Fatty liver hemorrhagic syndrome, characterized by sudden death in overconditioned hens due to hepatic rupture and hemorrhage, is one of the leading noninfectious idiopathic causes of mortality in backyard chickens. Nutritional, genetic, environmental, and hormonal factors, or combinations of these, have been proposed yet not proven as the underlying cause. In an attempt to characterize the hepatic changes leading to the syndrome, this retrospective case study examined 76 backyard chickens that were diagnosed with fatty liver hemorrhagic syndrome between January 2007 and September 2012 and presented for necropsy to the diagnostic laboratory of the California Animal Health and Food Safety Laboratory System. A majority of the birds were female (99%), obese (97.5%), and in active lay (69.7%). Livers were examined histologically, and the degree of hepatocellular vacuolation (lipidosis), the reticular stromal architecture, the presence of collagenous connective tissue, and vascular wall changes were evaluated and graded using hematoxylin and eosin, Gomori’s reticulin, oil red O, Masson’s trichrome, and Verhoeff-Van Gieson stains. Interestingly, there was no correlation between lipidosis and reticulin grades; hepatocellular lipidosis was absent in 22% of the cases and mild in 26% of the cases. Additionally, there was evidence of repeated bouts of intraparenchymal hemorrhage before the acute “bleed-out” in 35.5% of the cases. These data are not supportive of the previously proposed causes and provide a framework for future studies to elucidate the pathogenesis of this condition. Furthermore, the data shown in this study support hemorrhagic liver syndrome as a more accurate name, as hepatic lipidosis is absent in a significant proportion of ruptured livers.

Outbreaks of neurological disease associated with Sarcocystis calchasi have been observed in captive and free-ranging rock pigeons (Columba livia) in Europe and the United States as well as in wild Brandt's cormorants (Phalacrocorax penicillatus) and captive psittacines in California, USA. Experimental and field studies have identified northern goshawks (Accipiter gentilis) and European sparrowhawks (A. nisus) as definitive hosts in Europe while the definitive hosts elsewhere remain unknown. In this study, we aimed to identify the potential definitive host(s) of S. calchasi through molecular analysis of intestinal samples from seven predatory (n = 85) and one omnivorous (n = 11) bird species in California. In total, apicomplexan-generic 28S rRNA PCR products were obtained and sequenced for 42 raptors. Three of 16 (18.8%) Cooper's hawks (A. cooperii) and two of 26 (5.6%) red-tailed hawks (Buteo jamaicensis) also tested positive for the S. calchasi-specific ITS1 PCR and sequencing of the 28S rRNA PCR product was 100% homologous to S. calchasi. In addition to S. calchasi (5.9%; 5/85), other Sarcocystis spp. detected in raptors included: S. jamaicensis (21.2%; 18/85), S. columbae (8.2%; 7/85), S. turdusi (7.1%; 6/85), and S. halieti (4.7; 4/85%). Infections with closely related S. jamaicensis and S. (Frenkelia) microti (9.4%; 8/85) could not be distinguished for eight raptors. Eumonospora henryae (1.2%; 1/85) was detected in one raptor. Our results indicate for the first time that S. calchasi may have a definitive host range in North America that includes at least two raptors, Cooper's hawks and red-tailed hawks, within the family Accipitridae.

A 6-month-old dairy heifer calf with no premonitory signs was acutely down after the morning feeding and could not rise. On presentation, the heifer was in right lateral recumbency and moribund with opisthotonus and left hind limb paddling. Following euthanasia, gross examination of the brain revealed multifocal loss of gray-white matter distinction and extensive petechiae throughout the brainstem. On histopathological examination, there was striking white matter edema and marked perivascular proteinaceous edema surrounding many arterioles and venules (microangiopathy), mainly in the white matter of the internal capsule, thalamus, midbrain, cerebellum, and cerebellar peduncles. The perivascular neuropil was strongly positive for Alzheimer precursor protein A4. Clostridium perfringens epsilon toxin was detected in the intestinal contents. This is the first report of microangiopathy in postneonatal cattle associated with the detection of epsilon toxin in the intestinal contents.

SUMMARY Marek's disease (MD) is a major cause of mortality in backyard chickens. The diagnosis of MD is complex, however, and knowledge of Marek's disease virus (MDV) in spontaneous field cases such as in backyard chickens is largely unknown. In this study, 40 backyard chickens with a presumptive MD diagnosis based on histologic lymphoid infiltrations in peripheral nerves with and without lymphomas were investigated. Twenty-eight of the birds were submitted to the diagnostic laboratory for disease explorations, and 12 chickens were from a flock in which some members demonstrated anisocoria and pupil irregularities compatible with ocular MD. Histologic scores were established for brain, peripheral nerves, heart, lung, liver, kidney, and gonad sections, ranging from mild (+) to severe (+++) lymphoid infiltrations. Twelve chickens had gross lymphomas, and all but two chickens had mild to severe peripheral nerve lymphoid infiltrates. There were no age or breed predispositions in the study group. Quantificatio... RESUMEN Enfermedad de Marek en pollos de traspatio, un estudio de hallazgos patológicos y de cargas virales en aves con o sin tumores. La enfermedad de Marek (MD) es una causa importante de mortalidad en pollos de traspatio. El diagnóstico de la enfermedad de Marek es complejo, sin embargo, el conocimiento de virus de la enfermedad de Marek (MDV) en los casos espontáneos de pollos de traspatio es en gran parte desconocido. En este estudio, se investigaron 40 gallinas de traspatio con un diagnóstico presuntivo de enfermedad de Marek con base en los infiltrados linfocitarios histológicos en los nervios periféricos con y sin linfomas. Veintiocho de las aves fueron enviadas al laboratorio de diagnóstico para estudio de enfermedad y doce pollos eran de una parvada en la que algunas aves manifestaron anisocoria e irregularidades de la pupila compatibles con la enfermedad de Marek ocular. Se establecieron puntuaciones histológicas para cortes de cerebro, nervios periféricos, corazón, pulmón, hígado, riñón, y gón...

Reproductive failure represents an important cause of economic loss for the equine industry. We reviewed the cases of equine abortion and stillbirth submitted to the California Animal Health and Food Safety Laboratory System, University of California–Davis from 1990 to 2022. A total of 1,774 cases were reviewed. A confirmed cause of abortion was determined in 29.2% of the cases. Abortion or stillbirth was attributed to infectious agents in 18.7% of the cases, with Streptococcus spp., equine herpesvirus 1, and Leptospira spp. being the most prevalent. Noninfectious causes of abortion were established in 10.5% of the cases, with umbilical cord torsion being the most common. In 70.8% of the cases, a definitive cause of abortion could not be established. Our study demonstrated the difficulties in establishing an etiologic diagnosis, even when following a standard diagnostic work-up. New diagnostic approaches are needed to improve the likelihood of reaching a final diagnosis in cases of equine abortion and stillbirth.

Between March and May 2019, wildlife rehabilitation centers along coastal southern California admitted increased numbers of Brandt's cormorants (Phalacrocorax penicillatus) with neurological disease including head tilt, nystagmus, torticollis, tremors, paresis, paralysis, and ataxia. Seven cormorants from Los Angeles County and one cormorant from Orange County were submitted for postmortem examination. Gross findings included thin to fair body condition, generalized congestion/hyperemia, nematode parasites in the ventriculus, and diarrhea in the seven birds from Los Angeles County while the one bird from Orange County had icterus. Histologic examination revealed sarcocysts in the adductor muscles and meningoencephalitis characterized by coalescing infiltrations of macrophages, lymphocytes and plasma cells with severe perivascular cuffing and gliosis in all eight cormorants. Rare to few numbers of schizonts were seen in the cerebrum of the seven cormorants from Los Angeles County whereas the cormorant from Orange County had numerous schizonts in various stages of development in the cerebrum, cerebellum, and brainstem. All eight birds were positive for the generic Sarcocystis spp. 28S PCR. The seven cormorants from Los Angeles County tested positive for the S. calchasi-specific ITS1 and confirmed by sequencing, while the analysis of the 28S sequence in the cormorant from Orange County showed a 100% homology to S. falcatula. This bird also was positive by immunohistochemistry for Sarcocystis spp. using a polyclonal antibody that detects S. falcatula and S. neurona. This report demonstrates for the first time that seabirds such as Brandt's cormorants may be intermediate or dead-end hosts for S. calchasi and/or S. falcatula, and that S. calchasi can cause epizootic infection in a seabird.