Kevin Keel
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Kevin Keel
@ucpath.bsky.social
490 followers 310 following 230 posts
Veterinary pathologist, conservation advocate, wildlife-disease scientist, outdoorsman. And I love parasites, but especially the metazoans!

Scientific, one-health and naturalist content.
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ucpath.bsky.social
Beautiful representation of feather follicles from a chickadee. A happy accident from the histology lab. They are not supposed to be sectioned obliquely but it makes them look pretty interesting in an abstract sort of way. 🪶
July 16, 2025 at 9:42 PM
ucpath.bsky.social
California is no stranger to domoic acid, but this year it's much worse much earlier.

Stranded pinnipeds often exhibit listlessness, head bobbing, disorientation and seizures. Mortality rates are estimated to be ~25%

www.fisheries.noaa.gov/feature-stor...

#VetMed #MarineMammal #VetPath
A sea lion with domoic acid poisoning experiencing involuntary muscle spasms. This is a female sea lion lying on her side on a beach. Her muzzle and left flipper pointing skyward. She has domoic acid poisoning and was experiencing involuntary muscle spasms. Credit: Channel Islands Marine & Wildlife Institute
April 1, 2025 at 6:28 PM
ucpath.bsky.social
Not a new article, but it's worth posting again just in case you missed it. Bullfrogs are normally tadpoles for 2 or 3 years. Something disrupted this one's metamorphosis so it just kept on growing! I love the references for scale!

#frogs #wildlife

www.americanscientist.org/blog/from-th...
Photos of a giant bullfrog tadpole. the panel on the left compares it so a similarly sized banana, and a tape measure showing that it is nearly 11 inches long. The right panel compares it to a beer can. It is not the first time I have seen someone use a beer can or a beer bottle as a size reference. I guess you use what you've got. And they are a constant size.
March 25, 2025 at 7:30 PM
ucpath.bsky.social
An exhibitionist egret on display. These courtship threads beat millinery any day. Populations of common #egrets (and other spp.) were once decimated so we could put their nuptial plumes in women’s hats. Goshen Swamp, Liberty Co, Georgia.

#birds #wildlife #NaturePhotography #Photography
This is a profile of a common egret in full display, sitting in they top of a cypress tree. The nuptial plumes are Lacey feathers protruding from the body. The bird also has a green cere, that is a result of its breeding status.
March 20, 2025 at 5:55 PM
ucpath.bsky.social
These are some crazy kidneys! You don't have to be a pathologist to think these lesions are beautiful!

I have suspicions as to pathogenesis, but histo will tell.

9-yo dog. Clinicians susp granulomatous osteomyelitis of lumbar v but no gross lesions were evident.

#pathsky #vetpath #RenalPath
This is the cut surface of a kidney that has been sectioned longitudinally. Six poorly demarcated, dark-red, wedge-shaped foci extend from the corticomedullary margin to the pelvis and are 4 to 7 mm wide at the corticomedullary junction. One, which corresponds to a cranial cortical depression, is itself slightly depressed on cut surface (infarct).The cortex of the left kidney has five, focal to focally extensive discolored foci that are restricted to the superficial one-half of the cortex. The smallest of these are rectangular, dark red foci in which each edge of the rectangular focus is approximately 5 mm. The largest of the superficial cortical foci consists of a 6 cm long band in the outer one-half of the cortex. All of the larger foci have a pink core with a ground glass surface (necrosis) surrounded by a 1-mm-thick yellow margin that is in turn surrounded by a 1-mm-thick, red outer margin of tissue. Close inspection reveals congested glomeruli in the less affected cortex, but these are not visible in the necrotic regions. A macroscopic image of the canine kidney previously described. Less affected regions are uncharacteristically yellow. There are scattered aminar, supericial-cortical lesions. The smallest are dark red. The largest have a pink core with a ground glass surface (necrosis) surrounded by a 1-mm-thick yellow margin that is in turn surrounded by a 1-mm-thick, red outer margin of tissue. If you look closely you can see pin-point red structures scattered throughout the cortex that correspond to glomeruli. The image depicts the right kidney from this case that has been sectioned longitudinally through the hilum. The section on the left shows the cut surfaces. The one on the right shows the capsular surface with the capsule removed. The capsular surface is speckled red and yellow with hundreds of widely scattered, pinpoint, red foci that are only visible with very close inspection (suspect congested or hemorrhagic glomeruli). The larger red foci account for half of the surface of the right kidney and they extend into the outer one-half of the cortex on cut surfaces. The kidney is otherwise pale. This is a macroscopic photo of the right kidney. On cut surface the red foci are mostly limited to the superficial one-half of the cortex. Pinpoint red dots are clearly visible here, and they likely correspond to discolored glomeruli. The remainder of the cortex is yellow and it should be reddish brown.
March 19, 2025 at 11:29 PM
ucpath.bsky.social
It's that time of year again! The #egrets are getting frisky. My parents are lucky enough to have a rookery in their backyard.

Common egret, Liberty Co, #Georgia

#birds #nature #wildlife #NaturePhotography #Nikon #swamp
A common egret displays its plumes in the top of a cypress tree. The bird is holding its neck in a semicurl and the plumes are spread behind it like a snow white peacock. The photograph resulted in the whites being a little blown out in the birds back. Hard to get everything balanced with these white birds in a dark swamp.
March 19, 2025 at 4:38 PM
ucpath.bsky.social
Here's a case you don’t see every day! A hepatic sarcoma in a rat caused by tapeworm larvae. Taenia taeniaformis infestation with chronic inflammation and spindle-cell proliferation paves the way for neoplastic transformation.

Nature is weird sometimes!

#skypath #vetpath #parasites
This is a subgross image of liver with a large tumor containing a blood filled cavity that has multiple sections of tapeworm larvae. A bit of the hepatic parenchyma is on the upper right. H&E-stained section. Here are cross sections of the degenerate tapeworm larvae from the previous image. They lack detail but the calcareous corpuscles are still visible. These appear to be strobilocerci. As I understand it, this tapeworm initially forms cysticerci in the rat which then metamorphose into strobilocerci. H&E-stained section. This image demonstrates the fibrosarcoma on the right and the interface with the extant hepatic parenchyma on the left. The neoplasm is well demarcated in this section. In others it was more directly invasive and widespread metastases were all through the abdomen. This seemed to be a case of true sarcomatosis. Implantation of bits of neoplasia directly on the serosal surfaces of the abdomen, leading to additional tumors. A high magnification image of this neoplasm. Neoplastic cells have significant variability in size. They are generally oval to round. Mitotic figures and apoptotic cells are occasionally seen.
March 18, 2025 at 11:51 PM
ucpath.bsky.social
Coolest biopsy of the week! A coenurus from the brain of a cat. This tapeworm larvae has multiple invaginated scolices.

The cat was doing well when discharged 7 days post op.

#VetPath #PathSky #Parasites #Histopathology
MRI of a cat brain. There is a cystic mass in the right temporal lobe that extended to the frontal lobe. Subgross section of the biopsy sample from this cat. Multiple scolices are attached to the inside of the cyst visible on MRI. This is consistent with a coenurus. Taenia sp., including Taenia multiceps, Taenia serialis, Taenia brauni, and Taenia glomeratus are capable of producing coenuri. A hydatid cyst could have a similar appearance but a coenurus is more likely given the signalment and location of the patient. PCR and sequence results are pending. Histopathology slide demonstrating four scolices with hooks and suckers that are variably visible in this section. The presence of multiple scolices in a cysticercoid tapeworm larvae indicates a coenurus or a hydatid cyst. This was most likely a coenurus due to a Taenia sp. A detail of the scolex from the coenurus of the cat presented. Hooks are evident in the middle of the field with suckers to either side of it. It will have four suckers in total, but the others are out of the plane of section. Calcareous corpuscles are visible in the stroma.
March 8, 2025 at 12:25 AM
ucpath.bsky.social
The great-tailed grackle. My most favorite of all the grackles. Look at that tail! Look at that beak! He is seems pretty proud of the whole package. Woodland, CA.

I wonder how long before they try to change the name to Quiscalus americanus.

#birds #wildlifephotography #naturephotography
A long, sleek blackbird, a great-tailed grackle (Quiscalus mexicanus) sits perched on a limb looking over his back. The dark irridescent plumage indicates that this is a male. He has a piercing yellow eye, a very long beak and a large tail that is slightly longer than his body.
February 28, 2025 at 6:09 AM
ucpath.bsky.social
Looking for opinions on this (alleged) ovarian mass from a garter snake. I presume the amphophilic material is redundant basement membrane. Could this be a granulosa cell tumor? We have seen those in snakes (incl garter snakes) but this one is odd.

#pathsky #vetpath #veterinary #tumor #repro
Two sections ostensibly of ovary are present on this microscope slide. The subgross reveals the slightly basophilic masses with tortuous blood vessels adjacent to them. A high magnification view of an ovarian neoplasm from a giant garter snake. The tumor is composed of cords and islands of epithelial cells surrounded by a wide margin of amphophilic material interpreted to be basement membrane material. Alternate high magnification view of an ovarian neoplasm from a giant garter snake. The tumor is composed of cords and islands of epithelial cells surrounded by a wide margin of amphophilic material interpreted to be basement membrane material. Another high magnification view of the ovarian neoplasm from a giant garter snake. The tumor is composed of cords and islands of epithelial cells surrounded by a wide margin of amphophilic material interpreted to be basement membrane material.
February 27, 2025 at 11:59 PM
ucpath.bsky.social
I think it is almost certainly avian pox. Here is one on the eyelid of another crow. I should bring my telephoto lens to try for a better photo of this bird. It has been hanging around for a while now.
Lateral view of an American crow head. The inferior eyelid has a papillomatous mass that extends from the surface. This was confirmed to be a case of avian pox.
February 18, 2025 at 11:15 PM
ucpath.bsky.social
What's your diagnosis? American crow with a lesion on the back of the shank. I've seen this bird every day for a week and a half.

#VetPath #AvianDisease #Veterinary #DermPath
February 18, 2025 at 10:22 PM
ucpath.bsky.social
Normally we go to Lake Solano (Yolo Co, California) to see the migrator waterfowl, especially the buffleheads and goldeneye. This day the #RiverOtters were putting on more of a show.

#mammals #WildlifePhotography #Nikon #wildlife
This photo shows a river otter lying on a log on the bank of a river. The otter is very wet and is staring into the camera. There seems to be a scar on his lip, I presume from fighting.
February 5, 2025 at 2:04 AM
ucpath.bsky.social
A new kind of box #fish? Nope! It's much more interesting. This fishy cell has been stained with an antibody specific for rabies. They don't call it neurotropic for nothing! Antigen fills the cytoplasm but spares the nucleus creating a stark contrast betw the two.🧪

#histopath #PathSky #VetPath
This slide is a highly magnified sample of brainstem from a rabid bobcat. Ihas a single neuron with branched axon at one end and a large nucleus with a prominent nucleolus at the other end. The cytoplasm has been stained brown by an immunohistochemistry stain specific for the rabies virus. Another process extends from a point adjacent to the bifurcated axon. The unstained nucleolus and the processes give the distinct appearance of a fish.
January 31, 2025 at 12:10 AM
ucpath.bsky.social
A beautiful cleared example of Fascioloides magna that was submitted to the vet school. The large liver fluke leads to condemnation of beef livers and can cause significant disease in sheep and goats. I see it in white-tailed #deer, who don't seem affected.

#veterinary #parasitology #trematode
This is a photo of a fluke, a parasitic flatworm. This is Fascioloides magna, the large liver fluke. It has been cleared giving it an overall golden brown appearance with a clearly delineated GI tract. The oral sucker is visible at the apex of the anterior end. the ventral sucker is visible just behind it. The worm was provided by Dr. Lauren Camp. The photos are mine.
January 27, 2025 at 8:52 PM
ucpath.bsky.social
Here is an awesome case from our #histopathology conference this morning!

Lung from a #macaque. What's your dx? The residents hate it when I say, "It's a classic". But it is! 😊

#VetPath #PathSky #lung #parasites
Dome shaped histopathology section of lung with three dark nodules scattered in the parenchyma. The nodules are dark purple (basophilic) and have open spaces visible at low power. This is a medium-magnification of the lung previously described. The center consists of a nodular region in whch the parenchymais thickened by inflammtory infiltrates. The clef visible in the middle of the focus is presumably an airway. Two small structures in the middle of the airway are ovoid to round and are mottled pink to red. This is a higher magnification of the structures in the airway that was previously described. The tissue to the left and right of the open space (airway) is heavily infiltrated by inflammatory cells.The structures in the middle have a bosselated surface and contain structures that stain brightly eosinophilic (red) to basophilic (purple). The thin shell around the outside is refractile and brown. This slide contains sections of a jointed appendage from the intrabronchial structures previously described. A nonstaining, brown refractile cuticle of varying thickness is on the surface. Linear eosinophilic structures with attachment points at the ends are present inside the appendage. These have striations and represent skeletal muscle.
January 24, 2025 at 7:03 PM
ucpath.bsky.social
Last night friends asked me about the genetic test for intervertebral disk #disease (IVDD) in #dogs. I'm proud to say this comes from my department. Fibroblast growth factor 4 (FGF4) retrogene insertion on chromosome 12 (CFA12)

#Science #VetPath #neurology

journals.sagepub.com/doi/10.1177/...
This is a sagital section through two vertebrae and the associated intervertebral disk from a young dog. the intervertebral disk is slightly pear shaped and it's long axis is perpendicular to the vertebral column. There are some clefts that are features of chondrodystrophy. The intervertebral disk is bracketed by physes on either side. These are visible as vertical columns of purple cartilage. The photo is my own. I started to include a plate from the article, but I figured I would just get a nasty letter from Sage for copyright infringement!
January 23, 2025 at 9:52 PM
ucpath.bsky.social
One of my favorite #birds. Like many #neotropical migrants, numbers of prothonatary #warblers are declining due to #HabitatLoss. The #cypress swamp where I took this photo was clear cut last year. It's just a big muddy hole now.

#nature #wildlife. #WildlifePhotography
This image is of a deep golden-yellow prothonatary warbler sitting on the branches of bald cypress. The bird has grey wings and a dark eye.
January 21, 2025 at 6:50 PM
ucpath.bsky.social
When I was a resident we received a #parrot w/ #Chlamydia. The owner told us the ref vet said the bird prob got it from sexual contact with a person! 😂

Sounds dangerous! I hope our students now learn the difference between C psittaci and C trachomatis! 😬

#InfectiousDisease #Veterinary #bacteria
This is a golden conure sitting on a branch. The bird has raised its left foot to its mouth and is nibbling on it. The plumage is a rich yellow color with edge of green feathers just visible on the wings. This is a photo I took at ZooParque in Itatiba, Sao Paulo State, Brazil.
January 18, 2025 at 6:58 PM
ucpath.bsky.social
Come to Davis for the West Coast #Veterinary #Pathology Conference, May 2-3! We've got great speakers lined up, and we will have some fantastic cases for you to learn from. I promise it will be worth the trip.

davisthompsonfoundation.org/event/great-...

#VetPath #ReproPath #Theriogenology
This is the image of a poster advertising the 42nd Annual West Coast Veterinary Pathology Conference, May 2nd to 3rd, 2025. The title is Great Gonads and Tubular Tales of Reproductive Pathology. Photos of our speakers, Dalen Agnew, Al Conley and Justin Vidal, are included on the poster.
January 17, 2025 at 7:27 PM
ucpath.bsky.social
We identified spatiotemporal clusters of #Chlamydia buteonis infection in raptors in Northern California. Cases were concentrated in winter near Sacramento. Uncertain why the spatial clustering occurs.

#hawks #epidemiology #InfectiousDisease #Veterinary

avmajournals.avma.org/view/journal...
This is an image of the underside of a red-tailed hawk soaring in a clear blue sky. The hawk is looking downward and wings are outspread. Photo by Kevin Keel
January 17, 2025 at 7:02 PM
ucpath.bsky.social
I see many cases of #Chlamydia buteonis in #hawks @ UC Davis. I NEVER diagnosed it in 10 years of cases from the southeastern US. I'm sure I wasn't just missing cases in the SE. The hepatosplenomegaly and dark liver are profound. Airsaculitis is variable.

#VetPath #Veterinary #InfectiousDisease
This slide shows the abdominal viscera from a hawk. The liver is situated at the top of the image. It is very large and very dark. The spleen is red and is very enlarged as well. The airsacs are thickened but no discrete plaques are visible.
January 17, 2025 at 6:36 PM
ucpath.bsky.social
Check out the massive numbers of #microsporidia in these sections! How many times have you had to search for #Encephalitozoon cuniculi? This is E. pogonae in #kidney of a bearded dragon. The lizards know how to grow Encephalitozoon.

#PathSky #VetPath #Veterinary #Parasitology #Histopathology
This is a hematoxylin and eosin stained section of kidney from a bearded dragon. Encephalitozoan pogonae, a microsporidian, expands they cytoplasm of many cells. Nuclei of cells are dark purple and the parenchyma is mostly pink (eosinophilic). The microsporidians are elongate. They have a polar tube and posterior vacuole that create some differential staining of the organism. This is an acid-fast stained section of kidney from a bearded dragon. Encephalitozoan pogonae, a microsporidian, expands they cytoplasm of many cells and these organisms are stained a bright fuchsia color. The counterstain turns the background tissue light blue. This is a gram stained section of kidney from a bearded dragon. Encephalitozoan pogonae, a microsporidian, expands they cytoplasm of many cells. Nuclei of cells are verydark purple. The cells and fibrous connective tissue in the backgrounds are pink . The microsporidians are elongate. Although many are aggregated in host cells, some are scattered in the tissue.
January 16, 2025 at 8:59 PM
ucpath.bsky.social
A dark morph red-tailed hawk for any (other) birding pathologists out there. A small lesion is on the left aspect of the cere.

Apparent case of avian pox. Often self-limiting, but it can severely damage the rhamphotheca of raptors.

Cedarville, CA

#vetpath #birds #wildlife #InfectiousDisease
A red-tailed hawk in flight and facing the left side of the frame. This is a very darkly pigmented variant of the red-tailed hawk, but it still has a red tail. The wings are outstretched but flex slightly downward. A small nodule is at the base of the beak on the left side. This is likely a proliferative lesion caused by an avian poxvirus. A closely cropped image of a dark-morph red-tailed hawk in flight. The left-lateral aspect of the cere, at the base of the beak, has a small gray nodule. This is likely proliferation due to infection with avian poxvirus.
January 14, 2025 at 6:09 PM
ucpath.bsky.social

I took this photo of a sidewinder ages ago when I was doing my PhD in Tucson.  It was a good time to put my telephoto lens to use.  They are the fastest #rattlesnake. Most bites in AZ are due to the more common western diamondbacks.

#wildlife #wildifephotography #nature #snakes #herps
A sidewinder rattlesnake (Crotalus cerastes) coiled up and facing the camera. The raised super-ocular scales look like horns and impart a menacing appearance. The image has a shallow focal plane such that only the eye and adjacent parts of the head are in focus. The rattles, although blurry, are visible in the lower right part of the image.
January 13, 2025 at 11:34 PM