USGS Pathology Case of the Month
August 2019—Avian Cholera in a Ross’ Goose
Case History: An adult male 1545-g Ross’s Goose (Chen rossii) was found dead on a refuge in Kansas, US. Collectively at this location, over 300 birds including Snow Geese (Chen caerulescens), Canada Geese (Branta canadensis) and Mallard Ducks (Anas platyrhynchos) were found dead with no reported clinical signs.
Gross Findings: There were no significant findings from the external examination. On internal examination, there was moderate subcutaneous, visceral and epicardial fat indicating good body condition. Petechial hemorrhages were present on the epicardium along the coronary groove and the liver was pale red brown and friable with miliary pinpoint tan foci which extended into the parenchyma. (Fig. 1A). Intestines contained abundant creamy stringy yellow mucoid material (Fig. 1B).
September 2019—Strychnine Poisoning in a Mourning Dove
Case History: An immature female 122-g Mourning Dove (Zenaida macroura) was found dead in a park in Arizona, US. An estimated 18 birds including Inca Doves (Columbina inca), Great-tailed Grackles (Quiscalus mexicanus), and Mourning Doves were found dead with no reported clinical signs. Zinc phosphide was applied to ground squirrel burrows the day before the start of the mortality event.
Gross Findings: Lungs were pink, spongy and mildly wet. The proximal esophagus contained a few milo seeds. The crop was full and contained abundant milo seeds, a few corn fragments, several round ~1 mm in diameter round brown seeds, 4 x 3 mm brown seeds with a circumferential fringe and 2 whole sunflower seeds (Fig. 1A). A green coating was evident on the milo seeds (Fig. 1B). The mucosa of the crop was mildly reddened. The proventriculus was empty. The ventriculus contained a moderate amount of crushed seeds, mostly brown, and a small amount of grit. The liver, spleen and kidneys were moderately congested.