CAHFS Connection - April 2025

Avian

A perforating foreign body in the crop caused chronic sour crop and neck cellulitis in an 8-year-old backyard chicken. The hen had been losing weight and doing poorly for a month before death. Postmortem exam revealed a wooden stick perforating the crop with extensive chronic cellulitis in the surrounding soft tissue. The crop had decomposing content.

Yersinia pseudotuberculosis infection caused septicemia in an adult hooded pitta (exotic passerine bird). The bird was part of a mixed collection housed in an aviary and demonstrated no specific clinical signs prior to death. At necropsy, there was necrotizing hepatitis, splenitis and pneumonia. Y. pseudotuberculosis was isolated from liver. Over the years CAHFS has diagnosed Y. pseudotuberculosis infections in multiple avian species from zoos and private aviaries, with psittacine (parrot family) birds most commonly affected.

Bovine

Listeria monocytogenes was the cause of a second trimester abortion in an adult Holstein cow. The fetus was autolyzed, and no gross lesions were observed at necropsy. Placenta was not available for examination. Microscopically, there was fetal meconium aspiration (a nonspecific indicator of fetal stress in-utero), and abundant gram-positive rods in lung and blood vessels of many tissues. L. moncytogenes was isolated in large numbers from lung, liver, and abomasal fluid, and the bacterium was detected in lung by immunohistochemistry. Abortions by  this microorganism are generally sporadic in dairy cattle and may be associated with improperly ensiled forages or accumulated organic matter in feed bunks. 

Clostridium perfringens type C enteritis was the cause of death in a five-day-old Angus calf from a 100 head beef operation in which two calves had died within 24 hours of being found down. Scours was not noted. Small intestine tissue submitted had necrosis and hemorrhage, and Clostridium perfringens beta toxin was detected in the content confirming type C perfringens.

Equine

Equine herpes virus type 1 (EHV-1) infection was diagnosed in three horses from the same number of premises. Two of them had neurologic signs before being euthanized, and the third one had colic and died spontaneously. Gross and microscopic changes in the two horses with neurologic signs included hemorrhagic infarction of the cerebellum and spinal cord infarction, respectively. The horse with colic had a perforated esophageal diverticulum and sepsis; in this case, EHV-1 infection was considered to be an incidental finding. EHV-1 infection was confirmed in the three horses by PCR and in one of them by in situ hybridization.

Pigs

Swine erysipelas was diagnosed in a five-month-old Berkshire pig that died suddenly. On gross examination, there was a mild to moderate amount of yellow, thick joint fluid in the carpi and hocks, and the prescapular and inguinal lymph nodes were moderately enlarged. Histology revealed multiple lesions suggestive of sepsis, including lymphadenitis and polyarthritis, amongst other changes. Erysipelothrix rhusiopathiae was isolated from the liver, right carpal joint and inguinal lymph nodes. This agent can cause septicemia, polyarthritis and/or endocarditis, and can present as acute or chronic disease in pigs.

Small Ruminant

Type D enterotoxemia was the cause of death of a 7-year-old goat with a 1-day history of diarrhea and wobbliness. At necropsy, there was hydrothorax and hydropericardium, severe pulmonary edema and fibrinosuppurative typhlocolitis. Clostridium perfringens type D epsilon toxin (ETX) was detected in cecal and colonic contents by ELISA. ETX is the third most potent clostridial toxin after tetanus and botulinum toxins. It causes endothelial cell damage, increasing thus vascular permeability and edema in several locations, including, but not limited to lungs, brain and heart. In goats, type D enterotoxemia is also associated with enterocolitis and diarrhea.

Campylobacter jejuni was the cause of abortion of seven late term goat fetuses from three unrelated small herds in a ten-day period. The organism was isolated from abomasal fluid in all seven fetuses and usually one other site, including lung, liver and placenta. One farm reported high fever in the does prior to abortion. Microscopic lesions varied from none to severe hepatitis, mild hepatic necrosis, pneumonia, placentitis, peritonitis, and/or conjunctivitis.  All fetuses were severely copper deficient (range 0.52–13 ppm, normal 25–150 ppm) and selenium deficient (range 0.12–0.20 ppm, normal 0.25–1.5 ppm).