a genus belonging to the family Chlamydiaceae and encompasses 14 species including C.…”

“…C. ibidis and C. buteonis are host specific and affect the African sacred ibis, and Accipitridae and Strigidae raptor families, respectively. 11,13,16,19,22…”

Psittacosis: An Underappreciated and Often Undiagnosed Disease

“…Most cases are identified in domesticated avian species, or domesticated or farm animals, but rare cases have been identified in a variety of zoo animals, be they birds, mammals, or reptiles. The organism has also been identified in wild birds, such as eagles and doves [ 26 , 27 ], and feral pigeons in urban areas are a natural reservoir of C. psittaci [ 28 ]. Parrots are a major host, yet prevalence and risk factors for infection in wild parrots are largely unknown.…”