Autoimmune encephalitis (AIE) is a type of immunoreactive encephalitic disorder and is recognized as the most prevalent noninfectious encephalitis. Nevertheless, the rarity of definitive AIE diagnosis through biopsy or autopsy represents a significant hurdle to understanding and managing the disease. In this article, we present the pathological findings of AIE and review the literature based on a distinct case of AIE presenting as CD8+ T-lymphocyte predominant encephalitis. We describe the clinical progression, diagnostic imaging, laboratory data, and autopsy findings of an 80-year-old deceased male patient. The patient was diagnosed with pulmonary tuberculosis 6 months before death and received appropriate medications. A week before admission to the hospital, the patient manifested symptoms such as a tendency to sleep, decreased appetite, and confusion. Although the patient temporally improved with medication including correction of hyponatremia, the patient progressed rapidly and died in 6 weeks. The brain tissue revealed lymphocytic infiltration in the gray and white matter, leptomeninges, and perivascular infiltration with a predominance of CD8+ T lymphocytes, suggesting a case of AIE. There was no detectable evidence of viral infection or underlying neoplasm. The autopsy revealed that this patient also had Alzheimer\'s disease, atherosclerosis, arteriolosclerosis, and aging-related tau astrogliopathy. This report emphasizes the pivotal role of pathological examination in the diagnosis of AIE, especially when serological autoantibody testing is not available or when a patient is suspected of having multiple diseases.

The composition of the mammalian gut microbiome is very important for the health and disease of the host. Significant correlations of particular gut microbiota with host immune responsiveness and various infectious and noninfectious host conditions, such as chronic enteric infections, type 2 diabetes, obesity, asthma, and neurological diseases, have been uncovered. Recently, research has moved on to exploring the causalities of such relationships. The metabolites of gut microbiota and those of the host are considered in a \'holobiontic\' way. It turns out that the host\'s diet is a major determinant of the composition of the gut microbiome and its metabolites. Animal models of bacterial and viral intestinal infections have been developed to explore the interrelationships of diet, gut microbiome, and health/disease phenotypes of the host. Dietary fibers can act as prebiotics, and certain bacterial species support the host\'s wellbeing as probiotics. In cases of Clostridioides difficile-associated antibiotic-resistant chronic diarrhea, transplantation of fecal microbiomes has sometimes cured the disease. Future research will concentrate on the definition of microbial/host/diet interrelationships which will inform rationales for improving host conditions, in particular in relation to optimization of immune responses to childhood vaccines.

Laying hens (n = 2267) ranging in age from 2 to 4 yr in a study evaluating ovarian cancer prevention were necropsied. Those that died or were culled during the 2-yr study (n = 1591) were necropsied weekly to determine the most probable cause of death or culling and cancer status. Hens surviving until the end of the study (n = 676) were euthanized and necropsied. Hens necropsied before and after a hen with proventricular intussusception served as cohorts (n = 38). Nineteen hens (13 dead, 6 culled) had intussusceptions of the proventriculus into the ventriculus. Mean age of affected hens was 154 wk (range 110-204 wk). None of the hens in the study had an intestinal intussusception, and none of the hens euthanized at the end of the study had a proventricular intussusception. Hens with proventricular intussusceptions were severely emaciated; mean body weights were 1040 and 1736 g for affected and cohort hens, respectively. Necropsy findings included prominent keel, marked muscle atrophy, generalized serous atrophy of fat, no visible proventriculus, esophagus directly entering the ventriculus, and an enlarged, spherical, firm ventriculus, which contained an invaginated, swollen, diffusely ulcerated proventriculus. Eighteen affected hens were anovulatory (94.7%) compared to 27 cohorts (71.1%). Severe, diffuse necrosis and ulceration of the proventricular mucosa was confirmed microscopically, but no etiologic agent was identified. In conclusion, proventricular intussusception of undetermined etiology was identified as a cause of sporadic emaciation, culling, and mortality in older laying hens.
Reporte de caso- Emaciación y mortalidad esporádica causadas por intususcepción del proventrículo en gallinas de postura maduras. Se realizaron necropsias de gallinas ponedoras (n=2267) de dos a cuatro años de edad en un estudio que evaluó la prevención del cáncer de ovario. Las aves que fueron eliminadas semanalmente durante el estudio de dos años (n=1591) se sometieron a la necropsia para determinar la causa más probable de muerte o de desecho y el estado de cáncer. Las gallinas que sobrevivieron hasta el final del estudio (n=676) se sacrificaron y se les realizó la necropsia. Las gallinas a las que se les practicó la necropsia antes y después de la intususcepción proventricular sirvieron como cohortes (n=38). Diecinueve gallinas (13 muertas y seis sacrificadas) tuvieron intususcepciones del proventrículo dentro de la molleja. La edad media de las gallinas afectadas fue de 154 semanas (con un rango de 110 a 204 semanas). Ninguna de las gallinas en el estudio mostró una intususcepción intestinal y ninguna de las gallinas sometidas a eutanasia al final del estudio tuvo una intususcepción proventricular. Las gallinas con intususcepciones proventriculares estaban severamente emaciadas; los pesos corporales medios fueron 1040 g y 1736 g para las gallinas afectadas y para las gallinas cohorte, respectivamente. Los hallazgos de la necropsia incluyeron la quilla de la pechuga prominente, atrofia muscular marcada, atrofia serosa de la grasa generalizada, no proventrículo visible, esófago entrando directamente en la molleja y una molleja esférica y firme, que contenía un proventrículo, invaginado, abultado y difusamente ulcerado. Dieciocho gallinas afectadas fueron anovulatorias (94.7%) en comparación con 27 cohortes (71.1%). La necrosis y la ulceración severas y generalizadas de la mucosa proventricular se confirmaron microscópicamente, pero no se identificó ningún agente etiológico. En conclusión, la intususcepción proventricular de etiología indeterminada se identificó como una causa de emaciación esporádica, sacrificio y mortalidad en gallinas ponedoras maduras.

Although not well described, occasional reports of avian exocrine and endocrine pancreatic disease are available. This article describes the lesions associated with common diseases of the avian pancreas reported in the literature and/or seen by the authors.