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Abstract. Two 6-month-old raccoon kits, which had been rescued and fostered in preparation for return to the wild, became acutely ill and died 3 weeks before scheduled release. At necropsy, the kits had grossly enlarged livers and spleens, diffusely consolidated lungs, and generalized lymphadenopathy. Histologically, extensive infiltrates of macrophages containing yeast organisms were identified in lung, liver, kidney, spleen, lymph nodes, intestinal tissues, brain, adrenal gland, bone marrow, and thymus of both animals. Histiocytic inflammation with accompanying fibrosis was widespread, with necrotic foci evident in lungs, spleen, and intestinal sections. Fungal organisms were observed on sheep blood agar plates; however, repeated subcultures to fungal media designed to induce conidial structures for fungal identification were unsuccessful. Partial DNA sequencing of the 28S ribosomal RNA gene of the blood agar isolate identified 100% homology with Ajellomyces capsulatus (anamorphic name Histoplasma capsulatum). The kits were rescued and fostered in the San Francisco Bay area and it is likely that the exposure to H. capsulatum occurred in this area. Histoplasma sp. infection in wild mammal species is often used as an indication of spore contamination of a geographic region. Northern California is not known to be an endemic region for H. capsulatum, which is not a reportable disease in this state. The presence of severe, disseminated disease and the need for molecular identification associated with the isolate from a nonendemic region identified in the present report may indicate genetic adaptation and altered characteristics of this agent and may warrant further investigation.

Avibacterium paragallinarum is the causative agent of infectious coryza, a highly contagious respiratory disease in chickens. Given its fastidious nature, this bacterium is difficult to recover and identify, particularly from locations colonized by normal bacterial flora. Standard PCR methods have been utilized for detection but are labor-intensive and not feasible for high-throughput testing. We evaluated a real-time PCR (rtPCR) method targeting the HPG-2 region of A. paragallinarum, and validated a high-throughput extraction for this assay. Using single-tube extraction, the rtPCR detected 4 A. paragallinarum (ATCC 29545 T and 3 clinical) isolates with a limit of detection (LOD) of 10 cfu/mL and a PCR efficiency of 89-111%. Cross-reaction was not detected with 33 non-A. paragallinarum, all close relatives from the family Pasteurellaceae. Realtime PCR testing on extracts of 66 clinical samples (choana, sinus, or trachea) yielded 98.2% (35 of 36 on positives, 30 of 30 on negatives) agreement with conventional PCR. Duplicate samples tested in a 96-well format extraction in parallel with the single-tube method produced equivalent LOD on all A. paragallinarum isolates, and 96.8% agreement on 93 additional clinical samples extracted with both procedures. This A. paragallinarum rtPCR can be utilized for outbreak investigations and routine monitoring of susceptible flocks.

Infectious coryza is a severe respiratory disease of chickens associated with large economic losses in affected commercial flocks. The fastidious causative pathogen, Avibacterium paragallinarum, is difficult to recover and identify, resulting in delayed diagnosis and enhanced spread of the agent. Small poultry flocks are increasingly common in rural and suburban environments. We assessed the frequency of A. paragallinarum using real-time PCR and clinical conditions present in samples from such flocks submitted to the California Animal Health and Food Safety Laboratory System (Davis, CA) in 2018. From the 294 samples collected for our study, 86 (30%) were PCR-positive for A. paragallinarum. Juvenile birds (≤1 y) were significantly more likely to be PCR-positive (p = 0.017), and birds diagnosed with respiratory disease had lower Ct values (p = 0.001) than those without. Concurrent infections were also identified, including with Mycoplasma gallisepticum (18.6%), M. synoviae (18.6%), infectious bronchitis virus (12.8%), and infectious laryngotracheitis virus (7.0%). Only 46.5% of PCR-positive chickens had antemortem respiratory signs, making endemic infections in these flocks highly likely. Our study demonstrates that A. paragallinarum is present in small-flock operations including those without respiratory disease and may present a risk for airborne pathogen transmission to commercial poultry operations.