Listeria monocytogenes at the interface between ruminants and humans: A comparative pathology and pathogenesis review

The bacterium Listeria monocytogenes ( Lm) is widely distributed in the environment as a saprophyte, but may turn into a lethal intracellular pathogen upon ingestion. Invasive infections occur in numerous species worldwide, but most commonly in humans and farmed ruminants, and manifest as distinct forms. Of those, neuroinfection is remarkably threatening due to its high mortality. Lm is widely studied not only as a pathogen but also as an essential model for intracellular infections and host-pathogen interactions. Many aspects of its ecology and pathogenesis, however, remain unclear and are rarely addressed in its natural hosts. This review highlights the heterogeneity and adaptability of Lm by summarizing its association with the environment, farm animals, and disease. It also provides current knowledge on key features of the pathology and (molecular) pathogenesis of various listeriosis forms in naturally susceptible species with a special focus on ruminants and on the neuroinvasive form of the disease. Moreover, knowledge gaps on pathomechanisms of listerial infections and relevant unexplored topics in Lm pathogenesis research are highlighted.

Epitheliotropic lymphoma-induced disseminated ulcerative dermatitis in a dog

Diagnostic Exercise from The Latin Comparative Pathology Group. Clinical History: A young adult, spayed female dog was presented for necropsy by animal control, with concerns for abuse in the form of chemical burns. Necropsy and Microscopic Findings: There was marked alopecia and coalescing ulceration affecting approximately 60% of the integument, roughly evenly distributed over the body. Affected areas included the mucocutaneous junctions, the palmar and plantar surfaces of the limbs, the paw pads, and the nasal planum. Ulcers measured up to 1 cm in diameter, frequently coalesced, and varied in stage of development; some were prominent, dark red, and shiny with roughened borders and others contained pink granulation tissue. In areas of alopecia without ulceration, the skin was smooth and glistening. The nails were variably sloughed; some digits possessed a bare quick and some had nails up to 3 cm long, but which were separating from the underlying quick. The dog was in adequate body condition.

Bovine congenital babesiosis

Diagnostic Exercise from The Latin Comparative Pathology Group. Clinical History: A crossbred, stillborn bovine fetus, with nine months of gestation, was submitted for postmortem examination. The dam that aborted was a 2-year-old heifer that did not have any additional clinical signs. The owner observed several late-term abortions and stillbirths in this farm during the referred calving season. Necropsy Findings: Necropsy findings included moderate accumulation of light red fluid in the abdominal and thoracic cavities, mild hemoglobin imbibition, as well as collapsed lungs. The liver was markedly enlarged, had rounded edges, and moderate, diffuse yellow discoloration. The gallbladder was filled with thick, grumous bile, and the spleen was moderately enlarged. The kidneys had moderate diffuse dark red discoloration, and the urinary bladder was distended with dark-red urine. The grey matter of the brain and the spinal cord was markedly pink-red discolored. Squashes of the spleenand brain were prepared and routinely stained with PanóticoRápido® (Laborclin, Brazil).

Consensus Regarding the Diagnosis, Prognosis and Treatment of Canine and Feline Mammary Tumors - 2019

The aim of this paper is to discuss and update criteria that can guide the diagnosis, prognosis and treatment of canine and feline mammary neoplasms. It was elaborated during the IV Mammary Pathology Meeting: Diagnosis, Prognosis and Treatment of the Canine and Feline Mammary Neoplasia, held on April 29th and 30th, 2019 in Belo Horizonte – MG, Brazil, sponsored by the Laboratory of Comparative Pathology of the Federal University of Minas Gerais (UFMG), with the support of the Brazilian Association of Veterinary Pathology (ABPV) and Brazilian Association of Veterinary Oncology (ABROVET). Academics from several regions of Brazil were present and contributed to this work.

Comparative Pathology of the Peripheral Nervous System

The peripheral nervous system (PNS) relays messages between the central nervous system (brain and spinal cord) and the body. Despite this critical role and widespread distribution, the PNS is often overlooked when investigating disease in diagnostic and experimental pathology. This review highlights key features of neuroanatomy and physiology of the somatic and autonomic PNS, and appropriate PNS sampling and processing techniques. The review considers major classes of PNS lesions including neuronopathy, axonopathy, and myelinopathy, and major categories of PNS disease including toxic, metabolic, and paraneoplastic neuropathies; infectious and inflammatory diseases; and neoplasms. This review describes a broad range of common PNS lesions and their diagnostic criteria and provides many useful references for pathologists who perform PNS evaluations as a regular or occasional task in their comparative pathology practice.

Comparative Pathology of Pseudorabies in Different Naturally and Experimentally Infected Species—A Review

The pseudorabies virus (PRV) is an alphaherpesvirus and the causative agent of Aujeszky’s disease (AD). PRV infects a wide range of animal species including swine as the natural host as well as ruminants, carnivores, rodents and lagomorphs. In these species, except for the pig, PRV infection causes acute, severe disease, characterized by insatiable itching, and is always lethal. Horses, chickens and non-human primates have been shown to be largely resistant to PRV infection, while disease in humans is still controversial. PRV is a pantropic virus, which preferably invades neural tissue, but also infects epithelia of various organs, whereupon multisystemic lesions may result. Although AD is mainly associated with severe pruritus, also known as “mad itch”, there are notable differences regarding infection route, clinical signs, viral distribution and lesion patterns in different animal species. In this comprehensive review, we will present clinico-pathologic findings from different species, which have been either shown to be susceptible to PRV infection or have been tested experimentally.