Outbreak of epizootic hemorrhagic disease in captive reindeer (Rangifer tarandus).

In September 2020, an outbreak of epizootic hemorrhagic disease occurred in captive reindeer (Rangifer tarandus) and was associated with neurological signs and mortality. Four reindeer died or were euthanized after acute illness over a 12-day period. Affected reindeer displayed abnormal behavior, neurologic signs, lethargy, and/or lameness. The most consistent gross finding was dark red streaks throughout the adrenal gland cortices (4/4). One animal had acute hemorrhage involving the subcutis and skeletal muscles over the ventrolateral body wall and back, and abomasal serosa. Histologically, the most common lesions were adrenal gland cortical hemorrhage (4/4) with necrosis (3/4) and lymphoplasmacytic meningoencephalitis with gliosis, glial nodules, satellitosis, and nonsuppurative perivascular cuffing (4/4). The brain lesions were most frequent in the gray matter of the cerebrum, hippocampus, and thalamus but also involved the cerebellum and brainstem. Epizootic hemorrhagic disease virus serotype 6 was detected through PCR and sequencing of the spleen in all cases.

Cooperativity between H3.3K27M and PDGFRA poses multiple therapeutic vulnerabilities in human iPSC-derived diffuse midline glioma avatars.

Diffuse midline glioma (DMG) is a leading cause of brain tumor death in children. In addition to hallmark H3.3K27M mutations, significant subsets also harbor alterations of other genes, such as TP53 and PDGFRA. Despite the prevalence of H3.3K27M, the results of clinical trials in DMG have been mixed, possibly due to the lack of models recapitulating its genetic heterogeneity. To address this gap, we developed human iPSC-derived tumor models harboring TP53R248Q with or without heterozygous H3.3K27M and/or PDGFRAD842V overexpression. The combination of H3.3K27M and PDGFRAD842V resulted in more proliferative tumors when gene-edited neural progenitor (NP) cells were implanted into mouse brains compared to NP with either mutation alone. Transcriptomic comparison of tumors and their NP cells of origin identified conserved JAK/STAT pathway activation across genotypes as characteristic of malignant transformation. Conversely, integrated genome-wide epigenomic and transcriptomic analyses, as well as rational pharmacologic inhibition, revealed targetable vulnerabilities unique to the TP53R248Q; H3.3K27M; PDGFRAD842V tumors and related to their aggressive growth phenotype. These include AREG-mediated cell cycle control, altered metabolism, and vulnerability to combination ONC201/trametinib treatment. Taken together, these data suggest that cooperation between H3.3K27M and PDGFRA influences tumor biology, underscoring the need for better molecular stratification in DMG clinical trials.

Adenoviral infection in 5 red-tailed hawks and a broad-winged hawk.

Adenoviral infections among raptors are best described in falcons and are characterized most commonly by necrotizing hepatitis and splenitis; only one case has been reported in a hawk. Five red-tailed hawks (Buteo jamaicensis) and a broad-winged hawk (Buteo platypterus) had an adenoviral infection based on history, histopathology, negative-stain electron microscopy, and PCR. All birds had acute onset of illness resulting in death; 3 had evidence of a concurrent bacterial infection. Microscopically, all 6 birds had solitary, pale eosinophilic-to-amphophilic, intranuclear inclusion bodies within presumed hematopoietic cells in bone marrow and macrophages in spleen. Five of the 6 birds had similar inclusions within hepatocytes and Kupffer cells. All but one bird had severe bone marrow necrosis. There was moderate splenic necrosis (3 of 6) and mild-to-marked hepatic necrosis (4 of 6). Negative-stain electron microscopy demonstrated adenoviral particles in bone marrow (5 of 6), liver (1 of 5), and/or spleen (1 of 5). PCR was positive for adenovirus in bone marrow (3 of 5), liver (1 of 3), spleen (4 of 6), and/or intestinal contents (2 of 3). Viral DNA polymerase gene sequences clustered within the Siadenovirus genus. There was 99% nucleotide identity to one another and 90% nucleotide identity with the closest related adenovirus (Harris hawk, EU715130). Our case series expands on the limited knowledge of adenoviral infections in hawks. The splenic and hepatic necrosis, and particularly the hitherto unreported bone marrow necrosis, suggest that adenoviral infection is clinically relevant and potentially fatal in hawks.