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

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.

Evidence of bromethalin toxicosis in feral San Francisco "Telegraph Hill" conures.

During 2018, four free-ranging conures, from a naturalized flock in San Francisco, presented with a characteristic set of neurologic signs that had been reported in other individuals from this flock. The cause of morbidity or mortality in historic cases has not been identified. From these four subjects, fresh feces were collected during their initial days of hospitalization and submitted to the University of Georgia Infectious Diseases Laboratory and Center for Applied Isotope Studies for bromethalin and desmethyl-bromethalin quantitation. Using High Performance Liquid Chromatography, the laboratory detected bromethalin, a non-anticoagulant, single-dose rodenticide, in fecal samples from three subjects; half of these samples were also positive for desmethyl-bromethalin, bromethalin's active metabolite. In three subjects that died, the UGA laboratory screened brain and liver samples and found bromethalin in all samples; desmethyl-bromethalin was detected in all but one brain sample, which was below the detection limit. Our findings suggest the conures are more resistant to bromethalin than are other species in which bromethalin has been studied, and/or that the conures may be ingesting the toxin at a sublethal dose. More data is needed to better assess the long-term effects of bromethalin on animals exposed at the subacute/chronic levels, and also to better understand the compartmentalization of bromethalin and desmethyl-bromethalin in a wider variety of species.

ATYPICAL CHLAMYDIACEAE IN WILD POPULATIONS OF HAWKS ( BUTEO SPP.) IN CALIFORNIA.

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.

CHLAMYDIA PSITTACI IN FERAL ROSY-FACED LOVEBIRDS ( AGAPORNIS ROSEICOLLIS) AND OTHER BACKYARD BIRDS IN MARICOPA COUNTY, ARIZONA, USA.

In 2013, a mortality event of nonnative, feral Rosy-faced Lovebirds ( Agapornis roseicollis) in residential backyards in Maricopa County, Arizona, US was attributed to infection with Chlamydia psittaci. In June 2014, additional mortality occurred in the same region. Accordingly, in August 2014 we sampled live lovebirds and sympatric bird species visiting backyard bird feeders to determine the prevalence of DNA and the seroprevalence of antibodies to C. psittaci using real-time PCR-based testing and elementary body agglutination, respectively. Chlamydia psittaci DNA was present in conjunctival-choanal or cloacal swabs in 93% (43/46) of lovebirds and 10% (14/142) of sympatric birds. Antibodies to C. psittaci were detected in 76% (31/41) of lovebirds and 7% (7/102) of sympatric birds. Among the sympatric birds, Rock Doves ( Columba livia) had the highest prevalence of C. psittaci DNA (75%; 6/8) and seroprevalence (25%; 2/8). Psittacine circovirus 1 DNA was also identified, using real-time PCR-based testing, from the same swab samples in 69% (11/16) of species sampled, with a prevalence of 80% (37/46) in lovebirds and 27% (38/142) in sympatric species. The presence of either Rosy-faced Lovebirds or Rock Doves at residential bird feeders may be cause for concern for epizootic and zoonotic transmission of C. psittaci in this region.

Evaluating 21-day doxycycline and azithromycin treatments for experimental Chlamydophila psittaci infection in cockatiels (Nymphicus hollandicus).

To determine the efficacy of 21-day therapy with azithromycin and doxycycline in the treatment of experimental infection with Chlamydophila psittaci in cockatiels (Nymphicus hollandicus), 30 birds randomly assigned to 3 treatment groups and 1 control group were inoculated with C psittaci by combined intranasal and ocular routes. Morbidity, mortality, and results of polymerase chain reaction testing confirmed that infection was successful. Birds in group 1 (n = 8) received azithromycin at 40 mg/kg PO q48h for 21 days; in group 2 (n = 8), doxycycline at 35 mg/kg PO q24h for 21 days; in group 3 (n = 8), doxycycline at 35 mg/kg PO q24h for 45 days; and, in group 4 (controls; n = 6), no treatment. Six birds died either before or within 2 days of initiating treatment: 4 in the 3 treatment groups and 2 in the control group. Clinical signs resolved and mortality ceased 2-6 days after treatment was initiated in all treatment groups, whereas birds in the control group exhibited clinical signs for the duration of the study. Plasma doxycycline concentrations were measured during the treatment period and exceeded 1 microg/mL at all time points. The absence of clinical signs and mortality in the treatment groups, even after inducing an immunocompromised state with dexamethasone (3 mg/kg IM q24h for 5 days), starting on day 70 postinoculation, suggested that treatment resulted in elimination of the pathogen. After euthanasia of the remaining 24 birds, 23 of the carcasses were submitted for necropsy. Spleen and liver samples from the birds in all treatment and control groups were polymerase chain reaction negative for C psittaci nucleic acid, and organisms were not detected by Gimenez stain. No gross or histologic differences were observed in the livers and spleens of treated and untreated infected birds. Lesions consistent with avian chlamydiosis (hystiocytosis) were seen in all birds and were considered residual. In this study, a 21-day course of either doxycycline or azithromycin was effective in eliminating C psittaci infection in experimentally inoculated cockatiels. Additional studies are necessary to evaluate the efficacy of these treatments in naturally infected cockatiels as well as other species of birds.

Genotyping of Chlamydophila psittaci by real-time PCR and high-resolution melt analysis.

Human infection with Chlamydophila (Chlamydia) psittaci can lead to psittacosis, a disease that occasionally results in severe pneumonia and other medical complications. C. psittaci is currently grouped into seven avian genotypes: A through F and E/B. Serological testing, outer membrane protein A (ompA) gene sequencing, and restriction fragment length polymorphism analysis are currently used for distinguishing these genotypes. Although accurate, these methods are time-consuming and require multiple confirmatory tests. By targeting the ompA gene, a real-time PCR assay has been developed to rapidly detect and genotype C. psittaci by light-upon-extension chemistry and high-resolution melt analysis. Using this assay, we screened 169 animal specimens; 98 were positive for C. psittaci (71.4% genotype A, 3.1% genotype B, 4.1% genotype E, and 21.4% unable to be typed). This test may provide insight into the distribution of each genotype among specific hosts and provide epidemiological and epizootiological data in human and mammalian/avian cases. This diagnostic assay may also have veterinary applications during chlamydial outbreaks, particularly with respect to identifying the sources and tracking the movements of a particular genotype when multiple animal facilities are affected.